Yes, Global Warming is Real AND Caused by Humans

humans cause global warming

Nothing surprising here, but with a global warming skeptic that deniers were absolutely in love with a few months ago (Richard Muller) finding that the world is warming in his Berkeley Earth Surface Temperature study (BEST), the out-right deniers have kicked him out of their cult and are also claiming that his study was useless. Just a reminder, this is what leading global warming denier Anthony Watts wrote before the results were out:

I’m prepared to accept whatever result they produce, even if it proves my premise wrong….the method isn’t the madness that we’ve seen from NOAA, NCDC, GISS, and CRU….That lack of strings attached to funding, plus the broad mix of people involved especially those who have previous experience in handling large data sets gives me greater confidence in the result being closer to a bona fide ground truth than anything we’ve seen yet. Dr. Fred Singer also gives a tentative endorsement of the methods….Climate related website owners, I give you carte blanche to repost this.

Now, with the results out and the media actually posting feature stories on the fact that we now know (as if we didn’t before) that the world is warming, fossil-fuel front group the Heartland Institute is out trying to confuse people again….

James Taylor (no, not that James Taylor),  but the senior fellow for (anti-)environment policy at the Heartland Institute, has a completely inane op-ed published in Forbes this week that essentially says: “Oh, we knew the earth was warming — no one denied that — we just don’t know if it’s from humans or how much it will warm in the future.” Looks like deniers are finally dropping their first line of denial, but it’s of little, little, little surprise that they’re still trying to stop us from acknowledging that the warming is human-caused and acting to stop it. (I mean, that is his job after all. He works for the fossil fuel industry, and though he is essentially working to murder countless people who will die from global warming inaction, he is dutifully doing his job.)

–> Highly recommended: What is Causing Global Warming?

But back to the inane arguments, just in case you don’t follow the science enough to know that the claims are out of this world:

Humans Cause Global Warming

Just as it’s been known for decades that the globe is warming, it’s also been known for decades that humans cause it. But over the course of these last decades, the evidence has grown so strong that nearly ever (if not every) overarching scientific organization in the world has stated this is the case. No, not just all those career climate scientists, but overarching bodies evaluating the work those scientists have done.

The Washington Post actually published a great op-ed on this part of the story this week.

Broadly speaking, here are two reasons why the Earth could be warming up. Either more heat is reaching the Earth’s surface, or else less heat is escaping out into space. On the first, there’s no evidence of a significant increase in heat reaching the earth. True, solar activity can shift from year to year. But satellite data shows that total solar irradiance has declined slightly in the past 30 years, even as the planet continues to warm. Scratch that theory.

So something’s keeping the heat in. Physicists have long known from lab experiments that greenhouse gases like carbon-dioxide can absorb certain frequencies of infrared radiation and scatter them back toward the Earth. We also know these gases are increasing in the atmosphere, largely due to the burning of fossil fuels (checking this involves some fairly straightforward chemistry). And, indeed, satellite data has shown that less and less infrared in the specific frequencies in question is escaping out into space, while more is bouncing back to the Earth’s surface. There’s your culprit.

Now, that’s the quick and simple, and for those of you not satisfied with the quick and simple, here’s more below (images after the list):

I posted on 10 indicators showing that humans are causing global warming  a long time ago, mostly reposting the great work of folks over at Skeptical Science. Here are the “fingerprints” proving the case (some of the images are for items listed, some are additional points):

  1. CO2 has, “coincidentally,” been increasing at about the same rate as global temperatures (odd, eh?).
  2. It’s clear from measuring the type of carbon building up in the atmosphere that it is carbon from burning fossil fuels. (Manning 2006)
  3. Oxygen levels are declining just as CO2 is increasing from the burning of fossil fuels.. to a degree that matches like two neighboring puzzle pieces (in other words, exactly as one would expect of one theorized that the atmospheric changes are due to the burning of fossil fuels). (Manning 2006)
  4. Hundreds of years of coral reef measurements show a sharp rise in carbon from fossil fuels, matching the increased burning of fossil fuels by humans in recent years. (Get the picture? The puzzle pieces all fit together. Surprising! Unless you understand the basic fact that our burning of fossil fuels is having an effect on the atmosphere and the oceans.)  (Pelejero 2005)
  5.  OK, so we know CO2 from the burning of fossil fuels is rising. Next is to show how this influences the climate. From the post linked above: “Satellites measure less heat escaping out to space, at the particular wavelengths that CO2 absorbs heat, thus finding ‘direct experimental evidence for a significant increase in the Earth’s greenhouse effect’. (Harries 2001Griggs 2004Chen 2007).”
  6. It has also been confirmed that that heat not reaching out to space is being sent back to Earth. (Philipona 2004Wang 2009). And, in particular, at the wavelengths of CO2! As a climate scientist reports: “this experimental data should effectively end the argument by skeptics that no experimental evidence exists for the connection between greenhouse gas increases in the atmosphere and global warming.” (Evans 2006).
  7. “Greenhouse effect warming” should have specific fingerprints of its own. One of those should be that the Earth should warm faster at night than in the daytime. Confirmed.  (Braganza 2004Alexander 2006)
  8. And that the upper atmosphere (aka stratosphere) should be cooling. Confirmed. (Jones 2003).
  9. The tropopause — the line between the upper atmosphere (stratosphere) and the lower atmosphere (troposphere) — should also be rising. Confirmed. (Santer 2003).
  10. And for the last piece of evidence, I’ll quote the story linked before this list again: “An even higher layer of the atmosphere, the ionosphere, is expected to cool and contract in response to greenhouse warming. This has been observed by satellites (Laštovi?ka 2006).”

