Sweatin’ the Mediterranean Heat
Guest Commentary from Figen Mekik
This quote from Drew Shindell (NASA Goddard Institute for Space Studies, New York) hit me very close to home: "Much of the Mediterranean area, North Africa and the Middle East rapidly are becoming drier. If the trend continues as expected, the consequences may be severe in only a couple of decades. These changes could pose significant water resource challenges to large segments of the population" (February, 2007-NASA, Science Daily).
I live in Michigan, but Turkey is my home where I go for vacation on the Med. This year’s drought was especially noteworthy, so I would like to share some of my observations with you, and then explore the links between the North Atlantic Oscillation (NAO), Mediterranean drought and anthropogenic global warming (AGW).
The 10-hour flight from Chicago to Istanbul often inspires passengers to romanticize about Istanbul, both tourists and natives alike. Istanbul is the city of legends, forests, and the Bosphorus. It is an open museum of millennia of history with archeological and cultural remnants surrounded by green lush gardens. It is the place where east meets west; where blue meets green; where the great Mevlâna’s inviting words whisper in the wind “Come, come again, whoever you are, come!”
So you can imagine our collective horror as the plane started circling Istanbul and we saw a dry, desolate, dusty city without even a hint of green anywhere.
The Marmara region of Turkey where Istanbul is located received 34% less precipitation than average this past winter; and the Aegean Region, which includes the city of Izmir, received 43% less precipitation than average since October of 2006. Precipitation this low was unprecedented in these regions in the last three decades. So is this a freak year, you may ask?
This next graph shows observational spring precipitation data between 1950 and 2007 (shown with green dots) for Istanbul and multi-centennial (1635-2000) spring precipitation reconstruction from tree ring data for the NW Black Sea region in Turkey (pink and red dots show a 5-year running average for precipitation data from tree rings) (data). Multi-centennial tree ring precipitation reconstructions for the Marmara region are not available. Although the observational precipitation record for Istanbul is generally lower than the spring precipitation reconstruction for the NW Black Sea region, both observational and reconstructed data follow a similar trend, except for two unusually rainy springs in 1998 and 2000 in Istanbul. Also note in the tree ring precipitation data that although the amount of precipitation has fluctuated throughout centuries, it has not consistently dropped for more than 3-4 years until the 1970’s. Since then there has been a steady decline until 2000 (the red part of the graph).
In the summer of 2007, temperatures rose over 46°C in many parts of Turkey as well as the entire Mediterranean region. This heat combined with aridity is estimated to have cost Turkish farmers ~$3.9 billion. Turkey’s wheat crop dropped by about 15%. The Turkish Aegean region alone suffered from 30% lower harvest yields in cotton, corn and tobacco and a 50% drop in fig production.
By mid-summer, the drought started to affect major cities. Ankara (~4 million), the capital, suffered serious water rationing this summer (two days on, two days off). Car washing and lawn watering were outlawed within city limits. With the unforeseen burst of the main water pipe feeding the metropolis, the whole city was left without running water for an entire week. Hospitals had to be issued groundwater in tankers, and city officials started to debate whether to delay public school openings until mid-October to contain potential spread of disease. By mid-August, Ankara had only 5% of total capacity in its reservoirs and dams.
Tuz Gölü, a large salt lake in central Turkey within the Konya Basin, lost half of its water volume in the last four decades. The Konya Basin itself, which hosts a third of all groundwater reserves in Turkey and is the home to eight wetland bird species on the brink of extinction, lost 1,300,000 acres of wetland and witnessed a water table drop of 1-2 meters, also in the last 40 years.
It looks grim.
But not just for Turkey. Even popular vacation areas around the Aegean were hellish this year. Greece had to declare “state of emergency” at least twice this summer: once for forest fires killing over 60 people, burning half a million acres of land, and costing $1.6 billion; and once for drought on the Cyclades Islands due to water shortages.
Morocco experienced 50% less rainfall than average this year which will likely result in half of last year’s grain harvest. And because feed prices went up as a result of this drought, Moroccan livestock was also seriously affected. Again, is this an unusual year? Actually not. This next figure, which is from Esper et al.’s (2007) paper in Geophysical Research Letters, shows a significant drop in Feb. – June PDSI (which is a standardized measure of surface moisture conditions after Palmer, 1965) since 1980 in Morocco.
Some speculate that the tragic fires in Greece may have been arson, others say better maintenance of water pipes and anticipation of the coming drought early in the previous winter would have prevented Ankara’s water shortage, and better irrigation systems in Morocco would have mitigated agricultural disaster there.
Though it is “debated” in the US, most people in Turkey consider AGW to be a given. This is generally a good attitude, of course, but it opened the door for some government and city officials to simply blame AGW for drought instead of their incompetence in dealing with it. As a result, the Turkish General Directorate of Disaster Affairs started discussing whether AGW should be listed under “natural disasters” in order to provide better risk assessment and adaptation plans, and to prohibit building new structures in “high risk” areas. Even Al Gore came to visit Istanbul this summer to give a talk at a conference called “Climate Change and its Effect on Life.”
So, is AGW to blame for Mediterranean drought? Although bad land use practices and arson share the blame, AGW is most likely the culprit. Here’s how:
The North Atlantic Oscillation is an alternation of air masses between polar and subtropical regions of the North Atlantic. When the NAO index (difference between the normalized sea level pressure anomalies in the Iceland and Azores areas, respectively) is in a positive phase, a low pressure system prevails over Iceland and a high pressure system over the Azores. This causes cooler northern seas, stronger winter storms across the Atlantic Ocean, warm wet winters in northern Europe, and cold and dry winters in Canada and Greenland. However, this also causes less rain and reduced stream flow in southeastern Europe and the Middle East. In general, when NAO is in a positive phase, the Mediterranean region receives less precipitation.
The precipitation pattern in Turkey is well correlated with the phases of the NAO index. For instance Cullen and deMenocal (2000) showed that Euphrates’ spring stream flow varies by about 50% with the NAO index. The NAO index vacillates between negative and positive phases, but its oscillations had a more annual pattern before the 20th century, and since then has become more decadal. More importantly, since the 80’s it has remained in a prolonged positive phase. This is in keeping with the precipitation drop I described for Turkey and Morocco (and the Mediterranean region) in the last several decades.
But do we know that this recent prolonged positive phase in the NAO index is not simply a part of its natural decadal variability? And is this recent positive phase actually related to global warming?
These are tough questions to answer definitively, but it is likely that AGW will continue to keep the NAO index positive because both atmospheric CO2 rise and stratospheric ozone depletion cause a strong polar night vortex. The North Pole is dark and very cold in the winter. This creates a large temperature difference between high latitudes and subtropics. The resulting large pressure contrast forces east-west winds into a stratospheric spiral. And this stratospheric vortex likely causes the NAO to prefer a positive phase. This was first shown by Shindell and colleagues in 1999, and seems to still hold true in the IPCC AR4 runs - although the average signal is smaller. And if it stays that way, southern Europe and the Middle East are likely to continue to get drier.
Thus, the Mediterranean region is at high risk for desertification. Even if 2007 were an anomalously dry year, these disastrous events show us that small perturbations in weather patterns can lead to tragic and costly outcomes. They also show what is in store for this area in the next few decades as global warming progresses. And desert makes more desert. As land is overused and scorched by the hot sun and no rain, it dries up and vegetation cover diminishes due both to drought and wildfires. Lack of vegetation leads to further loss of humidity and increases erosion rates. So, deserts expand even more.
Having said all of this, here is one last thought: if AGW is affecting nearly all latitudes negatively, then we need to wonder where global awareness of this problem stands. The Pew Center Report (2006) found that while over 90% of the population had heard of AGW in countries like the U.S., Germany, France, Britain, Spain and Japan, this dropped to about 75-80% in Russia, Turkey and China and below 50% in Jordan, Egypt, Indonesia and Pakistan (only 12%!). So the peoples in Middle Eastern countries most at risk for growing desertification are barely aware of the problem of AGW. What is even more striking is that of the percentages of people aware of AGW I listed, 70-80% are concerned about it in Indonesia, Egypt, Turkey, Jordan and India; but only 50-60% of U.S. citizens and peoples of China consider AGW to be a serious issue. So the problem isn’t just ignorance, it is also that of profound apathy.
22 October 2007 at 6:20 AM
Thanks for that lucid posting Prof Mekik.
This leaves me once again pondering the wider implications of this years Arctic ice melt. The polar region will still be dark and very cold in the winter. But thinner ice means more heat flux between atmosphere and ocean and more water vapour. So it probably won’t be as cold as previous decades.
Anyone know if the vertical temperature difference between surface and stratosphere has a role in forcing the AO into a +ve regime?
Will this years Arctic events force a tendency back to -ve/neutral or reinforce the recent +ve tendency?
22 October 2007 at 6:23 AM
Things are not as simple in the Mediterranean. Last spring was one of the more rainiest of the last 50 years in most of the Iberian Peninsula (western Mediterranean), and last summmer one of the less warmest. Furthermore, it is not unusual that seasonal or annual climate anomalies were of different sign in parts of eastern and western Mediterranean.
22 October 2007 at 6:48 AM
I just noticed something, so please pardon any misunderstanding.
AGW in the climate science world refers to ‘Anthropogenic Global Warming’. In other areas, it seems to sometimes represent ‘Anti Global Warming’, as in those that refute the scientific consensus in favor of singular or narrowly scoped views.
So in case if there are any others that might be confused by what AGW means, take it in context because there are lots of acronyms in the world.
