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2009 temperatures by Jim Hansen

Filed under: — group @ 17 January 2010 - (Français)

This is Hansen et al’s end of year summary for 2009 (with a couple of minor edits). Update: A final version of this text is available here.

If It’s That Warm, How Come It’s So Damned Cold? 

 
by James Hansen, Reto Ruedy, Makiko Sato, and Ken Lo
 
The past year, 2009, tied as the second warmest year in the 130 years of global instrumental temperature records, in the surface temperature analysis of the NASA Goddard Institute for Space Studies (GISS). The Southern Hemisphere set a record as the warmest year for that half of the world. Global mean temperature, as shown in Figure 1a, was 0.57°C (1.0°F) warmer than climatology (the 1951-1980 base period). Southern Hemisphere mean temperature, as shown in Figure 1b, was 0.49°C (0.88°F) warmer than in the period of climatology.


Figure 1. (a) GISS analysis of global surface temperature change. Green vertical bar is estimated 95 percent confidence range (two standard deviations) for annual temperature change. (b) Hemispheric temperature change in GISS analysis. (Base period is 1951-1980. This base period is fixed consistently in GISS temperature analysis papers – see References. Base period 1961-1990 is used for comparison with published HadCRUT analyses in Figures 3 and 4.)

The global record warm year, in the period of near-global instrumental measurements (since the late 1800s), was 2005. Sometimes it is asserted that 1998 was the warmest year. The origin of this confusion is discussed below. There is a high degree of interannual (year‐to‐year) and decadal variability in both global and hemispheric temperatures. Underlying this variability, however, is a long‐term warming trend that has become strong and persistent over the past three decades. The long‐term trends are more apparent when temperature is averaged over several years. The 60‐month (5‐year) and 132 month (11‐year) running mean temperatures are shown in Figure 2 for the globe and the hemispheres. The 5‐year mean is sufficient to reduce the effect of the El Niño – La Niña cycles of tropical climate. The 11‐year mean minimizes the effect of solar variability – the brightness of the sun varies by a measurable amount over the sunspot cycle, which is typically of 10‐12 year duration.


Figure 2. 60‐month (5‐year) and 132 month (11‐year) running mean temperatures in the GISS analysis of (a) global and (b) hemispheric surface temperature change. (Base period is 1951‐1980.)

There is a contradiction between the observed continued warming trend and popular perceptions about climate trends. Frequent statements include: “There has been global cooling over the past decade.” “Global warming stopped in 1998.” “1998 is the warmest year in the record.” Such statements have been repeated so often that most of the public seems to accept them as being true. However, based on our data, such statements are not correct. The origin of this contradiction probably lies in part in differences between the GISS and HadCRUT temperature analyses (HadCRUT is the joint Hadley Centre/University of East Anglia Climatic Research Unit temperature analysis). Indeed, HadCRUT finds 1998 to be the warmest year in their record. In addition, popular belief that the world is cooling is reinforced by cold weather anomalies in the United States in the summer of 2009 and cold anomalies in much of the Northern Hemisphere in December 2009. Here we first show the main reason for the difference between the GISS and HadCRUT analyses. Then we examine the 2009 regional temperature anomalies in the context of global temperatures.


Figure 3. Temperature anomalies in 1998 (left column) and 2005 (right column). Top row is GISS analysis, middle row is HadCRUT analysis, and bottom row is the GISS analysis masked to the same area and resolution as the HadCRUT analysis. [Base period is 1961‐1990.]

Figure 3 shows maps of GISS and HadCRUT 1998 and 2005 temperature anomalies relative to base period 1961‐1990 (the base period used by HadCRUT). The temperature anomalies are at a 5 degree‐by‐5 degree resolution for the GISS data to match that in the HadCRUT analysis. In the lower two maps we display the GISS data masked to the same area and resolution as the HadCRUT analysis. The “masked” GISS data let us quantify the extent to which the difference between the GISS and HadCRUT analyses is due to the data interpolation and extrapolation that occurs in the GISS analysis. The GISS analysis assigns a temperature anomaly to many gridboxes that do not contain measurement data, specifically all gridboxes located within 1200 km of one or more stations that do have defined temperature anomalies.

The rationale for this aspect of the GISS analysis is based on the fact that temperature anomaly patterns tend to be large scale. For example, if it is an unusually cold winter in New York, it is probably unusually cold in Philadelphia too. This fact suggests that it may be better to assign a temperature anomaly based on the nearest stations for a gridbox that contains no observing stations, rather than excluding that gridbox from the global analysis. Tests of this assumption are described in our papers referenced below.


Figure 4. Global surface temperature anomalies relative to 1961‐1990 base period for three cases: HadCRUT, GISS, and GISS anomalies limited to the HadCRUT area. [To obtain consistent time series for the HadCRUT and GISS global means, monthly results were averaged over regions with defined temperature anomalies within four latitude zones (90N‐25N, 25N‐Equator, Equator‐25S, 25S‐90S); the global average then weights these zones by the true area of the full zones, and the annual means are based on those monthly global means.]

Figure 4 shows time series of global temperature for the GISS and HadCRUT analyses, as well as for the GISS analysis masked to the HadCRUT data region. This figure reveals that the differences that have developed between the GISS and HadCRUT global temperatures during the past few decades are due primarily to the extension of the GISS analysis into regions that are excluded from the HadCRUT analysis. The GISS and HadCRUT results are similar during this period, when the analyses are limited to exactly the same area. The GISS analysis also finds 1998 as the warmest year, if analysis is limited to the masked area. The question then becomes: how valid are the extrapolations and interpolation in the GISS analysis? If the temperature anomaly scale is adjusted such that the global mean anomaly is zero, the patterns of warm and cool regions have realistic‐looking meteorological patterns, providing qualitative support for the data extensions. However, we would like a quantitative measure of the uncertainty in our estimate of the global temperature anomaly caused by the fact that the spatial distribution of measurements is incomplete. One way to estimate that uncertainty, or possible error, can be obtained via use of the complete time series of global surface temperature data generated by a global climate model that has been demonstrated to have realistic spatial and temporal variability of surface temperature. We can sample this data set at only the locations where measurement stations exist, use this sub‐sample of data to estimate global temperature change with the GISS analysis method, and compare the result with the “perfect” knowledge of global temperature provided by the data at all gridpoints.