human fingerprint on climate change

human fingerprint on global warming

human fingerprint on climate change

humans cause global warming

humans cause global warming

humans cause climate change graph

climate change

global warming graph

Now, the only way someone could deny that the world is warming due to the greenhouse effect (which is caused by humans burning more fossil fuels) is by ignoring the evidence (lying), not looking into and finding the evidence, or being so incapable of understanding science that they don’t understand the evidence. I’m not going to conjecture which one of those Taylor is, since I don’t know him personally, but he is clearly one of them if he thinks global warming isn’t caused by humans.

How Much Will the Earth Warm?

Now, for his second point, that we don’t know how much the world is going to warm, that is true, of course. However, the climate scientists warning us that it is going to be catastrophic warming if we don’t change course soon have been tremendously more accurate in their projections for decades than global warming “skeptics” like Taylor. However, even they have been underestimating the warming and effects in some cases!

No, there is no comfortable reality where “this is not happening and there’s no evidence the future won’t be catastrophic if we don’t change course.” Sorry, Taylor. No one wants to be facing this challenge. But we are. Hiding under your blankets when your house is on fire isn’t going to help anyone. Telling your wife and children there is no fire in the house isn’t going to help anyone. It’s only going to make the situation that much worse.

Image Credits: Climate Progress & Skeptical Science (first eight); Union of Concerned Scientists (last one)

21 thoughts on “Yes, Global Warming is Real AND Caused by Humans”

  1. Come on with this crap, I mean I have an open mind but you people just keep going on and on about this, earth is alive and it heats up and cools down in cycles, us humans can’t change that, sorry but nobody listens to this stuff anymore, at least not anyone with common sense.
    What is your cure for all this global warming, let me guess, reduce the human population, wow, isn’t that new, or get rid of all the cars and factories, all these fancy charts and graphs who are you trying to impress? I will go along with your ideas if and only if you round up the other believer’s in this theory and you practice what you preach, meaning reducing the population, you all go first and then we’ll take some new readings and see if we have dropped the temps, if not then we will know that it wasn’t us humans.

    1. Sorry, you seem like you have good intentions, but your statements are incorrect or deceiving (i.e. the implied point is incorrect).

      1. “Climate reacts to whatever forces it to change at the time; humans are now the dominant forcing.”

      Also, the rate of change is the huge concern.

      2. People actually do listen to the science. The majority of the public still aligns with the view of the scientists, not your statement.

      3. There are many solutions: solar PV, solar thermal, wind power, wave power, tidal power, ocean thermal electric power, small hydro, biking more, electric vehicles, eating more vegetables and fruits (rather than livestock), and certainly better family planning in some places.

      as far as the last comment, that’s not very polite, quite frankly. but feel free to make such comments if it somehow makes you feel better about yourself.

  2. Stephen Ffanks, Ph.D.


    You don’t really address Robert Wilson’s comments in any sort of scientific or objectiver manner. You just list a bunch or organizations who have perhaps decided that they will take a stand in the issue. I suspect that if you polled all the members of each, you’d find considerable disagreement about the cause of global warming. As Wilson rightly points out, there have been many cycles of warming and cooling and also many cycles of high atmospheric CO2 (many times higer than today). Geoscientists (esp. paleoclimatologists)look much farther back in Earth’s history (hundreds of thousands and hundreds of millions of years) than many scientists involved in the present debate who only look back thousands of years. You criticize Wilson that the cycles he refers to were pre-human (you say, “the point is NOT that the world was warmer in the past (when humans didn’t live on it, by the way).” Well, actually that is exactly the point. If Earth has had much higher atmospheric CO2 in the past and also has had numerous warmer (and colder) periods– what caused them? As you say, humans and human CO2 emissions were not around then. Perhaps something other than humans are at play here.

