Global Surface Temperature Change

I really enjoyed reading “Global Surface Temperature Change“, by James Hansen and his team at GISS. Keep in mind that it’s still in the draft stages – they haven’t submitted to a journal yet, but they certainly plan to, and it’s a very credible team of scientists that will almost definitely get it published.

The paper is mostly about the methods of global temperature analysis. It’s more of a review paper than an account of a single experiment. However, their main discussion point was that even by using the same data, problems can be addressed in different ways. The two main problems with temperature analysis are:

  • “incomplete spatial and temporal coverage” (sparse data)
  • “non-climatic influences on measurement station environment” (urban heat island effect).

The authors explain the methods they use and why, and explore the impacts that different methods have on their results.

GISS measures anomalies in the temperatures, largely because they are much smoother and more consistent, geographically, than absolute temperatures. In 1987, they determined that anomalies could be safely extrapolated for a radius of 1200 km from a station and still be accurate. GISS smooths the whole map out by extrapolating everything and averaging the overlapping bits.

Extrapolating is also very useful in areas with very few stations, such as the polar regions and parts of Africa. In this map, grey indicates missing data:



The Arctic is particularly problematic, not only because its data is so sparse, but also because it has the largest anomaly of any region in the world. If you have incomplete coverage of an area that is warming so dramatically, it won’t pull its full weight in the global trend, and your result will almost certainly be too low.

This difficulty with the Arctic is the reason that GISS says 2005 is the warmest year on record, while HadCRUT, the team in England, says that 1998 is. GISS extrapolates from the stations they have, and end up getting pretty good coverage of the Arctic:

They’re assuming that areas with missing data have the same anomaly as whatever temperature stations are within 1200 km, which, as they determined in 1987, is a pretty fair assumption.

However, HadCRUT doesn’t do this extrapolating thing. When they don’t have data for an area, they just leave it out:

This might sound safer, in a way, but this method also makes an assumption. It assumes that the area has the same anomaly as the global average. And as we all know, the Arctic is warming a lot more and a lot faster than the global average. So it’s quite possible that GISS is right on this one.

Another adjustment that NASA makes is for local, anthropogenic, non-climatic effects on temperature data. The most obvious of these is the urban heat island effect. As an area becomes more urban, it gets more pavement, less vegetation, and its albedo goes down – it absorbs more heat. This often makes cities substantially warmer than the surrounding rural areas, which can obviously contaminate the temperature record. However, there are ways of eliminating urban influences from the data so we can see what the real trend is.

The first step is determining what stations are considered urban. The obvious way to do this is through population, but that’s actually not very accurate. Think of somewhere like Africa, where, even if there are thousands of people living in a small area, the urban influences such as concrete, absence of vegetation, or exhaust aren’t usually present. A much better indication is energy use, and a good proxy for energy use, that’s easy to measure, is lights at night-time.

So GISS put a bit of code into their analysis that singles out stations where nightlight brightness is greater than 32 µW/m2/sr/µm, and adjusts their trends to agree with rural stations within 1200 km. If there aren’t enough rural stations within that radius, they’ll just exclude the station from the analysis.

They did an even more rigorous test for this paper, to test just how much urban influences were contaminating the long-term trend, and it was pretty interesting.

There were enough stations considered “pitch-dark” at night, where they couldn’t detect any light, to run a global analysis all by themselves. The trend that came out was <0.01 °C/century smaller than GISS’s normal calculation, an amount of error that they described as “immeasurably small”.

The result of all this temperature analysis is a graph, with one new point every year, that is “eagerly awaited by some members of the public and the media”:

However, this graph isn’t actually as useful as this one – the 12-month running mean:

“From a climate standpoint there is nothing special about the time  of year at which the calendar begins”, so instead of only measuring January-December, you can also do February-January, March-February, and so on. This way, you get a data point every month instead of every year, and more data means more accuracy. It also solves problems with short-term influences, such as El Nino, La Nina, and volcanic eruptions, that the annual graph was having. These fleeting, but fairly substantial, influences can fall completely into one calendar year or be split between two – so their influence on global temperature could be overestimated or underestimated, depending on the starting month of the calendar. The 12-month running mean is much less misleading in this fashion.

As it is, we just set a new record for the 12-month running mean, and unless La Nina really takes off, 2010 will likely set a new record for the annual graph as well. But the authors argue that we need to start moving away from the annual graph, because it isn’t as useful.

The authors also discuss public perception of climate change, and media coverage of the issue. They say, “Our comments here about communication of this climate science to the public are our opinion…[We offer it] because it seems inappropriate to ignore the vast range of claims appearing in the media and in hopes that open discussion of these matters may help people distinguish the reality of global change sooner than would otherwise be the case.”

They make the very good point that “Lay people’s perception tends to be strongly influenced by the latest local fluctuation”, and use this winter as a case study, where a strongly negative Arctic Oscillation index caused significantly cooler-than-normal conditions across the United States and Europe. Consequently, a lot of people, especially in the US, began to doubt the reality of global warming – even though, in the world as a whole, it was the second warmest winter on record:

The authors also talk about data sharing. GISS likes to make everything freely available to the public – temperature station data, computer code, everything. However, putting it out there immediately, so that anyone can help check for flaws, has “a practical disadvantage: it allows any data flaws to be interpreted and misrepresented as machinations.” Multiple times in the past few years, when there have been minor errors that didn’t actually change anything, GISS was widely accused of making these mistakes deliberately, to “intentionally exaggerate the magnitude of global warming”. They realized this wasn’t working, so they changed their system: Before releasing the data to everyone, they first put it up on a private site so that only select scientists can examine it for flaws. And, of course, this “has resulted in the criticism that GISS now “hides” their data”.

Personally, I find the range and prevalence of these accusations against scientists absolutely terrifying. Look at what has become mainstream:

Scientific fraud is a very serious allegation, and it’s one thing for citizens to make it without evidence, but it’s another thing altogether for the media to repeat such claims without first investigating their validity:

I have been disgusted by the media coverage of climate science, especially over the past year, especially in the United States, and I worry what this will mean for our ability to solve the problem.

However, there is still fantastic science going on that is absolutely fascinating and essential to our understanding of global climate change. This paper was a very interesting read, and it helped me to better understand a lot of aspects of global temperature analysis.

Deniers?

I really enjoyed New Scientist’s Special Report: Living in Denial. What a fascinating phenomenon, and a fascinating batch of articles exploring it.

The denial of science is a growing problem. It’s not restricted to a particular ideology – while denying the harmful effects of smoking or the existence of climate change is typically a position of the far right, vaccine denial and H1N1 conspiracy theories are largely restricted to the left.

