Original URL: http://www.theregister.co.uk/2011/05/13/downing_cambridge_climate_conference/

Would putting all the climate scientists in a room solve global warming...

Skeptics meet Warmists at Cambridge

By Andrew Orlowski

Posted in Science, 13th May 2011 12:18 GMT

Entourages are not something that delegates bring to a conference. Especially if the delegate is a humble public sector scientist. But the private invitation-only event I attended at Downing College Cambridge this week was no ordinary conference. It was an attempt to bring together leading climate scientists and IPCC figures with their critics.

Who, then, had an entourage? Lord Lawson, a splendidly imperial figure, and former Chancellor of the Exchequer, may be expected to bring one, But Lawson had none. University of East Anglia luminaries Phil Jones and Andrew Watson did, however: consiglieres perhaps, taking notes, whispering sotto voce, and fetching the teas and ice cream. They were accompanied by others attached to the Climatic Research unit (CRU) and the Met, whose purpose was not known. It was a beautiful May day. It can't have been for safety, nobody mentioned Climategate all day. The entourages boosted the attendance figures substantially.

I suppose the future will look like this: public sector climate academics will arrive at conferences flanked by moped outriders (these will be zero carbon emission electric vehicles) pulling one of those new mini-Cafe Neros that look like a garden shed behind them, for refreshments. (This will be serving Fairtrade™ coffee).

The Downing event was assembled by Alan Howard, an academic rich enough to have a foundation in his name – and it was the first time many climate scientists have ever attended an event with their critics. "Science is not a religion," said Howard, "it must be criticised". Henrik Svensmark, who offered the most compelling alternative to the IPCC orthodoxy, was among those who gave a presentation. The audience was evenly split, and the IPCC orthodox view took up perhaps two thirds of the day.

On the science, there was little disagreement over the basics, such as the physical properties of CO2, but the degree to which it drives the larger climate was greatly disputed, because the larger system remains a mystery. Even the basics of how different clouds affect temperature is guesswork: water vapour feedback may have a slight negative cooling feedback, or it may have a large positive warming feedback. These must be guessed at, or imagined, through models.

A couple of anecdotes I thought typified the fundamental disagreement.

Dr Eric Wolff of the British Antarctic Survey was given the job of summing up the room's view after seven scientific presentations. He attempted to do this with a succession of statements to see how far the consensus could stretch. He inched the audience along with statements they might agree with ("CO2 levels are higher than they have been historically", and "Humans have contributed to CO2 increases") and then catapulted them across a chasm of logic ("So we're all agreed things will get warmer? Yes? Good! Send more money". He didn't actually say "Send more money" – I made that up.)

Yet not everything in the skeptic camp smelt of roses. Nils-Axel Morner had gone around the world and found sea levels haven't risen much, if at all, in places often cited to be most vulnerable, such as Tuvalu. Yet the instrumentation record says something different. I would very much like to know which of these is right, or if they are both wrong, or how they could both be right. The Maldives, Tuvalu and other islands have opportunistically jumped on the compensation bandwagon, and for sure they don't seem to be sinking beneath the waves. Then again, nobody has challenged the buoys data.

Morner also has a graph he likes to use tilted through 45 degrees so the upward trend line is horizontal. This sort of trick doesn't belong at a scientific event.

The Maldives cabinet meets underwater to raise awareness

Another example was sparring over the significance of trend data. IPCC academics repeatedly told the critics that one decade's isn't significant; the critics had pointed to a lack of dramatic warming in recent years – even CRU's Jones now admits this isn't statistically significant. But twice, the Met Office's chief scientist used just a decade's data to invalidate someone else's point. One was a dart aimed at Svensmark, and another decade's data was used to – take a deep breath – validate the climate models.

Sexy models and naughty stats

In short, the day lined up Phil Jones, oceanographer Andrew Watson, and physicist Mike Lockwood, the latter to argue that the sun couldn't possibly have caused recent warming. He was followed by the most impressive presentation from Henrik Svensmark, whose presentation stood out head and shoulders above anyone else. Why? For two reasons. The correlations he shows are remarkable, and don't need curve fitting, or funky statistical tricks. And he has advanced a mechanism, using empirical science, to explain them. At the other end of the scale, by way of contrast, the Met's principle research scientist John Mitchell told us:

"People underestimate the power of models. Observational evidence is not very useful," adding, "Our approach is not entirely empirical."

Yes, you could say that.

Phil Jones

Jones explained the temperature record. He said that biases are a real problem, and have a greater effect on the record than adjustments. He addressed the issue of UHI, the urban heat island effect, which critics say has skewed land temperature upwards, and hasn't been taken into account as much as it should have been. Jones pointed out that the UHI was evident in London 100 years ago – but it hadn't become greater over that time. "The trend is no different to outer London." Critics also point to the disappearance of 4,500 largely rural stations from the 6,000 formerly used by NASA, via the National Climatic Data Center (NCDC). Jones couldn't address this, but pointed out many stations aren't really independent; around 200 stations are needed to obtain a global average.