    1. Stephen, I’ve responded to these kinds of comments thousands of times. I’ve gone into the science with them. It doesn’t make any difference for deniers. They are not here to discuss. I’ve included links to pieces that debunk the points Robert is making. Tell me which points were not discussed enough for you and I’m happy to provide more.

      On your specific points, it seems you haven’t read some of my points here. YES, there have been cycles of warming and cooling. But the RATE of warming today is a clear threat. We know that based on study of climate changes over Earth’s history and based on what we’re seeing these days.

      To say that climate scientists only look at a few thousand years shows how little you have looked into their work.

      You miss the point of my human comment, as well. One of the main concerns of the warming is that it could make the Earth unlivable for humans. The fact that it was warmer when humans didn’t live here doesn’t counter that concern in the least.

      There’s a reason nearly every overarching scientific body in the world supports climate scientists and has spoken out about the matter. If you look into the science, you will come to the same conclusion they have — it’s nearly impossible not to.

      Climate scientists have studied all these matters you bring up. What caused warming in the past has been documented. What is causing it today is clear. What the results will be is clear. If you are genuinely interested in the science, LOOK INTO IT. Go into the scientific journals, read the IPCC’s report on it, talk or write to a climate scientist. Genuine “skeptics” who have done so have come to the same conclusion — oh, shit, we need to turn this boat around.

  3. Again they show climate change over a very short time. If you show the graph over 25,000 years, since the last ice age, you would see much different results. If I take the stock market growth over the last month, I would have a strong upward trend, but the same graph from the beginning of the year would show a flat trend line.
    Since the last ice age, 25000 years ago, the earth has been warming. If we move the starting pont back 500,000 years the eath is probably cooling.
    The molten core of the earth is cooling down. In a few million of billion years as the earth cools, the gravity of the earth will decrease and the atmosphere will be lost – this may be what happened to Mars.

    So is the earth warming -yes in the sort run until the next ice age. Is it cooling – yes over the next million or billion years.

    All answer are correct, it’s just the time frame you choose.

    1. Robert, you’re missing a few key, fundamental points. Are you just 100% dead-set on ignoring them? Do you really have good intentions but are just lost?

      Yes, there are natural trends, but we are FAR outside the natural trend.

      Did you look at the last graph in this post, or the numerous points before it showing how humans cause global warming? (Or just skip straight to the comments?)

      If you can’t get the picture form the above, I’m sorry, I spelled it out as simply as I could.

      The RATE of warming is what is of concern. We are warming tremendously fast because of human emissions. There is no doubt about it. Hence, the reason the following organizations have confirmed what climate scientists tell us (we are causing considerable global warming):

      U.S. Agency for International Development
      United States Department of Agriculture
      National Oceanic & Atmospheric Administration
      National Institute of Standards and Technology
      United States Department of Defense
      United States Department of Energy
      National Institutes of Health
      United States Department of State
      United States Department of Transportation
      U.S. Geological Survey
      U.S. Environmental Protection Agency
      University Corporation for Atmospheric Research
      National Center for Atmospheric Research
      National Aeronautics & Space Administration
      National Science Foundation
      Smithsonian Institution
      International Arctic Science Committee
      Arctic Council
      African Academy of Sciences
      Australian Academy of Sciences
      Royal Flemish Academy of Belgium for Sciences and the Arts
      Academia Brasileira de Ciéncias
      Cameroon Academy of Sciences
      Royal Society of Canada
      Caribbean Academy of Sciences
      Chinese Academy of Sciences
      Académie des Sciences, France
      Ghana Academy of Arts and Sciences
      Deutsche Akademie der Naturforscher Leopoldina of Germany
      Indonesian Academy of Sciences
      Royal Irish Academy
      Accademia nazionale delle scienze of Italy
      Indian National Science Academy
      Science Council of Japan
      Kenya National Academy of Sciences
      Madagascar’s National Academy of Arts, Letters and Sciences
      Academy of Sciences Malaysia
      Academia Mexicana de Ciencias
      Nigerian Academy of Sciences
      Royal Society of New Zealand
      Polish Academy of Sciences
      Russian Academy of Sciences
      l’Académie des Sciences et Techniques du Sénégal
      Academy of Science of South Africa
      Sudan Academy of Sciences
      Royal Swedish Academy of Sciences
      Tanzania Academy of Sciences
      Turkish Academy of Sciences
      Uganda National Academy of Sciences
      The Royal Society of the United Kingdom
      National Academy of Sciences, United States
      Zambia Academy of Sciences
      Zimbabwe Academy of Science
      American Academy of Pediatrics
      American Association for the Advancement of Science
      American Association of Wildlife Veterinarians
      American Astronomical Society
      American Chemical Society
      American College of Preventive Medicine
      American Geophysical Union
      American Institute of Physics
      American Medical Association
      American Meteorological Society
      American Physical Society
      American Public Health Association
      American Quaternary Association
      American Institute of Biological Sciences
      American Society of Agronomy
      American Society for Microbiology
      American Society of Plant Biologists
      American Statistical Association
      Association of Ecosystem Research Centers
      Botanical Society of America
      Crop Science Society of America
      Ecological Society of America
      Federation of American Scientists
      Geological Society of America
      National Association of Geoscience Teachers
      Natural Science Collections Alliance
      Organization of Biological Field Stations
      Society of American Foresters
      Society for Industrial and Applied Mathematics
      Society of Systematic Biologists
      Soil Science Society of America
      Australian Coral Reef Society
      Australian Medical Association
      Australian Meteorological and Oceanographic Society
      Engineers Australia
      Federation of Australian Scientific and Technological Societies
      Geological Society of Australia
      British Antarctic Survey
      Institute of Biology, UK
      Royal Meteorological Society, UK
      Canadian Foundation for Climate and Atmospheric Sciences
      Canadian Meteorological and Oceanographic Society
      European Federation of Geologists
      European Geosciences Union
      European Physical Society
      European Science Foundation
      International Association for Great Lakes Research
      International Union for Quaternary Research
      International Union of Geodesy and Geophysics
      Intergovernmental Panel on Climate Change
      World Federation of Public Health Associations
      World Health Organization
      World Meteorological Organization
      Source: Planetsave (