It occurs even among the well-educated, or among youth who are still immersed in up-to-date curricula. For example, this year at the university, a student group put up signs saying “Don’t get the swine flu shot – it contains mercury!” The chemistry students got mad, and said that labelling thimerosal as toxic mercury was comparable to saying “Don’t eat table salt, it contains chlorine gas!”

As Michael Shermer’s article explains, the defining mark of science denial is a refusal to change one’s mind based on evidence. This is easy to identify for something like Holocaust denial, where evidence is abundant in the public sphere.

It gets a little harder for more technical issues like climate change or vaccines. Scientific opinion is overwhelmingly on one “side”, but the average person does not know or understand the evidence to support this consensus. An article about the thermodynamics of the stratosphere won’t sell a lot of papers. Most people unconsciously follow the credibility spectrum and trust what their doctor or NASA scientists say.

However, some don’t realize that scientific credibility is not the same as an appeal to authority, and so express contrarian opinions. Vaccines cause autism. Global warming is nonexistent/natural/inconsequential. The way that the Twin Towers fell proves that it was orchestrated by the US government.

There are two groups of contrarians: the skeptics, and the deniers. The skeptics are the ones who will change their minds based on evidence – they just haven’t encountered that evidence yet. My favourite example of this is from the Friends episode when Phoebe declares she doesn’t believe in evolution. When Ross starts talking to her about fossils, she says, “Oh. I didn’t know there was actually evidence.”

It’s amazing how many insights you can get out of a supposedly “fluffy” sitcom. I could write an entire essay analyzing that clip…..

I have met dozens of very reasonable people who doubt climate change because they don’t know about the evidence for it. People my age throw around the phrase “it’s a natural cycle” a lot, until I explain that the climate doesn’t act like a pendulum. It doesn’t have to compensate for past periods of warming or cooling – it simply responds to forcings. If the forcing is cyclical, then the climate will be cyclical, but some forcings are a different shape altogether. Similarly, I know a teacher who previously thought that natural causation of the current warming was a legitimate scientific theory, due to a presentation from a teacher’s conference….until I did a bit of probing and discovered that this presentation was given by Tim Ball.

These people are very reasonable. They are willing to change their minds based on evidence. They’ve just been unlucky enough to be misinformed by our flawed system of science journalism.

Then there are the deniers. They call themselves skeptics, but they will not change their minds, no matter what evidence you give them. They either move the goalposts, change the subject, or continue to repeat the same claim even after you have rebutted it patiently multiple times. Go check out some YouTube comments to see what I’m talking about.

Often their ideology or worldview is extreme in some way. For many members of the far right, any problem that would be solved by the government (think cap-and-trade or smoking legislation) will be rejected out of hand. On the far left, anything that would benefit corporations (usually vaccines or traditional medicine) will face a similar reaction. As Michael Specter says, “We hate Big Pharma. We run away from Big Pharma….and leap right into the arms of Big Placebo.”

This phenomenon suggests that science communication is not the answer – for deniers. I learned long ago that trying to change the minds of deniers is a complete waste of time. However, I still feel that science communication and the rebuttal of common misconceptions is absolutely vital. The true skeptics need access to the evidence they are lacking, so that they will be more informed, and our population will move farther towards solving the many science-related problems we face.

These skeptics deserve our time, our efforts, and our respect. They are the target audience of my blog, even if my most active commenters and supporters are a different group altogether. The reason that any of us here do all this work in communication, I believe, is for the true skeptics.

Michael Fitzpatrick argues that we shouldn’t use the label “deniers” at all. I wouldn’t want to alienate the true skeptics by coming across as someone who insults others. However, I think that calling deniers “skeptics” is unfair to the skeptics. They are two completely different groups that we must distinguish between. Skepticism is a worthy quality in science, and giving the complimentary title of “skeptic” to someone who doesn’t deserve it is unfair to those who do. We need to cater to the people who are willing to learn and who don’t want to waste our time. Science communication shouldn’t have to be like No Child Left Behind.

Michael Shermer’s second article, similarly, says that we should participate in debates with deniers and give them a chance to be heard. The truth will prevail, he argues, even if the deniers refuse to give in. I would agree with this position if it were a matter of opinion or policy, which is wholly democratic. Yet science is completely different. Science isn’t about free speech and giving equal time for all views. It is about giving time to those who have the most accurate analyses and robust conclusions. In science, you shut up and listen until your ideas are strongly supported by evidence. Then you publish.

When papers skeptical of climate change get published (all three per year!), such debates are worthy. The authors passed the test of peer-review, and even if their papers are obviously sub-par and are soon to be retracted, they deserve some debate and discussion. Let’s debate contrarian science when it is actually science – when it is actually published.

By paying close attention to and publicly debating with the authors of blog science, however, we are further confusing the public’s already skewed image of science. “It doesn’t matter whether or not you publish,” we seem to be telling them, “it’s all about free speech.” The scientific process has rules, and if deniers can’t pass the necessary, but not sufficient, condition of peer-review, their work doesn’t deserve to be treated as scientific research, and we shouldn’t give them our attention.

Let’s ignore the people who aren’t worth our time, because we have limited time, and there are people out there who deserve every minute of it.

A Better Credibility Spectrum

It’s been over a year since I wrote The Credibility Spectrum, my first post ever. Since then I’ve learned a lot, and have altered the credibility spectrum in my own mind – so I thought I’d alter it here, too.

This credibility spectrum is sort of split into two: the scientific community, and the non-scientific community. The scientific community starts with scientists, and I want to stress that this category only includes scientists with experience in the issue at hand. Just because someone has a PhD in one area of science doesn’t mean that they are an expert in all areas. For example, it’s very easy for a computer scientist to go through ten years of university without studying any biology at all.  Treating them as an expert in evolution, therefore, would be illogical.

These scientists write peer-reviewed papers, published in journals like Nature and Science, which are another step up the credibility spectrum. Instead of just having the name of an expert attached to them, their methods and conclusions have been evaluated for robustness and accuracy. This is the minimum level of credibility from which I recommend citing scientific claims.

However, as thousands of papers are published every month, and they’re generally studying the frontier of their field, it’s inevitable that some of them will be proven wrong later. As Gavin Schmidt and Michael Mann wisely said, peer review is a necessary but not sufficient condition.

That’s why there are scientific organizations and assessment reports, like NASA or the IPCC, which compile peer-reviewed knowledge which has stood the test of time into consensus statements. Even the top level of the credibility spectrum isn’t infallible, but it sure has a low error rate compared to other sources.

