John Cook is the Brisbane-based founder and editor of, probably the definitive resource on anti-global warming claims and the scientific responses to them. Regularly updated, the site lists – and breaks down into an assortment of categories and sub-categories – probably every challenge yet made to the scientific evidence that humans are causing global warming. So far, Cook has written detailed responses to 92 of them.

Genuine skepticism, and the importance of thoroughly considering and evaluating evidence before reaching a conclusion, is a constant theme in his site, as is forthright and open discussion. He encourages readers to post new arguments against the evidence for climate change; he runs his discussion board with a zero-tolerance policy for rudeness and personal attacks, from either side, and as a consequence, it is one of the more thoughtful and educational arenas on the Web.

Cook recently spoke with Kieran Mulvaney of Discovery News.


Kieran Mulvaney: When did you first begin to put together your Web site?

John Cook: I

started the Web site around 2007. Before that, I hadn’t paid that much attention

to [the issue]. But I got into a conversation with my father-in-law, who’s a very

diehard skeptic. He handed me a speech by Senator Inhofe. I read his arguments,

and then began researching what the science said, and it surprised me that the

science said the opposite of what he had said. That piqued my curiosity, and I

started looking into skeptic arguments more in depth; at that time, my day job

was doing web programming and building databases, and so I just started

creating a database of all the different skeptic arguments. And as I started

doing that, I started researching what the peer-reviewed science said about all

the different skeptic arguments. And what I found was – well, I found that

there is a pattern. Most of (the skeptic arguments) just focus on a small part of the picture. It might be just a select piece of data. When you look at all the science,

what the full picture is, you can see how that narrow focus can lead to

misleading results, or misleading arguments.

And I thought, “OK, this could be a useful Web site.” So I

started publishing all the arguments, as an encyclopedic reference.


KM: I’m very impressed with the fact that you

have all the arguments, and you have them broken down into all kinds of


JC: I love

graphs, categories and hierarchies and all that kind of stuff. I’ve been

working on that for years, adding each argument as I go, then sub-arguments,

sub-sub arguments. When I get time, I research each one and write a response.

I’ve only written responses to 92 of them, and I think there’s about 260 of

them in there. I would have written responses to all of them if there were 10

times more hours in the day.

KM: One of my favorite aphorisms is “A Little

Knowledge Is a Dangerous Thing.” It seems to me it’s easy for someone to say,

“Oh, climate has always changed,” and thus feel confident in dismissing the reality of anthropogenic causes of current climate change. Rebutting that simplistic assertion can

sometimes be more involved, which it seems to me is a fundamental advantage the

deniers have.

JC: Yes, it is

hard. The first version of my Web site, I would just put the skeptics’ argument

in a single line, and then my answer, which would be pages and pages of

research. And then someone said to me, “Could you just write a soundbite

summary at the top of the page, so I don’t have to read all the way to the

bottom to get the punchline?” And my initial reaction was that you can’t reduce

all this to a soundbite, you have to read it all to get a proper understanding.

But as time has gone on, I’ve realized you have to find a way to boil it down

to a short, concise explanation or you’ll never be able to communicate it to



KM: There is a category of individuals, most of whom seem to lurk on our comments section at Discovery, who are convinced that climate science is some kind of global conspiracy to make Al Gore rich. And they are the kinds of

people who see conspiracies at work everywhere and will presumably never be dissuaded from their views. But there are a lot

of people who don’t have the time or the ability to read through reams of

scientific studies, who see conflicting reports and who would genuinely like to

know what they should believe. Do you have a basic response to those who

genuinely want to know: “Can you tell me in a couple of minutes why I should

believe this global warming stuff?”

JC: We can have

the most confidence in scientific results when we have multiple lines of

measurement showing the same thing. With global warming, there are multiple

lines of evidence that all point to humans being the main contributor. For

starters, we know exactly how much carbon dioxide is being added to the air. We

can double-check that by measuring carbon isotopes in the atmosphere. We can

triple-check that by measuring the amount of oxygen in the air to see if the

amount of oxygen is falling in line with the fossil fuel burning. So we know

we’re causing the rise in CO2.

