An illustrated guide to the latest climate science

Here is an update of my review of the best papers on climate science in the past year.  If you want a broader overview of the literature in the past few years, focusing specifically on how unrestricted emissions of greenhouse gas emissions are projected to impact the United States, try “An introduction to global warming impacts: Hell and High Water.”

I’m adding some of the best figures from those papers, too.  For those who like their science delivered through videos, let me suggest the panel I hosted earlier this month, may I suggest Video and PPTs of “The Science of Climate Change” with Dr. Christopher Field and Dr. Michael MacCracken (which is the source of the above figure showing the decadal temperature trend, together with the annual temps).

In 2009, the scientific literature caught up with what top climate scientists have been saying privately for a few years now:

  • Many of the predicted impacts of human-caused climate change are occurring much faster than anybody expected — particularly ice melt, everywhere you look on the planet.
  • If we stay anywhere near our current emissions path, we are facing incalculable catastrophes by century’s end, including rapid sea level rise, massive wildfires, widespread Dust-Bowlification, large oceanic dead zones, and 9°F warming — much of which could be all but irreversible for centuries. And that’s not the worst-case scenario!
  • The consequences for human health and well being would be extreme.

That’s no surprise to anybody who has talked to leading climate scientists in recent years, read my book Hell and High Water (or a number of other books), or followed this blog. Still, it is a scientific reality that I don’t think more than 2 people in 100 fully grasp, so I’m going to review here the past year in climate science. I’ll focus primarily on the peer-reviewed literature, but also look at some major summary reports.

Let’s start with the basics. Heat-trapping greenhouse gases are at unprecedented levels, and the paleoclimate record suggests that even slightly higher levels are untenable:

Since we have record levels of heat-trapping gases, it’s not surprising that we also learned that this was the hottest decade in the temperature record and that the Arctic is the hottest in at least two millenia.

A Hockey Stick in Melting Ice


In two key papers, we learned that the planet is warming from those GHGs just where climate science said it would “” the oceans, which is where more than 90% of the warming was projected to end up (see “Skeptical Science explains how we know global warming is happening.“). The key findings in the second study are summed up in this figure:

Figure [2]: Time series of global mean heat storage (0-2000 m), measured in 108 Jm-2.

That study makes clear that upper ocean heat content, perhaps not surprisingly, is simply far more variable than deeper ocean heat content, and thus an imperfect indicator of the long-term warming trend.

Unexpectedly, even Antarctica appears to be warming:


This global warming is driving melting at extraordinary rates every where we look, including places nobody expected:


And given that unexpectedly fast ice melt, it’s no surprise the science now projects much higher and much faster sea level rise than just a few years ago:

We continued to learn about the dangerous positive carbon-cycle feedbacks that threaten to amplify the impacts of human-caused GHGs.

Indeed, the best evidence is that the climate is now being driven by amplifying feedbacks — see, most notably:

Using the first “fully interactive climate system model” applied to study permafrost, the researchers found that if we tried to stabilize CO2 concentrations in the air at 550 ppm, permafrost would plummet from over 4 million square miles today to 1.5 million. If concentrations hit 690 ppm, permafrost would shrink to just 800,000 square miles:


High emissions levels + positive feedbacks = climate catastrophe:

This graph shows the percentage increase in area burned by wildfires, from the present-day to the 2050s, as calculated by the model of Spracklen et al. [2009] for the May-October fire season. The model follows a scenario of moderately increasing emissions of greenhouse gas emissions and leads to average global warming of 1.6 degrees Celsius (3 degrees Fahrenheit) by 2050. Warmer temperatures can dry out underbrush, leading to more serious conflagrations in the future climate.”

And the plausible worst-case scenario is even worse than this grim “business as usual” emissions case:

This is the “plausible worst case scenario” for 2060 from the UK Met Office that occurs in 10% of model runs of high emissions with the carbon cycle feedbacks [temperature in degrees Celsius, multiple by 1.8 for Fahrenheit]:

Figure 7.

And this is not good news for human health and welfare

So the time to act is most certainly now.