On the likelihood of prolonged NAO, it just seems logical that if you heat up the planet, the middle will still be hotter that the top and bottom (so history has evidenced). So anything in between the Tropics will be subjected to higher dangerous temperatures in the sense that water and food will continue to be constrained resources.
The rest of the world will be affected also of course. The head in the sand thing, and BAU will be the norm until leaders wake up in force. That just means it will be a more expensive problem as fixing later will cost more than fixing now. Caught in the middle of this are a lot of people that will suffer the fate of decisions made by people that are continuing to ignore reality and common sense. It is unfortunate that many will have to pay a higher price for the decisions of a few.
22 October 2007 at 6:53 AM
Thank you, Figen Mekik. You make vivid the interrelations of planetary processes. The natural thought processes of North American habitants indicate to me a positive forcing still. Or perhaps I am using precise words illegitimately. Oceanic inertia may leave inundation to later in the century, but the winds which have whipped around the Greenland ice cap in certain given directions with certain given forces are likely changing now with even the meagerest shrinkage of the cap. Of more imminent concern is the absolute believing of Southwesterners that they will treble their growth in the next two or three decades. I have tried mitigation with a friend located there. “Oh, I wouldn’t worry. We’re already planning desalinization plants on the Pacific to bargain for water rights.” I think I’d have better luck going to Greenland to wave the winds back into their “proper” places.
22 October 2007 at 7:05 AM
The situation for the people of Turkey sounds pretty dire - even compared to drought stricken Australia. If the current droughts are truly the result of AGW, then should we interpret this as evidence that the “reduce emissions and eventually stabilize” plans are insufficient and we need some sort of geoengineering to undo the damage we have done?
Also:
@1 - Does anyone have any idea/predictions whether the ice refreeze in the winter will lead to a lower ice mass during winter?
Joe
22 October 2007 at 7:41 AM
AGW … AGW ??? ahhhh!! Anthropogenic Global Warming … intuitively obvious eh? silly me, very very clear exactly what it means too eh? ‘anthropogenic’ being a word that I use EVERY day
[edit]
[Response: Actually it is a word we use everyday, and sometimes we forget that others don’t. A simple request is usually sufficient to clear up any misunderstanding. - gavin]
22 October 2007 at 7:46 AM
I’d like to know which standardization scheme was used in the tree-ring record.
Can you please post a reference to the treering precipitation record.
22 October 2007 at 7:55 AM
Drought conditions seem to becomming very widespread, and areas of flooding becomming smaller in extent (even though they are severe when they do occur.)
Repeating a comment that I made on this site a few months ago:
My conjecture is that as the atmosphere is heating faster than the oceans, that worldwide, the average relative humidity is the decline. The analogy is a bathroom… in order the get a bathroom less “steamy” (without getting rid of the water) is to heat the room (not the water). I assumed this is the reason that the tendency to drought is becomming widespread.
There was no response to my comment last time, hence the repeated post.
22 October 2007 at 8:53 AM
Not sure if it helps much, but my understanding from the UK Met Office is that the NAO is broadly neutral or trending negative at the moment - see their chart and explanation on their website:
http://www.metoffice.gov.uk/research/seasonal/regional/nao/index.htmlrecent)
This implies a winter in the UK and NW Europe that will be a bit cooler than those experienced in recent years, with perhaps some more rain for the Med. region. With that in mind, it looks as if there’s a subtropical-like storm developing in the western Med at the moment. These aren’t unheard of, but they are unusual. Watch out for news of how this storm develops later this week.
Regarding Arctic ice, has anyone given thought to the submarine ice off the coast of Canada, and presumably Russia/on the other side, and how this is likely to react/behave as the Arctic warms up? This is relict ice from the last glaciation that has been buried under debris and later submerged as sea levels rose. There’s loads of it, too - many metres thick, over large areas of the sea bed Strikes me as another highly non-linear facet of the system, which could make the local climate response to AGW even more chaotic or confused.
22 October 2007 at 9:00 AM
Thanks Gavin, and David I fully understand your point. I’m just gaging by the fact that you have 4.3 million visits on this web site, and guessing that probably not all of those visits are from scientists. I can only speak for one of your visitors
and I know I’m not a scientist.
22 October 2007 at 9:02 AM
@8 Lawrence:
Actually the humidity is predicted to go up, and it has recently been reported that it is indeed going up around the globe. In fact this is one of the main features of (excuse the acronym) AGW — raising the temperature a little causes more water to be held in the air, and since water vapor is a potent greenhouse gas, it raises the temperature still more. By itself, carbon dioxide etc. would not have nearly as big an effect.
Unfortunately simple reasoning by analogy doesn’t work for such a complicated system. The reason for more droughts is partly because the location of precipitation gets changed, with some dry areas tending to get drier while some wet areas tend to get wetter (with more flooding); and second, warmer days and especially warmer nights lead to more evaporation, drying out the soil… while adding to the humidity.
22 October 2007 at 9:20 AM
First, I’d like to acknowledge the very patient and constructive support I received from William Connolley and Gavin Schmidt, as well as from anonymous reviewers at RealClimate in writing this post. I learned a lot!
Then I’d like to thank these early posters for their very kind comments! Here are some replies:
Manuel, you are right, not all places were dry and there is a significant difference between the eastern and western Med region when it comes to precipitation patterns. Just check out the observational precepitation trend I show for Istanbul: it looks like it’s getting dryer but 1998 and 2000 got a LOT of rain!!
Yes AGW could satnd for anti-global warming. Thanks for pointing that out John.
David Wilson: As Gavin is pointing out we say anthropogenic every day, all day. It means human induced, but you could look that up too, right?
Aslak Grinsted: The centennial tree ring data is from the World Data Center for Paleoclimatology where the work of Akkemik, Dagdeviren and Aras is published (http://lwf.ncdc.noaa.gov/paleo/recons.html). The spring observational precipitation data for Istanbul is from NOAA National Climate Data Center.
If I am not answering anyone’s specific question, it isn’t because I am ignoring you, it is because I don’t know the answer
22 October 2007 at 9:26 AM
RE: #2 Maunel
Sadly, Iberian precipitation numbers dispute the value of your anecdote. Total rainfall is decreasing. Total spring rainfall is decreasing.
http://www.worldclimatereport.com/index.php/2007/02/16/the-rain-in-spain/
” … intense precipitation (lines d and e in the figure) is decreasing in all seasons (columns are spring, summer, autumn, winter from left to right) while light precipitation (line b) is increasing. Line a in the figure suggests that total precipitation has generally decreased in all seasons over much of the peninsula.”
” … light precipitation amounts and days with light precipitation are increasing, but the days with and/or amounts of moderate to very intense precipitation are decreasing. Not surprisingly, they also found “there was a decreasing trend in the mean precipitation value per rainy event in every season. This decrease is consistent with the aforementioned increase of the proportion of light rainfall relative to the total.” “
22 October 2007 at 9:36 AM
Ethan, consider the source, you’re quoting from a PR site notorious for making things up and twisting facts to fit the story line they’re paid to present. Look them up.
22 October 2007 at 9:53 AM
AGW: Perhaps RC could create an acronym glossary. I usually figure them out myself, but sometimes the use of acronyms here becomes overwhelming.
22 October 2007 at 10:02 AM
Although bad land use practices and arson share the blame, AGW is most likely the culprit.
Bad land use practices are anthropogenic - human-caused - and operate on a scale that could contribute to regional or global warming. The term AGW thus arguably includes changes due to land-use practices, rendering the sentence confusing.
This would be better: “Although bad land use practices and arson share the blame, CO2 is most likely the culprit.”
22 October 2007 at 10:12 AM
Thank you Figen Mekik for a positive article.
Since there are now several people saying that we humans go extinct in about 200 years because of global warming, is it time for a RealClimate article on H2S?
http://www.geosociety.org/meetings/2003/prPennStateKump.htm
http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=672
http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=1535
http://www.sciam.com/article.cfm?articleID=00037A5D-A938-150E-A93883414B7F0000&sc=I100322
22 October 2007 at 10:43 AM
Here in the Keystone State of Pennsylvania I have noticed something peculiar. The extremes between night and day are increasing, Sometimes I have to put on the heat at night, only to use the air conditioner during the day! Also, my wife got a bad sunburn, one you might get in mid-summer, but it is October. And Denver was seventy degrees one day, and then snowing the next. My analogy is once you lose control of a car, you overcompensate to correct and then you steer in the opposite direction, etc. This is what is happening to the weather patterns. When will we actually “crash”? It may be as soon as next year.
22 October 2007 at 10:49 AM
RE: Spencer
Someone can correct me if I am wrong, but I believe that you are talking about specific humidity while Lawrence is talking about relative humidity.
There was a recent (last week?) paper in Nature by Willet et al that indeed confirmed that specific humdiity has increased by ~0.25 g/kg since 1975, and that this increase is most likely due to human influences.
On the issue of relative humidity (Lawrence’s point), I was under the impression that relative humidity remains fairly constant — even with the changing of the seasons. A seminal paper on that issue is Manabe and Wetherald, 1967 (JAS). The prevailing wisdom on relative humidity’s constancy may have changed in recent years, but just last year I heard a prominent climate dynamicist say something along the lines of, “it’s a good approximation, but we still don’t have a satisfactory dynamical explanation for why it is the case.”
However, I am just a geochemist. Perhaps Gavin or one of the other climate dynamicists on this site could elaborate.
22 October 2007 at 10:57 AM
Thank you for a very informative and readable comment Madam Mekik.
It’s certainly tough being a Prof, almost as tough as being a member of the RC Group : I had a look at your Prof ratings and your students like you - well done.