1880‐1900 1900‐1950 1960‐2008
Meteorological Stations 0.2 0.15 0.08
Land‐Ocean Index 0.08 0.05 0.05

Table 1. Two‐sigma error estimate versus period for meteorological stations and land‐ocean index.

Table 1 shows the derived error due to incomplete coverage of stations. As expected, the error was larger at early dates when station coverage was poorer. Also the error is much larger when data are available only from meteorological stations, without ship or satellite measurements for ocean areas. In recent decades the 2‐sigma uncertainty (95 percent confidence of being within that range, ~2‐3 percent chance of being outside that range in a specific direction) has been about 0.05°C. The incomplete coverage of stations is the primary cause of uncertainty in comparing nearby years, for which the effect of more systematic errors such as urban warming is small.

Additional sources of error become important when comparing temperature anomalies separated by longer periods. The most well‐known source of long‐term error is “urban warming”, human‐made local warming caused by energy use and alterations of the natural environment. Various other errors affecting the estimates of long‐term temperature change are described comprehensively in a large number of papers by Tom Karl and his associates at the NOAA National Climate Data Center. The GISS temperature analysis corrects for urban effects by adjusting the long‐term trends of urban stations to be consistent with the trends at nearby rural stations, with urban locations identified either by population or satellite‐observed night lights. In a paper in preparation we demonstrate that the population and night light approaches yield similar results on global average. The additional error caused by factors other than incomplete spatial coverage is estimated to be of the order of 0.1°C on time scales of several decades to a century, this estimate necessarily being partly subjective. The estimated total uncertainty in global mean temperature anomaly with land and ocean data included thus is similar to the error estimate in the first line of Table 1, i.e., the error due to limited spatial coverage when only meteorological stations are included.

Now let’s consider whether we can specify a rank among the recent global annual temperatures, i.e., which year is warmest, second warmest, etc. Figure 1a shows 2009 as the second warmest year, but it is so close to 1998, 2002, 2003, 2006, and 2007 that we must declare these years as being in a virtual tie as the second warmest year. The maximum difference among these in the GISS analysis is ~0.03°C (2009 being the warmest among those years and 2006 the coolest). This range is approximately equal to our 1‐sigma uncertainty of ~0.025°C, which is the reason for stating that these five years are tied for second warmest.

The year 2005 is 0.061°C warmer than 1998 in our analysis. So how certain are we that 2005 was warmer than 1998? Given the standard deviation of ~0.025°C for the estimated error, we can estimate the probability that 1998 was warmer than 2005 as follows. The chance that 1998 is 0.025°C warmer than our estimated value is about (1 – 0.68)/2 = 0.16. The chance that 2005 is 0.025°C cooler than our estimate is also 0.16. The probability of both of these is ~0.03 (3 percent). Integrating over the tail of the distribution and accounting for the 2005‐1998 temperature difference being 0.61°C alters the estimate in opposite directions. For the moment let us just say that the chance that 1998 is warmer than 2005, given our temperature analysis, is at most no more than about 10 percent. Therefore, we can say with a reasonable degree of confidence that 2005 is the warmest year in the period of instrumental data.


Figure 5. (a) global map of December 2009 anomaly, (b) global map of Jun‐Jul‐Aug 2009 anomaly. #4 and #2 indicate that December 2009 and JJA are the 4th and 2nd warmest globally for those periods.

What about the claim that the Earth’s surface has been cooling over the past decade? That issue can be addressed with a far higher degree of confidence, because the error due to incomplete spatial coverage of measurements becomes much smaller when averaged over several years. The 2‐sigma error in the 5‐year running‐mean temperature anomaly shown in Figure 2, is about a factor of two smaller than the annual mean uncertainty, thus 0.02‐0.03°C. Given that the change of 5‐year‐mean global temperature anomaly is about 0.2°C over the past decade, we can conclude that the world has become warmer over the past decade, not cooler.

Why are some people so readily convinced of a false conclusion, that the world is really experiencing a cooling trend? That gullibility probably has a lot to do with regional short‐term temperature fluctuations, which are an order of magnitude larger than global average annual anomalies. Yet many lay people do understand the distinction between regional short‐term anomalies and global trends. For example, here is comment posted by “frogbandit” at 8:38p.m. 1/6/2010 on City Bright blog:

“I wonder about the people who use cold weather to say that the globe is cooling. It forgets that global warming has a global component and that its a trend, not an everyday thing. I hear people down in the lower 48 say its really cold this winter. That ain’t true so far up here in Alaska. Bethel, Alaska, had a brown Christmas. Here in Anchorage, the temperature today is 31[ºF]. I can’t say based on the fact Anchorage and Bethel are warm so far this winter that we have global warming. That would be a really dumb argument to think my weather pattern is being experienced even in the rest of the United States, much less globally.”

What frogbandit is saying is illustrated by the global map of temperature anomalies in December 2009 (Figure 5a). There were strong negative temperature anomalies at middle latitudes in the Northern Hemisphere, as great as ‐8°C in Siberia, averaged over the month. But the temperature anomaly in the Arctic was as great as +7°C. The cold December perhaps reaffirmed an impression gained by Americans from the unusually cool 2009 summer. There was a large region in the United States and Canada in June‐July‐August with a negative temperature anomaly greater than 1°C, the largest negative anomaly on the planet.


Figure 6. Arctic Oscillation (AO) Index. Positive values of the AO index indicate high low pressure in the polar region and thus a tendency for strong zonal winds that minimize cold air outbreaks to middle latitudes. Blue dots are monthly means and the red curve is the 60‐month (5‐year) running mean.