I’ll end with the best piece of scientific news I wrote about, which suggests it is not too damn late to act — a NOAA-led study, “Observational constraints on recent increases in the atmospheric CH4 burden” (subs. req’d, NOAA online news story here), which found:

Measurements of atmospheric CH4 from air samples collected weekly at 46 remote surface sites show that, after a decade of near-zero growth, globally averaged atmospheric methane increased during 2007 and 2008. During 2007, CH4 increased by 8.3 ± 0.6 ppb. CH4 mole fractions averaged over polar northern latitudes and the Southern Hemisphere increased more than other zonally averaged regions. In 2008, globally averaged CH4 increased by 4.4 ± 0.6 ppb; the largest increase was in the tropics, while polar northern latitudes did not increase. Satellite and in situ CO observations suggest only a minor contribution to increased CH4 from biomass burning. The most likely drivers of the CH4 anomalies observed during 2007 and 2008 are anomalously high temperatures in the Arctic and greater than average precipitation in the tropics. Near-zero CH4 growth in the Arctic during 2008 suggests we have not yet activated strong climate feedbacks from permafrost and CH4 hydrates.


Yes, early this year I reported that NOAA found “Methane levels rose in 2008 for the second consecutive year after a 10-year lull,” but so far that most dangerous of all feedbacks “” Arctic and tundra methane releases “” does not appear to have been fatally triggered.

The anti-science crowd use smoke and mirrors to distract as many people as possible, but the rest of us need to listen to the science and keep our eyes on the prize — reversing greenhouse gas emissions trends as quickly and rapidly as possible.

Please use the comments to add links to any major studies I didn’t cover here.  I will be updating this post continuously.

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29 Responses to An illustrated guide to the latest climate science

  1. Jeff Huggins says:

    For the New and Confused

    We humans put LOTS of carbon dioxide into the atmosphere these days, via our use of coal for electricity, gasoline and other liquid hydrocarbons for fuels, deforestation (which reduces the amount of CO2 absorbed from the atmosphere), and other activities.

    The CO2 concentration in the atmosphere has been going up and up and up, consistently, for a long time now. It’s easy to measure. No question about that trend.

    For a very long time, scientists have known that CO2 (and other greenhouse gases) absorb certain wavelengths of infrared light — i.e, energy being radiated by warm and somewhat hot things, including many things on the Earth’s surface, e.g., dirt, pavement, oceanic surfaces, and so forth. This is basic science. It’s not hard to understand. It can be measured.

    When CO2 in the atmosphere absorbs that energy, it converts the energy to heat and, thus, increases the temperature of the atmosphere. In other words, that energy has to go somewhere. If other specific factors (i.e., not one’s imagination) do not completely counteract that extra heat energy by cooling things down, the temperature of the atmosphere goes up. As the temperature of the atmosphere goes up, it radiates more of the energy into space, so the whole system reaches another “steady state” (unless the CO2 concentration continues to go up even more!), but the new “steady state” is at a higher temperature than before.

    The higher the CO2 concentration in the atmosphere, the more radiated energy is absorbed by all the CO2, and the more heat is transfered into the atmosphere from that process. All else equal, the temperature of the atmosphere must increase, until the new (higher) temperature is reached where the heat trapped in this way is balanced by the extra outflow of heat that the atmosphere itself radiates into space.

    The sea absorbs some of the CO2 (turning more acidic, which is a problem in itself) and also slowly warms up too, as the atmosphere warms.

    And ice melts and other sh_t happens.

    The basic science involved in most of this has been known for a long, long time.

    The media are mucking things up.

    We all need to wake up.

    Young people, especially, should get much more active: It’s their future at stake.

    There, that covers some of the key things.

    Be Well,


  2. PeteJ says:

    Joe, it sure would be nice if you could provide citations to these seminal papers, or even links to the papers themselves. You have plenty of links to your own work, but connecting your readers to the peer reviewed literature directly would be a great service.

    [JR: I do provide the links to every single one of those papers. But it wouldn’t make any sense to do so directly in this post since 1) most of them are behind a journal firewall and 2) this post is for people looking for summaries of the science. But all you need to do if you’re interested in one of these papers is to click on the link. Then you can either read the paper or my summary. I typically also include links to news articles and related studies. But this is just an overview post.]

  3. fj2 says:

    First heard the term global “weirding” from Amory Lovins a few years back.

    In a way the Himalayan Glacier snafu highlighted by deniers might ultimately be good since the New York City Panel on Climate Change (NPCC) is taking a lot more time to publish its report originally scheduled for Jan 2010 and now pushed back to March; hopefully, to minimize any further errors.