I dont post on this site very often because I feel I have nothing of scientific interest to say, but I do post on other sites : principally The Guardian and The Economist.
When I post on global warming I ask basic questions : where are all the mediterranean (and continental) people going to migrate to (to live in a climate where 40+ is the rule rather than the exception takes some doing), where are future food supplies going to come from, and so on. And it is not only drought : geopolitical behaviour is involved too - an example is the Russian position on defending their southern borders and extending their northern ones.
So my point is the same point I made in a recent previous thread about the accessibility of science to the average person on the street using simple numbers and simple measures. Everyone knows that the Dow Jones went down last Friday but nobody pays any attention to the NAO.
If you tell me that the NAO is a good measure then we should broadcast that in all office lifts (elevators) in mediterranean countries and on the front pages of all newspapers, at the same time as refining the models to make the NAO the reference statistic. Now, it may turn out that a refined NAO will be a better statistic, but we have to start somewhere with a good proxy. I am not sure that the problem of inaction on global warming is either ignorance or apathy : I suspect it is more to do with engagement.
People can engage with a number : particularly one that will punish them.
The same considerations apply to an index for sea level rise.
Is it difficult for scientists to come up with a climate index, like the Dow Jones for stock? Is it too un-scientific to do that? Not scientific enough perhaps? Dont want to get your hands dirty with the real world?
One thing is certain, when the City and Wall St. have something to relate to when assessing their own risks then you will see action on global warming, and law suits.
The excellent Mr Hansen (and Gavin) in the Hansen et al 2007 paper and in particular with section 6 started to move down the engagement road. Long may it continue.
Well done RC again, and dont weaken.
22 October 2007 at 10:59 AM
Re: #14
Hank, I didn’t look too closely at the rest of the site - I only found the blog post I cited thru Google. That said, nearly all the text I quoted was summarizing (or quoting) Gallego, et al, 2006, described as:
“An article in the recent Journal of Geophysical Research puts the spotlight directly on the rain in Spain as four scientists from the Universidad of Extremadura examined precipitation records from throughout the Iberian Peninsula from 1958 to 1997.”
WCR’s choice of the article and WCR’s (absurd) claim that the findings conflict with the IPCC are silly. But I’ve no reason to doubt the information cited from the recent JGR article, other than that the dataset stops ten years ago. Here’s another source discussing declines in aggregate rainfall in Spain (among other climate change effects and predictions):
http://www.iberianature.com/material/iberiaclimatechange.html
22 October 2007 at 11:04 AM
Nick O asked:
Regarding Arctic ice, has anyone given thought to the submarine ice off the coast of Canada, and presumably Russia/on the other side, and how this is likely to react/behave as the Arctic warms up? …
—
I’m no expert on buried relic ice, but I watched AIT at the Holiday Inn Express. Assuming it were to melt rapidly and escape into the ocean, wouldn’t water and earth just fill its former space and cause little to no increase in sea level?
On topic, my wife recently worked in Algeria. They don’t have much agricultural land to lose.
22 October 2007 at 11:26 AM
We do need to be more on the QT about acronyms like AGW, NAO and ENSO. We need an acronym list ASAP to be AOK here. It’s OK if you can’t get one up till next AM, but it should be up PDQ. Anyone with an IBM PC that can see HTML should be OK not just in the USA but also in the EC. TNT,
-BPL
22 October 2007 at 11:33 AM
Wow, that sounds ominous. So does this: http://www.nytimes.com/2007/10/21/magazine/21water-t.html?em&ex=1193198400&en=e32e766b398790c1&ei=5087%0A . Good thing the eminent environmental economist Richard Tol assured me on another blog that, “Water scarcity and heat stress have no obvious relationship, as water stress does not mean that drinking water is scarce.”. And here I was beginning to worry that the economists couldn’t chutzpah their way out of this. Never fear!
22 October 2007 at 11:46 AM
Hey all, I just stopped by to make the point that I made today in Dr. Mekik’s class that the scientific community needs to move away from the term “Global Warming” and begin to use “Global Climate Change” instead. I am aware that many climate scientists already use this phrase but it still isn’t necessarily “mainstream” at this point. I would like to argue that “Global Climate Change” while more ambigous than “Global Warming” allows for more variations in climate that are taking place to be accepted by those people who aren’t enlightened enough to belive in “Global Warming”. The point was made in class today that the hosts on SportsCenter were dismissing “Global Warming” due to the fact that is was snowing in Denver in October…(gasp!) I contend however, that if the community starts to use “Global Climate Change” more people especially in America where the “debate” still rages will begin to accept the anomolies that we are seeing worldwide that don’t always include warming, drying conditions. Thanks again for the pertinent info Figen, you rule!!!
22 October 2007 at 11:52 AM
Very quick..
Glen: that’s a great point, thanks. I’ll ask RC folks if we can make the edit.
Eachran: That is so kind of you to say that you checked my student ratings! I like to teach and I love ocean and climate science, and I think students pick up on both. And pizza. I buy them pizza.
22 October 2007 at 12:19 PM
Ethan, you write:
> I’ve no reason to doubt the information cited from the recent JGR…
Ethan, that’s my point.
You don’t need a “reason to doubt” — always doubt. Check. There’s far more misinformation out there that Google will find than reliable information. No “Wisdom” button as Cody reminds us.
You can look these sources of up. WCR is well known for biasing and spinning and taking out of context to claim support for their PR.
Even if you find a fact, check for omitted context.
“Trust, but verify.” — R. Reagan.
“The results of the papers were selectively picked up by the World Climate Report (WCR), a publication sponsored by the Western Fuels coal consortium, to assert that current human emissions will not lead to global warming …..” http://www.ucsusa.org/ssi/archive/climate-misinformation.html
22 October 2007 at 12:30 PM
There is a good, long, piece in this morning’s NYT (http://www.nytimes.com/2007/10/21/magazine/21water-t.html) about water problems in the American West. More about the problems and what people are doing about them than the “How” of climate of climate change.
Looks like 50 million people are at very high risk of AGW induced drought. We may be past the risk management stage, and into the event response phase.
Re 17
Denver always had a pattern of sharp weather changes, snowing one day, and sunny the next. What has changed is warm moist air from the Gulf of Mexico coming up in the winter to generate large snow events. The blizzards of my childhood, came out of the North as cold, realtivly dry storms. Now, there are some winter storms around Denver that result in more snow. Since this moisture falls east of the traditional snow catch areas, it does little to help the water problems discussed in the NYT piece.
22 October 2007 at 12:53 PM
[both atmospheric CO2 rise and stratospheric ozone depletion cause a strong polar night vortex. The North Pole is dark and very cold in the winter. This creates a large temperature difference between high latitudes and subtropics. The resulting large pressure contrast forces east-west winds into a stratospheric spiral. And this stratospheric vortex likely causes the NAO to prefer a positive phase.]
Figen, thanks for a very useful article, could you please spell out a bit more how (a) the CO2 rise and (b) stratoshperic ozone depletion cause a strong polar night vortex? Oh, and what is the polar night vortex? Google finds plenty of references, but all apparently assuming knowledge of the term!
22 October 2007 at 12:54 PM
[both atmospheric CO2 rise and stratospheric ozone depletion cause a strong polar night vortex. The North Pole is dark and very cold in the winter. This creates a large temperature difference between high latitudes and subtropics. The resulting large pressure contrast forces east-west winds into a stratospheric spiral. And this stratospheric vortex likely causes the NAO to prefer a positive phase.]
Figen, thanks for a very useful article, could you please spell out a bit more how (a) the CO2 rise and (b) stratospheric ozone depletion cause a strong polar night vortex? Oh, and what is the polar night vortex? Google finds plenty of references, but all apparently assuming knowledge of the term!
22 October 2007 at 1:19 PM
Re #18: [Denver was seventy degrees one day, and then snowing the next.]
This is not all that unusual for any place located near a mountain range. It’s happened here (in the Sierra Nevada) several times this year.
With regards to the main article, I still wonder how much of this local change is AGW-related, and how much is simply part of the several thousand year pattern of changes that’ve likely been caused by human agriculture.
22 October 2007 at 2:51 PM
Perhaps someone could comment on this question: How many years does it take for some new rainfall pattern or temperature regime to cease being ‘unusual weather’ and be generally considered ‘climate change’? For instance, if summertime day-time high temps have been in the 80 F range for decades, but are now in the 100 + F. range, how many years before this ‘extreme weather’ comes to be normal and that a ‘climate change’ has occurred?
22 October 2007 at 2:51 PM
“@1 - Does anyone have any idea/predictions whether the ice refreeze in the winter will lead to a lower ice mass during winter?”
Since the melting season in the Arctic bottomed out there’s not been as much mention of it but I’ve been following Cryosphere Today and it’s clear that the situation is still abnormal. Before this summer their anomaly plot hadn’t gone below -2million sq km, well during the summer they extended it to -2.5 and now to -3! It was only last week that the sea ice area got back up to the previous record minimum (a month late). I wouldn’t be surprised to see a record low maximum this winter. Also I suggested to them earlier this year that they might include a plot of global total sea ice and they have done so (whether it was in response I know not). This is showing a very different trajectory than in previous years.
http://arctic.atmos.uiuc.edu/cryosphere/
22 October 2007 at 3:00 PM
I am confused. How do you explain that the NAO index displays a negative trend in the last 15 years, as shown in your plot? Shouldn’t it be pointing up due to AGW?
22 October 2007 at 3:09 PM
This is purely anecdotal evidence, but I spent two weeks in Morocco on vacation this spring, and almost everyone I spoke with knew about global warming and knew that it was expected to dry out Morocco.