How do these large regional temperature anomalies stack up against an expectation of, and the reality of, global warming? How unusual are these regional negative fluctuations? Do they have any relationship to global warming? Do they contradict global warming?

It is obvious that in December 2009 there was an unusual exchange of polar and mid‐latitude air in the Northern Hemisphere. Arctic air rushed into both North America and Eurasia, and, of course, it was replaced in the polar region by air from middle latitudes. The degree to which Arctic air penetrates into middle latitudes is related to the Arctic Oscillation (AO) index, which is defined by surface atmospheric pressure patterns and is plotted in Figure 6. When the AO index is positive surface pressure is high low in the polar region. This helps the middle latitude jet stream to blow strongly and consistently from west to east, thus keeping cold Arctic air locked in the polar region. When the AO index is negative there tends to be low high pressure in the polar region, weaker zonal winds, and greater movement of frigid polar air into middle latitudes.

Figure 6 shows that December 2009 was the most extreme negative Arctic Oscillation since the 1970s. Although there were ten cases between the early 1960s and mid 1980s with an AO index more extreme than ‐2.5, there were no such extreme cases since then until last month. It is no wonder that the public has become accustomed to the absence of extreme blasts of cold air.


Figure 7. Temperature anomaly from GISS analysis and AO index from NOAA National Weather Service Climate Prediction Center. United States mean refers to the 48 contiguous states.

Figure 7 shows the AO index with greater temporal resolution for two 5‐year periods. It is obvious that there is a high degree of correlation of the AO index with temperature in the United States, with any possible lag between index and temperature anomaly less than the monthly temporal resolution. Large negative anomalies, when they occur, are usually in a winter month. Note that the January 1977 temperature anomaly, mainly located in the Eastern United States, was considerably stronger than the December 2009 anomaly. [There is nothing magic about a 31 day window that coincides with a calendar month, and it could be misleading. It may be more informative to look at a 30‐day running mean and at the Dec‐Jan‐Feb means for the AO index and temperature anomalies.]

The AO index is not so much an explanation for climate anomaly patterns as it is a simple statement of the situation. However, John (Mike) Wallace and colleagues have been able to use the AO description to aid consideration of how the patterns may change as greenhouse gases increase. A number of papers, by Wallace, David Thompson, and others, as well as by Drew Shindell and others at GISS, have pointed out that increasing carbon dioxide causes the stratosphere to cool, in turn causing on average a stronger jet stream and thus a tendency for a more positive Arctic Oscillation. Overall, Figure 6 shows a tendency in the expected sense. The AO is not the only factor that might alter the frequency of Arctic cold air outbreaks. For example, what is the effect of reduced Arctic sea ice on weather patterns? There is not enough empirical evidence since the rapid ice melt of 2007. We conclude only that December 2009 was a highly anomalous month and that its unusual AO can be described as the “cause” of the extreme December weather.

We do not find a basis for expecting frequent repeat occurrences. On the contrary. Figure 6 does show that month‐to‐month fluctuations of the AO are much larger than its long term trend. But temperature change can be caused by greenhouse gases and global warming independent of Arctic Oscillation dynamical effects.


Figure 8. Global maps 4 season temperature anomalies for ~2009. (Note that Dec is December 2008. Base period is 1951‐1980.)


Figure 9. Global maps 4 season temperature anomaly trends for period 1950‐2009.

So let’s look at recent regional temperature anomalies and temperature trends. Figure 8 shows seasonal temperature anomalies for the past year and Figure 9 shows seasonal temperature change since 1950 based on local linear trends. The temperature scales are identical in Figures 8 and 9. The outstanding characteristic in comparing these two figures is that the magnitude of the 60 year change is similar to the magnitude of seasonal anomalies. What this is telling us is that the climate dice are already strongly loaded. The perceptive person who has been around since the 1950s should be able to notice that seasonal mean temperatures are usually greater than they were in the 1950s, although there are still occasional cold seasons.

The magnitude of monthly temperature anomalies is typically 1.5 to 2 times greater than the magnitude of seasonal anomalies. So it is not yet quite so easy to see global warming if one’s figure of merit is monthly mean temperature. And, of course, daily weather fluctuations are much larger than the impact of the global warming trend. The bottom line is this: there is no global cooling trend. For the time being, until humanity brings its greenhouse gas emissions under control, we can expect each decade to be warmer than the preceding one. Weather fluctuations certainly exceed local temperature changes over the past half century. But the perceptive person should be able to see that climate is warming on decadal time scales.

This information needs to be combined with the conclusion that global warming of 1‐2°C has enormous implications for humanity. But that discussion is beyond the scope of this note.


References:
Hansen, J.E., and S. Lebedeff, 1987: Global trends of measured surface air temperature. J. Geophys. Res., 92, 13345‐13372.
Hansen, J., R. Ruedy, J. Glascoe, and Mki. Sato, 1999: GISS analysis of surface temperature change. J. Geophys. Res., 104, 30997‐31022.
Hansen, J.E., R. Ruedy, Mki. Sato, M. Imhoff, W. Lawrence, D. Easterling, T. Peterson, and T. Karl, 2001: A closer look at United States and global surface temperature change. J. Geophys. Res., 106, 23947‐23963.
Hansen, J., Mki. Sato, R. Ruedy, K. Lo, D.W. Lea, and M. Medina‐Elizade, 2006: Global temperature change. Proc. Natl. Acad. Sci., 103, 14288‐14293.


932 Responses to “2009 temperatures by Jim Hansen”

  1. 101

    Don Shor,

    You need 30 years to tell a climate trend. 10 years tells you nothing at all.

    Temperature has risen strongly over the past 30 years.

  2. 102
    Completely Fed Up says:

    Jim Bullis: “Right you are about my point, except I am trying to point out that the energy going into the oceans, ”

    But the heat capacity is likewise huge, therefore the temperature change is nowhere near as big as you imply with your huge *energy* figure.