  4. fj2 says:

    Lester R. Brown’s “A Wartime Mobilization” addresses the scale-appropriate action required by this crisis as detailed above.

  5. eidelon 8 says:


    Don’t know if you saw this one, a compendium of recent CC science, from last September:

  6. C. Vink says:

    Great overview, thanks Joe!

    For new readers of Climate Progress: please, also visit these fine sites where the endlessly recycled arguments of the global warming deniers are debunked thouroughly:

    Skeptical Science: getting skeptical about global warming skepticism

    How to Talk to a Climate Skeptic: Responses to the most common skeptical arguments on global warming

    Also see:

    Article series ‘The Island of Doubt’ on

    Consensus Matters: Don’t Believe the Climate ‘Skeptics’ (Treehugger, December 29, 2009)

    If you are impressed by ‘skeptical’ bluff like these 500 Peer-Reviewed Papers Supporting Skepticism of “Man-Made” Global Warming’ and the stuff on sites like Watts Up With That? and, please broaden your view and give some careful attention to the above mentioned material.

  7. paulm says:

    This is the most shocking graph I have come across in a while!
    You should include it also…

  8. Richard Brenne says:

    Welcome to Tom Friedman’s many readers!

    You’ve come to the right place here at Climate Progress.

    Thinking (and teaching, writing, speaking, moderating panels and filmmaking) about climate change a lot, I’ve come to the conclusion that the implications are so great that most folks’ natural mental state about this is denial.

    Only by becoming educated do we overcome this natural denial, and Climate Progress as the hub of the wheel of communication in climate change is the best single place to become educated.

    Yes Joe and many of us are advocates of action. Joe’s and the site’s honesty about that are unique. The science here is very, very sound. Joe has a PhD in physics from MIT, worked at Scripps Institution of Oceanography, Rocky Mountain Institute and in the Clinton Administration on energy – and has a great sense of humor to boot (the most uncivil and uninformed commenters)!

    If you needed the most advanced heart or brain surgery, I’m sure you’d want to go to the best doctor who got her or his knowledge from the latest science coming from the finest institutions. You wouldn’t want to listen to a dentist or veterinarian or have some wingnut wing it based on talk radio or TV, a website or blog denying all of the latest and most agreed-upon science.

    Joe constantly goes to the latest and best sources including NOAA, NASA, NCAR, etc. When the science is too conservative or out-of-date as some of the 2007 IPCC Report is, Joe tells us that. (More is being learned more quickly in climate change than any other area of science I know – but other than conservatism the IPCC is rock solid, averaging one bad mistake about every 3000 pages, or a rate thousands of times better than the average journalistic piece about climate change). He speaks truth to power in all arenas more effectively than anyone I know.

    Climate Progress is the best-organized blog of any kind I’ve ever seen, and improving all the time. Look at the quality of the comments as well. Scientists, authors and climate change experts comment regularly.

    There are a core of a dozen or two who I call “Romm’s Minions” who understand and communicate the totality of climate change about as well as anyone. You could become one of them over enough time and study – I’m guessing they’ve each read an average of about a dozen climate change books (Including Romm’s own “Hell and High Water”), 100 or so peer-reviewed climate change papers, and 1000 or so posts here, at RealClimate and Skeptical Science, the other two great climate change blogs.

    We look forward to hearing your questions now and comments when you (and the other commenters here who don’t suffer fools lightly) feel you’ve done your homework. Healthy, thoughtful skepticism is great, knee-jerk regurgitations of Wattsbeckrushdumb, not so much.

    Ask anything anytime or comment in good faith and you’ll be treated kindly and in kind – knee-jerk comments in bad faith tend to get vaporized about as quickly as one of Leif’s battleships (we welcome you to our inside jokes as well).

    And by the way, Tom, your column was as accurate and on-target as any I’ve seen in the mainstream media (in addition, of course, to the likes of McKibben, Goodell and Kolbert). Kudos and thanks – and many at NOAA, NCAR, NASA, etc are ready to do what you suggest, it’s just a little like herding (really smart) cats.