22 October 2007 at 3:28 PM
Nick Gotts (#30) wrote:
If I could hazard a guess…
In the troposphere, greater levels of greenhouse gas tend to raise the temperature as the result of moist air convection from the surface receiving more backradiation. In the stratosphere, above the both the effective radiating level and the tropopause, where one has a negative lapse rate, greater levels of greenhouse gases tend tool result in a net cooling. However, there is an exception: ozone. It absorbs UV directly from sunlight and as such tends to warm the stratosphere. With its depletion the stratosphere tends to cool.
The temperature differential between the stratosphere and the troposphere results in increased circulation of the polar vortex with its strong downward movement near the center, particularly at night as this is when the temperature differential between the surface (with its greater thermal inertia) and higher altitudes within the troposphere will be greatest. However, I would guess that winter is at least as important as night in determining the strength of the vortex.
PS
Here is something interesting (albeit from 2001):
22 October 2007 at 4:03 PM
Who somebody is funded by is immaterial. Bad argument. It’s like saying some environmental report was funded by Greenpeace and they’re biased so the paper is no good. Or that the US DOE published something, and the US government is funded in part by engergy companies so everything they put out is biased.
22 October 2007 at 4:13 PM
Nick Gotts, thanks for your question and sorry for my slow response. Actually I am going to offer a quick one now and work on a more detailed one to post later. And thanks Timothy Chase for your answer. Basically as the subtropics become warmer, both the tempertaure and pressure gradient between the poles and the subtropics steepens. During long dark polar night (winter) this gradient causes the east-west winds to coalesce into a spiral called the polar night vortex. The more the subtropics warm, the stronger the vortex whcih presumably keeps NAO in its +ve phase.
James, I agree with you. Desert makes more desert and agricultural overuse and degradation is adding to the desertification around the Med. People just want to burn a couple of acres to clear off farm land, but because the vegetation is so dry, the fires go out of control. But arson is arson!
22 October 2007 at 4:13 PM
Ps to 36
It would appear that the “Polar Night” is simply another way of refering to the arctic winter, except as it applies to the pole. As such, the Polar Night Vortex refers to the vortex as it exists during the winter, and my statement “However, I would guess that winter is at least as important as night in determining the strength of the vortex” quite literally makes no sense as night and winter are the same thing.
22 October 2007 at 4:19 PM
Re. #17
Re. H2S (hydrogen sulfide) extinction possibilities from AGW (human-caused warming).
“Since there are now several people saying that we humans go extinct in about 200 years because of global warming, is it time for a RealClimate article on H2S?”
I personally talked to several peer-review publishing scientists in our building (a national federal climate research lab) on this issue of H2S poisoning possibility in our near future (100-200 years.) One is researching and publishing in this area.
The correct answer according to them (~2 months ago) is “we don’t know…but very unlikely” according to a type of their sort of conscensus. (Note, they are not saying anything like a definite “yes” or “no” and it would be unethical for them to do so with the information they have).
According to them, it is very unlikely that the conditions necessary for H2S tipping points could be reached in this short time period…mainly the idea that for the major oceans to stop overturning enough in this timespan, to let the oceanic oxygen content decrease enough to stop reacting enough with H2S to start letting the H2S go to the ocean surface and go “airborne” in quantity from the ocean depths (I’m doing his from memory, so one of the details might be off a little). Remember, most climate models do not predict the North Atlantic thermohaline circulation (MOC) cutting off for at least 100 years.
http://www.springerlink.com/content/f2glxmjtbh6m2db1/
http://www.agu.org/pubs/crossref/2005/2005GL024368.shtml
That being said, a non-publishing meterologist in this disciplinary area)/(who is also paleoclimatist-leaning in this building) stated to me that we need to keep researching this to make sure…especially as more evidence keeps surfacing (ooooo, I’m full of puns today) that climate can change more rapidly than we had previously thought. So at least several of the world’s top publishing scientists are not losing sleep about this (unlike AGW according to them).
…BUT one was extremely concerned about the ACIDIFICATION OF THE OCEANS (as are a lot of publishing scientists in my building) due to humans putting 30+% more CO2 into the atmosphere and then into the oceans. This makes the oceans more acidic. This can cause problems with coral and plankton and their shells…and the base of the oceanic food chain.
22 October 2007 at 4:31 PM
as a matter of fact I know very well what Antropogenic means, and if I didn’t, I expect I am one of the few here who has a personal subscription to the Oxford English Dictionary (OED) on-line to look it up, but even at that I had to wonder what AGW was, GW I knew, AGW was new to me, and the author did, kindly and according to the drill, write it out the first time he used it, all very correct
a famous Canadian thinker, Northrop Frye, said this: “the simple is the opposite of the commonplace”, so I am thinking that wheras Antropogenic is quite absolutely correct, it is maybe just not necessary (?)
just a thought y’unnerstan … Gwynne Dyer has pointed out a disturbing spinoff from the recent fires in Greece (http://www.gwynnedyer.net/articles/Gwynne%20Dyer%20article_%20%20Extreme%20Climate%20and%20Extreme%20Politics.txt) I too have wondered what it may be like when large groups in urban settings begin to feel the pinch - it might not be very pretty
I know this is off topic, not so far in my mind (which thinks that communicating freely may be one of the few antidotes) but off-topic nonetheless, so I will stop lest Gavin [Edit] me again
22 October 2007 at 4:35 PM
Re #25
Paul, I fully understand you perspective on ‘Global Warming’ vs. Global Climate Change’.
My perspective is that there are certain special interests that would love it if the scientific community would not use the term ‘Global Warming’.
In my view, when it comes to publicly paid for science, science should serve at the pleasure of public and policy maker understanding.
While this is a web site for science, it is being read by the public and hopefully policy makers. I believe that it is important to use the term ‘Global Warming’ as it is illustrative and accurate to a large degree.
Actually Global Climate Change could mean global cooling also. In this case I would argue that the illustration of the descriptive is ‘very’ important to the presentation and therefore understanding of the audience this science is meant to serve, the public and the policy makers.
22 October 2007 at 6:23 PM
#41: Tha author is a she
22 October 2007 at 6:48 PM
“…both observational and reconstructed data follow a similar trend…”
I don’t understand this inference. I assume that the green dots in your graph are 5-year averages (there’s way too little year-to-year variability for them to represent individual seasons), so the green and red can be compared directly. The green and red seem to have similar changes on the scale of 5-10 years, but the trend from 1950-present in the observed (green) seems to be nearly zero, compared to a massive negative downward trend in the reconstructed data.
22 October 2007 at 7:28 PM
Re: #42
John, are the interests you’re referring to the automotive and petroleum industries? I totally understand where you’re coming from with Global Warming and would agree that the term is very much illustrative and accurate to what trends we are currently seeing worldwide. It’s just discouraging for me as an American to know that our country lags far behind the rest of the world when it comes to accepting AGW as a fact. It seems like for whatever reason, non-believers in this country are so quick to point out any climate change that isn’t directly warming as evidence that AGW must not be real. I know that progress is being made everyday, but there are many people in the US that cling so tightly to what the idiot box (TV) tells them that I find it hard to see them changing their opinions until their house on the Beach is swallowed up by rising sea levels.
22 October 2007 at 7:40 PM
#44 John Nielson-Gammon: You are right. I was just trying to point out that the ups and downs in both curves (red and green) follow each other. And yes, both the red and green are 5-year running averages. The pink too of course.
#34: viento: I haven’t been ignoring your question. What I get from the figure is the gray bars are positive and the white bars are negative. I don’t know why both 2’s on the axis are labeled -ve. Maybe Gavin or another RC editor can tell us why.
[Response: Fixed. It was like that in the original figure, but there is no doubt that +ve is up. - gavin]
22 October 2007 at 7:43 PM
Re. #37, Raplh Smythe:
No, it’s like saying that if a climate science paper was funded by Greenpeace, one should be question the study’s impartiality. There is considerable peer-reviewed evidence that studies funded by organisations that have a financial interest in the study’s outcome are much more likely to reach the desired conclusions than those which aren’t – see, for example, Okike et al 2007; Vartanian et al 2007; and Peppercorn at al 2007.
22 October 2007 at 8:24 PM
That’s what happens when you build freeways through the middle of town, and there by cut off and turn nice neighborhoods into shanty towns, and furthermore cut down trees to build car parks. To boot, the place is now ringed by shanty towns. How they have fouled the place.
22 October 2007 at 8:32 PM
Re: #11 and #19 Thanks Spencer and Brian for your replies.
Spencer you have not yet given me reason to abandon my conjecture and the bathroom analogy. The same laws of physics apply in my bathroom and the earth. As Brian stated, you did miss the point that I am talking about relative humidity.
My gut feel is that relative humidity averaged out over the entire earth is in the decline (driven by the increased ratio between atmospheric to ocean temperatures). Certainly in Australia, humidity levels are so low that any clouds that do blow in just evaporate away!
I will abandon my conjecture, if worldwide, the amount of low to medium level cloud cover has increased as a result of AGW. I suspect it has reduced. Does anyone have the numbers?
22 October 2007 at 10:42 PM
The Mediterranean south west of Western Australia experienced a “step decrease” in rainfall from the mid 1970s continuing to the present. This comprised a loss of early winter rainfall and an overall reduction in average annual rainfall of about 15%. The rainfall reduction has had implications for fire risk, surface and ground water resources and associated implications for agriculture, biodiversity and so on. Attribution of this change in rainfall to AGW has not been determined, but it is a suspect. Further information can be gained from the climate research program website concerned with this matter: http:www.ioci.org.au The 2007 AMOS conference included a session on the SAM for which see http://www.amos.org.au/conf2007/AMOS07_ABSTRACTS.pdf
22 October 2007 at 11:40 PM
Re: #45
Paul,
It spooks me a little whenever anything in science is treated as a popularity contest - when people seem to be concerned about whether the US “lags far behind the rest of the world when it comes to accepting AGW as a fact”. Facts are not subject to majority opinion.
