How a global warming skeptic came to change his mind
August 7th, 2012
10:20 AM ET

How a global warming skeptic came to change his mind

There is broad scientific agreement global warming is happening and that humans are at least partially to blame. But there are some important scientific skeptics. Last month, in the New York Times, one of the most important of them did a public about-face. Richard Muller, a physicist at the University of California at Berkeley, now says it’s real and humans are almost entirely to blame. Here’s his conversation with Fareed Zakaria from the latest episode of GPS.

You say in that piece that all scientists should be skeptics. And I think you’re right. I remember Niels Bohr once said that every statement should be taken by a scientist as a provisional hypothesis that has to be tested. So what made you start doubting your original skepticism? What evidence convinced you that something real was happening here?

The issues were so large that about two-and-a-half years ago, my daughter and I began a major scientific research effort in which we recruited a dozen of some of the top scientists in the world, including Saul Perlmutter, who won the Nobel Prize last year – well after he joined our team. So we felt there were questions that were valid, questions about data reliability, about data adjustment, about the choice of the stations which had been used. These demanded attention and I couldn’t get the answers. The only way to do it is to do the study ourselves.

So, after a great deal of work, largely done by Robert Roady, who I can’t compliment enough for his superb work in data analysis, which we all carefully participated in...I came to the conclusion that, yes, global warming was real. Then, over the last three to six months, Roady was able to extend the record back to 1753. We now had a really long record, beginning before the American Revolution, when Benjamin Franklin and Thomas Jefferson were the ones taking the data. With this long record, we could look for the signatures of the various possible causes. We’re able to rule out solar variability, able to rule out volcanoes. They had an effect, but it was short-lived. When we tried fitting it to see whether it looked like carbon dioxide, it was right on. It was a shock to me at how well that carbon dioxide curve fit our new temperature data set.

So when you look at the historical data now, is it fair to characterize the situation thus, that ever since the Industrial Revolution, human beings have been pumping more carbon dioxide into the atmosphere and that that increase in CO2 has been having the effect that we call global warming?

That is my viewpoint on this. You can’t prove it. It’s always possible that something random is happening that just happens to match the carbon dioxide data. But [the data] leads me to conclude that essentially all of this warming over the last 250, 260 years, has been caused by greenhouse gases emitted by humans.

Now, do you also worry about the potential effects that this will have on life on Earth? Because a lot of people talk about global warming and then they say, if it gets to a certain point, the higher end of the U.N. estimates, you could have very significant coastal flooding. You could have unintended consequences, the sort of follow-on effects that could be even more damaging to life on Earth.

Well, I am deeply worried about it.  [With] the coastal flooding, the U.N. estimate is something like between two and three feet. That’s not huge. But I am concerned.  I think rising temperatures soon will be in a realm that’s higher than we, Homo sapiens, have ever experienced.  I don’t personally believe that’s good for our civilization.  I think we really do need to do something about it.

When you look at the issue of what to do about it, there are people who say, look, the only thing we can do is what’s called adaptation. We should rotate crops.  We should build dikes. We should do those kinds of things. And then there are people who say, no, the problem is so serious, you have to actually get at the root cause and slow down the emission of CO2.

I believe in the latter. [W]e’re a very adaptable species. But adaptation is always disruptive and it hurts…The biggest thing we have to do, we have to recognize that the reason that carbon dioxide is shooting up is not because of the United States. Ours has actually been going down over the last few years, as we switch from coal to natural gas. Natural gas emits only one third the carbon dioxide that coal does. If we are going to do something about this, there are two things we have to do. One is energy conservation and efficiency. That’s really important. A huge amount we can do there. Number two is we’ve got to switch the world – China, India and particularly the developing world – away from coal and onto natural gas. Now, that’s a solution that a lot of my environmentalist friends don’t like, because they’ve decided they have to oppose hydraulic fracturing, known as fracking. But, in fact, that is one of the two biggest things we could do – energy conservation and a switch to natural gas from coal.

Some of your funding came from the Koch brothers, who are famously anti-global warming or believe that it isn’t happening. How did that play out? Were they disappointed by the results of your research? Have they asked for their money back?

I actually find it amusing how many people think they know what the Koch brothers are thinking. It’s a caricature…I did speak with them, and they made it clear to me, from the very beginning, that they recognized that there were serious issues raised about prior estimates of global warming, everything from urban heat islands to data selection bias to other things. And they knew that I wanted to look into that, that our team would do a good, unbiased job. And all they were asking for was scientific objectivity. So I was very pleased with their funding. I really sensed they wanted to have this problem solved and they never gave me any suggestion, any hint of a suggestion about which side they were hoping we would come out on.