  9. Hi ~ your graph of warming over Antarctica (reposted from Jan 21) shows the strongest warming is over the continental portion of West Antarctica rather than over the Peninsula region, but I’m under the impression that it is the peninsula that has warmed the fastest. Any thoughts on reconciling this? I wonder if it is the product of the resolution of the map data, affected by sea temps around the peninsula or something. West of the peninsula SSTs have increased dramatically, while I do not believe the same is so for the area immediately east, in the Weddell Sea. Site specific, certainly the Peninsula has shown dramatic temperature increases – a reference: D. Vaughn et al., 2001. Science 293:1777-1779 (but this is dated, sorry, and I’m sure there are better references). Certainly due to the Peninsula region being Antarctica’s warmest, and closest to an average temperature near 0°C, a small amount of warming has the greatest impact on mass balance and ice loss, as is clearly being seen in ice shelves collapsing and glaciers retreating.

  10. Barry says:

    I particularly like the government’s own climate science website:

    It has a simple dashboard of measured climate changes so far.

    It also has interesting overview sections with great images and clear charts on topics such as “evidence”, “causes”, “effects”, “uncertainties” and “solutions.”

    Also here are a few quotes from scientists on why humanity should be cutting greenhouse gases rapidly to provide our kids with climate “insurance”:

    — “The climate system is an angry beast, and we are poking at it with sticks” Dr. Wallace Broecker

    — “we’ve got one planet, and we are heading it in a direction that, quite fundamentally, we don’t know what the consequences are going to be” Dr. Chris Thomas

    — “If it were only a few degrees, that would be serious, but we could adapt to it. But the danger is the warming process might be unstable and run away…It could be too late if we wait until the bad effects of warming become obvious. We need action now to reduce emission of carbon dioxide.” Dr. Stephen Hawking

    — “You’ve got a big boulder sitting there on this rolling hill. [Y]ou start rocking it, and you get a bunch of friends, and they start rocking it, and finally it starts moving. And then you realize, Maybe this wasn’t the best idea. That’s what we are doing as a society. This climate, if it starts rolling, we don’t really know where it will stop.”
    Dr. Donald Perovich,

    — “We are tampering with the earth. The earth is a twitchy system. It’s clear from the record that it does things that we don’t fully understand. And we’re not going to understand them in the time period we have to make these decisions. We just know they’re there. We may say, ‘We just don’t want to do this to ourselves.'” Dr. Robert Socolow

    –“Interestingly, this is not a gloom-and-doom story. In fact, the things we need to do have many other benefits in terms of our economy, our national security, our energy independence and preserving the environment — preserving creation.” Dr. James Hansen

    We buy insurance for homes, businesses and lives to protect ourselves and our kids from very unlikely events. Time for us all to now buy ourselves and our kids “insurance” from the 95% chance of destabilizing climate threats. Let’s price climate pollution and invest in a more sustainable, made-in-America solutions.

  11. max says:

    I am glad Tom Friedman is writing about the climate crisis-even if he is a pompous, self-important —. See Bob Somerby’s take at the blog: “Daily Howler”.

  12. mauri pelto says:

    Joe: In writing the BAMS state of the Climate 2009 section on glaciers and climate, each section was supposed to produce a graphic of decadal trends. In my case glacier mass balance over the last 30 years. Looks very much like your diagram of decadal temperature. The preliminary data used in this article make 2009 look highly likely to be the 19th consecutive year of negative mass balance. glacier mass balance.htm

  13. Edwin Hubble says:

    Thanks very much for putting all this great info in one place. I only have one suggestion: Could you copy and paste the captions for the figures underneath them, so we at least know what the different colors and errorbars correspond to? I’m sure that by clicking through the links one could find out this information and much more, but I think adding the captions would increase the amount of information disseminated to the average reader without taking up too much space or distracting from the flow of the blog.

    And I agree, Tom Friedman is so glib it’s incredible but hey, he’s doing a good job on the climate change front so can’t complain too much.

  14. Tom says:

    I’m looking for a good source of information that shows both sides of the debate and was hoping your site might provide just that. Unfortunately, it doesn’t appear to do so. Please think about creating a site that shows the best arguments for and against human caused (or exasperated) global warming. That way people can educate themselves better and make a more informed assessment. Without some balanced view, your website comes off as an advocacy page rather than an objective assessment and loses some credibility right off the bat. Please consider my proposal. I’m curious to learn more but really want to do so from an objective source. Thank you.