I also think the word “fact” tends be used a bit too loosely in these debates. That the Sun is larger than the Earth is a clear fact. Evolution may be a fact, but would it be proper to say that any specific model of evolution is a fact? Probably not. In the same way, I have no problem with saying that “GW” is currently a fact, but I have a little trouble when the “A” is dropped in front of this acronym. Anthropogenic components play a role, but the extent of that role is by no means a fact. Does anything with a certainty less than 100% constitute a “fact”? When the role of this human factor or that is given a probability of say 95%, what does it mean to say that such a thing is a fact?
Suppose that, for whatever reason, humans were really crappy astronomers and we could only estimate with 95% certainty that the Sun was larger than the Earth. Under such conditions, it would not be a fact that the Sun is larger than the Earth. [Bizzare analogy I admit, but I think it makes my point clear.]
23 October 2007 at 12:11 AM
In The Guardian today by David Adam. Is this news to anyone.
“Scientists warned last night that global warming will be “stronger than expected and sooner than expected”, after a new analysis showed carbon dioxide is accumulating in the atmosphere much faster than predicted.
Experts said that the rise was down to soaring economic development in China, and a reduction in the amount of carbon pollution soaked up by the world’s land and oceans. It also means human emissions will have to be cut more sharply than predicted to avoid the likely effects.
Corinne Le Quere, a climate expert at the University of East Anglia and British Antarctic Survey, who helped conduct the study, said: “It’s bad news because the increase in atmospheric carbon dioxide has accelerated since 2000 in a way we did not expect. My biggest worry is people are discouraged by this and do nothing. I hope political leaders will act on this, because we need to do something fast.”
The study worsens even the gloomy predictions of this year’s report from the Intergovernmental Panel on Climate Change. The IPCC, which shared the Nobel peace prize this month with Al Gore, said there were only eight years left to prevent the worst effects of global warming, by acting to curb emissions.
Dr Le Quere said: “We are emitting far more than anticipated when the IPCC scenarios were drawn up in the late 1990s.” Global carbon dioxide emissions from fossil fuel burning has risen by an average 2.9% each year since 2000. During the 1990s the annual rise was 0.7%.
The new study explains abnormally high carbon dioxide measurements highlighted by the Guardian in January. At the time, scientists were puzzled why dozens of measuring stations across the world were showing a CO2 spike for 2006, the fourth year in the last five to show a sharp increase in the greenhouse gas.
Carbon dioxide concentration in the atmosphere is measured in parts per million (ppm); from 1970 to 2000, the concentration rose by about 1.5ppm each year; since 2000 the annual rise has leapt to an average 1.9ppm.
The new study, published in the US journal Proceedings of the National Academy of Sciences (PNAS), says three processes have contributed to this increase: growth in the world economy, heavy use of coal in China, and a weakening of natural “sinks” - forests, seas and soils that absorb carbon.
Pep Canadell, executive director of the Global Carbon Project, which carried out the research, said: “In addition to the growth of global population and wealth, we now know that significant contributions to the growth of atmospheric CO2 arise from the slowdown of natural sinks and the halt to improvements in the carbon intensity of wealth production.”
The overall growth of the economy is the only one of the three factors accounted for in scientists’ forecasts of climate change, which means the growth in atmospheric CO2 is about 35% larger than they expected. About half of this is down to the Chinese reliance on coal, which has forced up the carbon intensity of the overall world economy since 2000, reversing a trend of increasing energy efficiency since the 1970s. The rest of the rise is explained by the weakening of the natural carbon sinks.
Scientists assume about half of human carbon emissions are reabsorbed into the environment, but computer models predictincreased temperatures will reduce this effect. The PNAS report is the most convincing evidence so far that the global sinks have weakened over the last 50 years, though the large natural variations in carbon exchange between the earth and the atmosphere mean the team can be only 89% certain they have found an effect, short of the usual 95% confidence required to publish scientific findings.”
I especially liked (irony) the last bit contrasting 89% with 95% and the implied criticism of the Chinese.
I am not a pessimist : at least not yet.
I shall repeat again, sorry to be so boring, that we really need a deadline for people to work to : a real deadline, a measurable effect which people will know approaches and more rapidly as each year passes. The amount of carbon in the atmosphere doesnt give that immediacy and doesnt engage people : it’s complicated understanding the consequences of yet more carbon.
But an NAO based index for drought and a similar one for the mass balance of ice sheets for sea level rise might just do the trick.
I shall pen a message to our world leaders today.
I was wondering if Madam Mekik might feel qualified to comment on the oceans’ capacity to absorb : I think that I read on this site that wind change in the S Pacific reduced the churn of water and reduced that part of the world’s capacity to absorb by 30%.
By the by, I hope Madam Mekik wasnt offended by my reference to her students. It is just that if I dont know someone I check up on them to see if they might be OK. Scientists are no different from lawyers, doctors and other professionals : you get good and not so good.
The reason I come to this site for info is that I trust the Group to get it right. The fact that they allow you to comment as a guest is all to the good.
23 October 2007 at 5:42 AM
Barton, excuse my acronym ignorance but what do QT and PDQ stand for?
David Wilson: AGW is an acronym frequently used on this site, and I didn’t want to repeatedly write “anthropogenic global warming” in my text to save space. However, it is important to qualify GW with “anthropogenic” because [1] that is the point that is most disputed by denialists-whether global warming (or climate chnage as Paul wants to say
) is indeed caused by human activities, and [2] our planet has experienced global warming in its past when no human being was around like about 55 milion years ago during the Paleocene-Eocene Thermal Maximum.
Eachran: Of course I am not offended that you checked up on me. That’s what the internet is for…
23 October 2007 at 5:58 AM
Re. #45
Paul, Yes, we are lagging behind and that also has many factors, I think much can be attributed to our system of education as well as media systems that are more predatory than informative (referring to much of what is generated through the ‘idiot box’ as you say. There is not enough space here to discuss the problems of lack of foresight and lag time in governance.
If people learned that media is in many ways inherently flawed with regard to factual transmission of information, then we could make faster progress. But in many ways the public may in fact be hypnotized by this media for the reasons stated above.
Based on my observations, and what I am hearing, the energy industry that is engaged in using petroleum wants to keep the argument alive while they are figuring out ways to exploit the future energy development that is needed. basically they want to buy some time to come up with solutions that will make them money. Much like the tobacco argument, they will work to reduce their culpability in favor of profit and advantage as they see it, at any given point in time.
Government policy could help in restructuring tax basis in order to help speed up transition processes but there are a lot of special interests in the way still.
If you have noticed, the energy companies are already starting to flaunt their green feathers and that has an effect on the public subjected to such ads. The fact that green energy from Chevron is being touted as a banner to prove they are green does not negate the fact that the oil they sold has likely caused billions of dollars of damage past, present, and future. Like the tobacco industry, these questions will be addressed sooner or later and we will all have to work our way through it.
It will take a lot of understanding to address the bigger questions pertaining to: humans using energy, industrial humans use more energy, and we are using too much energy, and/or from the wrong source. None of these subjects will be easy to cope with.
23 October 2007 at 6:55 AM
I’m sure I recall that 5 years ago an increase in global average precipitation was predicted by now, the term being ‘wetter, warmer world’. No mention of ‘global drying’. The term ‘oscillation’ suggests counterbalancing effects. I assume that global mean rainfall statistics are kept.
I’ve noted that rain proneness seems to involve more than just temperature and humidity; why for example thin wispy cloud can produce rain and dark billowing cloud does not. Is there some Factor X at work?
23 October 2007 at 7:31 AM
[[Barton, excuse my acronym ignorance but what do QT and PDQ stand for?]]
“Quick Time” and “Pretty Damn Quick,” respectively.
23 October 2007 at 8:02 AM
Rob Huber asked: “When the role of this human factor or that is given a probability of say 95%, what does it mean to say that such a thing is a fact?”
Rob, actually, there are very few things in life that are subject to 100% certainty, so science has learned–and is still learning–how to deal with such propositions. Probability can have many meanings–from the inherent probabilistic nature of quantum mechanics to the measure of uncertainty in flipping a coin. There are different ways of dealing with these different probabilities.
If we flip a coin and it comes up heads, we can say little about whether the coin is “honest” (equal probability heads and tails). However, if we flip it 10 times and it comes up heads every time, we would have strong suspicions of its honesty, and after 100 times, we would have a virtual certainty that we were dealing with a trick coin. Note, however, we can never state as a “fact” that the coin is dishonest. Now, let’s say we flip a coin and it comes up heads, 19 straight times. Are you going to bet on tails on the 20th toss? How about if I give you 20:1 odds? That is one measure of a probabilistic “fact”.
After 150 years of climate science, we have a model that has flushed out the basic drivers of the theory and their relative importance to a high degree of confidence. We have lots of evidence from multiple independent investigations that humans are affecting climate. We have NO evidence that strongly contradicts this hypothesis, albeit there are some studies where the evidence has been ambiguous. So, I ask, on what empirical basis would a scientist reject anthropogenic causation? Or put another way, the coin has come up heads (anthropogenic) 19 times. How are you going to bet?