Everyone who isn’t a scientist, which is most of us, falls into the lower half of the credibility spectrum. The category I refer to as “communicators” includes the mainstream media, projects like Manpollo or 350.org, high school teachers, politicians…….They’re not part of the scientific community, so you should always always always check their citations, but they’re held more accountable for what they say than just any random person on the street. If they make glaring errors, people will be more upset than if the same errors were made by individuals – comments on YouTube, discussions with your neighbours – which make up the lowest rung of our credibility spectrum.

Something that I found really interesting  when I put this together was the general flow of information between different sources. In the scientific community, research starts with scientists, and the best research is published in journals, and the best journal articles are picked up by major organizations. As the scientific knowledge progresses through the different sources, the weaker assertions are weeded out along the way. The flow of information is going up the pyramid, towards the narrower part of the pyramid, so that only the best is retained.

However, in the non-scientific community, the flow of information goes the other way. Communicators present information to individuals, which is a much larger group. Information travelling down the pyramid, instead of up, allow rumours and misconceptions to flourish much more easily.

This isn’t to say that, when they come head-to-head, organizations are always right and individuals are always wrong. But given the history of such disagreements, and the levels of credibility involved, you’ll know where to place your bets.

We Have Slides!

After a marathon PowerPoint-session yesterday I finally got my 63 slides out of the way. Here is the presentation for anyone who is interested. The script is written in the notes beneath the slides.

I like to have things fading in and out of my slides, so sometimes the text boxes and images are stacked on top of each other and it won’t make sense until you view the animation.

Researching the median lethal dose of arsenic during my spare at school was really awkward. I had to do a lot of hasty explaining to my friends about how it was a metaphor for small concentrations having large effects, and no, I wasn’t planning to poison anyone.

Anyway, enjoy.

Mind the Gap (12 MB)

Mind the Gap

This is the script of a presentation I will make to several groups of high school students on Earth Day. I was originally going to use the same script from my PowerShift presentation, but in light of recent developments and my ever-expanding thoughts on climate change, I decided to create an entirely new presentation.

I would greatly appreciate any thoughts, input, suggestions, etc. Keep in mind that I don’t have my PowerPoint created yet, so some of the text may seem a little confusing without the visuals I’ll be pointing to.

Enjoy!

Update: Thanks for all the helpful comments and critiques. I’ve made some changes here, but feel free to keep them coming.

Welcome everyone, nice to see you all here. My name is Kate, I’m in my last year of high school, and I am here to talk to you about climate change, or global warming. After I graduate I want to be a climate scientist, so until then, I’m channelling my obsession into a website. For the past year, I’ve been writing the blog ClimateSight.org, which has allowed me to meet a lot of cool people and correspond with a lot of scientists.

I’ve spent several years doing a lot of research on climate change, and something that’s been really interesting to me is the link between climate scientists and the public – the communication between these two groups. And the very first thing I want to talk about is assessing credibility, which is probably the most important tool I can give you. How much weight should you give different statements from different sources about scientific issues?

The scientific community that is actually studying the issue is going to be more credible than the media and the public. And that scientific research starts with scientists. They write peer-reviewed articles, published in journals like Nature or Science. Anything that is a serious scientific idea will be in one of these journals at some time or other. But there are thousands of journal articles published every month, and because they’re generally studying the frontier of their field, it’s inevitable that some of them are going to be proven wrong later. That’s why there are scientific organizations and assessment reports that look back at all these papers and compile what we know about the major issues. So statements from organizations like NASA, or from assessment reports like the IPCC, means that something has stood the test of time.

Among all the people who are not scientists, some know more than others. People who communicate science, like journalists and high school teachers and some politicians, are held a little more accountable for what they say than just any random person on the street.

So let’s see what the different levels of the credibility spectrum say about global warming. Who would disagree – who would say that humans are not causing the Earth to warm? 0% of scientific organizations say no. Pretty much 0% of peer-reviewed articles say no – there is the odd one out there, but they’re so small in number that they round right down to zero. And less than 3% of publishing climatologists say no. But 57% of articles in leading newspapers say no (or probably not, or maybe, maybe not), and 53% of the public says no.

As you can see, there is a big gap right here. The top half of the credibility spectrum is very confident about human-caused global warming, and the bottom half is very confused. Why is this? How can an issue that is so important to public policy have such drastically different levels of support between those who study it and everyone else?

There are all kinds of common objections that you and I hear about global warming. What if it’s a natural cycle and we’re just coming out of an ice age? What if the Sun is heating up? And how could there possibly be global warming when it is so cold outside? There are all kinds of arguments against the idea of climate change that everybody knows. But the scientific community is still saying this. They are still sure that yes, it’s going on and yes, it’s us.

So there are three possible explanations. Scientists could be ignorant and overconfident. Maybe they never considered the idea it could be a natural cycle. Scientists could be frauds, part of some Communist conspiracy to take over the world somehow. Or, maybe scientists know what they’re doing, and have evidence to say what they’re saying. So let’s look at the evidence that they do have.

We’ve been studying this problem for a long time, and it all started in the 1800s, when the greenhouse effect was discovered – the gases in the atmosphere that trap heat and keep the planet warm enough for life. The idea that emissions of carbon dioxide from our burning of fossil fuels – like coal, oil, and natural gas – would eventually cause warming was first proposed in 1896. So this is not a new theory by any means.

We began measuring the carbon dioxide content of the atmosphere in the 1950s, and we can see that it’s steadily going up. Over the last 2.1 million years, CO2 never exceeded 300 ppm, but right now it’s at 390. This might not seem like a lot, but 390 ppm of arsenic in your coffee would kill you.

We can confirm that this increase in CO2 is due to human activity because of its isotopes. The carbon in CO2 from fossil fuels has fewer neutrons, on average, than CO2 from natural sources like volcanoes or the ocean. That makes it lighter, so we can tell the difference in samples from the air.

So we know that an increase in greenhouse gases causes warming, and we know that we are increasing greenhouse gases. So it’s not really a surprise that we’re starting to see the warming show up. There are five independent research teams worldwide that measure the average global temperature, some from weather stations and some from satellites, and all five of them are finding a very similar pattern of warming since about 1975.

But what if it’s a coincidence? What if something else was causing the warming, and it just happened to be at the same time that we were dumping fossil fuels into the air? Something that a lot of people don’t know is that there are ways that we can confirm that the warming is caused by us. First of all, there’s nothing else going on that could be causing it. Actually, if you took human activity out of the picture, we would be slowly cooling: the cycles of the Earth’s orbit show that we should be very very slowly going into a new ice age.

