Speaking to climate change skeptics

This week on the show, we spoke to John Cook, proprietor of the website Skeptical Science (www.skepticalscience.com). For over 3 years, John has been responding to the arguments of climate change skeptics with the force of solid, peer-reviewed science.

Read the full transcript of our chat after the jump.

Q: Can you tell us how the website came about, how you got started?

John: I started the site in 2007, and how I actually began was just getting into a few robust discussions with a few family members about global warming. Particularly my father-in-law, he had some quite strong views on it. He’s a fairly die-hard skeptic, I guess you would characterise him. And so you never want to let your father-in-law get the better of  you in an argument.

So I went home and started really researching and looking in-depth into the whole subject of global warming. And, because I’m pretty much just a computer nerd, the way I organised it all was I just created a database of all the different skeptic arguments. And for each argument, I started collecting just what the peer-reviewed science said about each skeptic argument.

And as I started building up this database, I just saw this pattern with all the skeptic arguments. What they all did was, they would just look at one little piece of data and ignore the rest of the full body of evidence. So I just started collecting the full body of evidence for all these different arguments.

Over time, as this database started to grow, I thought maybe other people might find this a useful resource as well. So I put it online.

Q: What will someone find on your website?

Well, the main feature of the site is just a fairly comprehensive list of all the most common skeptic arguments that you would encounter on the internet, or if you see climate skeptics on TV or on the radio. And over the years, I’ve just been recording all the times that I encounter all the arguments, so that the database then gave me a list of the most popular ones.

So for example, the number one argument is blaming global warming on the sun, rather than fossil fuel burning.

Q: So people still say that, do they?

Yes! Yeah, they do. I would have thought that by now it would have fallen out of favour, because over the last half-decade or so the sun’s been steadily getting colder and colder, to the point where in 2009 it was at its coldest levels in over a century.

And meanwhile, the climate’s been getting hotter and hotter, so that last year was the hottest year on record. To me, I would have thought it was obvious, that the sun’s getting colder, the Earth’s getting warmer, that the sun couldn’t possibly be causing global warming.

But, I guess a lot of people look up and see that big, fiery ball in the sky and think, “well that’s a lot bigger than me, so that must be the cause”.

Q: I don’t want to get off topic, but when you say the sun is getting cooler, what does that actually mean? Do we need to send a big bomb up to restart it, like in the movie Sunshine, or is this sunspots again?

Until about 30 or 40 years ago, the amount of light that we were getting from the sun was called the solar constant. We thought it was pretty much staying the same.

But as we started launching satellites and measuring the amount of energy coming from the sun with greater accuracy, we realised that it actually does change. A very small percentage, like 1/1000th, or 0.1%, is how much it would change over a decade or two.

And what the sun does, is over 11 years it has this cycle, where it goes from solar maximum to solar minimum every 11 years.

Q: That’s the famous sunspot cycle, isn’t it?

That’s right, yeah.

And the reason why it gets brighter or dimmer is because of the sunspots that move across the surface of the sun. So where there’s sunspots – they’re like these dark blemishes, kind of like solar pimples, I guess – it’s obviously darker, so there’s less brightness.

But around the sunspots it’s a lot brighter. And so, when there’re more sunspots on the sun’s surface, it’s actually brighter. And so during solar maximum, there are a lot more sunspots; and then during solar minimum, when it gets cooler, there’s less sunspots.

Q: It sounds like a lot more complicated than you’d expect.

The problem is, we can only see the surface of the sun, but what’s causing this is all the turbulence and stuff in the middle of the sun. We don’t really know what’s happening there: we can speculate and create models to simulate what happens on the surface, but predicting what the sun will do in the future is actually quite difficult.

Q: Much like predicting the Earth’s weather is difficult, is that correct?

Well, we know a lot more about what’s happening with our climate than we do with the sun, because we can observe it. We have observation systems all over, in the atmosphere, satellites measuring what’s happening at every layer of the atmosphere, ocean buoys measuring what’s happening in the ocean down to the depths, and weather stations all over the surface.

So our climate is complicated as well, but we do know enough to have a general sense of where our climate is headed.

Q: You’ve had some pretty severe weather up in Brisbane recently – how much of that can we pin on climate change?

It’s a tough question, because weather is obviously chaotic. One of the mantras that climate scientists will say is that you can’t pin climate change on a single weather event.

But what we can do is look at long-term trends. Over time, we’ve observed more and more extreme rainfall events happening – they’re happening more often.