23 October 2007 at 8:24 AM
This is a well written and chilling article by Figen Mekik deserving of a wider circulation - to help address the issue of “lack of awareness” (as raised in #51 above) and to emphasise the need for more of a focus on local and regional studies in the debate on global warming / climate change.
The earth is warming, much of the warming is man-made arising primarily, at this stage, from emissions of CO2 (as Arrhenius predicted in the 1890s), natural sinks are being depleted, positive feed-backs are starting to speed up the rate warming, and local climates are changing as this extra energy is redistributed by natural circulation processes.
In the debate on global warming / climate change there has probably been too much emphasis on global and annual temperature means. The general public finds it difficult to identify with, and see the local relevance, of such a focus. The public needs to know what global warming / climate change means to them, at the local level, where they live. Scientists need to develop ways to better understand local impacts and to provide this information to a wider audience.
This article by Figen Mekik is a welcome contribution to this process.
Gareth Evans
23 October 2007 at 9:08 AM
#29 Nick Gotts:
Sorry for the somewhat delyaed response. First off, yes the “polar night” is the polar winter. Six months of darkness with temps at -70 to -100 degrees C around the north pole.
CO2 rise and AGW causes the subtropics to become warmer which creates a stronger temperature and pressure gradient between the cold polar night (winter) and the subtropics. This steepened gradient is what causes the east-west winds in the stratosphere to develop into a vortex, a spiral. And many researchers think this spiral (cyclonic circulation or polar night vortex) is where ozone-destroying chemicals are trapped, like chlorine. In spring the sunlight causes photochemical reactions which break down ozone in the stratosphere. And as the ozone is depleted in the stratosphere, it creates an additional reduction in sea level pressure, thereby exacerbating the gradient in sea level pressure between the tropics and poles. This increases the strength of the polar night (winter) vortex. This last part about ozone is more important for the south pole and Antarctica though.
23 October 2007 at 9:25 AM
#41, “anthropogenic” would not be necessary, except for denialists who partly (in addition to saying GW is not happening) argue that GW is happening, but not due to us.
I’ve never had trouble with the term. But then I’m an anthropologist.
23 October 2007 at 9:48 AM
Question:
Is there a current summary out there anyone is aware of that measures crop yields on a regional and global basis?
23 October 2007 at 10:11 AM
#58 Gareth Evans:
Thanks so much for your very kind words. I am not anywhere near being in the league of the editors at RC in climate sceince, so I consider it a huge honor and privilege that they post my commentaries. This gives me a chance to interact with people (other commenters) I wouldn’t normally be able to speak to about topics that I find interesting or concerning. And I really appreciate it that it is getting positive responses from the commenters. Thanks again.
23 October 2007 at 10:13 AM
RE (#17 & 40) hydrogen sulfide outgasing and killing off large segments of life on earth. It doesn’t really matter when it might happen (I myself figured in a couple of thousand years, maybe more), but that we are currently pushing the system in that direction, and there will be some tipping point (I think soon), beyond which it will more or less be a done deal for the distant future. In other words I’m not too concerned it will happen to me in my lifetime, only that I may be causing it to happen to others — and it doesn’t matter whether those others are in the century 2300 or 4300.
RE # 51 & “Anthropogenic components play a role, but the extent of that role is by no means a fact”
For people looking beyond mere cognitive rational scientific facts into how it relates to them on a emotional level — such as what’s my part in it & what can I to help the situation? — the “anthropogenic” is most important.
However, in answer to anyone saying the human role is small or nil, I would answer that it means that we must reduce our GHGs all the more to effect even a small slowing this GW in hopes of saving a few lives.
23 October 2007 at 11:07 AM
Re 61
I mostly use USDA numbers. (http://www.usda.gov/wps/portal/!ut/p/_s.7_0_A/7_0_1OB?parentnav=AGRICULTURE&navid=CROP_PRODUCTION&navtype=RT)
FAO also does numbers.
Financial advisors supply research related to commodity futures that include grain and meat.
The food and grain producer’s organizations track conditions related to projected markets and sale prices. (Farmers need to know how much to plant and whether to sell at harvest or hold for better prices. Animal producers need to know if they should buy at harvest or wait for lower prices.)
Perhaps the best source is “Feed Stuffs”, which is a weekly publication by subscription.
23 October 2007 at 11:11 AM
Re #59 I assumed that polar amplification will reduce the temperature gradient. Can someone explain how this fits in?
23 October 2007 at 11:40 AM
Re # 24 Majorajam: “…economist Richard Tol assured me on another blog that, “Water scarcity and heat stress have no obvious relationship, as water stress does not mean that drinking water is scarce.”’
Hmm…tell that to the people of Atlanta:
ATLANTA, Oct. 22 — For more than five months, the lake that provides drinking water to almost five million people here has been draining away in a withering drought. Sandy beaches have expanded into flats of orange mud. Tree stumps not seen in half a century have resurfaced. Scientists have warned of impending disaster…
http://www.nytimes.com/2007/10/23/us/23drought.html?em&ex=1193284800&en=8a04b9fdb71465cf&ei=5087%0A
23 October 2007 at 11:55 AM
A quick question:
California is being ravaged by fires, is AGW also a contributing factor?
23 October 2007 at 12:10 PM
Re. #57: Ray - good comments, well put.
For some more of the latest on the effectiveness or otherwise of natural carbon sinks, see the below and related links:
http://news.bbc.co.uk/1/hi/sci/tech/7058074.stm
I have to say that I am still v. concerned about the possible long upper tail of the climate sensitivity pdf. It’s bad enough that most people have lack of familiarity with ideas such as the normal distribution, let alone factors/parameters which could heavily skewed such as this. An uphill battle still, I fear.
23 October 2007 at 12:12 PM
Re. #57
Ray, great explanation, thanks!
PS, I’m betting on heads
23 October 2007 at 12:46 PM
For the acronym illiterates, of which I am one, and in fact often keep a second browser page open just to check what I have just read.
http://www.acronymfinder.com/
23 October 2007 at 12:51 PM
Congratulations Figen Mekik for a lucid and enlightening report on the Turkish and Med region, which combined with the feedback from climate scientists, t’other scientists and lesser morsels !!! makes for stimulating and often chilling reading..
Also coming from a non-Anglo point of view, I would propose that - Alas, however, notwithstanding …most politicians (democratically elected or otherwise) with an average life span of 8 to 12 years and civil servants in the majority of countries HAVE, ARE and WILL in the future of ‘climate change’ be less, less inclined and/or able to implement effective awareness programs and ‘adapt to extreme climate events’ measures.
Actions speak louder than words - as amply demonstrated by the continuous utterances from the British government and Prime ministers regards climate change etc:, Having lived in England and 4 of her former colonies there is little evidence to support the implementation of widespread programs concerning ‘adapting to climate change’. France is certainly no better - Mon Dieu, radioactive clouds originating from Chernobyl stopped at the French border because they didnt understand French…now that is positive climate engineering !!!.
However at least in Germany, where I have scurried to, there is a physical scientist, Angela Merkel as Chancellor,promoting and endeavouring to implement a wide range of measures. I have the impression that across the broad political German spectrum this position is adhered to and implemented..as is the case in Scandinavia, Holland, Switzerland and Austria. But the automobile industry, petro-chemical industries and olde brown coal are powerful lobbies in Germany…racing along at plus 160km is very much a sacred ‘right’ here. Talk of reducing this is as taboo as proposing the widespread use of seperator-flushless toilets, double clean-grey water systems etc which should become mandatory in certain southern European regions and parts of France and Germany….
With all due respect, you striving climate scientists can present more and more valid and ‘getting closer to reality models’ you want, but for the average Joe, Pierre, Hans or Nakagawa San (I lived in Japan for 8 years) a practical life style change in adapting to climate extremes will have to be thrust upon him and probably forced down his throat too. Certainly, 2-3 year drought-flood cycles in most industrial countries will oblige the implementation of more effective and UNPALATABLE measures while shifing the emphasis from often dubious democratic processes to ‘every day survival’ security and maintenance.
Moving between RealClimate.Org and the ICH.org InformationClearingHouse (US,foreign misadventures and geo-strategy)with their lively blogs helps to edge me towards a more ‘realistic’ but ‘pragmatic’ outlook on our ‘3 steps forward 2 steps back’ approach to ‘climate change’ and ‘peak oil’..
Thanks for a wonderful source of honest and straightforward news reporting & discussion..
23 October 2007 at 12:56 PM
re 67
A quick question:
California is being ravaged by fires, is AGW also a contributing factor?
=====================
http://en.wikipedia.org/wiki/2007_Western_North_American_heat_wave
http://en.wikipedia.org/wiki/California_wildfires_of_October_2007
23 October 2007 at 1:34 PM
Mr. McIntyre, it takes a long time to detect whether there’s a change —there are baseline studies:
http://www.sdfirerecovery.net/docs/SDFRN_Workshop_Chaparral_21apr04/7_Mensingetal1999SantaAnaFires500years.pdf
“Microscopic charcoal from varved Santa Barbara Basin sediments
was used to reconstruct a 560-yr record (A.D. 1425 to 1985) of Santa
Ana fires. Comparison of large (>3750 mm2) charcoal with documented
fire records in the Santa Barbara Ranger District shows that
high accumulations correspond to large fires (>20,000 ha) that occurred during Santa Ana conditions. The charcoal record reconstructed a minimum of 20 large fires in the Santa Barbara region during the study period. The average time between fires shows no distinct change across three different land use periods: the Chumash period, apparently characterized by frequent burning, the Spanish/ Early American period with nominal fire control, and the 20th century with active fire suppression. Pollen data support the conclusion that the fire regime has not dramatically changed during the last 500 yr. Comparison of large charcoal particle accumulation rates and precipitation reconstructed from tree rings show a strong relationship between climate and fire history, with large fires consistently occurring at the end of wet periods and the beginning of droughts.”