    Given you’ve already used the weird global figure over 20 years accumulation to big up your numbers, I would have hoped you would be more careful.

  3. 103
    Completely Fed Up says:

    “67
    Don Shor says:
    17 January 2010 at 7:49 PM

    Aerosols.”

    Language…

    :-)

    “I really don’t understand why juvenile name-calling of this sort continues to be allowed on thjs blog.”

    Shall we go back over Don’s posting history and see how much name-calling is here from him?

    And please, what is juvenile about it?

    “What caused the cooling in the 50’s then???” is a zombie argument. And the zombies say it again and again, in different venues, never hearing the answer.

    I don’t understand why zombies are allowed on here.

  4. 104
    Marco says:

    @evagrius:
    Done here:
    http://www.guardian.co.uk/environment/2010/jan/11/climate-change-global-warming-mojib-latif
    David Rose himself managed to get one comment in on Deepclimate’s criticism of his piece, showing his blatant disregard to take on the big flaws in his nonsense-filled piece:
    http://deepclimate.org/2010/01/11/mojib-latif-slams-daily-mail/

    But then again, the Daily Mail isn’t to be taken serious on much related to science. It jumped on the MMR-autism bandwagon, and recently had this howler:
    http://www.dailymail.co.uk/sciencetech/article-1240746/Prehistoric-sat-nav-set-ancestors-Britain.html
    (for a few comments on the laughable matter in that research, see:
    http://www.badscience.net/2010/01/voices-of-the-ancients/)

  5. 105
    Completely Fed Up says:

    Matt: “and we have only been measuring temperature (reliably) for a hundred years, then there are simply too few data points to work with – so you have to get into the job of prediction.”

    The second part doesn’t follow from the first.

    Prediction doesn’t come because we don’t have enough elapsed time and doesn’t solve the problem either.

    What you can do is be more clever with your analysis.

    But then you’re back into the realm of the speci alist and you and I are left going “well, they seem to know what they’re doing, and there’s a lot of different ways people get the same answer, so I guess that’s solid”.

  6. 106
    Completely Fed Up says:

    “The magnitudes of the seasonal anomalies are on the same order as the monthly anomalies; you average the monthlies to get the seasonal.”

    3 measurements randomly differed from the mean with a standard deviation of s.

    1 measurement is likely within s of the mean.

    3 measurements are likely to average to s/sqrt(3) of the mean.

    s ~ 1.7 times bigger than s/sqrt(3).

  7. 107
    Completely Fed Up says:

    Doug: “I -think- Jim’s point is that there’s a lot of additional energy trapped on the planet that’s hidden from us air breathers. He’s not calling the essay into question.”

    I think he’s obfuscating the difference between heat and temperature to say that the simple graph is far too simple.

    Then, when the more complex graph is made, it will be denounced as too complex for the ordinary person.

    So it will be simplified…

    …brains…

  8. 108
    Ray Ladbury says:

    Nigel Jones,
    A lot of people think that the satellites are making a simple measurement that equates directly to temperature. Not so! Extracting lower troposphere temperature from the instrument readings–as exemplified by the fact that both MSU and RSS have repeatedly had to revise their temperature series.

    What is more, the satellite readings tend to be more distorted by El Nino and La Nina, which makes them less reliable in these periods.

  9. 109
    Brian Carter says:

    No 32, Matthew L; No, people don’t need a memory for temperatures. There are obvious indicators. Looking out of my window, across the road is a palm tree that is nearly 5 metres high, when I was a child in the 1940’s and 50’s we used to marvel at palm trees growing outdoors at south coast seaside resorts, the only other places we saw them was in the palm house at the local botanical gardens. Perhaps palm trees have become hardier, but it is more likely that the weather has grown milder. In my garden I have a three metre + high flowering speciman of Rhododendron Falconeri var. Eximium. Read textbooks about rhodies that were published 30 years ago and you would have the impression that this rhodie could not possibly be grown successfully in the English Midlands, but there it is! When I was a child my father took up his stock of dahlias at the first frost in autumn, usually in september, and stored the tubers in the cellar…and even so got the occasional losses due to cold. Now they continue flowering well into the autumn and can be left in the ground if covered with a good mulch.

    There are a multitude of similar indicators, just talk to somebody who has held an allotment garden for a number of decades and he/she will tell you about earlier planting seasons and later first frosts. If you are not into gardening and don’t appreciate the force of what I am saying, check with the wildlife enthusiasts instead: how about for the last few years swallows attempting to overwinter in Cornwall, and various warblers deciding not to go south for the winter? Our blast of Siberian air in December will undoubtably be a setback for them, but the trend is clear.

    No, we don’t need temperature statistics to know in our water that things are changing. We need the science to tell us how and why, and to predict trends, but not to tell us what we can see for ourselves.

  10. 110
    JasonW says:

    #79: Try this article (from Climateprogress – Joe Romm is often pretty heavy-handed in his wording, but the facts speak for themselves): http://climateprogress.org/2010/01/14/science-dr-mojib-latif-global-warming-cooling/

  11. 111
    Steve Brown says:

    evagris @ 79:

    Deep Climate has done a good refutation of that Daily Mail article:

    http://deepclimate.org/2010/01/11/mojib-latif-slams-daily-mail/#more-1409

  12. 112
    Gilles says:

    Please,could you please help me and indicate the proportion of areas on the Earth on which GW will worsen significantly the life condition? (and incidentally why it would worsen exactly?)

    and please also could you give an estimate of the average distance I have to travel to reach the closest region where the conditions won’t worsen significantly ?

    I need to plan my future next decades, say.

    If it can help : I live in France. The local annual average fluctuates typically by one degree, from a year to another. The difference between north and south of France is also a few degrees (around 4°C I guess). I am mainly interested by the local temperatures, but neither by the average temperature of the Earth, nor that of the solar system, or the entire Universe (which anyway stands very close to 2.7 K if I understand correctly).