There is also a specific pattern of warming we can look at. If warming were caused by the sun, the entire atmosphere would warm in a uniform fashion. But if greenhouse gases were causing global warming, the first layer of the atmosphere (the troposphere) would be warming, but the next layer up, the stratosphere, would be cooling. This is referred to as the “fingerprint” of greenhouse warming, because it’s like DNA evidence or the smoking gun. And that’s exactly what we’re seeing – stratospheric cooling. (Randel et al, 2009).

So we can be very sure that yes, our activities are causing the Earth to warm, at a rate that we haven’t seen for at least the past 55 million years, which was before humans even existed. That’s really the problem – the rate of change. It’s not the actual temperature that poses a threat, it’s all about how much it changes and how fast. The world has been plenty warmer than this at times, like when dinosaurs were around. And dinosaurs were okay with that because it had been like that for a really long time and they had adapted to it. But a change in temperature at the rate we’re seeing now? It might seem slow to you and me, but on a geological timescale, it’s incredibly quick, too quick for species – including humans – to adapt. Yes, the climate has changed many times before, but it never really ended well.

For example, the largest extinction in our Earth’s history, the Permian extinction 250 million years ago, was most likely caused by warming from greenhouse gases that came out of supervolcanoes much larger than anything we have today. It got so warm that the ocean couldn’t hold any oxygen and produced hydrogen sulphide instead. That’s what makes rotten eggs smell bad, and it’s actually poisonous in large enough quantities. It killed 97% of species in the ocean and 70% of species on land. It has been nicknamed “The Great Dying”. So this is the absolute worst-case scenario of what can happen when too many greenhouse gases go into the atmosphere at once. It means a whole lot more than just nicer Winnipeg winters.

So, to the people who really look at this issue, the evidence is undeniable. In academic circles, there really is no argument. All the objections that we have – they thought of them long ago, and covered them all, and ruled all of them out, before you and I even knew what global warming was. The evidence for climate change is not a house of cards, where you take one piece out and the whole theory falls apart. It’s more like a mountain. Scrape a handful of pebbles off the top, but the mountain is still there.

As for the second option, that scientists are part of a conspiracy – if you stop and think about it, like, really? Scientific fraud happens, but on the scale of one paper, or at the most one scientist, not an entire field stretching back for over a century. Scientists are not that organized. And that only leaves one explanation – that the field of climatology does know what it’s doing, and does have evidence to say what it’s saying: that humans are causing the Earth to warm, and it’s not going to be good.

We’ve established that the top half of the credibility spectrum is the one that we can trust on this issue. So what’s going on in the communication between the top and the bottom so that the public has got totally the wrong idea? This is what I spend most of my time working on, and there are a lot of factors involved, but it really comes down to three points.

Firstly, climatology is a complex science, and it’s not a required course in high school, so the public doesn’t understand it the way they understand Newton’s Laws of Motion. Most people do not know all this stuff I just told you, and that’s only scratching the surface; there is so much more science and so many more lines of evidence. And when you only have bits and pieces of this story, it’s easy to fall prey to these kinds of misconceptions.

Second, there are, sadly, a lot of people out there trying to exploit number one. There are a lot of very prominent people in the media, politics, and industry who will use whatever they can get – whether or not it’s legitimate, whether or not it’s honest – as proof that global warming is not real. You’ll hear them say that all scientists said an ice age was coming in the 70s, so we shouldn’t trust them now. In reality, most scientists were predicting warming by the 70s, and the single paper to talk about an ice age was proven wrong almost immediately after its publication. You’ll hear them say that volcanoes emit more CO2 than humans, but volcanoes only emit about 1% of what we do. They’ll say that the Greenland ice sheet is getting thicker, so therefore, it cannot be warming. But the reason that Greenland is getting thicker is that it’s getting more snow, caused by warmer temperatures that are still below zero.

Some of these questionable sources are organizations, like a dozen or so lobby groups that have been paid a lot of money by oil companies to say that global warming is fake (Hoggan and Littlemore, 2009). Some of them are individuals, like US Senator James Inhofe, who was the environment chair under George W. Bush, and says that “global warming is the greatest hoax ever imposed upon the American people.” Some of them have financial motivations, and some of them have ideological motivations, but their motivations don’t really matter – all that matters is that they are saying things that are inaccurate, and misleading, and just plain wrong.

The third reason that the public is so confused about climate change is that the media has been very compliant in spreading the message of these guys. You would expect that newspapers and journalists would do their research about scientific issues, and make sure that they were writing science stories that were accurate, but sadly, that’s not what’s happening.

One of the major problems is that there are fewer journalists than there used to be, and there are almost no science journalists in the mainstream media – general reporters cover science issues instead. Also, a few decades ago, journalists used to get a week or two to write a story. Now they often have less than one day, because speed and availability of news has become more important than quality.

And, finally, when it comes to climate change, journalists follow the rule of balance, or presenting “two equal sides”, staying neutral, letting the reader form their own opinion. This works really well when the so-called controversy is one of political or social nature, like tax levels, a federal election, how we should develop infrastructure. In those cases, there is no real right answer, and people usually are split into two camps. But when the question at hand is one of science, there is a right answer, and some explanations are better than others. Sometimes the scientists are split into two equal groups, but sometimes they’re split into three or four or even a dozen. And sometimes, like we see with climate change, pretty much all the scientists are in agreement, and the two or three percent which aren’t don’t really publish, because they can’t prove what they’re saying and nobody really takes them seriously. So framing these two groups as having equal weight in the scientific community is completely wrong. It exaggerates this extreme minority, and suppresses everyone else.

All these problems are perfectly explained by a man named James Hrynyshyn, a journalist himself. He says, “Science journalism….is too often practiced by journalists who know so little about the subject they’re covering that they can’t properly evaluate the reliability or trustworthiness of potential sources. The result is that sources with no credibility in the field routinely appear alongside genuine experts as part of an effort to provide balance.”

One of the best examples of how this kind of journalism can really go wrong happened quite recently. Someone hacked into the email server of the Climatic Research Unit in the UK, stole thirteen years of emails between scientists, sifted through them all to find the juiciest ones, and put them on the Internet. The police are trying to figure out who did this, because it’s quite illegal, but it wasn’t some teenage kid in their basement.

Some of the emails certainly were embarrassing, the scientists said some things that weren’t very nice and insulted some people. But can you imagine if all of your email was released to the world? Scientists are people too, and they say stupid stuff that they don’t mean over email just the same as you and I do – especially when there are so many people actively spreading lies about their work.

The most important thing, though, is that there was nothing in there that compromised any science, any data sets, anything that we know about climate change. Nothing actually changed…..but the scary part was that a striking amount of the media reported that the entire field of climate science was potentially a political scam.

