This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense Fund.
An article in this week’s Nature predicts that Europe and North America will cool slightly over the next decade. No, this doesn’t mean that global warming has stopped.
The new paper describes a climate model that makes short-term (decadal) predictions based on ocean dynamics. The decade-long cooling is just a temporary offset to warming from human activity. After it passes, temperatures will begin climbing again. By 2030, the model forecasts the same global temperatures as the IPCC.
16 Comments
Hi folks,
There’s been a lot of interest in this story, so I’ll take a little space here to add more detail.
First of all, from a scientific perspective, the most important aspect of this study is not the prediction per se, but rather its description of a climate model that does a good job capturing internal climate variation. As the authors note in their last sentence, “useful decadal predictions may be in reach”. This is an exciting frontier in climate modeling, as I described in my post “Predicting Short-Term Change”. (Incidentally, the model I described in that post also predicted a short reprieve from warming, followed by a steep rise in temperatures.)
But on to the prediction itself: What does “cooling” mean? For Western Europe and North America, the model predicts that surface temperatures will “cool towards 1994-2004 levels” (emphasis mine). It’s not a steep drop, but a tiny respite from long-term warming. Globally, temperatures remain essentially steady until about 2010. The next decade (2010-2020) is predicted to be warmer than anything we’ve seen in the instrumental record. Not only that, the rate of warming, which can have substantial ecological effects, is predicted to be extremely high in coming decades.
Bottom line: now two separate state-of-the-art models have predicted that we’re going to see a lot of warming in coming decades, despite tiny offsets from internal climate variability in the next year or two.
Climate Progress has even more about this study, including the paper’s graph of global temperatures.
Lisa,
The quoted statement, “surface temperatures will cool towards 1994-2004 levels” is nonsensical because temperatures are ALREADY below those levels. See: http://wattsupwiththat.files.wordpress.com/2008/04/hadcrut_mar08.png .
That said, the validity of the climate models is critically important issue and central to the AGW debate. Can we expect them to make an accurate forecast of the weather 20 years into the future?
You conclude: “Bottom line: now two separate state-of-the-art models have predicted that we’re going to see a lot of warming in coming decades, despite tiny offsets from internal climate variability in the next year or two.” Underlying your comment is the assumption the models have credibility when used for this type of forecasting. The evidence suggests otherwise.
The climate models are simply tools for research and have zero demonstrated ability to accurately forecast the weather weeks, months, or years (let alone decades) into the future. The ink is hardly dry on the recent IPCC report yet the atmosphere is already behaving quite differently than forecast.
MIT’s Kerry Emanuel summed up the situation rather well a couple of weeks ago: “The models are telling us something quite different from what nature seems to be telling us.” (from NY Times’ “dot earth”)
Now that the earth’s atmosphere and oceans are cooling, in spite of recent model predictions to the contrary, at what point would these demonstrable inconsistencies amount to a falsification of AGW model predictions?
Dr. Roger Pielke, Jr. said yesterday: “For a while now I’ve been asking climate scientists to tell me what could be observed in the real world that would be inconsistent with forecasts (predictions, projections, etc.) of climate models, such as those that are used by the IPCC. I’ve long suspected that the answer is “nothing” and the public silence from those in the outspoken climate science community would seem to back this up. Now a paper in Nature today suggests that cooling in the world’s oceans, according to Richard Woods who comments on the paper in the same issue, “temporarily offset the longer-term warming trend from increasing levels of greenhouse gases in the atmosphere”, and this would not be inconsistent with predictions of longer-term global warming.
I am sure that this is an excellent paper by world class scientists. But when I look at the broader significance of the paper what I see is that there is in fact nothing that can be observed in the climate system that would be inconsistent with climate model predictions. If global cooling over the next few decades is consistent with model predictions, then so too is pretty much anything and everything under the sun.
