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Two degrees

Filed under: — david @ 8 July 2009

The countries of the G8 today approved a target of 2° C rise in global average temperature above the natural, preanthropogenic climate, that they resolve should be avoided. The Europeans have been pushing for 2 degrees as a target maximum temperature for several years, but this is something of a development for the Americans. We posted recently on two new papers about what it would take to limit global average warming, finding that it would require fairly strong change in trajectory. About 2° C as a target, we wrote,

… even a “moderate” warming of 2°C stands a strong chance of provoking drought and storm responses that could challenge civilized society, leading potentially to the conflict and suffering that go with failed states and mass migrations. Global warming of 2°C would leave the Earth warmer than it has been in millions of years, a disruption of climate conditions that have been stable for longer than the history of human agriculture. Given the drought that already afflicts Australia, the crumbling of the sea ice in the Arctic, and the increasing storm damage after only 0.8°C of warming so far, a target of 2°C seems almost cavalier.

Nevertheless, we view today’s development as a constructive step.

411 Responses to “Two degrees”

  1. 201
    Bill Woolverton says:

    #186 David Benson: While you may be correct about the GIS and Swiss glaciers, the Laurentide Ice sheet retreated from northern Quebec (i.e. the mainland) about 6500 years ago. It’s remnants still exist, though thinning, as Barnes Ice Cap on Baffin Island.

  2. 202
    MacDoc says:

    #1 – you state
    “Information from our own US government proves them wrong”

    Perhaps you may want to reconsider that statement

    From the site which integrates all federal research on climate and global change ( 14 agencies including NOAA and NASA and Dept of Defence amongst others… )

    ” 1. Global warming is unequivocal and primarily human-induced.
    Global temperature has increased over the past 50 years. This observed increase is due primarily to human-induced emissions of heat-trapping gases. (p. 13)

    2. Climate changes are underway in the United States and are projected to grow.
    Climate-related changes are already observed in the United States and its coastal waters. These include increases in heavy downpours, rising temperature and sea level, rapidly retreating glaciers, thawing permafrost, lengthening growing seasons, lengthening ice-free seasons in the ocean and on lakes and rivers, earlier snowmelt, and alterations in river flows. These changes are projected to grow. (p. 27)

    3. Widespread climate-related impacts are occurring now and are expected to increase.
    Climate changes are already affecting water, energy, transportation, agriculture, ecosystems, and health. These impacts are different from region to region and will grow under ”

  3. 203
    Martin Vermeer says:

    Rob #188

    Does planet earth emit any infrared rays in the wavelengths the CO2 is supposed to stop? Or put like this, how does the earth look like from “out there” does its signature/spectrum still contains the wavelengths within the 13-17um band in any significant amount or has most of it already been absorbed by the current CO2 layer? If not, how much is it left for CO2 to absorb.

    Rob, if you are not of a religious persuasion that bans any kind of climatic modelling ;-) you might look at David Archer’s 1D radiative transport model:

    This model gives you as the default what a satellite sees looking down from 70 km. Note how less radiation comes from the 13-17 um band; this is because it comes from higher up, around the tropopause where it is colder — note the coloured temperature curves. What adding greenhouse gas does, is make this band broader, so more radiation gets emitted from high, cold layers. The whole climate system including the surface must then heat up a little to compensate and restore equilibrium.

    I remember having seen really observed IR spectra looking similar… somewhere on the Wide Wide Web.

  4. 204
    Mark says:

    “Did you read what they’re actually passing? The bill will prohibit the state equivalent of DEQ from *enforcing* any law that mentions global warming.”

    Then they don’t mention global warming.

    Or they don’t pass a state law, they enact a federal one (thereby not overriding the international committment by saying “we shall reduce the CO2 output by 25% by 2030 and stop there.”

    Or someone will point out it’s dumb to pass a law against a law and it won’t be passed.


  5. 205

    Jacob Mack writes:

    I do not think we will have a run away global climate at 2 degrees or such drought and weather changes that the human population will be threatened in a major way. The data does not really point in this direction either.