And you haven’t heard from them since you’ve gone public on these issues?

Oh, I actually have talked to them. And they appear to be very pleased.

Richard Muller’s new book is ‘Energy for Future Presidents.’ You can download the full version of this episode of Global Public Square on iTunes here.

Post by:
Topics: Energy • Environment • GPS Episodes • GPS Show

soundoff (141 Responses)
  1. joe

    This article is a total fraud. For starters, this EXACT same news was released about 6 months ago. Why they are bringing it up again now, I have no idea. Secondly, Google Judith Curry. She is the ONLY climatologist on the team and she says Mueller is totally wrong with his "findings". Just Google and read what she says. FINALLY, If you do some digging, you will see Mr. Mueller here believed in global warming as far back as the '80s. I know most people won't do any searches since their minds are already made up on the matter...but I implore everyone to see what a total fraud Richard Mueller is. As if a Berkeley professor doubted Global Warming for 20 years. What a joke. You can just tell he's lying when you listen to him.

    August 7, 2012 at 7:22 pm | Reply
    • Magic Rat

      So Joe, it's unclear to me what your agenda is. Mueller has long been a noted gadfly to the global warming faction of the scientific community. Now that he has publicly flipped, you are saying, he was "one of them" all along? So you advocate disbelieving and disavowing any scientist who uses the scientific method and data to come to a conclusion that offends your political sensibilities? Even if that scientist was once on "your" side? I hate those annoying facts, don't you? They so get in the way of my agenda and afternoon Scotch.

      August 7, 2012 at 11:49 pm | Reply
  2. James Tracy Pure Power Corp

    The Irony is that Pure Power Corp has clean coal, waste to energy and other technologies to clean up 90 % of emissions, with a new gain in output. But Cannot find the right backers, even with a NASA Plasma Physicist's recommendations for funding? Oh well, regardless of whether we are causing global warming, we are poisoning ourselves, and there is a solution. Google Me: James Tracy Pure Power Corp. Pass this on to the right smarter people please.

    August 7, 2012 at 7:35 pm | Reply
    • less t

      no one has clean coal, what the theory is take the co2 out bury it in the ground and hope it does'nt leak out, like nuke waste, that has'nt worked out so well either.

      December 29, 2013 at 3:43 pm | Reply
  3. eroteme

    When we think of global waming we are for the most part thinking of USA warming and how we are going to fix the problem. When one looks at a globe one sees that the USA is quite a small portion of the globe, alhough we are quite sure we are its most important parrt. That is, should we solve 'our' global warming problem, which is unlikely if the problem is simply climate change which has been going on for the past several billion years, global warming may continue for the rest of the earth.

    August 7, 2012 at 7:47 pm | Reply
    • randy

      No. Releasing carbon creates a lens blanket trapping heat. Go sit in your car with the windows rolled up on a warm day for a demonstration. Pull a sheet of transparant plastic over a pool and you get the same effect. By the way, climatologists do know that climate has always changed.

      August 23, 2015 at 5:22 pm | Reply
  4. David

    Thirty-five years ago the same scientific community was telling us Earth was going to turn into a giant popsicle, and we needed to cover the poles in a carbon blanket.

    August 7, 2012 at 8:29 pm | Reply
    • Magic Rat

      Yeah. The amazing thing about science and scientists is that they constantly re-visit theories and update them based on new data made possible by advancing technology. That's why it's so fun to look back and laugh at those who thought the sun revolved around the moon and Nixon was the answer to bring those darn anti-war activists back into line.

      August 7, 2012 at 11:54 pm | Reply
    • randy

      No. One article in Newsweek said that. I remember being waned about the Greenhouse Effect, heating the earth back in the mid 1980's.

      August 23, 2015 at 5:23 pm | Reply
  5. Banjo bob

    Dr. Muller was never a sceptic, he had a problem with Mann's "Hockey Stick."

    August 7, 2012 at 10:23 pm | Reply
  6. 100 % ETHIO

    I buy your ideas for the sum of ££££$$$$$$€€€€€, if there are no restrictions.
    Some of your contributions (voluntarily and forced), helped me for my ... books. Thank You.

    Those are:- your ideas.

    Why our weights are lighter (smaller) in North-West Territory and Arctic Regions than any other places around the World?