This means that from a practical standpoint climate models are of no practical use beyond providing some intellectual authority in the promotional battle over global climate policy. I am sure that some model somewhere has foretold how the next 20 years will evolve (and please ask me in 20 years which one!). And if none get it right, it won’t mean that any were actually wrong. If there is no future over the next few decades that models rule out, then anything is possible. And of course, no one needed a model to know that.
Don’t get me wrong, models are great tools for probing our understanding and exploring various assumptions about how nature works. But scientists think they know with certainty that carbon dioxide leads to bad outcomes for the planet, so future modeling will only refine that fact. I am focused on the predictive value of the models, which appears to be nil. So models have plenty of scientific value left in them, but tools to use in planning or policy? Forget about it.”
See: http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/001413global_cooling_consi.html#comments with some enlightening ‘debate’ in the Comments section.
Considering the recent divergences of the actual climate as compared to the forecast climate, the statement “we’re going to see a lot of warming in coming decades” seems highly speculative.
Mike
The following discusses the causes of the warming/cooling periods. It appears that CO2 is of minimal effect.
http://www.climatescience.org.nz/images/PDFs/alexwjr.2-3.5.08.pdf
Hi Mike,
I think a lot of your confusion has to do with different time scales. This is very common but absolutely key in any discussion about climate. For example, these climate models are not meant to predict weather.
Over the long term (many decades to centuries), in scenarios with no reductions in GHG emissions, climate models show warming. Scientists have only recently begun to tackle the challenge of capturing shorter term variation. And even “shorter term” is still pretty long – in the latest paper, the authors use ten-year averages to compare their model to observations. In the HadCRUT graph you cite, temperatures over the last four years – even with a couple of relatively cold months – are still at or above 1994-2004 levels.
The fact that the latest model does pretty well in hindcasts is encouraging. Successful hindcasts build scientists’ confidence in any model’s ability to simulate climate. Of course it’s not perfect (for example, it underestimated global warming from the late 1990s onward), but it’s generally better than the older models.
Every bit of improvement – indicative of greater understanding – is exciting and that’s why it’s great to see papers like this.
“The following discusses the causes of the warming/cooling periods. It appears that CO2 is of minimal effect.
http://www.climatescience.org.nz/images/PDFs/alexwjr.2-3.5.08.pdf”
It would appear that way…..if you decided to take this hydrologist’s somewhat random comments that attempt to show that he’s been right about everything all along, and is now right where all the peer-reviewed science is wrong about the relative effects of sunspots and CO2.
It would appear that way if you weren’t really interested in data, evidence, cause and effect and good science. It would appear that way if you decided to ignore the terrabytes of data, the satellites, the tens of thousands of reviewed articles, the retreating glaciers, the models, the basic greenhouse properties of CO2, the fact that the air you just breathed in has 1/3 more CO2 in it than any break taken by Lincoln.
If you are remotely interested in the truth, however, it does not appear that way. Even to a casual observer. And that may be why all the governments in the world, all the major scientific bodies, all the scientists, and the vast majority of the world;s population now accept as shown:
1) CO2 is a greenhouse gas
2) Mankind has increased concentrations by 30%
3) This amount is predicted to cause global warming
4) We are seeing this warming already
5) This is a major problem
What is not so easy is deciding what to do because it uses a highly uncertain near-science called ‘economics’ which can only dream of achieving the predictability and acceptability of climate science. However economists, though they generally disagree amongst themselves about both the future and the past, and have never made collective predictions of any great worth, DO agree that the cost of dealing with the results of climate change are much less than the cost of reducing it.
We know that the ‘costs’ can be very low, and even negative for the first movers. We know that reduced global warming, reduced pollution, and massive savings in energy are all available to us using existing technology. We know that the smart players are already there or going there, and that as a country all we need is a clarity about the legislative future for everyone else to join the greatest industrial, economic, cultural, and environmental development of the last 50 or the next 50 years.
Thanks to EDF and others I think we’ll get it.