    “Very dry” areas have increased from 12% of the globe to 30% since the 1970s, according to:

    Dai, A., Trenbert, K.E., and T. Qian 2004. “A Global Dataset of Palmer Drought Severity Index for 1870–2002: Relationship with Soil Moisture and Effects of Surface Warming.” J. Hydrometeorol. 1, 1117-1130.

    For “very dry” read “drought.”

  6. 206
    Mark says:

    “No, the poster at 13 asked your opinion of the paper, wondering if you think their 2.4C figure is plausible or not.”

    Well it’s not 2.4C now, and the error bar is 1.4C, so it’s likely that the right answer is within that range.

    ” Something tells me he won’t be doing that again .,..”


    Why did they think I’d know? It was prompted by me answering someone’s query “what is the 2C based on?” and I answered “pre-industrial” well, actually 1900’s temperature, but that isn’t a lot different from the 1850 generally taken as the beginning.

    But all that required was READING THE STATEMENT.

    How that is supposed to indicate in depth understanding of a paper I’ve never read I fail to comprehend.

  7. 207
    Larry says:

    I think the science being discussed here and elsewhere in R-C is good and vital. However, I strongly believe that here and as a society we are perilously confusing the role of research scientists (developing understanding and accurate estimates) with the role of engineers (applying that scientific knowledge safely).

    There is a gulf of difference between the scientists’ confidence limits and probabilities and the engineers’ factor of safety. Safe application of science takes into account not only scientists’ view of uncertainties, but also other contingencies. Even as well as the physics of flight and aircraft structures are known, you would not want fly in an aircraft that was designed literally on that science, without a significant factor of safety (1.5, by FAA regulation). Same principle for bridges, buildings, etc. But no factor safety for planet Earth?

    Failures in the Earth system are already beginning to occur in a number of ways at a GMT increase of only 0.8 oC; GMT does not address huge regional differences in temperature increase; a temperature target doesn’t even address ocean acidification; and we are frittering our time here (and in numerous scientific papers) addressing 2oC as if it is a reasonable target???

    For me, it comes down to the need to “hit the brakes hard” – and I mean much more so than the tap on the pedal suggested in the R-C article of that title. I say that partly because I believe it is what the situation demands, and partly because the reality of the climate change problem won’t sink in to very many people until there is strong, persistent, pervasive advocacy that we all have to be accepting and making lifestyle sacrifices – right now. Not a decade or two or four from now. (I am thinking of those of us in the U.S. – we need to turn this corner.) Alternative energy technology will help, but we can’t build our way entirely out of the problem. Significant sacrifice is required too, and we had best get on with it.

    A token way to get the ball rolling would be advocacy of the elimination of frequent flyer miles, as an element of the climate bill. That is, elimination of an inducement to travel. I think that would grab attention, and bring reality to those who are affluent enough to have significant personal impacts on climate not just through air travel, but in other ways too. Aviation is but a small slice of GHG emissions, but the move of advocating this would be potently symbolic. What greater hope is there? The 2oC target, or even plaintive language such as “as far below 2oC as possible” offers no hope. We have already consumed our factor of safety — it is time to slam on the brakes.

  8. 208

    Edward writes:

    China and India are interested in improving living conditions and the standard of living for their people by making cheap energy available. If that energy is most easily provided by the coal or oil resources they have available to them so be it.

    If 200 million Chinese citizens find themselves without fresh water because the glacier melt they depend on to feed their rivers goes away, so be it.

    If Shanghai is under water, so be it.

    If 400 million Indians lose their fresh water from Himalayan glacier melt, so be it.

    If a billion or more people in Asia starve to death when human agriculture collapses due to exploding drought, so be it.

    That’s what you’re saying, in effect.

  9. 209

    Richard Kinder, CEO of Kinder-Morgan, wrote an interesting article in the Houston Chronicle last Thursday.

    He claims the following USA energy use, measured in equivalent barrels of oil:

    US consumption – 47.4 MBOE/D (million barrels per day)
    Oil – 19.0
    Natural gas – 11.9
    Coal – 11.5
    Nuclear – 3.8
    hydro – 1.1
    wind & solar – 0.8

    My question is — are these numbers correct?

    He argues for natural gas and nuclear as answers for the next 10 to 20 years.