A lot of hot air water

The most significant adjustment he'd made, said Jones, had actually had the effect of making late 20th Century warming less dramatic. Sea temperatures were once taken by thermometers in wooden buckets, then canvas buckets, but since 1940, they're sampled on ships' engine intakes. A scientist in the audience said they really should be taking air temperature at sea, not the temperature of the surface water – and disagreed with Jones' assertion that the man-made "signal" in the record is discernible.

Jones said he'd attempted to take the Pacific Decadal Oscillation out of the record but had been heavily criticised for it. "I doubt it's going to be time invariant," he said. "It's strong in some decades, and weak in others".

Jones was followed by Andrew Watson, the most active climate scientist throughout the day, who gave an overview of the case for man-made warming. A doubling of CO2 by itself theoretically adds, if the climate doesn't compensate for it. For example, the biosphere can respond to greater levels of CO2 by sucking more out – or making it worse. By itself, a doubling of CO2 (or the climate sensitivity) adds just 1.1C to global temperatures. Water vapour feedback adds more – around 2W/m2. Watson acknowledged many uncertainties before positing that climate sensitivity – a doubling of CO2 over pre-industrial levels – added 2 to 4.5C to global temperature. "This can be wrong – but it's hard to see how it can be a long way wrong," said Watson.

Other scientists disagree, with Lindzen putting sensitivity at 0.7C, which suggests we've had already had the manmade warming we're going to get. Clouds are poorly understood, and more low clouds means cooling.

The audience also challenged evidence of the causal relationship between CO2 and temperatures. Warmer temperatures mean more CO2 is released through outgassing, and the Antarctic ice core record shows temperature rising, then CO2 following closely behind. Watson said that with feedbacks, it was impossible to separate the two as cleanly as critics would like: more CO2 must surely have an amplification effect, he said.

"There is a good reason to believe ... that climate sensitivity is substantially changing the global climate. Such rapid global change is very rare in the earth's history," he concluded.

The telltale signature of greenhouse gas warming should be warming at the surface and in the troposphere, but not the upper stratosphere. It's even been suggested that carbon taxes should reflect the tropospheric temperature anomaly, rather than surface production. But while the models predict such telltale warming, the observational evidence shows it isn't there. More recently it has been cooling. This really shouldn't be happening.

"We can't explain it ... we have wide uncertainty estimates," acknowledged Watson. "Clouds is a very uncertain area." He again stated that CS was in the range of 1.1C-4C – with more no's from the skeptical side of the room.

Francis Farley, who helped invent microwave radar in World War II, then came on briefly to explain greenhouse gases and feedback effects, concluding "the system is unstable" and "a runaway chain reaction is very likely" - illustrated by a man pushing a large ball down a hill, which then rolled away. Solar physicist Mike Lockwood began with an odd observation: "The stewardship of the planet - and lifestyles - would be much easier if [climate change] was all about the sun." It was a rare example of the IPCC academics letting their intellectual prejudices slip out. Our lifestyles are surely up to us, and policies in response to climate change should be decided coolly and rationally, not handed down as instructions from academic priests. People can get carried away with their own importance at times - particularly scientists.

Lockwood's presentation was quite lucid, though – and surprisingly generous to the next speaker Henrik Svensmark.

"I think it's a lovely idea and I do think it happens, actually. It's very clever. But it happens slowly, and we think it happens in clean maritime air. Over land, there are already enough aerosols present for cloud formation".

(I'll cover Svensmark's work next).

Lockwood outlined the sun's influence: its irradiance (TSI), obviously the primary factor in climate change, and also changes in its magnetic field, which modulate to varying degrees its UV output, and its effectiveness in shielding us from cosmic rays. In a nutshell, Lockwood believes modulations in total solar irradiance contribute around 0.75W/m 2to temperature changes, but around 5Wm/2 is needed to explain them. He acknowledged that solar activity – like the value of your portfolio – can go up as well as down. Tracking the last 24 sunspot cycles he thinks there's an 8 per cent chance of arriving in a Maunder Minimum – a period of low sunspot activity and colder weather – in the next 40 years. The strongest argument, according to Lockwood, for the sun not being a driver in recent climatic activity is that "it has been going in the wrong direction for 30 years".

Lockwood was asked about the recent Shapiro paper (PDF/380KB), published in peer-reviewed journal Astronomy & Astrophysics, which suggested that solar irradiance was much more important than previously thought. Alexander Shapiro, at the World Radiation Centre in Switzerland, looked at magnetic fields as a proxy for TSI and concludes that historical reconstructions have underestimated both TSI and UV – by a factor of six.

Lockwood didn't think much of it. "It's based on the premise that there are small magnetic fields between the sunspots. There's no doubt that over 30 years the trend was downward."

Cosmic rays wot dunnit?

The director of Sun-Climate Research at the Danish national space institute DTU Space, Henrik Svensmark, was next. Svensmark explained the idea that cosmic rays have a much greater role in climate than previously thought – one we have mentioned before, here. The theory led to the CLOUD experiment at CERN.