  13. 113
    Richard says:

    Why does NOAA/NCDC’s analysis (released 15 Jan) say 2009 was the fifth warmest year in the history of temp records, whereas GISS says it’s the second? Could somebody explain the difference in analysis – or point me to a link where it’s been done? Which is supposed to be the better analysis of the data?

    [Response: As discussed above the differences between the top 5 or so years are all very small, and so minor differences in analysis will make a difference in the ranking, but not in anything substantive. – gavin]

  14. 114
    Completely Fed Up says:

    Doug: “If I remember correctly you were originally wondering less about the absence of oceans in the model, more about what level of detail is involved?”

    The original start of Jim’s querying of the ocean was in relation to a graph that shows the energy balance (which was in answer to a question about how much GG do, etc).

    Though I’m trying to pick up where, but Jim’s cross posted his queries from another thread to make sure it gets maximum traction and loses its original intent.

  15. 115
    Jason says:

    “There is a contradiction between the observed continued warming trend and popular perceptions about climate trends. Frequent statements include: “There has been global cooling over the past decade.” “Global warming stopped in 1998.” “1998 is the warmest year in the record.” Such statements have been repeated so often that most of the public seems to accept them as being true. However, based on our data, such statements are not correct.”

    [edit – comments that deliberately confuse statements about the global anomaly and the US anomaly are pointless]

  16. 116
    Chris Dudley says:

    Gavin in #64,

    I think you need to switch low for high and high for low in the second paragraph after fig. 6 as well. The AO index seems to be backwards somewhat in the way magnitudes are in astronomy. It also seems to be in units of sigma. Do you know the formula?

    [Response: Thanks. Those have been fixed too. The AO is defined as the principle component of the sea level pressure first EOF and you can define that either in an unitless way by leaving the units in the EOF pattern, or vice versa. – gavin]

  17. 117
    greg kai says:

    This is true that gardeners have been able to grow less and less hardy variety in Europe and US those last years. However, those last 2 winters, many of those “exotics” growing north of their recomended regions have died, except if the gardeners have been very carefull protecting them effectively. Many species are more sensitive to the lowest temperature than the average, and a few mild winters can gives false impressions, makeing gardeners overenthusiastic and real sad when a hard winter hit after their precious tree has thrived for a few years. I know it, here in Belgium i am not sure my bamboo will make it through this winter (last one was too hard), and I know some people crying over dead olive trees (they have been really optimistic)…

    So I think that southern species extending their habitat to the north is a good indicator of a warming climate, but only after a few years or dozen of years, you need time to catch low probability hard winters that really limit a species expansion. In this respect it is not really better than 10 years temperature averages…

  18. 118
    Richard Palm says:

    When scientists talk about this or that year being the second warmest on record, etc., doesn’t that play into the hands of the denialists by conditioning the public to think that individual years are significant in defining the trend?

    Seems to me that Levenson’s analysis of statistical significance on his Web page is much more valid, and therefore a stronger argument.

    [Response: Agreed. But people will rank things anyway – the best you can do is stress the ‘statistical tie’ issues, but that is frequently ignored. – gavin]

  19. 119
    KSW says:

    I hope that RC can have a column on the AO soon. Perhaps something like “Shindell 2001 for the climate hobbiest” (BTW your link to http://tao.atmos.washington.edu/ao/ is dead).

    [Response: Try this instead: http://www.atmos.colostate.edu/ao/ – gavin]

    I never heard the term Artic Oscillation until Hansen’s 2009 summary; but live in Calgary Canada and it has been obvious to me for a long time that some thing like this was responsible for our winter weather. During the winter we have many hours of darkness and are well aware that within a mere 15 degrees of latitude there are those that are living though 6 full sunless weeks.

    All that dark makes things cold and it is virtually invariable that if we experience an unusually warm winter we will also get what we refer to as a “crappy summer”.

    So what is know about the causes of changes in the AO index?

    Also what effect on artic sea ice is expected from the changes in AO? and vise versa?

  20. 120
    Ray Ladbury says:

    Gilles,
    When the climate caca hits the fan, you will not be the only one seeking better conditions. I hope you like it crowded.
    Regional projections are not as reliable as global projections.

    Here’s a start. Be aware that different regions may be affected by different threats. The coastal regions may have more moderate climate in general, but will be more prone to inundation. Inland areas are safer from inundation, but will have highly variable precipitation and probably more extreme temperatures:

    http://www.realclimate.org/index.php/archives/…/regional-climate-projections/

  21. 121
    Ray Ladbury says:

    Al Fresco says, “I still think, however, that it would be beneficial to the cause to have a more comprehensive response to the Smith/D’Aleo article.”

    Why? Either they know their points are bogus, in which case they are disingenuous, or they do not know, in which case they are ignoramuses.

  22. 122
    John says:

    There was an article in New Scientist early last year about a PI for a thermokarst (permafrost) study, Katey Walter from the University of Alaska. She has links from her NSF project site to just the sort of descriptions that earlier posters here have suggested GW needs to communicate to a wider range of the public.

    I couldn’t find a reference to it in RC index so I’ll list a couple here.

    New scientist article:
    http://www.newscientist.com/article/mg20127011.500-arctic-meltdown-is-a-threat-to-humanity.htm

    Katey’s UA cv:
    http://www.newscientist.com/article/mg20127011.500-arctic-meltdown-is-a-threat-to-humanity.htm

    utube videos in Alaska and Siberia:
    http://www.alaska.edu/uaf/cem/ine/walter/videopage.xml

    Don’t get “turned off” because it’s methane and oil company supported. She’s not at all a denier.

  23. 123
    Completely Fed Up says:

    greg: “So I think that southern species extending their habitat to the north is a good indicator of a warming climate, but only after a few years or dozen of years”

    We’ve had the dozens of years.

    The effect has been noticeable in extent for biologicals to change behaviour for the last 30 years, near enough.

  24. 124
    NJ Tom says:

    I think I get it now. Most of the warming is occuring in places where almost nobody lives. How clever!