Quentin
Hi Lisa,
No confusion here.
With regard to the ten year lagged average for the HadCRUT data, you are correct. However, those averages lag behind the recent cooling. The fact is that current temperatures are – significantly — below what was forecast (see below).
You are correct that the climate models are “not meant to predict weather” but that is exactly what they do. As previously stated, the meteorological “guts” of climate models are the same as the day-to-day meteorological forecast models. The theory is, assuming both a meteorologically correct and unbiased model, that over a long period of time the ‘weather’ forecast errors will average out leaving a picture of future climate.
The problem is: Are the models unbiased? The answer is “probably not” but we do not know for sure because they have not been sufficiently verified in “climate forecast” mode.
“Pastcasting,” (i.e., running a climate model forward from some time in the past to see if it accurately captured what occurred) while useful in constructing a model, is not close to sufficient to validate a climate model. Models must be robustly tested in “forecast” mode (i.e., make a five year forecast and compare it to what actually occurred). There has been almost no forecast validation.
We know (see some of Pielke Jr.’s and Lucia’s recent work) many of the IPCC scenarios have “overforecast” the observed warming (i.e., forecast more warming than actually occurred) the last decade. We know that recent atmospheric events have differed rather significantly from what more recent models scenarios have forecast. Here is Lucia’s graph, which I urge our readers to view: rankexploits.com/musings/wp-content/uploads/2008/03/gmt_testnoextra.jpg . Of course, this is not conclusive. However, it should give one pause before putting too much faith in the predictive ability of the climate models.
This may account for some of the large difference in perception of the state of climate sciences between meteorologists and others. We are intimately familiar with the limitations of the models and their predictive ability.
Therefore, I stand by my opinion that the statement “We’re going to see a lot of warming in coming decades” is highly speculative.”
Mike
This paper sure is producing some interesting discussions! Scientists over at RealClimate have proposed a friendly bet with the authors of the latest study, to see whether their short-term prediction pans out.
Whatever the outcome, everyone agrees that the study is exciting because modeling short-term variation is the new frontier in climate science.
i am also still interested in how you respond to the fact that the latest IPCC report discounted the urban heat island effect as having a minimal impact on temperature readings used to identify regional and global trends. having said this then why is it when the weatherman (or woman) on the evening news gives the standard “lows in the lower 50’s in the city and lower 40’s in the outlying suburbs”, isn’t that significant to poke holes in the accuracy of our temperature recording stations? since most are located in cities, built up suburbs or airports…all at the center of urban heat islands…
here is scientific data for my statement… check out this link…a significant number of reporting stations in the U.S are not within NOAA standards….we can’t even trust the data. http://www.surfacestations.org/ note this guy is not pushing an agenda but wants to find the truth about station temperature readings which is at the heart of your GW arguments.
And, temperatures have fallen further since I posted the graph in my comment above. Here is the RSS data through May, 2008:
http://wattsupwiththat.files.wordpress.com/2008/06/uah_may_08.png
The “blank sun” continues:
http://sohowww.nascom.nasa.gov/data/realtime/mdi_igr/512/
fred1,
Scientists are aware of and take great pains to deal with the complexities of temperature records. Check out RealClimate’s post about urban heat islands.
Different groups process the data in different ways, but in the end, all of these independent methods show warming. And urban heat islands can’t explain why the oceans are warming or why the sparsely populated Arctic is warming faster than the global average.
mikes,
Please see our post about why short term cooling does not disprove long-term global warming. Also, scientists can explain the short-term cooling: a strong La Nina and the Sun reaching a natural minimum. And yet 2007 was still one of the warmest years on record.
Lisa,
Did you read what your link says about the solar situation?