      For more on your specific concerns, please see:

      1. If we look back a few million years we see periods of warming and cooling. I remember in the 1970 the paper saying the earth is cooling and we should produce more co2 to prevent the cooling process.
        If you look at the graphs at:
        you will see the climate cycles. Compared to the Cambrian, Silurian, Jurassic , Cretaceous, Tertiary periods we are actually cooling down.
        All I am saying is the time frame you select changes the analysis outcome.
        Compared to the Cretaceous we are a lot cooler, but compared to the Early Permian period we are warming.

        We have a long way to go to reach the temperatures of the past – but someday we will reach these temperatures. It has happened in the past and will happen in the future. The climate cycles are part of the earths history.

        I think man can influence temperatures a little he short run, but nature will control it in the long run.

        1. Robert, are you a robot? Or do you just ignore everything I write?

          1- there was never anywhere near the consensus on “global cooling” as there is on global warming. In fact, at the same time as a few scientists postulated that, others were discussing global warming. decades of research clearly showed who was right.

          mid-century cooling:

          on 1970s ice age predictions:

          from 1977:

          from 1956:

          2- again, the point is NOT that the world was warmer in the past (when humans didn’t live on it, by the way). the points are that it is warming at an unprecedented rate (from greenhouse gas emissions) and it could very likely make the planet unlivable for humans if not stopped.

  4. We just got 4 inches of snow and the east coast is being pounded by snow weeks before it should of been. So all this global warming rhertoric is BS. If anything there is a global freeze happening. Just look outside and you can see there is no global warming. I wish the left would stop with this lie. We dont want it and cant afford to waste our money on your crowney programs. Stop the lies.

    1. Jes** Chr**, how many times do you have to explain to people, very simply, that 1) snowstorms increase with global warming and 2) weather is not climate. the GLOBE is warming. There are dozens of lines of evidence showing this, and showing that it is happening at a breakneck pace.

      i’m not going to spend my day finding the individual posts & explanations for the 1000th time. look it up:

    1. Haha, i noticed it in my Google Reader feed afterwards, but didn’t actually take a look since I had spent enough time on this one 😀 (But as you can see, linked to a lot of the great work you SkS is doing :D) Thank goodness for SkS! Just happy I can use what they (and others, like Peter Sinclair and Joe Romm) produce to bring the news and the science to more people 😀

  5. Dear Mr. Shahan,
    Thank you for these important facts and I hope Mr Taylor of “Forbes” is able to follow them. I read his articles myself and comment on them to no avail. It is rather perplexing that these points shed from his (and his fellow deniers) eyes. After over 20 years since Dr. James Hansen got up before a Congressional panel and stated that it was time to act, we did the opposite and INCREASED our emissions!. Now it looks like we ARE headed for 3-5 degrees C even if we do ACT NOW! That’s because of “lead time”, “capital budgeting” and “backtracking” of the developing countries, such as, China and India.
    I will save your article and post it as a link at the sites it will have the most impact.
    Again, as far as the deniers, they have too much “invested” in their position to change and we can no longer hope to change their minds, it won’t happen.

    1. Thanks a ton. Yep, can’t see anything that is not convenient to their fossil fuel backers. The sad part is the hundreds of millions of people who are confused by them. Thanks for the good work! Hanging out in the comments on Forbes must be agonizing. But it’s needed.

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