  10. 210

    #164 Mark,

    “Ah, a statement with NOTHING AT ALL to back it up.

    Well done.”

    Really?? I didn’t know I have not invented something? Wait a bit and see… I am trying to state, so much talent here, and so much fixation over impossibilities, and the “end of the world” will not be avoided without some huge sacrifices… How about sacrificing the limits imposed on your imagination! And unleash sheer energy from the sky!

    Now for those out there in love with standard wind turbines, good for you! But wind is not only confined near the ground. There is so much energy to tap in up there in the atmosphere, when I sleep, and hear the wind howl, I dream of dollars flying in the sky…..

  11. 211
    Eli Rabett says:

    The argument about developing nations participation has two threads. The first is ownership, most of the damage to date comes from the developed nations. Second, that of per capita equity going forward. The answer to the first is ok, but going forward China and India will be major contributors. The answer to the second is that the per capita in China and India has increased by between three to four times since 1950 so they are not exactly innocents walking in the park.

    Eli, of course, has a simple plan to save the world (Part II)

    India and China and many other developing countries should reduce their emissions of black carbon by 90% or more in the next decade. This will not only significantly reduce warming of the climate, it will make a major contribution to the health of their people. Simple and economical methods of doing this are available.

    PS: Several sites including Rabett Run have been down for a couple of days due to Blogger unpleasantness. Visitors are now being accepted.

  12. 212
    Rod B says:

    Martin V., it might be just a nit, but something is amiss in your explanation (203): 70km is way above the tropopause and even higher than the stratosphere.

  13. 213
    Hank Roberts says:

    John Burgeson, when someone (like Kinder) posts numbers without cites, they’ll be arguable because not precisely defined (energy use within the country? or also bought and paid for elsewhere on our account including shipping? used in/for products we import? etc), usually the best bet is to ask him for his sources. You could ask:

  14. 214
    Jerry Toman says:

    …”Now for those out there in love with standard wind turbines, good for you! But wind is not only confined near the ground. There is so much energy to tap in up there in the atmosphere, when I sleep, and hear the wind howl, I dream of dollars flying in the sky…”

    You’ve got some sense, Wayne, of where we should be looking to get abundant energy, but I submit that energy won’t be harvested by dangling (perhaps heavy) tethered machines in a region of unstable, albeit abundant air flow.

    If, for a moment, you would consider using a vortex, instead of tethers, to connect the surface with upper level winds (these would perform a function similar to the water stream in a “lab aspirator”), your dreams of $$$ (and who hasn’t had them?) could be, IMO, more readily realized.

    In other, less windy regions lacking kinetic energy, there is still in the air, abundant CAPE (residual solar), existing either naturally (day, evening, summer), or through augmentation by transfer to air from waste heat sources, to produce a virtually inexhaustible supply of electrical energy.

  15. 215
    Tad Boyd says:

    #20 (Australian drought/.8 degree C rise)

    “Given the drought that already afflicts Australia, the crumbling of the sea ice in the Arctic, and the increasing storm damage after only 0.8°C of warming so far, a target of 2°C seems almost cavalier.”

    I’ve found many stories about the drought in Australia but haven’t been able to find an authoritative piece showing how the 0.8 degrees Celsius rise is linked to the drought in Australia as David has indicated. (showing the temp rise has changed this or that wind pattern and/or water flow around Australia, etc, etc) As I mentioned in post #20, I’m trying to sort through the hype and come to RC to help me do that. I asked David for some pointers to info but understand that answering blog questions is likely not his primary concern.

    Having just seen an emotional WWF commercial showing polar bears standing on pieces of ice, and indicating that these polar bears are in peril, I went searching for more information. I found stories about 4 polar bears that drowned in a storm and stories about 2 that were killed by scientists studying them when the scientists tranquilized the bears and the bears made their way back into the water and drowned. Other than that, all I could find was that some polar bears were struggling because of land use issues.

    I know polar bears have nothing to do with the topic but wanted to emphasize what I pointed out in post #20 that common members of the public, me, are indeed being fed half truths if not all out lies concerning global warming; I don’t think from the scientists themselves but I’ll put up WWF as an organization that is attempting to make us believe that those polar bears in the commercial were in imminent danger when they were probably just hanging out on some pieces of ice.

