Eight Must-Have Charts Summarize the Evidence for a “Human Fingerprint” on Recent Climate Change

Click to Enlarge

The Yale Project on Climate Change Communications asked Americans “If you had the opportunity to talk to an expert on global warming, which of the following questions would you like to ask?”

The top question, as reported in their “Global Warming’s Six Americas in May 2011” report, is “How do you know that global warming is caused mostly by human activities, not natural changes in the environment?”

So this is a question that all climate hawks should be able to answer, and the figures/charts in this post are ones that you can refer to.  I just used this post myself today during a radio interview.

Given the popularity of my recent “Illustrated Guide to the Science of Global Warming Impacts,” which collected and summarized dozens of posts covering some 50 scientific articles,  I thought I would occasionally repost updated versions of other important pieces and reviews.

Last year, physicist John Cook, who runs the must-read website Skeptical Science, published “The Scientific Guide to Global Warming Skepticism.” It’s a good introduction to global warming science and skepticism.

He sent me the 8 figures of the “human fingerprints on climate change,” which I repost below.

The clever deniers these days don’t deny the painfully obvious reality that the planet is warming or that climate is changing — they simply deny that humans are a major cause.

But in fact there is an overabundance of evidence that humans are warming the planet and changing the climate, so much so that the U.S. National Academy of Sciences labels as “settled facts” that “the Earth system is warming and that much of this warming is very likely due to human activities.”

Here are key fingerprint figures:


I  wouldn’t recommend referring to all 7 when asked the question.  Just  pick 2 or 3 to familiarize yourself with, and then  give people this link.

For those who want to dive in deeper, here is a post that contains links to one scientific study for each of the 7 fingerprints, plus 3 more:   10 indicators of a human fingerprint on climate change

Related Posts:

38 Responses to Eight Must-Have Charts Summarize the Evidence for a “Human Fingerprint” on Recent Climate Change

  1. Dave says:

    Great resource.

    FYI, the formatting of the site cuts off the right side of the graphics on my screen (using Chrome browser).

  2. bill waterhouse says:

    Me too using safari on ipad – happens frequently

  3. Clinton M says:

    And there is no ‘print’ function like the old format which allows these pages to be printed off for others to see.

    I really don’t like this format for the lack of time-saving print format alone.

  4. prokaryotes says:

    Awesome collection! But some article fingerprint images are not displayed completely.

    I will re-post this at my bloch later.

  5. prokaryotes says:

    I think Climate Progess should have a image gallery. This could be a linked flickr group or a wordpress widget or picas photoalbum etc etc.

  6. kermit says:

    And I, using Firefox 7 on a Win 7 PC.

    Right-click, view image, offers me options for seeing it all, however.

  7. catman306 says:

    me too using Firefox on Mac OSX 4.11

  8. Joe Romm says:

    Ah, this is a narrower blog than it was.

  9. Joe Romm says:

    It prints out fine for me using the print button. I just need to fix the wide figures.

  10. I don’t come in out of the rain and sleet. They are natural developments rather than man made.

    The idea that we shouldn’t respond to climate change if it were from natural variation is insane. In fact, it doesn’t hold up beyond 3 seconds of investigation or analysis. The fact that it’s raised as an issue at all shows that it’s a manufactured controversy.

  11. prokaryotes says:

    Go back to your rathole Exxon.

  12. Paul Magnus says:

    Climate Portals
    ‎”…even science fiction writers such as George Orwell, Aldous Huxley or Doris Lessing did not envisage a civilisation that would knowingly, against the best scientific evidence, devastate its own atmosphere and ocean system as comprehensively as has been and continues to be done through anthropogenic (human-induced) climate change.

    An Orwellian climate
    “Everyone is entitled to his own opinions, but not to his own facts” – Senator Daniel MoynihanScience is a systematic, evidence-based, testable and self-correcting way of investigating the world. This…

  13. Juergen says:

    It is self-evident that humans are the main cause.
    That said, it is irrelevant whether humans cause climate change or not. Climate is changing, even climate-skeptics agree there, deniers are hopeless. That CO2 is a greenhouse gas is also undisputed. That mankind produces CO2 is unquestionable. So being the climate changes not to the better, should we not do whatever is in our power to keep our contribution to climate change as little as possible?