It’s the same problem as with hurricanes — people like the locations and build in them, over and over.
23 October 2007 at 1:36 PM
How can the NAO, being an index for the climate in winter be measured through tree-ring width/density which responds to the summer climate?
[Response: In Morocco, the trees are most sensitive to winter precipitation - not summer temperatures. Hence that is what gets reconstructed. - gavin]
23 October 2007 at 1:45 PM
AGW ??? - California ravaged by fires…
Not only, but also Greece (not even serious cadastral, even GIS-GRASS coverage..I doubt if 600 million euro emergency EU funding will change an iota..), Spain, Portugal, Australia, southern France, Croatia, Bulgaria etc ravaged by fires..
other valid contributing factors are often:
- inappropriate bush-undergrowth management which is overgrown and unchecked without grazing, human intervention -and ‘quick burning’ fire is an essential ecological element in many regions..
- inappropriate highly inflammable trees and bushes planted too near and too densely toresidences ie hi-oil content,’exploding’ behaviour, not regularly pruned…Fire-resistant trees (to a degree) are listed and studied
- inappropriate maintenance of fire breaks - labour is expensive and hilly terrain is sweating- but of course high wind driven fires can jump most breaks
- VERY INAPPROPriate housing materials and design, looks great and burns great !!! Check out for example some Ozzie ‘Permaculture’ recommendations, especially David Holmgren, regarding ‘fire proof’ housing and building materials. The fires in Victoria state Oz, Ash Wednesday 1980s ?? etc were real killers almost hitting greek 2007 fatality levels..but folks learnt from it..
- Finally… Too many people and too many houses in high risk areas and unregulated wishy-washy urban planning- German, Austrian and English floods 2002 to 2007 epitomize ineffective urban planning for recognized natural disasters..
Fires are part of our future - we can and must adapt accordingly…
AGW is the icing on the cake…’cuse the pun !
23 October 2007 at 2:01 PM
John and Nick,
Thanks. Good to see somebody hasn’t succumbed to the gamblers fallacy.
23 October 2007 at 2:11 PM
Perhaps a new post is needed, to talk about the SoCal wildfires.
That is a dry, hot region, getting drier and hotter. The mountains which artificially feed that region with water are losing their snowpacks, reducing the water flow even as demand increases exponentially.
These fires release an enormous amount of CO2, am I correct? The burning of these lands will allow some of the region (much of which is already desert) to turn to desert because their plant life will have been burned off, and there is no water coming to allow new plant life to grow. Am I correct about this?
In other words, are we witnessing land change based on global warming? The post could also address the American southeast, which is in a drought emergency.
Are these warming-related? More to the point, is there any way they can be reversed?
If not, are we not at the beginning of what will become a mass migration away from those areas?
23 October 2007 at 2:32 PM
Re: 77
Your comments are well-taken. Your questions are ultimately unanswerable. This is part of how I get by these days: I don’t have to know the answers. Whoever gave me a right to know anything?
Sorry for the imprecision. It’s a bit disconcerting, but it can be thought of as intellectual rigor, akin to the Copenhagen interpretation of quantum physics: we don’t know, we probably never will.
That said, the sentiments behind your questions remind me of that too-famous last stanza of TS Elliot’s The Hollow Men: this is the way the world ends, this is the way the world ends, and so forth.
23 October 2007 at 2:44 PM
Re. #77
Walt, sounds like this is starting to sink in with you. As to your questions
yes, yes, yes (generally speaking)
While singular incidents are difficult to attribute to global warming, trends are. and the trends are more acres burned per year, averaging upwards. So I would say yes, it is related.
As to can it be reversed? Good question. The faster we take action the better a chance we have to mitigate the affects. There are not short term solutions other than reducing consumption in many areas. Reversing Global Warming is not something that can happen overnight, if we are really ingenious we might be able to reverse the affect in say 100 years, if not then hundreds of years will be required.
I personally lean towards the innovation capacity and the axiom that necessity is the mother of invention.
On the other hand, we clearly have some major challenges ahead of us. Let’s just hope we don’t cross too many tipping points.
23 October 2007 at 3:11 PM
re 77. Walt Barnett
Agree suggested new post for SoCal fires, as we ‘is drifting away from Sweatin Med.
Available space/carrying capacity and Mass migration seen perhaps in a historical perspective of max 1 billion world population living 30-55 years, without provoking TV coverage, was an accepted and viable necessity for some but usually unknown issue for most unless directly concerned..
Population of US at Dust Bowl time of Steinbeck’s Grapes of Wrath and 10,000s - 100,000 Oakies heading to Calif..?
Where would your present day Californians trot off too ? New England, Great Lakes ?? as drought is hardly confined to the west coast !!!
Population of Judea, pseudo-Palestine etc at time of old testament, max. 50,000 to 100,000 ?? plus every 6-7 years fallow farm cycle!!!
Scant historical evidence of land change-global climate change being reversible, rather scamper away, allow boom-bust cycle with subsequent die-off, wait a few decades -hundred years and perhaps drift back..
Modern Mass migration away from important areas in Calif, other parts USA, within Europe, within the middle east and northern china etc IS A POLITICAL NO-NO, TABOO SUBJECT to be AVOIDED at all costs.
It’s political suicide..at the moment !!
Apparently, many academics avoid this topic too..
Apart from suspect CIA-RANK studies..
Unsubstantiated gossip:: the Dutch government is supposedly providing subsidies-financial assistance to certain !! Dutch citizens to NOT build a house in Holland but move to higher lands of French speak Belgium ??
23 October 2007 at 3:19 PM
re 73
Mr. McIntyre, it takes a long time to detect whether there’s a change —there are baseline studies
===============
I really wasn’t attempting an answer to the question. The my posting of the two links was not meant as offering an opinion one way or the other, simply as a reference of what is happening this year - and today. Frankly, any opinion I have is just that - an opinion. My apologies if I came off as saying something I didn’t mean to.
“It’s the same problem as with hurricanes — people like the locations and build in them, over and over.”
Yes, I know. I have family in the U.S Forest Service stationed in the area that is burning right now, directing a portion of the operation (though there is little they can do until the winds die down, and there is talk they won’t calm for three more days).
Suffice to say one of the big problems are the development of communities in the area of canyons - canyons that, in Santa Ana conditions, behave as natural blast furnaces. This is particularly bad in the San Diego region. Add to that the Bug Kill that is prevalent throughout the region and the understanding the Southern California has received less rain than even Death Valley averages in a year, and it’s a climate for disaster.
While I’m watching those fires with interest, the place I’m really worried about is Arrowhead and the areas around it. If that really catches, things could get very nasty.
23 October 2007 at 3:22 PM
#67 Kebab: “A quick question:
California is being ravaged by fires, is AGW also a contributing factor?”
Don’t know.
Averages, averages averages… including 30+ years of evidence and from multiple locations… that’s what the world-wide climate science communtity works on. No single event can be easily ascribed to AGW (human-caused warming).
For instance perhaps, the current San Diego fires are just a freak 500 or 1000 year natural event…
BUT, this sort of increase in fires around the world has been increasing from an average point of view…but you probably want more years of averages from more locations just to make sure… Following are some scientific references on increasing world-wide fires.
“If climate change is increasing wildfire,. as Westerling et al. suggest,”
“They show that warmer temperatures appear to be increasing the duration and intensity of the wildfire season in the western United States”
A. L. Westerling, H. G. Hidalgo, D. R. Cayan, T. W. Swetnam, Science 313, 940 (2006); published online 6 July 2006 (10.1126/science.1128834).
http://www.sciencemag.org/cgi/content/full/313/5789/940
http://www.agu.org/pubs/crossref/2004/2004GL020876.shtml
N. P. Gillett et al., Geophys. Res. Lett. 31, L18211 (2004).
Balzter, et al. Coupling of vegetation growing season anomalies with hemispheric and regional scale climate patterns in Central and East Siberia, Journal of Climate 20:15, 3713–3729,
http://www.sciencedaily.com/releases/2007/07/070731191203.htm
http://www.sciencemag.org/cgi/content/full/313/5789/927
G. R. van der Werf et al., Science 303, [73] (2004).
http://www.sciencemag.org/cgi/content/abstract/303/5654/73
23 October 2007 at 3:48 PM
Thank you for the replies. There seems to be a consensus that the conditions are not likely reversible in the foreseeable future, which is also my view.
Whether or not warming is a key contributing factor in the prevalence and intensity of these fires, it seems certain to me that much of the area will be left without significant plant life, and that water scarcity will prevent that plant life from regenerating.
I am wondering if this land change, as well as the inability to acquire water for other purposes - drinking, cleaning, manufacture and so forth - will inevitably lead to migration. I wonder if this is the opening scene of a story which will keep getting told, over and over.
It really makes me wonder why we cannot effectively desalinate sea water on a large scale. It seems to me that this is an obvious solution in which investment should have long ago been made.
Instead we keep divvying up declining mountain water. Even if that supply was to remain constant - a complete fantasy - demand continues to escalate.
The combination of increased demand and decreased supply seems, to me, to be an enormous stressor. When it bends too far it will break.
23 October 2007 at 4:07 PM
#46 Again, I honestly do not see how the observed NAO index supports model projections for the future. In the 20th century we have mostly a negative trend - only between 1960 and 1990 was the trend positive. And the trend in the last 15 years is again negative. Is’nt it more reasonable to interpret this just as natural variations, so far?.