The proposition is that high energy particles released from cosmic rays hitting the atmosphere – particularly muons – provide the seed material for clouds, via ionisation. So if more cosmic rays reach the atmosphere, there are more clouds, which generally means a cooler climate. (On balance, that is: high clouds have an albedo effect, and nighttime temperatures are raised by low clouds). The amount of cosmic rays that reach earth is determined by the density of the cosmic rays, and the strength of the earth's and sun's magnetospheres, which act as umbrellas.

The "shower" illustrated by the NASA artist above is a bit misleading. The true picture is much denser than it suggests: around 12 million muons pass through a human body in 24 hours, noted Svensmark.

The net cooling effect of clouds is 30W/m2, which is much greater than any of the figures mentioned above. So small changes in clouds will have significant impacts on temperatures. He explained the process of cloud formation, via UCNs (Ultra Fine Condensation Nuclei) which seed clouds. Over the past 15 years, experiments have been conducted to find out the ionisation effects of cosmic rays at varying altitudes. Svensmark isn't involed in the largest of these, CLOUD.

Svensmark saw four primary factors to climate change: solar activity; volcanoes; a curious "regime shift" that took place in 1977, and which has led to subsequent warming; and residual anthropogenic (manmade) components.

Svensmark has alluded to this before. The idea is that the Pacific Oscillation undergoes periodic "shifts" – and the shift in 1977 had significant consequences, with a period of rapid warming following. The idea that something dramatic happened to the Pacific in 1976, isn't new, and has been explored in this paper, and biologists note how rapidly plankton responds to these shifts.

"If regime shift is ignored, the net AG contribution increases by 2x to 5x", said Svensmark.

The afternoon saw some fiery exchanges. Australian geologist Ian Plimer spent a lot of time on CO2 emissions from submarine volcanoes, which he said are not measured. Andrew Watson said his team could measure oceanic CO2 emission to 1ppm, and the output was negligible about 1km away. Plimer said he wasn't looking before and after eruption.

Plimer was convincing on the long-term geological record.

"I would like to see why 3 per cent anthropogenic CO2 drives climate, and the other 97 per cent doesn't". The official answer is that the 97 per cent of natural CO2 is perfect equilibrium, but the wicked (fossil fuel) 3 per cent tips everything out of balance.

"For people to call me a Climate Change denier is a demonstration of public ignorance – geology is all about change – it's the science of climate change," he said.

Concluding the science sessions was one of the most senior figures in the Climate Industry, John Mitchell of the Met Office. Mitchell was review editor of Chapter 5 of the IPCC's most recent report (AR4) but hasn't been able to meet FOIA requests, despite the IPCC's pledge to keep all written expert comments on record for five years. "For my own part, I have not kept any working papers. There is no requirement to do so, given the extensive documentation already available from IPCC," Mitchell has claimed. This, like Climategate, was not mentioned.

Mitchell's contribution was a mixture of the sophisticated and the simple. He rebutted the idea that you could not model a chaotic system and come out with anything useful. Obviously there's plenty of maths that begs to differ, and Mitchell mentioned some of it, such as Lorenz. Other arguments were odd: Mitchell used the examples of Mars and Venus – two planets which don't have biospheres. This example may prove that there's a greenhouse gas effect – but not much else. And it wasn't seriously in doubt.

John Mitchell

John Mitchell, chief research
scientist at the Met

"People underestimate the power of models. Observational evidence is not very useful," he said. "Our approach is not entirely emprical."

From the audience, Professor Michael Kelly, who served on the Oxborough Report, wasn't impressed with the thoroughness of this.

Referring to using parameters as variables, Kelly said: "It strikes me as what you're doing is what we did in solid state physics in the 1970s, which wasted a lot of time. We didn't go back to our modeling as we should have, because it produced the right results. We quit while we were ahead."

It was nearing 5pm, and a long session loomed on the economics of climate change with Czech President Vaclav Klaus, and former Chancellor Lawson, which I was unable to attend.

The audience had been good enough to heed Howard's opening advice that "if anybody mentions Climategate, they'll be evicted". Nobody ambushed the CRU crew all day - it was all very polite. I noted that the skeptics made a point of listening politely to the warmists, and applauding them all. A group of students and a few others, simply giggled and mocked the skeptics, however from start to finish. One of their tutors (I presume) was in hysterics all day. I wondered why they had attended at all.

So the disagreements really break down into two. There's the science: human influence is either significant or not so significant; and there's economics: we must have policies which make drastic changes to society, lifestyles and industrial policy – what George Monbiot called "a war against ourselves" – or we must sensibly adapt, and are foolish to create more unnecessary human poverty and misery when we don't need to.

This isn't so surprising, really. The most passionate believers in the view that man is irreparably changing the climate are the people with the long lists of radical remedies already prepared; their politics needs the catastrophe, for nobody would entertain their politics for a moment – it wouldn't be mainstream – if it didn't come with a catastrophe attached. Take away the catastrophe, and their politics collapses like a house of cards. Politically we're in a sort of limbo: a few countries have pledged themselves to the course of radically changing lifestyles and industrial policy – but the price of implementing them is political suicide. Things meander along without resolution.

The day ended with as much disagreement as it had begun, and it felt for much of the day as if two Navies had passed in the night. But it had at least taken place. Much credit to Alan Howard and the Howard Foundation for arranging it. ®