The way I like to think about it is to think of weather as a boxer throwing punches at us. Over history, weather’s always thrown these punches at us – in Brisbane we had floods in 1974, and in the late 1800s we had floods that went through Brisbane as well. So there’s always been these punches coming at us, but what we’re doing now with global warming is like training the boxer to throw harder and faster punches at us.

The way that it’s happening is that, as it’s getting warmer, the ocean’s are getting warmer and sea surface temperatures are going up. And as it gets warmer, as the water gets warmer, you get more evaporation and the atmosphere is able to hold more water.

So all this water vapour is up in the atmosphere – I worked out the other day that over the last 40 years it’s gone up by as much as 900 Sydney Harbours, so that’s how much water vapour is up there.

Q: So it’s no surprise what happened in Brisbane in January, then?

Yeah, so with more water vapour it increases the odds of having an extreme rainfall event, like what we had. Brisbane copped it bad and now it’s heading down south to you guys.

Q: It’s amazing that there are still people who aren’t convinced the world is actually warming. I know that there are fluctuations from year to year and we shouldn’t get too simplistic about it, but it is January now, so how does 2010 compare to previous years on the hotness scale?

2010 was probably the hottest year on record. There are a couple of different temperature records, some by satellites and a couple assembled by thermometers. One of them, by the English Hadley Centre, combining with the Climatic Research Unit, I think their hottest year on record is 1998. But that doesn’t cover the whole globe – what they miss out is the Arctic, where the strongest warming’s happened.

So the temperature records that cover the whole globe, such as NASA, and there’s a European one and a couple of others, they find that either 2005 or 2010 are the hottest years on record. Both of those are pretty much a dead heat as the hottest.

Q: So it’s pretty undeniable then?

Well yes, the temperature is definitely going up, but I think you even need to be aware that there are a lot more signs than just temperature, of global warming happening now.

The ice sheets in Greenland are losing more and more ice: about 20 years ago they were pretty much in balance, it wasn’t really losing any ice. A decade ago it was losing about 100 billion tonnes of ice per year, and now it’s losing over 200 billion tonnes of ice per year.

Q: You’ve got to wonder how much longer it can last.

Well there’s a hell of a lot of ice in Greenland. Currently it’s only contributing, I think, about 1 mm of sea level rise globally, but if it continues, and the whole Greenland ice sheet collapsed, that would contribute 7 metres of sea level rise.

Q: OK, so all this evidence that you’re presenting on your site, and I’ve got to say that there’s a huge wealth of stuff there, you’ve got as you said all the peer-reviewed papers, links to all the data and research at various levels of explanation, from beginner to advanced. Is this getting through? Are you winning over any of the climate change skeptics, or contrarians, or deniers, whatever you want to call them?

I guess there’s really two groups that my site is written for. One is the hardcore climate skeptics, the ones who are very strong in their opinions. But my experience has been that those types of person are very difficult to persuade.

I’ve heard one quote that goes along the lines of “a person whose opinion is not based on facts or evidence is not going to be persuaded by facts and evidence”. I could talk till I’m blue in the face and it probably wouldn’t make a difference.

But who my website is really written for is the much larger majority of undecided people, who are still searching and are genuinely trying to figure out what’s happening with our climate.

Q: And that’s what we need, because despite the fact that 97% of climate scientists agree humans are causing global warming, there is still a lot of debate out there. And both sides of the debate say, “look at the evidence”, but they seem to be looking at different evidence. So it’s very important to have somewhere that people can go to, to sort the fact from the fiction, so to speak.

Yeah, there’s this misconception that it’s their evidence versus our evidence, but there’s no different sets of evidence, there’s only the full body of evidence.

And what you really need to do – in fact, what any genuine skeptic should do, and this is how I would define skepticism – is, you don’t decide what you believe and then gather the evidence to back up your opinion. You first, without coming to a conclusion, you look at what all the evidence says and then the evidence should point you to the natural conclusion.

Q: Excellent. Well, thank you again for joining us John, I want to finish with giving your full website address. So that was skepticalscience.com.

So please, go to the site, or you can download an iPhone app, or an Android app, or a Nokia app I think, so you can carry the answers to all the skeptical arguments around in your pocket.

And also at the site you can take part: you can donate to keep John’s work going, or you can become part of the Skeptical Science community that helps to answer these arguments.

So thanks again for speaking to us, John.

Thanks Chris, it was my pleasure.

And keep up the good work.

Will do.

See John’s full list of rebuttals to skeptic arguments at www.skepticalscience.com/argument.php

Other good places to go for the scientific facts include:

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