    It would be great to get direction from an official member of RC but there are many who seem knowledgeable blogging here, so if anyone can point me to substantive information showing clearly how the .8 degree Celsius change has caused the Australian drought, I would appreciate it much. I think that RC was set up to give the public real climate change information, helping us to separate reality from hype and I appreciate your efforts in that endeavor.


  16. 216

    #214 Jerry, The tether idea is fantastic, I hope they resolve the engineering problems, it is a step upwards in the right direction :)… There is always winds up there, even over the less windy regions.

  17. 217
    Martin Vermeer says:

    Martin V., it might be just a nit, but something is amiss in your explanation (203): 70km is way above the tropopause and even higher than the stratosphere.

    Yes. An (imaginary) satellite looking down. Sees eveything coming out of troposphere and statosphere on its way to space, precisely what the questioner (Rob) wanted to know.

  18. 218
    Doug Bostrom says:

    Tad Boyd 11 Jul 2009 at 12:08 pm

    Tad, some links. One superficially amusing common thread many articles is, the bears will likely turn to us as a food source. Funny on the face of it but presumably we’ll then engage in some ugly interactions, with the bears lacking the essential edge provided by high velocity rifles.

  19. 219
    Jacob Mack says:

    LOL Bart… I did not say nothing has changed, but it is not all from AGW and it is certainly not a global catastrophe either; no way near yet.

  20. 220
    Martin Vermeer says:

    Re #210, on a historical note, already space pioneer Hermann Oberth proposed wind turbines suspended from giant kites in the upper atmosphere…

  21. 221
    Rick Brown says:

    Re: Tad Boyd # 215

    Since you managed to weave polar bears into your question about Australia, perhaps you should put a little more effort into your search for information about their status (hint: they’re in more trouble than you suggest). You might start with Andy Revkin’s post on dotearth today:

  22. 222
    James says:

    Edward says (10 Jul 2009 at 1:16 pm):

    “In the meantime, China and India are interested in improving living conditions and the standard of living for their people by making cheap energy available.”

    That deserves a bit of thought. Are they in fact interested in improving living conditions? (I see no evidence of this, and much that suggests that living conditions have gotten worse.) Or are they instead interested in increasing their national GNPs, as a means of increasing the power & prestige of the leaders, with the effects on the ordinary people being a distant afterthought?

  23. 223
    Mark says:

    ” Really?? I didn’t know I have not invented something? ”

    No, you invented nothing.

    And then argued it.

    And now you think that this is something?

    [edit-lets keep this civil]

  24. 224
    Dean says:


    “so if anyone can point me to substantive information showing clearly how the .8 degree Celsius change has caused the Australian drought, I would appreciate it much.”

    Tad – There is a post on RC about the situation in Australia that you can search for that goes into some detail. We can never know for sure what causes an individual heat wave or drought. But when something happens that we expect global warming to cause and/or exacerbate, then there is a growing likelihood that climate change is playing a role. Whether you consider this “clear” enough is up to you. This is just something that we’re not going to have absolute proof on until it is too late to do anything about it.

  25. 225
    Jerry Toman says:

    Actually, Wayne I said I had doubts about tethers.

    What I suggested was to tap into greater wind speeds at higher levels by creating a “vortex tunnel” (wormhole, stargate…) in which buoyant air (natural or made-made) is sucked upward with greater speed and energy than it would be in the “no wind” case.

    I made the connection, because some months ago, don’t remember where, I read that strong “upper level winds” can actually, in some cases, intensify a thunderstorm, by increasing the strength of the updrafts within the cell. Can anyone verify this?

    Anyway, some suggestions on how the vortex could be created are given at

  26. 226
    Greg Simpson says:


    I see substantial effort by China to reduce pollution. China is closing many of their dirtiest coal power plants, and they are building much clean nuclear and wind generation. They are still building many new coal plants, of course, but the new one produce less pollution, especially locally.

  27. 227
    Mark says:

    [edit-lets keep this civil]

    Tell Wayne that!

    [moderator: Wayne, goes for both of you. Play nice!]