  25. 125
    Paul C says:

    I am not an expert, but I do understand that perception is everything. As I remember, the earth is not flat. The nice colorful and flat temperature anomoly charts show very large areas of deep red warm areas in the northern latitudes. If this were an accurate flatten chart of the globe, those areas would not be so large, and the perception would not be the same.

  26. 126
    Hank Roberts says:

    > 94, Jeannick, asking about the hydrologic cycle

    This might be a start; there’s so much written, I’d guess you may be using the wrong words in searches.
    Try keywords you find in this article, following footnotes and citing papers for example
    Andrew Dessler and Sun Wong on ‘Estimates of the Water Vapor Climate Feedback during El Niño–Southern Oscillation‘ in Journal of Climate.
    (link found and stolen from http://delayedoscillator.wordpress.com/ )

    If you’re looking for global scale hydrologic changes rather than shorter term ones, try for example
    http://jgs.geoscienceworld.org/cgi/content/abstract/164/6/1093
    “Although the Earth’s environment is constantly changing, there have been a few unusual episodes Each event was associated with a major carbon isotope excursion, significant levels of biotic extinctions, severe global warming, an enhanced hydrological cycle, and evidence for widespread seawater anoxia. Both carbon isotope excursions can be subdivided into distinct stages with broadly similar characteristics and durations; based on a detailed comparison, the Palaeocene–Eocene thermal maximum may have been an incipient Oceanic Anoxic Event. The geochemical and biotic changes during these two events are most readily explained by the abrupt, large-scale dissociation of methane hydrate that followed a period of more gradual environmental change linked to the emplacement of a large igneous province. Carbon release rates at those times were of the same order of magnitude as the current anthropogenic release rate of carbon to the atmosphere, indicating that ancient events such as these may usefully serve as analogues for present-day environmental change….”

  27. 127
    Completely Fed Up says:

    “Most of the warming is occuring in places where almost nobody lives.”

    Really? Nobody lives in central north america?

    See:

    http://www.youtube.com/watch?v=l0JsdSDa_bM

    And check out the weather report for 15th Jan…

  28. 128
    Jeff Boarman says:

    Emailed to my congressmen with a request for an investigation:
    http://www.judicialwatch.org/news/2010/jan/judicial-watch-uncovers-nasa-documents-related-global-warming-controversy

    [Response: Curious. What do you think should be investigated? – gavin]

  29. 129
    Completely Fed Up says:

    “The nice colorful and flat temperature anomoly charts show very large areas of deep red warm areas in the northern latitudes.”

    They also show lots more blue in mid-high lattitudes and less blue in equatorial and most of the southern hemisphere.

    The equatorial changes would, by your admission, be less well represented than the blue still.

  30. 130
    Hank Roberts says:

    > NJTom, “warming is occurring in places where almost nobody lives”

    You’re probably using at a distorted map, if you think nobody lives where it’s warm this month.
    This one, maybe? http://strangemaps.files.wordpress.com/2007/02/newyorker2.JPG

    How clever is that?

  31. 131
    Ray Ladbury says:

    NJ Tom says “I think I get it now. Most of the warming is occuring in places where almost nobody lives. How clever!”

    Yeah, like the Indian Subcontinent, China, Africa… Hardly anybody there. Did you even bother to read the friggin’ charts?!

  32. 132
    Completely Fed Up says:

    [Response: Curious. What do you think should be investigated? – gavin]

    Hopefully GW Bush’s administration canning scientists who even allowed some hint of veracity to the idea that fossil fuels were affecting the climate significantly…

  33. 133
    sam says:

    Gavin, how do you guys respond to this:

    http://www.express.co.uk/posts/view/152422/The-new-climate-change-scandal

    [edit]

    [Response: Unlike the pope, no-one has ever claimed that the IPCC is infallible. There are indeed some errors that will have crept in (shock!). However, this particular issue is not ‘a key finding’. It is not mentioned in the WG1 (the climate science section), nor in the Synthesis report, nor in any of the summaries for policy makers. It is possible that the full WG2 got less attention from physical climate scientists than it should have, and in any case, un-peer reviewed statements shouldn’t have been cited. However, mountain glaciers – in the Himalayas or elsewhere – are still retreating dramatically. I trust you are as hard on all your other sources of information. – gavin]

  34. 134
    Deech56 says:

    RE evagrius

    Could someone give a response, ( in the media), to this?

    It would be nice to see a refutation intelligible to laypeople, ( such as myself).

    http://www.dailymail.co.uk/sciencetech/article-1242011/DAVID-ROSE-The-mini-ice-age-starts-here.html

    You might try this for a start. Also, the subject of this post.

    http://www.youtube.com/watch?v=yDTUuckNHgc

  35. 135
    Jeffrey Davis says:

    I think this year’s “cold” is just a case of people being spoiled by the unusual warm winters we’ve had. The coldest it got here was 6 degrees and it got down to around 10F for around 10 days or so. Cold, but that was normal for most winters just 20 years ago. In 86 or 87, for example, we went to our family’s Christmas Eve gathering with temp readings of -10F and wind chills of around -45F.

    The forecast for the rest of January looks like it will hard pressed to even dip below freezing. Not freezing in January is the “new normal” but because it’s cold in January people don’t associate that with anomalous increases in temps.

    I saw the maps of the anomalous temperatures during the cold spell. It looked like the Earth was wearing an ice pack for a toothache. The Arctic was much warmer than normal, but the cold air was right there where the decision makers live. If I believed in Gaia, I’d say she was laughing at us.

  36. 136
    Chris Dudley says:

    Gavin in #116,

    Thanks. So it is derived from pressure measurements only. Cool.

  37. 137
    Chris Dudley says:

    Gavin in #116,

    One other thing. I’m thinking of low pressure at the pole holding winds in (and more organized) in the same manner that the eye of a hurricane keeps drawing winds that would depart the storm back towards it. Is that a picture that has some use?