For example, some scientists are working on reconstructing temperatures from before we had thermometers, using tree rings or ice cores or ocean sediment. In one of the most widely circulated emails, the scientists discussed how to “hide the decline” in a set of tree ring data that’s known to have some serious problems – the tree growth is going down while thermometers show local temperatures going up, which is the opposite of what you’d expect. It probably means there was a drought or something. So they were trying to see if they could still use the first part and cut out the useless part at the end. They’re only hiding it in a mathematical sense, they’re not hiding it from their colleagues or from the media. In fact, they’ve written about this decline in one of the most prestigious scientific journals in the world, so if they’re trying to pull off a conspiracy here, they’re not doing a very good job.

But somehow, in the media, the story changed. Instead of saying that scientists were “removing regional tree ring data known to be erroneous,” the media said they were “covering up the decline in global temperatures”. That’s so fundamentally different, so removed from the facts – these scientists don’t even work with global temperatures! – but you heard it everywhere. The story that reached virtually every newspaper in the world was that the world is cooling and scientists are trying to hide it from us.

That’s only one example of how a single phrase can be taken out of context and have its meaning completely twisted. It doesn’t surprise me, you see it from these guys all the time, but what absolutely amazes me is how the media just sat and lapped it right up without doing any research into the validity of these serious allegations.

Subsequently, two independent investigations into the contents of these emails have been released, and the scientists involved were basically cleared in both cases. The British Parliament found that “the focus on CRU has been largely misplaced”, that the scientists’ “actions were in line with common practice”, that “they were not part of a systematic attempt to mislead”, and that all of the CRU’s “analyses have been repeated and the conclusions have been verified”. (British House of Commons, 2010). The University of East Anglia found “no evidence of any deliberate scientific malpractice in any of the work of the CRU”, “no hint of tailoring results to a particular agenda”, and that “allegations of deliberate misrepresentation and unjustified selection of data are not valid”. (UEA, 2010) So this affirms what the climate science community already knew: the stolen emails do not change the science one bit.

But look at what newspapers told us for weeks on end. Every time the Winnipeg Free Press mentioned the emails, they would say something along the lines of, “The correspondence appears to suggest researchers may have manipulated data to exaggerate global warming.” These are very serious allegations to make, and they were made without evidence in serious, credible and widely read newspapers, and they’re not being retracted or corrected in the media now that the investigations are coming up clear.

Spencer Weart, who is a science historian, had some great words to say on this issue: “The media coverage represents a new low. There are plenty of earlier examples of media making an uproar without understanding the science….but this is the first time the media has reported that an entire community of scientists has been accused of actual dishonesty. Such claims….would normally require serious investigation. But even in leading newspapers like The New York Times, critics with a long public record for animosity and exaggeration are quoted as experts.”

Many of the scientists featured in the emails received death threats. Phil Jones, the director of CRU, says that he’s been suicidal. The story of these stolen emails is not a story of scientists engaged in conspiracy – it is a story of how desperate some people are to make it seem that way, and how gullible and irresponsible the mainstream media can be.

And not long after that, story after story broke that the IPCC, which is a huge UN publication about everything we know about the science of climate change, had all kinds of mistakes in it. So what were these mistakes? In 3 000 pages, two examples of overestimating climate change were found. First, the report said that the Himalayan glaciers would disappear by 2035, and we now know that it’s going to take a lot longer than that. Second, it said that 55% of the Netherlands is below sea level, when in fact 55% of the Netherlands is susceptible to flooding, and only some of that is below sea level. This last one is background information. It really isn’t all that relevant.

So should that have happened? No. But does it actually matter to our understanding of the science? No.

Then several British journalists managed to invent five or six other “IPCC scandals”. When these were investigated more seriously, they were found to be completely false. But they were still reported in virtually every newspaper around the world. Again.

However, the IPCC has made a lot of mistakes, much more serious than these, that none of the newspapers are reporting. The difference is that the mistakes that make the media scream scandal are examples of overestimating climate change, while the ones you don’t hear about are examples of underestimating climate change. There was recently a report published that evaluated the last IPCC report, and this is what it found:

Over the past three years, there was about 40% less Arctic summer sea ice than the IPCC predicted, and melting in the Arctic is far exceeding its worst case scenarios. Recent observed sea level rise is about 80% more than the IPCC predicted.  Global sea level by 2100 is expected to rise at least twice as much as the IPCC predicted. (Copenhagen Diagnosis, 2009)

So which seems more important? The exact date at which a specific glacier is expected to melt? Or the amount of sea level rise we can expect all over the world? I have yet to find a newspaper in the world that covered this, but I have yet to find a newspaper in the world that did not cover this. Yes, the IPCC makes mistakes, but they are almost always mistakes that say, “oops, it’s going to be worse than we thought.”

So, as you can see, the real message about the reality and severity of climate change is not getting through. Communication of science is always important, but it’s especially important for climate change, because it could potentially screw up our civilization pretty bad, and we want to minimize that risk.

Scientists, in general, are not that great at public communication – that’s why they’re scientists and not journalists or salesmen or whatever. They want to sit in the lab and crunch numbers. And there’s always been sort of a stigma in the scientific community against talking to the media or the public. But the one good thing about all these rumours and all this awful journalism is that it’s finally making the scientific community wake up and realize how bad things are and how much their voice and their input is needed.

In the period of just a few months, over 300 American climate scientists signed an open letter to the US government about how two small mistakes in the IPCC do not impact the overall message that humans cause climate change, and should not impact our efforts to stop it.

And the National Academy of Sciences, which is one of the most prestigious organizations in the world – 1 out of 10 members have a Nobel Prize – has all sorts of plans for public lectures and articles in newspapers and a science show on prime time television.

The one good thing about things getting this bad is that it makes the people involved mad enough to step up and finally try to stop it. To finally narrow this gap that has existed for so long. That’s why I’m here today, that’s why I’ve been writing my blog for over a year, because I’m mad, and if I don’t do anything about it my head is going to explode. I cannot just sit and watch while these rumours threaten our ability to preserve a good future for me and for us and for everyone who will come after us. And I sincerely hope that all of you will not just sit and watch it happen either. We need to fix this together.

Academic Culture From the Inside – a Guest Post by Steve Easterbrook

Steve Easterbrook is a comp-sci professor at the University of Toronto who has also worked at the University of Sussex and NASA. Recently, he decided to apply his software engineering expertise to the challenge of climate change, particularly relating to climate models.

This post began as a comment on a recent RealClimate post about media coverage of the CRU hack. I liked it so much that I requested his permission to reprint it here. Enjoy!

