Are scientists making "misleading climate change claims"?

Vicky Pope, head of climate change advice at the Met Office Hadley Centre, says scientists should be careful not to exaggerate the evidence for climate change:

The reality is that extreme events arise when natural variations in the weather and climate combine with long-term climate change. This message is more difficult to get heard. Scientists and journalists need to find ways to help to make this clear without the wider audience switching off.

She cites the fuss over dwindling Arctic sea ice cover (or extent) as "just one example" of going beyond what the data really say:

Recent headlines have proclaimed that Arctic summer sea ice has decreased so much in the past few years that it has reached a tipping point and will disappear very quickly. The truth is that there is little evidence to support this. Indeed, the record-breaking losses in the past couple of years could easily be due to natural fluctuations in the weather, with summer sea ice increasing again over the next few years. This diverts attention from the real, longer-term issues. For example, recent results from the Met Office do show that there is a detectable human impact in the long-term decline in sea ice over the past 30 years, and all the evidence points to a complete loss of summer sea ice much later this century.

Little evidence to support the notion that Arctic sea ice is nearing a tipping point? Let's ask Mark Serezze of the National Snow and Ice Data Center, which is where most of the data on this subject come from:

"When the ice thins to a vulnerable state, the bottom will drop out and we may quickly move into a new, seasonally ice-free state of the Arctic," Serreze said. "I think there is some evidence that we may have reached that tipping point, and the impacts will not be confined to the Arctic region." (U of Colorado press release, March 2007)

And here is he is with some colleagues writing in Science, back in 2006:

This ice loss is best viewed as a combination of strong natural variability in the coupled ice-ocean-atmosphere system and a growing radiative forcing associated with rising concentrations of atmospheric greenhouse gases, the latter supported by evidence of qualitative consistency between observed trends and those simulated by climate models over the same period.

Both of those quotes come from before the big melt of 2007. Since then, the voices daring to associate "Arctic" and "tipping point" have become more numerous and louder.

So is Pope saying Serezze and those who agree with him are out of line? I think not. If you read her comments closely, she's careful to criticize those who say we have reached the tipping point, without qualification. Just about every scientists who has ventured into tipping point territory, however, qualifies such statements with "may."

No doubt there are some careless headline writers, but I have to wonder what prompted this unusual and public appeal to dial down the alarmism. Here's Pope's explanation:

For climate scientists, having to continually rein in extraordinary claims that the latest extreme is all due to climate change is, at best, hugely frustrating and, at worst, enormously distracting. Overplaying natural variations in the weather as climate change is just as much a distortion of the science as underplaying them to claim that climate change has stopped or is not happening. Both undermine the basic facts that the implications of climate change are profound and will be severe if greenhouse gas emissions are not cut drastically and swiftly over the coming decades.

When climate scientists like me explain to people what we do for a living we are increasingly asked whether we "believe in climate change". Quite simply it is not a matter of belief. Our concerns about climate change arise from the scientific evidence that humanity's activities are leading to changes in our climate. The scientific evidence is overwhelming.

I think we all agree that it would nice if everyone stuck to the facts and no one ever exaggerated or downplayed anything. But that's not going to happen. So is it reasonable to worry as much as about overplaying the evidence for anthropogenic climate change as underplaying it? Give the stakes, surely I would hope that reasonable people can agree that the latter carries far greater risks.

Which isn't to say we shouldn't call anyone out for misrepresenting the science. Just that some transgressions are more troubling than others.

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I was going to rant about Lord "I know what you should hear" Ahmed but that's just the religious suppressing freedom of speech, which is hardly news. But then along comes a much more interesting rant, from Vicky Pope, about the good old Arctic sea ice. 'Apocalyptic climate predictions' mislead the…
I spent five years of my life in Canada's Arctic and not a day goes by that I'm not reminded just how powerful an impression those years left made on me. When I read the latest news on arctic sea-ice extent, I wish more people would recognize just how important what happens up there is to the rest…
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So is it reasonable to worry as much as about overplaying the evidence for anthropogenic climate change as underplaying it? Give the stakes, surely I would hope that reasonable people can agree that the latter carries far greater risks.