    ...Earth was a Hot-Gas before. The 'Stone Mountain' in Atlanta, Ga. is one proof. Go and see.

    Since the year 1670's to ..., we kept adding Hours and technically, our current Hours, Days, Months and Years are not the same, if we didn't make the changes from its originality.
    Our Religious Holly Books, seems also changed its some Words as well.

    What did George Orwell wrote, knocks some of US doors.

    August 7, 2012 at 10:28 pm | Reply
    • 100 % ETHIO

      Global warning! Is the right word to use and it's meaningful.

      August 8, 2012 at 5:30 am | Reply
  7. Terry Brookman

    It is warming but we are good for only twenty percent of it. The proof is in the measurements from other planets, they are all warming up. The only source for this is the sun and the galactic rift, we are being hit by more neutrino emission. They go right through us and most other matter but lose energy as they go through the earth, that energy is released in the form of heat. All the data points to this but it is being pushed by All Gore for political gain and profit, like the carbon tax. You have to remember that All said he invented the INTERNET and Tron is his favorite movie, he pushes nothing but junk science, By the way the INTERNET was built by the military and AT&T before WWII for the purpose of military communication between bases and brain trusts like MIT, Berkley,edu and such, I was playing on the net before there was a browser using BBS and UNIX command line. If you use the resources you now have you can weed out the BS offered up by our government, like we can stop the planet heating up somehow, try stooping a volcano or a tsunami.

    August 7, 2012 at 10:33 pm | Reply
    • Hadenuffyet

      The internet was made before WW2...rofl..dude , eniac was the first computer built and it wasn't finished until after WW2 also it wasn't mush more than a friggin big calculator. It had no data transmission capability and more importantly , nobody to talk to as it was one of a kind. Where do you get this drivel?

      August 7, 2012 at 10:52 pm | Reply
      • Terry Brookman

        I did not say data but there was voice and a crude form of data dot dash dot dot, 1011 it's called Morris code smart guy. As far as temperature all the charts going back a hundred and fifty years do show the temperature rising and that is a fact. There have been more species lost and gone forever than exist today and that includes insects to apes, the only constant is change. We are going to die one way or another and sometimes we do it in mass. Fukushima is bigger than Chernobyl and only a close earthquake away from poisoning the entire planet, if number four spent rod cooling tank falls over we are fu(ked, right now instead of thirty feet of water covering and cooling them there is only two feet, If you stood next to one rod, they are twelve feet long by one half inch in diameter, for a half hour you would be dead within a month. There are hundreds of tons of them in number four containment chamber, without water they melt and go into the ground and then up into the atmosphere.

        August 7, 2012 at 11:19 pm |
      • Hadenuffyet

        I did not say data but there was voice and a crude form of data dot dash dot dot, 1011 it's called Morris code smart guy.

        No , you said and I quote " By the way the INTERNET was built by the military and AT&T before WWII " , but now you are saying they had telephone and telegraph. I think most educated people already knew that.

        August 7, 2012 at 11:33 pm |
      • Magic Rat

        "Morris" code? Really?

        August 8, 2012 at 12:01 am |
    • Magic Rat

      "only" 20%? That's one fifth, my little math genius. Just half a degree rise in mean ocean temperatures in one part of the Pacific causes catastrophic changes in ocean currents and affects U.S. weather patterns. Stop treating scientific data as a unpatriotic attack on your beloved country or a threat to your family's income. Data is raw and emotionless and must be dealt with head-on and with open eyes and minds.

      August 8, 2012 at 12:00 am | Reply
  8. Hadenuffyet

    Very good , you've proved to yourself the planet is getting warmer , just as it has for the past 10,000 years. Oh, but it's accelerating you say? Mankind won't stop or cure it , but nature will , as it will run it's course. And if mankind is eliminated in the process , so be it . It was a fun ride while it lasted.

    August 7, 2012 at 10:39 pm | Reply
    • randy

      As usual, for a right-winger, you think this is all about humans. What about all the other species we are dragging down with us? I know they are considered stuff for you guys to shoot, but they are blameless in this scenario and are dying off and or migrating to the poles as we speak.

      August 23, 2015 at 5:27 pm | Reply
  9. Terry Brookman

    People will buy anything to try to stay alive, they once called it snake oil. The usual ingredients were water. alcohol, sugar, flavor of some kind and opium or cocaine. Our elected officials are the very best snake oil salesmen, no party preference and rotting tomato's should be taken to any party rally. I would prefer a hand gun, nothing better for cleaning up a lying SOS. It might give them pause before they start lying, everyone with a lap top or I-pad for fact finding and a hand gun.