23 October 2007 at 4:12 PM
Viento,
The trend between 1970 and 2004 looks positive and 2007 is a high positive number. Are we talking bout the same graph?
23 October 2007 at 5:49 PM
RE #67, I’m from California and remember doing a class ecological project on a chaparral forest in the early 60s. We learned that these forests naturally burn every so often, and this would explain many of the past fires.
However, when you consider that a warming atmosphere holds more water vapor and desiccates the land and brush; and that GW is also expected to increase storms and winds; add in the natural tendency for these areas to burn, and you get what we’re seeing now.
“Climate” is on a more macro-level of scientific inquiry than weather — it is the aggregate statistics for weather — so climate scientists cannot say a particular event (at the micro-level) is caused by global warming (at least not yet), only that the warming will entail higher probabilities of such events.
However, since I’m not a climate scientist, I say, yeh, the California mega-fires we are witnessing today are due to global warming (even if its role was merely the straw that broke the camel’s back, so to speak). We live in a globally warmed and warming world, so I say everything that can reasonably be attributed to GW is due to GW (not tooth-aches, of course), unless proven otherwise. We have to imagine what the world would have been like without global warming, and whether the fires (and droughts, and hurricanes, and such) would have been as big or harmful. I think not.
Also Dr. Mekik raises an important point when she writes, “small perturbations in weather patterns can lead to tragic and costly outcomes.” It is those final inches of floodwater that breach the levee (the ones caused by GW on top of the natural conditions), that last “huff” that blows or burns the house down (that small increment caused by GW on top of natural & other human-made conditions), that often does the most severe damage.
There are many necessary (but insufficient) causes for such great harms; the addition of GW may finally make the set of causes sufficient for much greater harms in certain cases. Or, as they say, the whole is much greater than sum of the parts.
I’m thinking catastrophe theory in mathematics might be helpful here, but I don’t know much about it, only the idea that there are other than smooth linear functions, some with big leaps.
23 October 2007 at 6:31 PM
Just an add-on re the SoCal fires.
The evacuation number is up to one million, the firefighters have given up any attempt at containment because of the winds, and the governor is quoted as saying about 68,000 homes are threatened.
This is going to be very ugly barring a miracle.
23 October 2007 at 9:45 PM
It’s interesting to look at these areas on the graphic of the globe on page 16 of the SPM : Projected Patterns of Precipitation Changes.
Is the future playing a little peekaboo with the present?
23 October 2007 at 10:17 PM
Mr. McIntyre, where’s your ‘one million’ evacuation number from?
I’m looking for a reliable source.
23 October 2007 at 10:34 PM
Oh. http://www.kcbs.com/pages/1119024.php?
Back around 1990, when I first started trying to get some advice about restoring a burnt-over mountain site in N. Ca., the best advice I got was from people around the Mediterranean. They told me that they had accepted it was sure the climate was changing and expected more warming, more extreme weather, and more erosion problems, and said that they were basically building contour berms on difficult sites, just little ditches with raised edges along slopes one above another, as ways of interrupting sheet erosion from wind and water.
I took that advice — the results were amazing. Each little groove I’d cut by dragging a pickaxe the first fall had by springtime filled up with a little ribbon of black carbon runoff from the burned over hill, and in each of those little trenches there were lined up orange manzanita seeds starting to sprout, and pine seeds, and a whole lot more.
The other advice I got from the Mediterranean folks was not to clear all the brush, but to make sure that any bare patch had some dead branch laid across it, again to break up sheet erosion.
And that worked too — each of those accumulated a little pile of dead leaves and pine needles and bits of burned bark, and had a few seeds sprouting, surrounded by the bare gravel the fire had left behind the previous fall.
This was before the Web, I had gone to Usenet newsgroups for advice. It was way ahead of the advice I got from the local agencies in the USA — there the standard was to pile and burn every bit of fire debris and leave a clean pruned smooth hillside.
Believing that the worst that has happened in the past is indeed likely to happen again, and probably sooner with climate change moving faster, seems a good idea.
23 October 2007 at 11:15 PM
I believe we are about to discover first hand what happened to the water on Mars.
Too bad there isn’t a lush, green planet next door.
23 October 2007 at 11:28 PM
Walt Bennett wrote:
> allow some of the region (much of which is already desert) to
> turn to desert because their plant life will have been burned
> off, and there is no water coming to allow new plant life to
> grow. Am I correct about this?
No. This is normal fire behavior. The big worry is that European and Asian annual grasses (cheatgrass, Bromus tectorum; medusahead, Taeniatherum caput-medusae) will take over like crazy on the burned areas.
The only tactic I know of for those is expensive — spray the hillside with sugar water, so the soil microbiota can use that plus all the excess minerals and nitrogen in the ash during the winter, starving those fire-adapted invasive grasses. Otherwise they grow like crazy. If those and their ilk can be discouraged for a few years, the native California perennials come back.
The California Native Plant Association has a lovely T-shirt design.
It shows a horizontal line, and above the line is a tiny stem and a few little leaves, and below the line is a _huge_ network of deep widespread roots.
When I worked on my burnt off site, a botanist dug around in the gravel and showed me a California lupine root — a big thing the size of a thumb — and told me it was likely a hundred years old, and would come back fine after the fire if we could discourage the invasive annuals.
We did. The slopes we worked on — which had burned down to orange gravel and black silt in many places — are thick with lupine after 18 years, and covered with pine straw where we scattered a few branches across them the first winter and left them alone but for attacking the invasives (with flame weeding, during the wet weather just as they set seed).
Look at any of the So. Cal. fire sites. Look at Yosemite since its big fires. Fire works fine in these environments if it happens often enough, and if it happens gracefully enough — and you manage that by avoiding big piles of stuff that causes huge conflagrations.
Like, well, houses.
24 October 2007 at 1:46 AM
Re. #89, Hank Roberts:
The BBC is claiming “more than half a million”. They don’t cite their source but their fact-checking is usually very reliable.
24 October 2007 at 2:44 AM
Hank Roberts wrote:
“Mr. McIntyre, where’s your ‘one million’ evacuation number from?
I’m looking for a reliable source.”
Well, not to suggest that the New York Daily News is a reliable source, but the media in general is using the one million figure this evening. Additional evacuations are being ordered as the fires continue, especially since the end of the Santa Ana winds may result in westerly winds turning the fires eastward.
“Nearly one million Californians were ordered to evacuate their homes on Tuesday night as wind-whipped wildfires roared across the parched landscape from Malibu south to the Mexican border.”
http://www.nydailynews.com/news/wn_report/2007/10/23/2007-10-23_nearly_1_million_californians_forced_to_.html
Walt Bennett wrote:
“Whether or not warming is a key contributing factor in the prevalence and intensity of these fires, it seems certain to me that much of the area will be left without significant plant life, and that water scarcity will prevent that plant life from regenerating.”
As Hank Roberts wrote, many California native plants are “fire” species which come back quickly after a fire. Most of the chaparral hillsides will be showing new growth after the first winter rains. Indeed, the cones of some pine species do not even open to release their seeds until they are exposed to fire.
Some of the lands burning this week were burned in the huge fires of 2003. So the vegetation did re-grow enough in just four years to carry the current fires.
Unfortunately, many exotic annual grasses are changing the picture in parts of California. In parts of the Mojave Desert, for example, the annual grasses now are allowing fires to spread to some plants that seldom were affected by fires in the past, such as Joshua trees and some cacti. The spacing of these native plants kept fires from spreading in the past, but the grasses allow fires to travel further than they used to.
If global warming results in extended droughts in southern California, catastrophic fires may become more common, and the species composition of plants and animals may change. But even though parts of California suffered they driest season since humans have been recording rainfall, there still were a lot of plants growing this year.
24 October 2007 at 2:49 AM
So far on this thread, we have worries about drought and the ravages of fire, crop yields and migration as well as the normal worries about temperature increase and sea level rise.
And now for extinctions, in The Guardian today, just to cheer you all up.
“Predicted levels of global warming could trigger a “mass extinction event” like the one which wiped out the dinosaurs, new research suggests.
Such a disaster would not necessarily mean the end of humanity, but it could kill off more than half of all the animal and plant species on Earth.
British scientists have uncovered the first strong evidence of a close coupling between the Earth’s climate and extinctions.
The researchers from the University of York analysed the relationship between the two over the past 520 million years - almost the whole of the available fossil record.
Matching marine and terrestrial species diversity against temperature estimates, they found that the range is relatively small during warm “greenhouse” climate phases. Meanwhile, extinction rates are relatively high.
The opposite pattern is seen when cooler “icehouse” conditions prevail. Then, biodiversity increases and more species survive.
Climate change predictions for the future fall within the range of the warmest greenhouse phases associated with mass extinction events in the fossil record, said the scientists.
Dr Peter Mayhew, a member of the York team, said: “Our results provide the first clear evidence that global climate may explain substantial variation in the fossil record in a simple and consistent manner. If our results hold for current warming - the magnitude of which is comparable with the long-term fluctuations in Earth climate - they suggest that extinctions will increase.”
Computer simulations point to global temperature rises of around 1.5C by the middle of the century, and 3C in the next 100 years. Some experts believe these estimates are too conservative.
The research is published in the journal Proceedings of the Royal Society.
Copyright (c) Press Association Ltd. 2007, All Rights Reserved.”
JS McIntyre, I tried something similar earlier in the year and started with the FAO website which I found to be un-navigable. Fortunately I have a friend there who arranged for the stuff to be dug out for me. If you cant nav