  28. 228
    Mark says:

    James says: “That deserves a bit of thought. Are they in fact interested in improving living conditions? (I see no evidence of this…”

    But the people in power want better lives for themselves.

    And, unless “trickle down” is complete bunkum, this better life will trickle down.

    They also have a much lower standard of living. It’s a populace that is fat, rich and happy that are the least problem to people in power: it’s ALWAYS the poor who have nothing to lose in revoultion that are the problem for those in power. Those who have no cake have nothing to lose in their life.

  29. 229
    Doug Bostrom says:

    Greg Simpson 11 Jul 2009 at 1:52 pm

    China is also taking some serious steps on the consumption side:

    “Experts project that by 2010 the number of solar water heaters installed in China will equal the thermal equivalent of the electrical capacity of 40 large nuclear power plants.”

    Happily, there is -some- equivalent policy work being done in the U.S:

    Here in Washington state, architects, the building industry association and a loose coalition of assorted cavemen are staunchly opposing the introduction of solar hot water requirements into building codes.

  30. 230
    Ron Crouch says:

    Tad you may want to read this by Neville Nicholls at the BOM in Australia.

    It’s from 2004 and refers to the 2002 drought, but the conclusion still applies in 2009.

  31. 231

    I did a page on Pielke Sr. I did my best to respect the body of his contributions while separating the context of his work v. opinions in the realm of the AGW debate.

    My goal is to treat the separation fairly and point out what looks like rather obvious errors in his opinion.

    As always, if anyone has relevant comments please inform me through

    I will correct relevant errors for the page with a bias towards relevance and substance of the argument.

    Trying to move the debate away from the ‘bleating edge’ remains a good universal target.

    2C = 3.6F

    This is going to get interesting.

  32. 232
    Jerry Toman says:

    On a related issue–the temperature in Almeria, Spain (southeast corner), which has the world’s greatest concentration of greenhouses, with reflective roofs (seen from space), the temperature is said to have dropped 0.3 C over the past few decades, while in the rest of Spain, it has risen 0.6 C.

    While superficially this is in the right direction, it has come at a cost–depleting ground water. It would seem that, at some point they’re going to have to consider the technology that can be found at

    Instead of relying on trade winds (weak), they could use a solar tower, or preferably, an “AVE” to draw air through the system, humidifying it first. Concentrated brine would either be sent back to the sea or to evaporation ponds.

  33. 233

    Thanks Moderator, I agree, [edit–I said lets play nice!] I am interested in bringing out the true potential in us all. And focus on solutions rather than bickering… Edit at will when I deviate…

  34. 234
    Tad Boyd says:

    #218 Doug

    Thank you for the links. I couldn’t get to the first one for some reason but the other two did have good information as to why we should be concerned about the well being of the polar bears.

    I moved my family into a neighborhood in a rural area, in the forest and we often have coyotes and other predators roam through. I’m far from being an Urban dweller type and love interacting with nature, but as you suggested, if push comes to shove (and I hope it never comes to this) I do have a rifle and I’m glad the animals can’t shoot back. (I appreciate the coyotes, rabbits are cute but we’d be overrun without them. The occasional cougar tracks make me nervous at times).

    #221 Rick

    Thank you also Rick. I checked out Andy Revkin’s post. I have found articles at that level of information but tried clicking on some of the links to get deeper. I’m sure you are right, that more effort would certainly yield deeper information. I wasn’t actually trying to weave polar bears into my question but rather using that ad as an example of how in news and advertising for donations, we the public, are getting hype, making it difficult to determine what is real and what is hype. The NASA article Doug pointed to was the most useful I think because it actually talked about how polar bear fat content at a certain time of year gives an indication of their well being.



    Searching RC for Australian drought I did find an article about the brush fires. Thank you for that but the rest of your reply really answered my question concerning our ability to link current events to global warming. In the end “Is it clear enough for me?” is something I continue to struggle with. I thought that there may have been some very reliable computer model (or something) that showed cause and effect with sufficient vigor to make it “clear enough” for me, for the assertion that the Australian drought was brought on by global warming. I’m a software developer and I’ve worked with statistical models (not creating them, just coding them as specified by the actual statisticians). I worked in the financials industry 90 – 96 , then in supply chain from 98 – 01, now I’m in the clinical trials industry (but not coding anything to do with statistical models); so, I find it interesting that we can use such tools to make linkages like are reported for climate. I know that some climate modeling software is available for public consumption but haven’t put forth the effort to dig into what is actually there and make it run.