Now the next step is: What are the effects of all the CO2 in

the air? And we can measure that by satellites that measure how much radiation

is escaping from Earth out into space. And what they are observing is that

there is less radiation escaping at the very wavelengths that greenhouse gases

absorb energy. So that’s the human fingerprint, that CO2 is trapping heat.

Another confirmation of this is that surface measurements also measure the

amount of radiation that is coming back down from the atmosphere, and they find

the same thing: That there is more radiation coming back down at the very

wavelengths that greenhouse gases trap heat. So there are multiple lines of

evidence that CO2 is trapping heat.

Then there’s a mountain of evidence that Earth is warming. We

have surface temperature, we also have satellites measuring the atmosphere

temperature. We’ve got ocean buoys going down to 2,000 meters and measuring

ocean heat, finding that the oceans are accumulating heat. And then there’s all

little signs, all throughout the climate: Species are migrating at different

times because the seasons are changing, the distribution of plants and forests

are slowly moving up toward the poles because it’s getting hotter in the

tropics … Lots of all these different measurements, all pointing to the same

results. It’s not all dependent on one little piece of data; it’s not all dependent

on the hockey stick, or on the data that comes from the University of East Anglia.

The evidence is fairly clear and all points to one result: That humans are the

main contributor to global warming.


KM:I believe it was Gavin Schmidt over at RealClimate who posted a blog

saying that TV crews would come to interview him about the IPCC Himalayan

glacier brouhaha, and would be very surprised when he would dump the Assessment

reports on his desk, and they would see how thick they are, and how much

information is in there. It’s as if they expected a 12-page brochure, with two

pages devoted to Himalayan glaciers.

JC: I think there’s

a really strong attempt to distract people from the physical realities of

global warming – either by tiny little nicks in the IPCC report, or emails

from scientists that are often taken out of context anyway or misunderstood. Anything

to not get people to focus on the melting ice sheets or the retreating

glaciers. If we could get people to refocus on these observed real phenomena,

it might go a long way to getting people thinking and talking about real

science again.



must confess, I totally underestimated the likely impact of the UEA emails,

because it was so obvious that there was no scandal there. But their

exploitation has been a very effective way of casting some doubt on the very

nature of climate science.

JC: There are

thousands of scientists all over the world, all measuring different phenomena,

and all point to the same picture. If you’re of the opinion that every

scientist is dodging up their data – satellite data, on-site data, ocean data –

well, it would have to be the greatest conspiracy of all time. It would make

the Moon landing hoax conspiracy theory seem plausible in comparison. It would

have to be a wide-ranging conspiracy among just about every climate scientist

on earth. There’s no evidence of such a conspiracy. The emails don’t show that

at all: They show a number of scientists struggling with the issues, trying to

understand their data.

KM: You talked about how

much more effective we all need to be about communicating the science. To that

end, you’ve created an iPhone app. I wonder if you can say something about


JC: Late last year, I got an email from a software company in

Melbourne. The owners are passionate about climate and they suggested, “What

about putting together all the contents of the site onto an iPhone app?” The

idea hadn’t occurred to me, but I realized it would be a good way of getting

the science out there. They spent a couple of months developing it, and it came

out in early February. Now they’re working on updating it, adding more features

to it, and possibly different versions for other platforms. It’s got heaps of

attention, which has been good for getting it out there to more people; a

couple of days after the app came out, a skeptic blog uploaded a post saying, “We

have to get the word out to all the skeptics to oppose this app. We need to get

our own app going.”


KM:They seemed

particularly offended by the fact that your site is called Skeptical Science. “Oh,

it has the word ‘Skeptical.’ It must be on our side.” The post was like a

warning: “Do not be hoodwinked by the word ‘skeptic’”.

JC: Yeah, that’s right. I consider myself a skeptical person. Skepticism is a theme of the site. To

me, skepticism is not believing what someone tells you, investigating all the

information before coming to a conclusion. Skepticism is a good thing. Global warming skepticism is not

that. It’s the complete opposite of that. It’s coming to a preconceived

conclusion and cherry-picking the information that backs up your opinion. Global

warming skepticism isn’t skepticism at all.