    August 7, 2012 at 10:52 pm | Reply
  10. Werner Brozek

    According to satellite data by RSS, the slope for the last 15 years and 8 months is flat, meaning there has been no global warming according to RSS since December 1996. Check it out for yourself at:

    August 7, 2012 at 11:41 pm | Reply
  11. Gene

    Using ice core sampling the temperature and CO2 levels have been measured back about 800,000 years.
    In that period the levels and temperatures have been rising and falling. Over a short time frame we may be in a cooling or
    a warming period. But one must look at the overall trend. Until the nineteenth century the graph is somewhat level. In the
    mid-century it began a very noticeable rise. It has been rising rapidly since that time. That overall trend curve is now
    quite steep.

    August 7, 2012 at 11:57 pm | Reply
  12. Bellanca

    Instead of arguing about whether or not global warming exists, lets focus on the facts we already know:

    1) Oil and energy prices are going to continue to rise. Unless you have money just dripping from your pores, it doesn't hurt to scale back on your consumption. Make a reasonable effort to use less energy. Next time you are buying a car get a car instead of an SUV, or a compact instead of a sedan, look into clean diesels, etc. When shopping for new appliances get buy energy efficient. Don't leave your lights on in your house when you aren't using them or idle your car when you aren't driving. Small things help the environment, save you money and protect our economy by allowing you to spend your money elsewhere.

    2) Less dependence on foreign oil = security and financial stability. The people we buy a good percentage of our oil from are not our friends. A lot of money we spend on gas ends up in the hands of people who hate us: terrorists and people killing our troops overseas. You don't have to agree with global warming to want to protect our national security. By purchasing a car that gets more mpg, you are indirectly helping our national security and protecting the troops. Also, our country would become less subject to the whims of OPEC and it will be harder for them to play hardball with us.

    3) Fossil fuels are a finite resource. Eventually we are going to run out. Also, the more we drain them for the planet, the more the law of supply and demand kicks in, and prices will go up. Lets consume less, and promote coming up with ways to become less dependent on them in the future.

    4) If the global warming crowd is right, then maybe we will be able to help the planet with these reasonable changes. If not, we are affording ourselves some financial security, national security and setting ourselves up from having to deal with the crisis of depleted natural fossil fuels in the future.

    August 8, 2012 at 12:45 am | Reply
  13. Jack

    Hello folks. Everyone is cordially invited to visit –

    August 8, 2012 at 1:14 am | Reply
  14. lsn2me

    too bad that he cannot think outside of the box. natural gas burns cleaner than coal, but extracting it through hydraulic fracturing is an inevitable disaster for the environment, in my opinion. it is true that fracking releases methane, which is 3 times more of a global warmer than co2? how many millions of gallons of water does fracking use up per site? is it true that the precious water, once laced with the hundreds of poisonous fracking fluids can never be used for common consumption? or will never be reintroduced into mother earth's water cycle? yes, global warming is real. global warming is due to fossil fuel consumption. let's get going on the green technologies. solar, battery efficiency, wind without annihilating birds, etc.

    August 8, 2012 at 2:27 am | Reply
  15. dougaussie

    the planet is stuffed, i'm moving to mars, book me on the next flight. 800,000 years ago mars had a prosperous middle class civilisation who cooked their planet, they then moved to earth, they would have moved to venus but the venusians had cooked their planet a thousand years earlier, that's when the scientologist moved out.

    August 8, 2012 at 2:48 am | Reply
  16. JimfromBham

    Bellanca (a few comments above) is exactly right. An additional reason to conserve: it helps stretch out the fossil fuel supply longer, which gives us more time to develop cheaper alternatives. This is also a reason to switch to natural gas as the article suggests.

    The biggest problem, however, is that we never respond economically until the crisis is nearly upon us. As we conserve the fissile fuel supply, pressure on the prices for the fuels will go up more slowly, making it more difficult to economically justify the invention and mass production of alternatives.

    As a result, we have a problem that the free market is not well equipped to solve with Adam Smith's "invisible hand". The recent government investments/subsidies with Solyndra and other environmental companies makes it look like government is not well equipped to handle this either. So where is the solution going to come from?