I’m afraid to say that a lot of the personal emails between academics in any field are probably not very nice. We tend to be very blunt about what appears to us as ignorance, and intolerant of anything that wastes our time or distracts us from our work. And when we think (rightly or wrongly) that the peer review process has let another crap paper through, we certainly don’t hold back in expressing our opinions to one another.

Of course, this is completely different to how we behave when we meet one another. Most scientists seem able to distinguish clearly between the intellectual cut and thrust (in which we’re very rude about one another’s ideas) and social interactions (in which we all get together over a beer and bitch about the downsides of academic life). Occasionally, there’s someone who is unable to separate the two, and takes the intellectual jabs personally, but such people are rare enough in most scientific fields that the rest of us know exactly who they are, and try to avoid them at conferences!

Part of this is due to the nature of the academic research. We care deeply about intellectual rigor, and preserving the integrity of the published body of knowledge. But we also know that many key career milestones are dependent on being respected (and preferably liked) by others in the field, such as the more senior people who write recommendation letters for tenure and promotion and honors, or the scientists with competing theories who will get asked to peer review our papers, etc.

Most career academics have large egos and very thick skins. I think the tenure process and the peer review process filter out those who don’t. So, expect to see rudeness in private, especially when we’re discussing other scientists behind their backs with likeminded colleagues, coupled with a more measured politeness in public (e.g. at conferences).

Now, in climate science, all our conventions are being broken. Private email exchanges are being made public. People who have no scientific training and/or no prior exposure to the scientific culture are attempting to engage in a discourse with scientists, and these people just don’t understand how science works. The climate scientists whom they attempt to engage are so used to interacting only with other scientists (we live rather sheltered lives- they don’t call it the ivory tower for nothing) that they don’t know how to engage with these outsiders. What in reality is a political streetfight, we mistake for an intellectual discussion over brandy in the senior commonroom. Scientists have no training for this type of interaction, and so our responses look (to the outsiders)  rude, dismissive, and perhaps unprofessional.

Journalists like Monbiot, despite all his brilliant work in keeping up with the science and trying to explain it to the masses, just haven’t ever experienced academic culture from the inside. Hence his call, which he keeps repeating, for Phil Jones to resign, on the basis that Phil reacted unprofessionally to FOI requests. You don’t get data from a scientist by using FOI requests, you do it by stroking their ego a little, or by engaging them with a compelling research idea you want to pursue with it. And in the rare cases where this doesn’t work, you do the extra work to reconstruct it from other sources, or modify your research approach (because it’s the research we care about, not any particular dataset itself). So to a scientist, anyone stupid enough to try to get scientific data through repeated FOI requests quite clearly deserves our utter contempt. Jones was merely expressing (in private) a sentiment that most scientists would share – and extreme frustration with people who clearly don’t get it.

The same misunderstandings occur when outsiders look at how we talk about the peer-review process. We’re used to having our own papers rejected from time to time, and we learn how to deal with it – quite clearly the reviewers were stupid, and we’ll show them by getting it published elsewhere (remember, big ego, thick skin). We’re also used to seeing the occasional crap paper get accepted (even into our most prized journals), and again we understand that the reviewers were stupid, and the journal editors incompetent, and we waste no time in expressing that. And if there’s a particularly egregious example, everyone in the community will know about it, everyone will agree it’s bad, and some will start complaining loudly about the editor who let it through.

Yet at the same time, we’re all reviewers, so it’s understood that the people we’re calling stupid and incompetent are our colleagues. And a big part of calling them stupid or incompetent is to get them to be more rigorous next time round, and it works because no honest scientist wants to be seen as lacking rigor. What looks to the outsider like a bunch of scientists trying to subvert some gold standard of scientific truth is really just scientists trying to goad one another into doing a better job in what we all know is a messy, noisy process.

The bottom line is that scientists will always tend to be rude to ignorant and lazy people, because we expect to see in one another a driving desire to master complex ideas and to work damn hard at it. Unfortunately the outside world (and many journalists) interpret that rudeness as unprofessional conduct. And because they don’t see it every day (like we do!) they’re horrified.

Now We’re Talking!

Another batch of private emails from climate scientists has been leaked/hacked/stolen/whatever. These ones, though, are very different than the last.

It’s a thread of emails from the NAS, and these guys are mad. They are mad about vested interests skewing the discussion. They are mad that journalists have sat and lapped it right up without checking their facts. They are mad that the public is suddenly more confused than ever about a field of science that is more united than ever.

They want to get hundreds of scientists to sign a declaration that yes, the anthropogenic combustion of fossil fuels is still causing the Earth to warm, and print it in newspapers like the New York Times, using only NAS money. They want to start a prime time science program on PBS. They want to have dozens of public lectures communicating climate science. They want a concise assessment report by the NAS written in layman’s terms. They want a nonprofit group to bridge communication between scientists and the public. They want “nothing short of a massive publicity campaign to educate the citizenry about what our best science is saying and why.”

“We will need funds to make something happen,” says Paul Falkowski, and by February 27th, about 15 NAS scientists had pledged $1000 each, out of their own pockets.

“How can we sit back while many of our colleagues and science as a whole is under attack?” writes Paul Ehrlich.

William Jury describes public presentations he’s given since the CRU hack, and how a common question is, “If the recent charges by anti-warming people aren’t true, why is nobody coming forth to prove it to us?”

And why not? All of us here have done our part, but it’s still not enough. I’m sure I’m not the only one who’s felt pretty powerless over the past few months. It’s incredibly obvious, to those who have all the context, that the theory of AGW is as rock-solid as ever. But truth is not enough, not when we’re up against the most effective spin machine in history. I feel like no matter how much work I put into the communication of real science, this machine will always be ten steps ahead.

Reading this string of emails gave me the most hope I’ve felt in months that we might actually be able to steer public opinion in a more accurate direction, so that we can get to work on fixing this problem. It was exhilarating to read that so many scientists are ready and willing to mobilize public communication when we need it the most. I wanted to jump up from the computer and wave my arms around and shout in joy. If I hadn’t been in the school library, I probably would have.

There has long been a stigma against communication in science – for example, Stephen Schneider faced demeaning remarks from his colleagues in the 70s for even speaking to the newspapers about his work. Couple this with the big difference between these two sides fighting for public opinion: one academic, the other political/industrial. When our academic institutions get money, they’ll spend it on research, not on public communication……while the lobby groups and oil companies are hard at work on advertising like this. (Worth a watch, it’s hilarious.)

The amount of public communication and education proposed by the NAS scientists is enormous, but it’s never been more justified than now.

Freedom of Information

The only real issue that the hacked CRU emails brought up, the only allegation that didn’t fall apart if you were familiar with the literature (*cough cough hide the decline*), was the failure of Phil Jones to respond to some of the FOI (Freedom of Information) requests.