  14. Paul magnus says:

    “Here is a summary of some of these realities:

    1) Global temperature has already exceeded the upper target of a +2°C relative to pre-industrial levels set by the international community at both Copenhagen and Cancun.

    Thus, atmospheric greenhouse gas-forced energy rise (solar heat trapped in the atmosphere) has now reached levels equivalent of +2.3°C.

    This figure is masked only by a short-lived -1.1°C cooling effect, caused mainly by industrially emitted sulphur dioxide stratospheric aerosols – particles, which partly block sunlight from reaching the surface and warming the earth.

    Incredibly the +2°C target is still discussed in political and economic reports as if it hasn’t been reached.

    2) The connection between the spate of extreme weather events around the globe and climate change (see figure below) is still largely ignored by governments and most of the media, which either overlook extreme weather events, or dismiss such events as once-in-a-century event.

    Arguably people would only be motivated to seriously tackle climate change if and when they understand the connection between the rising spate of cyclones, floods, heat waves and fires and the rise in temperatures over continents and ocean.

    3) Despite political pre-election promises, development continues on infrastructure for extracting economic carbon from coal, oil (including from the Arctic Sea), coal seam gas, oil shale and tar sands.

    These developments can only lead to the further release of hundreds of gigatons of carbon into an atmosphere already at 393 parts-per-million of CO₂.

    As established by multiple studies of the history of the atmosphere, a concentration of 500+/-50 parts-per-million CO₂ in the atmosphere leads to the breakup of the Antarctic ice sheet.

  15. Paul Magnus says:

    “Incredibly the +2°C target is still discussed in political and economic reports as if it hasn’t been reached.”

    What do say about this Joe?

  16. Brooks Bridges says:

    A nice trick for old eyes on sites with small print works on these graphs too:

    You can make the graphs(or text) larger:
    Windows: Cntrl key and the + key;
    Mac: the apple/command key and the + key.

    Make them smaller by using the minus key instead of the plus key.

    On some sites, layout will be screwed up when you change size – just change size back.

    I’m using Chrome on a Mac

  17. Ed Hummel says:

    The manufactured controversy is that there is a difference between “natural” and “man-made” phenomena. In fact, humans are just as much a part of nature as are mice or seaweed, though there seems to be a large faction of our population that tends to think there is something special about us in the grand scheme of things. It is established science that CO2 is a greenhouse gas (has been for 150 years) and that its atmospheric concentration has a direct bearing on what the average temperature of the atmosphere is. It has been the thermostat for the general climate regime for the last 4 billion years according to all the best research that covers many disciplines. It doesn’t matter how the CO2 gets into the air or is removed from the air, it still controls the average atmospheric temperature. Since the only known source of the precisely documented increasing atmospheric concentration of CO2 over the last 200 years is human fossil fuel use (taking all the other sources and sinks into account), the conclusion is that humans are the drivers of the current warming trend. Very simple logic if one wants to be logical and not ideological.

  18. BBHY says:

    All of these fingerprints are impressive evidence but to me number 2 is is the one that provides the most unquestionable proof.

    It is a direct measurement showing that CO2 is preventing the Earth from radiating heat into space. So many denier arguments are based on “it’s all just statistics that are manipulated” or “it’s all just computer modelling”. This is a direct physical measurement so it crushes all those denier canards. It also provides direct proof that it is not just “natural variation”, a favorite denier hand-waving. There is no natural mechanism that can explain the loss of heat radiated into space. If the sun was responsible, (yes, they are STILL using that one), then as the Earth warms there would be more, not less heat radiating into space.

  19. Spike says:

    Great collection. Unfortunately more confusion likely after this article in the UK…shoots self in foot duh…..

  20. BoulderBob says:

    Nicely put.

  21. DSL says:

    Joe, where’s the ice, ice, baby? You should have #8: ice volume, area, and extent declines.

  22. Joe Romm says:

    That that wouldn’t prove a human fingerprint (by itself).