    [Response: Actually yes. If you plot the contours of the of particular temperatures at the 500mb height level such that you circle the polar regions, you’ll see that for AO +ve periods, the contours all line up very neatly in a roughly circular pattern. In AO -ve periods, the contours are all over the place. So one way of thinking of this is organised vs. disorganised circulation. – gavin]

  38. 138
    Lynn Vincentnathan says:

    RE #76 & the Himalayan glacier melt, I also spotted (and thought odd) the use of WWF information in the IPCC, and decided not to include that 2035 claim in my recent paper on FOOD RIGHTS AND CLIMATE CHANGE, although I did use a couple of non-peer-reviewed studies by such types environmental and humanitarian organizations for other issues. I’ve found such “overview” studies, in general, to be based on mainly peer-reviewed studies themselves and to be of high quality, and they are valuable in making meta-assessments and conjectures, bringing together a lot of scientific piece-work.

    RE the glaciers I instead wrote: “With glaciers melting at alarming rates and many possibly disappearing by 2100, there could be massive rain events and floods during winter, with no water for irrigation in summers,” and this was based on more recent 2008 peer-reviewed studies of Himalayan glaciers.

    This Himalayan glacier fiasco sort of misses the point of the many many climate change threats to India and other countries in the region, including but not limited to glacier retreat. And it misses the whole injustice of rich nations (per capita) being the biggest cause, both now and historically, of global warming (and that includes emissions involved in whatever products people of rich countries buy from poor countries, as in “Made in China”), while poor countries are facing the most severe threats from global warming.

    Whoever is writing articles criticizing the IPCC, should point out these larger issues, at least in passing, or they themselves should be very severely criticized.

    Global warming isn’t just glacier melt — and it looks like they eventually will melt, if not all by 2035. It isn’t just sea rise. It isn’t just more intense storms and cyclones. It isn’t just more heat deaths. It isn’t just decreasing crop yields (even in the northern latitudes after mid-century, despite carbon fertilization and longer growing seasons). It isn’t just increased floods. It isn’t just increased droughts and wild fires. It isn’t just increasing disease spread. It’s all of these and much much more. And global warming is only one (big) environmental problem; there are many more environmental problems.

    Picking (and dwelling) on one aspect of global warming because one scientific claim might be wrong (and using this to disprove global warming), is like saying a terminal cancer patient’s claim to having a tooth ache is false.

  39. 139
    Ray Ladbury says:

    Jeff Boarman@128

    Yawn.

    I mean really. This is so fricking sad. They file a fricking FOI, and THIS is the most they can come up with. Seriously, I don’t know whether to laugh or cry.

    Now…About the evidence…

  40. 140
    Mal Adapted says:

    I liked the last paragraph from that JudicialWatch press release:

    “This email traffic ought to be embarrassing for NASA. Given the recent Climategate scandal, NASA has an obligation to be completely transparent with its handling of temperature data. Instead of insulting those who point out their mistakes, NASA scientists should engage the public in an open, professional and honest manner,” stated Judicial Watch President Tom Fitton.

    I think insulting McIntyre is open, professional and honest 8^)!

  41. 141
    caerbannog says:

    Regarding Jeff Boarman,

    Here’s what he posted here almost two months ago: http://www.realclimate.org/?comments_popup=2036#comment-145683

    Secondly, there are rumors afoot that much more data/emails, etc. were hacked, and the hackers are waiting for an opportune time to release them.

    So, Jeff…. how have all those rumors panned out?

  42. 142
    Chris Dudley says:

    Gavin in #137,

    Thanks.

  43. 143
    sam says:

    Gavin, how do you guys respond to this:

    http://www.express.co.uk/posts/view/152422/The-new-climate-change-scandal

    [edit]

    [Response: Unlike the pope, no-one has ever claimed that the IPCC is infallible. There are indeed some errors that will have crept in (shock!). However, this particular issue is not ‘a key finding’. It is not mentioned in the WG1 (the climate science section), nor in the Synthesis report, nor in any of the summaries for policy makers. It is possible that the full WG2 got less attention from physical climate scientists than it should have, and in any case, un-peer reviewed statements shouldn’t have been cited. However, mountain glaciers – in the Himalayas or elsewhere – are still retreating dramatically. I trust you are as hard on all your other sources of information. – gavin]

    I see…. nothing to see here. Gavin, you are not talking to an idiot. There is definitely something to see here. This is (was) a central claim by UNIPCC and you know it.

    [Response: Hmmm… how am I supposed to know that something on p493 in vol 2 of a three volume report is a ‘central claim’? Generally, ‘central claims’ make it to the summaries. But maybe you have a different metric. Please enlighten us. – gavin]

    Even in your response you make unproven claims about glacier melt. (I love the AGW buzz words like “dramatically” btw) The people studying these glaciers most closely (in India) don’t have any such certitude. Only 30 glaciers are even being studied out of thousands and they are all in different states of retreat or advance. Your claims were (I’m guessing) based on the UN report which itself turns out literally to be based on a article, based on news story based on a phone interview. What other evidence do you have?

    [Response: Oh, I don’t know – maybe some of the photos? Try here, here, here, or if you prefer the technical literature try some remote sensing. Now what evidence do you have that this isn’t happening? – gavin]

  44. 144

    100 BPL

    JB: The 10×10^23 Joules that went into the ocean from 1985 to 2005 would raise the air temp by 7.46 degrees C if that energy had gone into the atmosphere instead.

    BPL: If it happened all at once, yes. If it happened at the same RATE it had gone into the ocean, most of it would have radiated away into space by now.

    JB: Nope. It did not get radiated. The 10×10^23 Joules accumulated in the oceans over the period 1985 to 2005. That is what the NOAA chart says. And they only measure down to 700 meters. And if it had been radiated, the air temperature would have gone up roughly another 7.5 degrees.