    Thank you all for replying,


  35. 235
    Tad Boyd says:

    #230 Ron (Australian drought)

    Thanks Ron. That article pointed out that warmer weather makes a drought worse than it would have been with cooler weather because it increases evaporation. Makes perfect sense. The article was really helpful to helping me with my original question by referencing Australian droughts all the way back to 1902. Concerning my search for links to Global warming causing the Australian drought, this article seams to show that drought in Australia is a regular occurrence. A more relevant question then may have to do with severity and frequency in regards to global warming.


  36. 236
    Ron Crouch says:

    (#235) Tad

    “A more relevant question then may have to do with severity and frequency in regards to global warming.”

    That’s only an educated guess on anyone’s part Tad, and based largely on observations to date, but then that applies to any unknown within science. One can only guess based upon the evidence so far that things will only get more exaggerated and exacerbated in a warmer world. That applies not only to the Australian drought, but to all aspects of climate change, whether it be loss of sea ice, loss of glaciers and ice caps, acidification of the oceans, desertification, mass migrations due to sea level rise, and so on. Things will simply change due to a domino effect, or, knock-on effect if you prefer, and that does not bode well for the economic upheaval that will ensue as a result thereof. Add in such factors as energy demands vs energy supply, shortcomings in potable water, a population that is projected to hit 9 billion from the present 6.5 billion by 2050, regional (and possibly global) conflicts over resources. Res ipsa loquitur. The bigger picture tells the whole story, not just climate change.

    But then this is not really a forum for discussing all of mankind’s ills. Only one aspect of them. What most fail to comprehend is the interrelationship between all of the issues.

  37. 237
    David Horton says:

    #235 Tad as you say, droughts have a long history in Australia. The overall weather patterns in Australia are a function of its latitudinal position and of oscillations in the water temperatures in both the Pacific and Indian Oceans. El Nino brings droughts to eastern and southern Australia (La NIna brings floods). Under normal conditions southern Australia gets winter rainfall as a result of fronts coming in from the southern ocean and crossing the continent. Northern Australia is in the tropics and gets rain as part of the monsoonal systems. Eastern Australia can also get addition rain from onshore winds from the Pacific as a result of either the southern systems or tropical lows heading south. South eastern Australia (southern Queensland, NSW, Victoria, Tasmania) could get rain from several different sources, had most of the major rivers, and has good deep soils, and so is a major agricultural region, supplying wheat and wool and meat etc to the world.

    The problem with global warming is that it seems to be changing these long established patterns. The southern fronts are being pushed further south, the tropical systems are not reaching as far south, and overall the continent is warming so that evaporation is increasing. As a result major rivers are drying, and droughts are lasting longer and being more severe. My gut feeling (sitting in the middle of the NSW agricultural regions) is that agriculture in southern Australia is not going to survive in any significant way (although there are individual regions where some activities will remain viable). There is already talk of farmers switching enterprises. Irrigation (which currently produces large quantities of fruit and vegetables and even rice) is dying out and water licenses being bought back by government. It is already so serious that even that arch sceptic, former prime minister Howard, sent one of his Senator friends north to see whether it was going to be possible to switch agriculture production to northern Australia (the answer is probably no because of nature of soils and weather patterns and tropical diseases etc), an astonishing move (quietly done) by a man representing conservative parties that see the 200 years of agriculture in southern Australia as a fundamental part of Australia’s character.

    So this is serious business, this climate change. If agriculture is greatly reduced in Australia there are countries that will have to look elsewhere for food. And which other agricultural countries are going to see similar changes?

    So plenty of room for a variable climate.

  38. 238
    David B. Benson says:

    Bill Woolverton (201) — While almost all of LIS was gone by 6000 BP, we have “Final disappearance of ice sheet remnants … occurred around 5000 BP.” from
    concerning Ungava Pennisula.