  23. Buzz Belleville says:

    Anyone can answer this, but it seems most pertinent to your post BBHY. while I am not a scientist, I am well read on the topic (an in fact teach the “Science of Climate Change” as one class each year in my Sustainable Energy Law course. While I understand the proposition that is supported by graph #2 (less radiant energy escaping as a fingerprint of human-induced GHG effect), I can’t seem to wrap by little brain around what it is that graph #2 is showing that supports that proposition. I’m not dumb … you don’t need to do it in 3rd grade language, … but can someone help me out on what #2 is depisting and how it supports that proposition.

  24. Buzz Belleville says:

    Sorry for all the little typos.

  25. How broad does irony have to be before you pick up on it? Did you read both paragraphs or respond after 1?

  26. Chris K says:

    I am reading graph 2 as increases in each of these GHGs has reduced the infrared outflow in their respective wave number bands by a certain amount that has the effect of displacing the outflow point to space higher in the atmosphere corresponding to the lower temperature there. At face value it looks like the increase in CH4 has had more of an effect than the increase in CO2, but when I look at the black body curves in David Archer’s book it is clear that the reduction in temperature where the big CO2 bite is will have much more impact than where the CH4 bite is. Graph 2 without the weighting for the black body intensity variation may be misleading to some in this respect, but I think I understand it now.

  27. PAUL DONOHUE says:

    Why don’t the charts include faster warming of the poles? I think that is the most dramatic evidence of CO2 warming. On Venus, the poles are as hot as the equator due to the green house effect.

  28. John says:

    For fingerprint #1, it might be easier to explain if you show the increase in 12C relative to 13C, rather than the decrease in 13C/12C. Air has a certain mix of 12C and 13C, fossil fuels have more 12C and less 13C, so burning fossil fuels puts more 12C into the air.

    While it’s more natural for scientists to think in terms of examining the 13C content, which is smaller, it’s easier to explain burning fuels as putting excess 12C into the air rather than diluting down the fraction of 13C. As long as it’s correctly calculated and worded, it’s the exact same information that’s currently shown, but perhaps easier to explain.

  29. grant says:

    The points that most directly affect me (and I extrapolate that to all mankind) are all beneficial!! Why is this loooked upon as a bad thing?

  30. Dr.A.Jagadeesh says:

    Excellent article and very useful information Joe Romm.

    Dr.A.Jagadeesh Nellore(AP),India

  31. Carol says:

    I agree that the warming is happening and that we need to work on dealing with the possible results. What I don’t understand is how “very likely” constitutes a “settled fact.”

  32. S says:

    Firstly I agree that it’s due to our CO2 emissions.

    However, not sure how the above will help me ‘prove’ it to sceptics?? They all prove the greenhouse effect, not the man-made effect – other than perhaps Fingerprint 1 combined with one of the others.

  33. Michael Y says:

    I once said the same thing–that we have a problem that we have a greenhouse problem that we need to deal with, regardless of the source–and similarly got quickly excoriated. ;)

    Great collection, Joe. Thanks!

    Michael Y

  34. Michael Y says:

    yup! smart!

  35. Michael Y says:

    Most skeptics have two lines of argument:

    (1) There is no warming
    (2) If there is warming it is caused by something other than the greenhouse effect.

    These graphs are strong arguments against both.

    If a skeptic uses a third line of argument, i.e.

    (3) There is warming, it is caused by increased greenhouse gases, but this is not caused by humans,

    Then the game is pretty much up for them with Graph 1 and the burden of proof would fall to them to explain another likely non-human source of an increase in greenhouse gases.


    Michael Y

  36. S says:

    Thanks Michael. I guess. It never seems to work out so logically though! :)

    I suppose one of the greatest wins for the purposefully-sceptic side (eg fossil fuel companies), has been the adoption of the phrase ‘climate change’ over ‘global warming’.

    As better people than me have argued…
    – ‘Change’ is something ‘that just generally happens’ in our daily lives.
    – ‘Warming’ on the other hand generally implies an ‘agent’ in our daily lives (entropy naturally flows the other way).

    We need to revert back to using ‘global warming’ as a phrase (also more accurate…the problem is global warming, not local warming, as is often confused).

    The skeptics I meet would probably tend to believe that the greenhouse effect is simply ‘change’ (for example “didn’t it occur during the dinosaurs”, etc).

  37. Clinton M says:

    my apologies. I print to PDF (make a PDF file out of it) and was having a technical problem on my end.

    sorry for the false-alarm.