This looks bad on the surface, and it certainly has been spun that way – climate scientists hiding their data because they know it’s wrong and they don’t want anybody to find out. And ignoring FOI requests is a really stupid thing to do, no matter what the situation is. However, as with all the other allegations, some more context as to the nature and volume of these requests makes ignoring them understandable, if not excusable.

The Freedom of Information Act is important to a democratic society, but its major flaw is that it fails to distinguish its abuse. An article from the Sunday Times describes, in an interview with Phil Jones, what the FOI situation at CRU was.

In July 2009 alone, they received 60 FOI requests – most asking for data that was already freely available online. However, turning down a request takes 18 hours of work, and they only had 13 staff at CRU – all of which had better things to do than respond to needless FOI requests.

In another instance, over a matter of days, they received 40 FOI requests, which obviously all came from the same form letter – but each asked for data from a different 5 countries. So in total, temperature data for 200 different countries (again, most of which was already freely available) was requested, and all the forms came to CRU rather than the offices in the countries the data came from, or even the countries the authors of the FOI forms lived in. Phil Jones is sure that this coordinated attack originated at Climate Audit, which “just wanted to waste our time….they wanted to slow us down.”

Out of irritation, Phil Jones made some comments over email to his colleagues about how he wished that they could just get rid of the data rather than do all this work distributing it needlessly. This was purely a hypothetical proposition, though, as CRU doesn’t own any of the data. “We have no data to delete,” he says. “It comes to us from institutions around the world….it’s all available from other sources.”

When you are abused with FOI requests, ignoring them is not the right thing to do, and Phil Jones knows it – “I regret that I did not deal with them in the right way,” he says. His actions and words cannot be excused, but with more context, it’s obvious that his motives were not to cover up flaws in the data or hide it from critics. He just wanted to do his work.

It’s a great example of how the CRU hack compromises the professional reputations of some of the scientists involved, but it does not compromise one iota of the science. “I am obviously going to be much more careful about my emails in future, ” remarks Phil Jones. “I will write every email as if it is for publication. But I stand 100% behind the science. I did not manipulate or fabricate any data.”

CRU was not the only institution to be abused with FOI requests. The field of climate research has been grappling with this issue for the past few years. Take Benjamin Santer, for example. In a story he relays here, he describes how, following the publication of his 2008 paper, an FOI request by Stephen McIntyre asked for all the raw data used in his study so it could be replicated. Santer pointed him to the data, which was already freely available online. But then he was given two subsequent FOI requests, which asked for all of his intermediate calculations and two years of email correspondence related to the data. Obtaining this information is completely unnecessary to replicate a study, and it is certainly not normal scientific practice – the only reason you would want them would be to find material that could be framed as embarrassing and used to discredit the study and the researcher – as if Ben Santer hasn’t been through enough already. So he turned the FOI requests down, and was immediately flooded with hate mail from Climate Audit readers until he released the intermediate calculations, purely because he “wanted to continue with my scientific research…….I did not want to spend all of my available time and energy responding to harassment incited by Mr. McIntyre’s blog.”

Gavin Schmidt, a climate modeler at NASA, adds to the list of instances of FOI abuse in climate science. He remarked that “In my previous six years I dealt with one FoIA request. In the last three months, we have had to deal with I think eight…..These FoIAs are fishing expeditions for potentially embarrassing content but they are not FoIA requests for scientific information.”

James Hansen, the director of GISS at NASA, has similar opinions. Following the CRU hack, he writes, “I am now inundated with broad FOIA requests for my correspondence, with substantial impact on my time and on others in my office. I believe these to be fishing expeditions, aimed at finding some statement(s), likely to be taken out of context, which they would attempt to use to discredit climate science.”

The broad abuse of the Freedom of Information Act in the field of climate science is worrying, and it calls for some kind of caveat that will distinguish it from legitimate use of FOI. Research into climate change is vital at this point in human history, but if top researchers are forced to spend their time filling out needless paperwork instead, the field will suffer. The past few months have shown us that institutions of climate science are in need of representatives specialized in media relations. Perhaps they also need to employ dozens of students to fill out FOI forms, or lawyers to defend them from the constant attack they are under.

IPCC Reform

The IPCC is far from ideal, and we knew this even before word got out that WG2 had made several minor mistakes. I’ve written about this before – here I discuss how the IPCC is naturally biased towards understating climate change: being too optimistic in its results. And here I discuss the difference in public attention when the IPCC understated central claims (such as sea level rise, Arctic sea ice melt, and emission scenarios) to when they overstated a detail that didn’t even make it into the technical summary – exactly how fast the Himalayan glaciers would melt.

Several British journalists have managed to construct several other “scandals” in the IPCC claims, which have little to no merit. Tim Lambert has spent the past few weeks investigating the legitimacy of these allegations, and one thing stands out above all others: facts do not matter in the way the media reports alleged IPCC mistakes or misconduct. One journalist in a minor British paper can make an erroneous claim that shouts “IPCC scandal”, and even after scientists have patiently explained, multiple times, why it is untrue, the claim is repeated in every major newspaper in the world. Consequently, even though virtually all of these “scandals” have to do with the WG2, the opinion pages use it as an excuse to vehemently question the idea that humans are causing the Earth to warm. This is obviously WG1 material, which is based on the laws of physics and decades of peer-reviewed science – but that doesn’t matter to the media, does it?

For people like us, who are so intent on scientific accuracy, it is incredibly frightening when accuracy becomes irrelevant in the sources that virtually everyone else relies on for climate change information. Even after factual errors that fundamentally change the message of the story are pointed out, no retraction is printed, and the authors are dealt no consequences. As scientists and concerned citizens, our greatest weapon is truth. But that can no longer be enough – not when our fourth estate drops its responsibility to truth, at least for this issue.

The IPCC was formed in the late 80s, and the relationship between climate science and the rest of the world has changed fundamentally since then. We have gained much more understanding of what climate change could mean for the world, so creating a document that encompasses absolutely everything we know is longer and more tedious. Governments fearful of climate change action have abused their powers of IPCC editing and review, as Stephen Schneider describes in his excellent book Science as a Contact Sport. Special interests muddled the lines of communication between scientists and the public, and when, due to the Internet, this communication became impossible to stop, the special interests decided to smear the reputations of scientists, scientific organizations, and science itself. The media and the public fell willingly to this muddling and smearing, so these special interests have gained far more influence than truth should allow them.