    Unfortunately I can’t find my original reference, but it is just possible that the reference was to mainland ice which reformed (in what is now mainland Nunuvik) during LIA.

    As I have time I’ll keep digging.

  39. 239
    David Horton says:

    Sorry, I meant to add that there is also a debate about whether rising sea temperatures will add to the severity of future El Nino events. So a warmer drier continent with more severe “droughts” (relatively) more often.

  40. 240
    David B. Benson says:

    However, Mount Caubvick, Labrador, still has icefields. See the photo and map:
    So in some sense the very last remnants of LIS on the mainland are still there.

  41. 241
    GlenFergus says:

    Drought in Australia:

    The 2007 CSIRO Technical Report contains a discussion of attribution for the current series of droughts. Yes, “Recent Australian droughts (1994, 2002-03 and 2006-07) have not become drier than droughts that occurred earlier in the 20th century. However, the recent droughts have been accompanied by higher temperatures (refs).” Also has an extensive discussion of projections.


  42. 242
    David Horton says:

    #237 The phrase “So plenty of room for a variable climate”, inexplicably sitting at the end of my post and puzzling all who see it, was actually meant to appear near the end of my first paragraph. My apologies.

  43. 243
    Jim Bouldin says:

    Tad (215), there have been a couple papers come out in the last year that place the Australian drought in the context of natural variation and global climate change:

    Murphy and Timbal, 2008. A review of recent climate variability and climate change in southeastern Australia. Intl. J. Climatology 28:859-

    Abstract: Southeastern Australia (SEA) has suffered from 10 years of low rainfall from 1997 to 2006. A protracted dry spell of this severity has been recorded once before during the 20th century, but current drought conditions are exacerbated by increasing temperatures. Impacts of this dry decade are wide-ranging, so a major research effort is being directed to better understand the region’s recent climate, its variability and climate change. This review summarizes the conditions of these 10 years and the main mechanisms that affect the climate. Most of the rainfall decline (61%) has occurred in autumn (March-May). Daily maximum temperatures are rising, as are minimum temperatures, except for cooler nights in autumn in the southwest of SEA closely related to lower rainfall. A similar rainfall decline occurred in the southwest of western Australia around 1970 that has many common features with the SEA decline. SEA rainfall is produced by mid-latitude storms and fronts, interactions with the tropics through continental-scale cloudbands and cut-off lows. El Niño-Southern Oscillation impacts on SEA rainfall, as does the Indian Ocean, but neither has a direct influence in autumn. Trends have been found in both hemispheric (the southern annular mode) and local (sub-tropical ridge) circulation features that may have played a role in reducing the number and impact of mid-latitude systems around SEA, and thus reducing rainfall. The role of many of these mechanisms needs to be clarified, but there is likely to be an influence of enhanced greenhouse gas concentrations on SEA climate, at least on temperature.

    Ummenhoffer et al, 2009. What causes southeast Australia’s worst droughts? GRL 36: L04706, doi:10.1029/2008GL036801.


    We have demonstrated that Indian Ocean variability, more than ENSO, is the key driver of the major droughts over the past 120 years in the region of southeastern Australia examined in this study. In particular during virtually all of Australia’s iconic droughts, including the Federation Drought (1895–1902), the World War II drought (1937–1945), and the present “Big Dry” (post-1995), the IOD [Indian Ocean Dipole] has remained persistently ‘positive’ or ‘neutral’. During the negative phase of the IOD, unusually wet conditions dominate across southern regions of Australia, due to an interaction between the tropics and the temperate zone that increases regional moisture advection. The conspicuous lack of the “negative” phase of the IOD during the major droughts thus deprives Southeast Australia of its normal rainfall quota. Future work will use climate model output to test the robustness of our main findings. Despite the prominent role of the Indian Ocean in driving southeastern droughts, the severity of the “Big Dry” is still exceptional; this appears to be linked to recent large increases in air temperature.