Well, colour me a layperson leaning toward unreasonable.

It seems to me that even underplaying the evidence still points to alarming effects. Overplaying it, however, leads to a real risk of the "boy who cried wolf" syndrome.

By Scott Belyea (not verified) on 11 Feb 2009 #permalink

I haven't exactly kept notes, but it seems to me that each of the major reports from scientific sources so far predicting near- and medium-term changes in climate has been shown to have understated the case when follow-up time has arrived.

By Pierce R. Butler (not verified) on 11 Feb 2009 #permalink

"So is it reasonable to worry as much as about overplaying the evidence for anthropogenic climate change as underplaying it?"

Yes. In addition to the risk that overplaying the risk will distort societys response to the problem there is the bigger problem of the effects it will have on science itself and its perception in society if we decide that certain distortions of the evidence aren't so important since they fit with what we want politically.

Sadly, the cranks will leap all over this as proof that AGW isn't worth worrying about or a hoax while ignoring the underlying message. (c.f. the climate porn warning from a few years back, or Darwin Was Wrong from a few weeks back).

I find her identification of "scientists" as the culprits along with her specific example problematic. As noted in the OP and subsequent comments, 'real' scientists rarely make unqualified, exaggerated claims. However, activists do. There's another new article on the counter-productivity of climate porn in the new issue of Science Communication.

Saffron O'Neill and Sophie Nicholson Cole. (2009) "Fear Won't Do It": Promoting positive engagement with climate change through visual; and iconic representations. Science Communication, 30(3), pp. 355-379.

By winnebago (not verified) on 11 Feb 2009 #permalink

My children are grown and my ex-husband is long gone, but this entire debate reminds me so much of the exchanges I had with them.

Them: "The reason we don't do the dishes/pick up our dirty laundry/feed the dog/take out the garbage/make our bed is because we don't like the way you ask us to/remind us to/complain that we don't.

Me: "Bullshit. It has nothing to do with the way I ask/remind/pester and everything to do with the fact you just DON'T WANT to!"

p.s. my kids have since come a long way and are wonderful citizens. ex-husband, not so much!

Thatâs the important figure, not 350.
100ppm less than 280ppm CO2 ment 5 degrees cooler.
100ppm greater than 280ppm means > 3 degrees hotter.

It is quite straightforwardâ¦you dont have to be a climatologists or meteorologist for that matter.

Hansen knows itâ¦.

An initial 350 ppm CO2 targetâ¦

â¦Hansen says Arctic sea-ice passed its tipping point decades ago, and in his presentations has also specifically identified 300-325ppm

and now others are coming round to it, Hans Joachim Schellnhuber, head of the Potsdam Institute and climate adviser to German Chancellor and the EU

â¦only a return to pre-industrial levels of CO2 would be enough to guarantee a safe future for the planet⦠He said even a small increase in temperature could trigger one of several climatic tipping points,

350 parts per million carbon dioxide is the wrong targetâ¦

Climate Crisis is now!

Pope's article reads like 100% pure concern troll.

I dont know how factual this comment in the above link is but if accurate it demonstrate the smaller tipping points that are not clearly present to the public.

William H. Calvin
February 11th, 2009 at 7:08 am
Climate models, for all their success, seldom capture the known tendency of the real system to shift abruptly at tipping points. After three decades of relatively flat global temper¬ature as the CO2 rose from 308 to 326 ppm, there was a marked shift in 1976 to a rising global fever. This suggests that a 350 ppm target is not low enough.
Seven years into this new climate regime, global drought suddenly doubled and has never returned to the earlier baseline (from 1950 to 1982, the global land surface in severe drought stayed near 14 percent). This doubling in 1983 occurred when CO2 was only 342 ppm.

If true, I think we can safely assume that civilization is going to collapse due to escalating Climate Change extreme events in the near future rather than in say a 100yrs time.