    #84 Doug Bostrom,

    My current point, starting back about a week ago, was that the NOAA chart here posted on Dec28,2009 seemed to indicate that ocean heat had accumulated faster than expected over those years especially. Simply calibrating the climate models for this unexpected, but actual, data might account for the also factual data of temperature not rising as fast as the models seem to have expected.

    If the net heat downward at the TOA was 4 W/m^2 and the heat into the oceans was 3 W/m^2, as would be consistent with an accumulation of 10×10^23Joules, you have 1 W/m^2 for warming the atmosphere over that time period. This should be about 3.3×10^23Joules into the atmosphere. This would be an atmospheric temperature increase of about 2.5 deg C by my very rough estimates. This is all just a sanity check that I got into because of the sequence of misinformation that I encountered through the sequence of my questions.

    And even before that, my point has been for about a year that the oceans seem to be getting underestimated as a counter to atmospheric warming. This does not mean that things are good, but it does suggest a different climate scenario than was being discussed a year or two ago.

    And if this point is correct, it would be better to focus the argument on the problem of global heat accumulation, which might be far worse than atmospheric temperature indicates.

    Thus the superstitious crowd has been given an anti-science club, since temperature might not play out in a way that confirms the fundamental heat imbalance problem.

  45. 145
    Radge Havers says:

    Matthew@51

    The resolution of the images should reflect the resolution of the data.

    The white isn’t hot so much as tending to bleed with large areas of yellow. This is a problem of the nature of how we perceive both aereal extent and different colors. There’s always a trade-off between logic, perception, and convention. Bottom line, you have to look at the key, read the data and adjust your intuition to it, not the other way around.

    If I have a quibble with the ramp it’s the use of purple at the low end, but it works well enough in this context.

    Paul@125

    “If this were an accurate flatten chart of the globe, those areas would not be so large, and the perception would not be the same.”

    So what projection system would you prefer?

    I suppose they could use an animated rotating globe. Is that really necessary here?

    Fed Up@129
    I think his complaint is that, in these projections, the top and bottom portions of the world maps are over-represented relative to the middle. If you look at it as each square cm on the map representing the same number of square miles on the ground, the upper and lower potions are rubber-sheeted out, which also expands the relative extents of red.

    The answer, I think, is that the map has to be read first then intuited, not the other way around.

  46. 146
    dhogaza says:

    “Most of the warming is occuring in places where almost nobody lives.”

    Really? Nobody lives in central north america?

    Or the Pacific NW? About a million and a half here in the greater Portland area, about twice as many in Seattle.

    Maybe we’re not bitching enough about the fact that it’s warmer than normal here, and that we’re not freezing our bums off.

    For example, yesterday:

    Normal Max, 46F. Yesterday’s Max, 55F.
    Normal Min, 34F. Yesterday’s Min, 46F.

    Temps were closer to, but still above, normal during the Big Freeze a week or so ago.

    So even if we pretend the US is the world, the Big Freeze was an event limited in extent.

  47. 147
    Completely Fed Up says:

    Radge: “I think his complaint is that, in these projections, the top and bottom portions of the world maps are over-represented relative to the middle”

    But the middle is the equatorial, where there’s more red dots.

    *HE* is talking about the mid-latitudes around 50N, which isn’t the middle, it’s three quarters the way up.

  48. 148
    Gilles says:

    Ray, thank you for your attention. Actually I live in the Alps, with no real risk of flood, and the temperatures are already rather extreme compared to France (often – 10 °C in winter and + 30°C, sometimes up to 40°C in summer). Actually this doesn’t prevent me to live normally like any other French guy, you know , those living near the coast have often rain but they can also go the beach when it’s sunny. And by me, I enjoy snow in winter and go hiking in summer, where the temperature decreases rather rapidly , – 1°C every 100 m. So very concretely, in the all day life, could you give me some indication of what would change in my life, or my children’s life ?

    concerning the “poor” people who will suffer the most from AGW, I understood that BAU scenarii assuming the burning of a lot of fossiles would also assume that these fossiles would be burnt by the very people who are currently poor, but would not be that poor once they burn fossiles. Specifically, I heard that A1 scenarii assume something like a multiplication by 20 or so of the GDP, and the reduction of a factor 10 of inequality, so actually the “poor” people on the earth would be on average as rich as current europeans, or may be more. And have a lot of fossile to build new houses, well heated and air-conditionned, and that they could be smart enough to built not exactly at the lowest points on the ground. But may be I misunderstood something in the SRES ?

  49. 149
    Al Fresco says:

    My reason for thinking a more comprehensive response to the Smith/D’Aleo article would be useful is based on the predictable use of that article by the deniers to summarily discount any findings based on NASA data. I am aware that this article is an anti-warming propaganda piece. My concern is not what effect it will have on the principle players on either side of the issue. It is the fence-sitting layperson (who elects the policy makers) who is trying to make some sense of all this seemingly contradictory information who I am afraid will be duped by this accusation of fraud and data manipulation.

    Most of the public has neither the time nor inclination to wade through a comments section such as this to uncover the facts. Nor do they have the scientific expertise to understand much of what is said here. That is why I think an official response (even one that the average person might not fully comprehend) that specifically addresses the points raised in the article in some detail would be of value. At least those of us trying to defend consensus opinion would then have something of substance to point to that would help put the matter into perspective.

    I think it is important to remember that, just as with the evolution/creation debate, good science suffers if the lay public is unduly influenced by the merchants of bad science.

  50. 150
    Paul C says:

    Radge@145
    Wow…calm down a notch. Looking at the flat earth plot Hansen used, it does appear at second glance that a equal-area plot was used, and if I had to guess, it looks like the Lambert cylindrical equal-area projection, but the aspect ratio is not as large as I’ve seen and therefore doesn’t look right. But since you were kind enough to ask my preference, I would be interested to see the same plot using a sinusoidal projection, preferably the classic-looking interrupted sinusoidal projection.

    [Response: It’s a plate-caree cylindrical projection. If you want to plot it differently, you can download the data from gistemp. I’m a fan of the Robinson projection myself…. – gavin]


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