    IOD events may be predictable out to several months in advance [Luo et al., 2008]. Exploitation of this predictability could therefore lead to significant improvements in water planning and agricultural management in a drought-stricken region. This heightens the need for improved and sustained Indian Ocean observations. Recent non-uniform warming trends in the Indian Ocean [Ihara et al., 2008] raise the possibility that the characteristics of positive and negative IOD events might be changing. Modifications to the frequency and decadal cycles in the IOD could result in major impacts for Indian Ocean rim nations.

  44. 244
    Jim Bouldin says:

    Correction: Ummenhofer et al.; one f not two.

  45. 245
    Eli Rabett says:

    #217, one of the interesting things you can do with the web MODTRAN is move your sensor up and down in the atmosphere, as well as pointing it to the surface or up into space. It is a delightful learning tool.

  46. 246
    Patrick 027 says:

    Re 243 Jim Bouldin – that is very interesting.

    It raises an issue in my mind – the Asian Brown Cloud. Of course, without any additional understanding, it’s concievable that recent changes are actually opposite what the ABC would do, requiring some additional causes (internal variability, AGW, ozone depletion, …) (PS I really don’t know much about the IOD). But more generally, something I’ve wondered is: while in the global annual average, aerosols could be said to partly cancel (net effect) the warming from anthropogenic greenhouse forcing, the circulatory, latitudinal, regional, seasonal, diurnal, and internal variability changes would be some combination of reduced changes from reduced AGW + some other changes related to aerosol forcing. How would that look on climate model output graphics? – I haven’t really found it.

    Tad – global warming is generally expected (so far as I know) to result in poleward shifts in the midlatitude storm tracks, which will cause poleward expansion of subtropical arid regions – although with some regional variations, of course. However, ozone depletion in the Southern Hemisphere may also have a qualitatively similar effect (I don’t know offhand the magnitude relative to the AGW effect). There is some natural variability in the latitudinal position of the midlatitude storm tracks.

    Re 188:
    clarification of 196:
    “There is some added complexity in that downward radiation from the stratosphere will increase at wavelengths where CO2 is not saturated, but what is especially important is that the net upward radiation at the tropopause level decreases with increasing CO2 ”

    I got mixed up and made it sound as if the increase in downward radiation subtracted from the effect of decreased upward radiation, but the opposite is of course true – both effects contribute to a decrease in the net upward radiation at the tropopause level.

  47. 247
    Patrick 027 says:

    ” – I haven’t really found it.”

    Except that GHG forcing + cooling aerosol forcing results in less precipitation globally in general than reduced GHG forcing that produces the same global average temperature, as found in “Climate Change Methadone” elsewhere at RC.

  48. 248

    195. Jerry Gardner:
    1. Small cabins don’t qualify.
    2. Anything attached to the grid doesn’t qualify.
    3. Anything with a generator doesn’t qualify.
    4. Anything in Hawaii doesn’t qualify because people in Hawaii need neither heat nor air conditioning. If I were in Hawaii, I would need air conditioning, but I am not you. California doesn’t qualify because the climate is too nice there also.

    That disqualifies all of your entries. I was talking ONLY about a house like most Americans have with American energy use habits completely disconnected from the grid and without any supplements from any other source of energy. Put the house in a reasonable climate like Illinois or New York or Alaska. My highest energy bills happen in August.

    NOW provide ALL of the energy for the house with solar cells and storage batteries only. No cheating by adopting an energy conserving lifestyle or a heat pump. It has to be like most American houses. One brownout in 10 years and you loose.

  49. 249
    Chris Dudley says:

    Burgy (#209),

    Your source seems to be giving numbers for primary resource consumption as they appear to scale with the left side of this graph:

    The numbers seem OK if you include biomass with wind and solar.

    One should be cautious though. Nuclear power is not very efficient while hydro power is. The amount of primary energy consumed in nuclear power is more than is delivered as electricity. Thus the comparison is a little skewed towards nuclear power.

    New nuclear power is about the most expensive form of new power generation, more than wind, gas, or solar. so that your source’s crystal ball only works if nuclear power is forced on us.

  50. 250

    128 Philip Machanick

    Thorium isn’t in use yet for the same reasons coal hasn’t been replaced by nuclear yet: KING COAL is a $100 Billion per year industry in the US alone. In other words: politics.
    Thorium is attractive because there is more than twice as much thorium as there is uranium.