Is it necessary, or even desirable, to reform the structure of the IPCC to better suit its communication with the public? In terms of producing the most accurate science, I feel that it’s doing just fine the way it is, with the exception of needing some new WG2 review editors, and a delayed deadline for the WG2 and WG3 publications (instead of having all three reports released simultaneously).

Nature recently published recommendations from five diverse climatologists as to how to reform the IPCC. Subscription or payment is needed to read the full article, so I’ll give a quick summary here:

Mike Hulme wants to split the IPCC into three – a Global Science Panel that frequently publishes smaller reports about WG1 topics, five or ten Regional Evaluation Panels that report on region-specific WG2 topics, and a Policy Analysis Panel that frequently publishes examinations of different policy options.

Eduardo Zorita wants the IPCC to employ full-time scientists, instead of doing all the work on a volunteer basis.

Thomas Stocker wants the IPCC to stay the way it is, but to pay extra attention to following their self-imposed rules.

Jeff Price wants to select more lead authors to produce “short, rapidly prepared, peer-reviewed reports” instead of a set of massive ones every six years.

John Christy wants the IPCC to be removed from UN oversight and adopt an open, continually updating “Wikipedia” structure. I think a more accurate allusion to Christy’s proposition is the Encyclopedia of Earth, which has lead authors and a basic review system.

Personally, I agree with Jeff Price’s proposal. Mike Hulme’s seems to be very similar, and I like the way he separates and organizes the different panels. John Christy’s idea of a continually updating report intrigues me, but the more open approach to peer-review and a policy to “hear all sides” could easily be abused through artificial balance – equality over accuracy.

Any thoughts, further suggestions, background information to share? What changes, if any, should be made to the IPCC? And how can we possibly immunize the public to this incredible excuse to be misled?

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How to Prove Global Warming Wrong

Over the past twenty years, vested interests and political lobby groups have done a fantastic job confusing the public about anthropogenic climate change. To many, they seem to have proven the whole theory wrong.

But how could you actually prove global warming wrong – not just in the minds of the public, but through the established scientific process? What scientific discoveries – if they held up through peer-review, further criticism, and replication – would render climate change a non-problem?

One of the surest ways to stop all this cap-and-trade discussion would be to disprove the greenhouse effect itself – the mechanism by which the Earth absorbs and emits the same energy multiple times, due to the presence of greenhouse gas molecules that “bounce it back”. This keeps the Earth substantially warmer than it would be otherwise. Additionally, if the concentrations of greenhouse gases increase, so will the temperature of the Earth. This process was first hypothesized by Joseph Fourier in 1824, and was experimentally confirmed by John Tyndall in 1856. The first prediction of eventual man-made global warming came from Svante Arrhenius, in 1896. It wasn’t a theory as much as a logical result of a theory, one that was deeply rooted in physics and chemistry.

Unless our understanding of entire fields of physical science is totally off base, we can be sure that our greenhouse gas emissions will cause climate change eventually. But hey, if you could overturn all of thermodynamics, you wouldn’t have to worry about carbon taxes.

  • Cheap-out option: Svante Arrhenius was Swedish, but his name sounds sort of Russian, and 1896 wasn’t very long before the Russian Revolution. Therefore, Arrhenius was a Communist, and none of his scientific work can be trusted.

Knowing that something is sure to happen eventually, though, is different from knowing that it is happening right now with substantial speed. We know that the Earth is warming – even if you found some statistical way to disprove three separate temperature records, the physical and biological systems of our planet still stand: 90% of observed changes in the natural world, like the blooming of flowers, the peak flows of rivers, and the spawning of fish, are in the direction expected with warming (Rosenzweig et al, 2008).

But how do we know that the warming is caused by us? Climate change has been caused many times in the past by factors unrelated to greenhouse gases – like solar influences, whether they’re direct (a change in solar output) or indirect (a change in the Earth’s orbit). How do we know that’s not happening now?

If the warming was caused by the sun, the atmosphere would warm uniformly at all levels. However, if the Earth was warming from greenhouse gases, the troposphere (the layer of the atmosphere closest to the planet) would warm while the stratosphere (the next level up) would cool. This is because more heat is getting bounced back to the surface by greenhouse gases, and is subsequently prevented from reaching the stratosphere.

A cooling stratosphere has been described as the “fingerprint” evidence of greenhouse-induced warming. And, in fact, the stratosphere has been cooling over the past 30 years (Randel et al, 2009). Therefore, if you could somehow show that something else was causing this pattern of a warming troposphere and a cooling stratosphere, and that the significant, anthropogenic rise in greenhouse gases was somehow not affecting it, you would have a case for global warming being natural.

Update (18/2/10): About half of this cooling can be attributed to ozone depletion, and the other half can be attributed to greenhouse gases (NOAA, 2006). The flat trend in stratospheric temperatures from 1995-2005 (see the Randel citation above) can be explained by the recovery of ozone, which is temporarily offsetting the greenhouse gases. Interesting how the temperature of the stratosphere has just as many factors as the temperature of the troposphere…..but in both cases, you can’t explain the temperature trends without including human activity. Scott Mandia has a great explanation here.

  • Cheap-out option: Omit the explanation of why greenhouse warming causes stratospheric cooling. Just point to the graph that goes down and say, “The atmosphere is cooling! Therefore, the IPCC is a hoax!”

Finally, even if you couldn’t disprove that global warming is expected, observed, and anthropogenic, you could still show that it isn’t very significant. The way to do this would be to show that climate sensitivity is less than 2 C. Climate sensitivity refers to the amount of warming that would result from a doubling of carbon dioxide equivalent, and 2 C is generally accepted as the maximum amount of warming that our society could endure without too much trouble. The current estimates for climate sensitivity, in contrast, average around 3 C (a range of 2-4.5), and it is very unlikely to be less than 1.5 C (IPCC AR4).

However, a climate sensitivity of less than 2 C only means that climate change isn’t a problem if our greenhouse gases stop at a doubling of carbon dioxide equivalent from pre-industrial levels. Even without taking methane and other greenhouse gases into account, this brings us to a CO2 concentration of 560 ppm, which we are well on track to surpass, even with cap-and-trade. So you’d have to argue for a climate sensitivity of even less. Seeing as we’ve already warmed 0.8 C, it doesn’t leave you with a lot of wiggle room.

  • Cheap-out option: Build a climate model that does what you want it to, without any regard for the laws of physics. ExxonMobil will probably sponsor the supercomputers. Widely publicize the results and avoid peer-review at all costs.

Daunting tasks, certainly. But if you really believe that global warming is natural/nonexistent/a global conspiracy, this is the way to prove it. If you managed to prove it, and change the collective mind of the scientific community (not just the public), you’d probably win a Nobel Prize. So it’s certainly worth your time and effort.