  15. Richard Brenne says:

    Tom (#14) –

    You seem sincere and so I don’t want to appear snarky (though I can’t seem to help myself), but you could just as easily ask “I want to educate myself about whether there’s really any link between smoking and cancer and want to hear both sides.”

  16. Tom says:

    I am sincere. I’ll look elsewhere for a fact-based opposing view and will keep your website in mind for a final assessment. Thank you.

  17. Blip says:

    I hear all this stuff about how there’s this global warming….

    But I got this box in my house and you put stuff in it and it freezes.

    So, if this “global warming” is real, then how come things still frozen in my house?

    ANswer that, smartguy!

  18. max says:

    Tom- Please come back and tell us what source you have found for a fact-based opposing view and why.

  19. Colorado Bob says:

    Just some items from this winter, observed events …..

    Dec. 09′ was the wettest month ever recorded at New Orleans, this followed the wettest fall ever recorded in the souteastern U.S.

    The Jan. 22 storm coming ashore at LA was the lowest pressure ever recorded in the southwestern U.S. Phoenix, Vegas, San Diego , all set this new record.

    It was 120 F in southern Brazil this week, Brisbane & SYDNEY got one of those extreme rain events, thet both got 4″ in 1 hour. Israel basks in longest winter heat wave in almost 40 years . Havoc in Greece and Turkey from floods.

    The list is endless .

  20. Eric Edlund says:

    Tom (#14 and #16): I think it’s going to be very hard to find a fact-based “opposing view”–I’m going to check back in this comment thread and see if there are any useful replies to your query, because I’m certainly curious. But the data and the mechanisms of “AGW” are so well-established that I honestly can’t say I’ve seen any good “fact-based” counter-arguments. Of course there are uncertainties–the science is not “settled” in many important details, but we know a lot and we’re learning more.

    In partial answer to your query, I usually look to first if I have a scientific question about global climate change. I look here at this website if I want to see to read a well-argued position.

  21. Colorado Bob says:

    State of the Climate
    Global Analysis
    January 2010

    The combined global land and ocean average surface temperature for January 2010 was 0.60°C (1.08°F) above the 20th century average of 12.0°C (53.6°F). This is the fourth warmest January on record.

  22. Mal Adapted says:

    Tom (#14, #16),

    SkepticalScience ( lists specific opposing arguments, with citations to their sources.

  23. Michael T says:

    That must be a record breaking heat wave for Brazil. Here is news about it from msnbc last week:

  24. Jim says:

    JR, this is a great service. It’s not even about the models anymore – though they reaffirm the observed data.

    Maybe we just have to write the headlines for the media in terms or a crime analogy:


  25. Michael T says:

    I noticed this update at GISS:

    Feb. 16, 2010: Urban adjustment is now based on global nightlights rather than population as discussed in a paper in preparation.

    I suppose that affects the U.S. temperature record, because I noticed some years are ranked differently now.

    1. 1998 was 1.31 is now 1.32
    2. 2006 was 1.31 is now 1.30
    3. 1934 was 1.22 is now 1.20
    4. 1921 was 1.12 is now 1.08

    and several others…

    Just minor changes to the record but still updated. That is the way science works, when new data comes in, it is updated or corrected.

  26. David B. Benson says:

    Tom (14, 16) — The debate, if that’s what it was, over the science was concluded decades ago. You can read the history in “The Discovery of Global Warming” by Spencer Weart:

  27. Matt Gattis says:

    This is all frankly very stupid. Are you not even going to acknowledge the counterpoints to all these papers? If you really want to summarize the “best scientific papers on every aspect of climate change” (that support your theory), you should at least do it in some organized fashion, perhaps with this logical order:

    1) The earth is getting warmer
    2) Man is responsible for it
    3) That it will affect our lives with some cost
    4) There is something that can be done about it for less than this cost

    I’m tired of hearing how everyone who disagrees with you is “anti-science.” Clearly those people are out there, but there is no point arguing with them. Why don’t we turn this back into a scientific argument instead of an ideological one?

  28. Peter Brunson says:

    How does nightlight measurement account for lighting projects for cities and towns. In our state a rural town can put in miles of street lights with grant money but no accompanying urbanization?