It says, “If the sun were to remain “stuck” in its present minimum for several decades, as has been suggested (e.g., Independent story) in analogy to the solar Maunder Minimum of the seventeenth century, that negative forcing would be balanced by a 5-year increase of GHGs. Thus, in the current era of rapidly increasing GHGs, such solar variations cannot have a substantial impact on long-term global warming trends. Furthermore, recent sighting of the first sunspot of reversed polarity (reported Jan. 4 by, e.g., SpaceWeather.com and NOAA) signifies that the ~ 4-year period of increasing solar irradiance is about to get underway.”
Oops. That Jan. 4 reverse polarity sunspot did NOT signal the end of Cycle 23 and “The Blank Sun” continues (see: http://sohowww.nascom.nasa.gov/data/realtime/mdi_igr/512/ ), contrary to NASA’s predictions. Falling temperatures (see link already posted) also continue with no sign of solar Cycle 24 at present.
The oceans are NOT warming. The ARGOS probes have proven that. Even Dr. Josh Willis of NASA (a warmer) concedes the oceans are cooling, although he says it is “not significant.”
The urban heat island problem is real but the worse effect is the change in instrumentation used by the NWS and foreign governments starting in the 1990’s. Go to: http://surfacestations.org/ and page down to see two nearby stations with radically different temperature histories due to a flawed instrument and poor siting. Because these instruments were installed in the 1990’s when the warming (supposedly) accelerated, it is hard to know how much of the warming is real (I believe some actual warming occurred) and how much is defective measurement caused by defective instrumentation.
It may be fine to contend that the current cooling is “not significant” or “won’t last.” Neither of us knows. But to keep arguing the earth is warming, at present, is just silly and its certainly bad science.
By the way, I looked at your link regarding arctic temperatures. Did you notice the current RSS world temperature anomaly of -0.083°C is far below the 95% error bars for 2001 (the year the graph ends), all four trend lines, and extrapolation?
What would it take to change your mind about the current trend in earth’s temperatures?
Mike
Mikes,
Be sure you define your word “trend” carefully. As you and/or others have noted this link for global temperature anomaly measurements:
http://wattsupwiththat.files.wordpress.com/2008/06/uah_may_08.png
I see the temperature “trend” from January 2007 to May 2008 (16 months) indicating a drop of 0.774 C. If that is your “trend,” then in May 2020 (160 months from 1/07), the temperature anomaly would be -7.74 C! Trying to use some-term trends to make long-term statements is a poor methodology in science/math. If I used the same analogy from month 220 to month 232 (1998 peak), the delta would be +0.95 C, i.e. +9.5 C per decade! As you can tell, using a short-term “trend” from a chart that looks like a seismograph print-out is unrealistic.
As Lisa mentioned, while it is easy to identify small issues, i.e. heat island, faulty equipment, other blips in the data, if the overall long-term trend is less ambiguous, I’d tend to look at that data. A 12-18 month string might be useful to predict the next 1-3 months, while a 10-20 year data set can help to justify longer projections, etc. In this case, a 5-year or 10-year moving average as the Nature article used helps to dampen the “noise” in their 40 year data set (1960s – 2000, then predictions).
Drew
Drew,
Thanks for your comment. But, it is not just atmospheric temperatures that are falling. The oceans have cooled each of the last four years and sea levels have been falling — significantly — the last two.
The temperature trend I was speaking of is from 1997 to 2008 (I am omitting the 1998 El Nino spike).
It is interesting to note world temperatures were cooler in June, 2008 (when Hansen made his 20th anniversary appearance before Congress) than they were in June, 1988.
Atmospheric CO2 concentrations are higher now than in recent human history. If the IPCC’s case is correct, temperatures would have been soaring over the past decade. In fact, the opposite is true.
The switch to the cold phase of the PDO and the “blank sun” (which has continued since my post above, just click on the link) seem to be better correlated to atmospheric temperatures and the earth’s heat content than CO2.
This is why I strongly recommend holding off on legislation and regulation at this time. Congress hates to admit mistakes. Otherwise, we may have to live with bad policy for decades.
Mike