I think (know) the whole AGW concept is pure bullshit and it gets over hyped both ways. CO2 is such a minor gas in such small amounts that it is irrelevant to almost anything. Al Gore and climate modelers are todays snake oil salesmen selling a "man is bad" religion.

I have been developing software models for 25+ years in heavy physics domain, and I can say without a doubt that all models are wrong!! Some models are more useful than others, but models like climate models that extrapolate are always horribly wrong. The climate and sun are too complex and we know too little about them to make any real assessment of what is going on, much less build a model to predict the future, especially 100 years from now. What pure horse shit. A simple look at the sun spot history clearly shows that the sun has been increasing activity from 1911 through 1961. While it is has dropped a little from 1961 to 1974, since then it has been a elevated levels relative to recorded history (granted which is only a few hundred years). As a scientist, I say "duh" no wonder the earth is getting a little warmer the sun is more active.

By Tony Says Mode… (not verified) on 12 Feb 2009 #permalink

@ Modelers, I think (know) that what you think is pure BS.

Summer '08. While arctic sea ice melts to a minimum - suggesting accelerated warming -, antarctic sea ice is freezing to a maximum - suggesting some cooling.
Has our planet warmed up and is Antarctica cooling for some unrelated reason, or has the Earth cooled down a bit and did the arctic ice melt for some reason?

Mean global temperatures give a bit of cooling for 2007, and yes, there are mechanisms that have caused melting of the arctic ice.
1. Uncommon winds have blown the ice to warmer waters. Artic ice floats and is pushed around by the wind.
2. Because of soot and dust from industrial activity in the northern hemisphere, the arctic ice is not so white anymore. It reflects less sunlight, (in science jargon: it's albedo is lower), it melts easier.

The diminished albedo of the arctic sea ice will be here for a long time and is strengthening with every new coal powered electricity plant the Chinese build.

By Robin Kool (not verified) on 12 Feb 2009 #permalink

Hi James, I linked to this post of yours in my new blog at It's called "100 Days of Science," and the new climate change post is on Day 24 ... Check it out! Cheers, Anne

paulm, if modelers think (know) what I think is pure BS, then I suggest a quick read of another ScienceBlog post referenced below. Clearly, only 5% think the study of climate change is mature. There, they even admit it, and shows I am right. While 51% think it is "fairly mature", that still shows that half do not think the science is even fairly mature. Again, more eveidence I am correct. But I find the opinion that they think it is "fairly mature" interesting. My question, is how do you conclude it is fairly mature? In order to know that the model is accurate, you have to know truth, and since we do not know truth, then how can you conclude that you are close? It is a catch 22 problem.

So, just curl up with your pseudo religion of global warming, and preach doom and gloom. You've got your Bible (the Climate Models), some prophets (Al Gore and the modelers), nice conflict of good versus bad, you have blasphemers (the GW deniers), and eternal damnation (cut CO2 now, we're already past the tipping point, blah blah). Actually, it is quite amazing how much AGW is just like religion based on similar tactics and rhetoric.


"A need to know more
Overall, only 5% describe the study of global climate change as a âfully matureâ science, but 51% describe it as âfairly mature,â while 40% see it as still an âemergingâ science. However, over two out of three (69%) believe there is at least a 50-50 chance that the debate over the role of human activity in global warming will be settled in the next 10 to 20 years.

Only 29% express a âgreat deal of confidenceâ that scientists understand the size and extent of anthropogenic [human] sources of greenhouse gases,â and only 32% are confident about our understanding of the archeological climate evidence. "

By Tony Says Mode… (not verified) on 17 Feb 2009 #permalink

The global warming is present in all the solar system. And, I do not think whether it is the Martians with their flying saucers which pollute.
I do not think either that there will be 1 billion deaths before the year 2020 further to the global warming.
The global warming is one benefaction for all the humanity. The expansion of the agricultural zones is going to allow to feed more people.
Since the world is world, the Earth has no droplet furthermore or at least. The water moves in sea currents. The volume of an ice cube is superior has his volume in water. When the ice bottom the sea level falls.