    August 8, 2012 at 7:13 am | Reply
  17. Melissa

    I'm glad he did this, but it speaks of his distrust of his own scientific community that he thought so many scientists my be doing their research and data correction wrong. That is the crux of the problem. All of a sudden he's in a hurry to do something about this tragedy in progress when apparently he was one of the voices that has thwarted full-bore action. Would he, I wonder, now consider his former self as a kind of environmental villain? Or criminal?

    August 8, 2012 at 12:35 pm | Reply
  18. Melissa

    I mean "date collection."

    August 8, 2012 at 12:36 pm | Reply
  19. WhatSomeSay

    Everyone is always saying something about the Koch brothers. How they are this and how they are that..eveil to the core and all that other stuff...Look, i can think of a helluva lot more people who would be worse if they had that kind of money..I was just surprised that they funded the research. I didn't really think they would have cared for this kind of stuff..

    August 8, 2012 at 12:44 pm | Reply
  20. miked826

    "Roady was able to extend the record back to 1753". Wow that's 259 years worth of records. Let me do the math. The Earth is 4,500,000,000 years old minus 259 years is basically 4.5 BILLION YEARS. 4.5 BILLION YEARS worth of missing records. Any assumption with 4.5 BILLION YEARS worth of missing records must be accurate right? You can take it to the bank, just don't try and cash it.

    August 8, 2012 at 6:37 pm | Reply
  21. XiaoJack

    It was not just change his mind ~ It change us too ~ The problem of global warming keep increasing in these few years ~ The ice berg is getting smaller and smaller ~ Polar bear going to extinct ~ We need to work together to stop the global warming ~ Perhaps my Kechara Wish Fulfilling Chakras will work to wish that the global warming will not getting more serious ~

    August 9, 2012 at 9:18 am | Reply
  22. Buddypup

    I can remember, as a young 1st Lt flying out of Myrtle Beach,, NC. The Air Force had a term, CAVU or Clear and Visibility Unlimited and it really was. You could see back to the Big Bang without a telescope. By the time I was a senior Captain and flew out of Wright Field, CAVU had a whole new meaning. A CAVU day was one when I could see a B-52 on its takeoff roll on Patterson Field about 6 miles away. True Wright-Patterson was up in the industrial midwest with its more polluted air but still the difference was stark. Now sitting in the window of a commercial cattle car at 36000 ft, there is little to see but haze. In 50 years, we have poluted the air so bad that we can no longer see the beauty of the earth. It doesnt take a Nobel prized scientist to prove to each of us that we have fouled the air, sea, and land. We have to make a big change immediately if our children are to survive here on earth and Earth is not to become a second Mars. God told our forefathers more than 2000 years ago that we were reponsible for the care of the land and the animals. We have definately screwed that up so far.

    August 9, 2012 at 3:44 pm | Reply
  23. Remember to believe the lie

    Geoengineering, nuff said. Nicola Tesla warned that over heating of the atmosphere and waters of the planet could occur due to over use of stratospheric spraying, of aluminum oxide and barium. Remember to inhale through the Devine chambers.

    August 9, 2012 at 8:26 pm | Reply
  24. Davehuckle

    Certainly he would change his mind. Bush isn't making him debunk Global Warming any longer and now he is free to say what he actually feels. For those who still do not believe in Global Warming being caused by man, it is time to wake up and do something about it before the planet enters a "Runaway Greenhouse Effect" similarly to what has happened on the planet Venus.

    August 10, 2012 at 12:44 pm | Reply
  25. Blog

    I have been exploring for a bit for any high quality articles or blog posts on this kind of area . Exploring in Yahoo I finally stumbled upon this site. Reading this information So i am satisfied to show that I've an incredibly excellent uncanny feeling I found out just what I needed. I most no doubt will make certain to do not fail to remember this site and provides it a glance on a constant basis.

    October 11, 2012 at 11:25 am | Reply
  26. Attorney

    We uncovered your web page by way of research motors even when searching for the actual connected topic, your internet web page demonstrated up. Provide many as a result of you for the fantastic blog. Amazing skills! Hang on man, you rock! Attorney

    August 13, 2013 at 9:15 pm | Reply
1 2

Post a comment


CNN welcomes a lively and courteous discussion as long as you follow the Rules of Conduct set forth in our Terms of Service. Comments are not pre-screened before they post. You agree that anything you post may be used, along with your name and profile picture, in accordance with our Privacy Policy and the license you have granted pursuant to our Terms of Service.


Get every new post delivered to your Inbox.

Join 5,028 other followers