Clive Cookson

Painting urban roofs white is perhaps the simplest and most benign of the various schemes that have been proposed to fight climate change through geo-engineering.

Steven Chu, the US energy secretary, advocated white roofs last year but some experts doubted whether the idea would make enough impact to be worth pursuing.

Now the first computer modelling study to simulate the impact of white roofs on cities worldwide, carried out at the US National Center for Atmospheric Research, has confirmed that they could significantly cool urban areas and mitigate some effects of global warming. The study will be published in Geophysical Research Letters.

“Our research demonstrates that white roofs, at least in theory, can be an effective method for reducing urban heat,” says NCAR scientist Keith Oleson. “It remains to be seen if it’s actually feasible for cities to paint their roofs white, but the idea certainly warrants further investigation.”

The study team used a new computer model to simulate the amount of solar radiation absorbed or reflected by urban surfaces. The simulations, which provide an idealized view of different types of cities around the world, indicate that, if every roof were entirely painted white, the urban heat island effect could be reduced by 33 percent.

While the model did not have enough detail to capture individual cities, it did show the change in temperatures in larger metropolitan regions. The New York area, for example, would cool in summer afternoons by around 1 degree centigrade.

White roofs are evidently not going to save the planet on their own but it does sound as though we should be considering a painting programme.

Clive Cookson

The main science-related event of the past fortnight, while I’ve been on holiday, has been the “big freeze” affecting the normally temperate regions of the northern hemisphere.

Some climate change sceptics have seized on this with glee, like children handed a surprise ice lolly in a heatwave.

But there is an opposite way of looking at the cold, which supports the case for global warming.

The immediate cause of the freeze is the Arctic Oscillation, a change in the atmospheric pressure distribution of the northern hemisphere between the mid-latitudes and polar regions.

When the AO is positive, the combination of high pressure in the mid-latitudes and low pressure further north blocks the outflow of extremely cold air from the arctic. A more “negative” AO allows the cold to slip further south.

Adam Scaife, seasonal forcasting chief at the UK Met Office, told the FT that this December’s oscillation over the Atlantic was the most negative for more than 100 years. Pressure was actually higher over Iceland than over the Azores – normally it is much lower.

The extremely negative AO has indeed allowed very cold air to flow down to normally temperate regions, leaving Alaska, Greenland and other areas around the Arctic Ocean up to 10degC milder than usual.

However the intensity of the cold has been moderated by man-made global warming. If an identical pressure distribution had arisen in the mid-20th century or earlier, before human activities had added so much carbon dioxide and other greenhouse gases to the atmosphere, the current freeze would probably be a degree or so more severe.

It feels cold in northern Europe at the moment, because we have become so used to mild weather, but veterans of the 1962/63 and 1946/47 winters have seen much worse.

By Joseph Milton, FT science intern

Simulations run by a team at the University of Bristol suggest that the melting of the Greenland ice sheet could be prevented by reflecting sunlight from the earth’s surface, a geoengineering technique.

Geoengineering offers radical solutions to climate change, involving large-scale alterations to the environment, directly affecting the climate. Discussion of these potentially risky procedures is increasingly common as many scientists reach the conclusion that CO2 emission reduction targets are not being met, and are unlikely to be. The Royal Society recently invited a panel of scientists to look into the subject and produce a report: Geoengineering the climate: science, governance and uncertainty.

The research at Bristol, led by Peter Irvine and published today in Environmental Research Letters, found that the temperature of the planet could be reduced to pre-industrial levels, saving the ice sheet, by reflecting 4.2 per cent of incident sunlight back into space.

But reflecting such a high percentage of sunlight, while doing nothing to reduce atmospheric CO2 levels, could reduce rainfall and change weather patterns, so the team also investigated reflecting 2.5 per cent of sunlight. They found this reduced the undesired side effects, but still cooled the planet enough to avoid the collapse of the ice sheet.

The Bristol team suggest sunlight could be deflected using geoengineering techniques known as solar radiation management. One option is the use of space reflectors – trillions of tiny reflective particles at the Lagrange point, the point in space at which the Earth and the Sun’s gravitational fields cancel each other out.

Professor Peter Cox at the University of Reading, who worked on the Royal Society report, says it might work: “It would be like just turning the sun down a bit.” But obviously there are technical considerations. As Professor Joanna Haigh of Imperial College, another of the report’s authors, points out: “The costs and the timescales involved would be absolutely enormous.” Neither thinks this technique is feasible in the near future.

Another option suggested by the Bristol team involves the addition of sulphate particles to the atmosphere, where they would reflect solar radiation. Prof. Cox says this is more difficult to rule out than he had imagined before the report was written, but Prof. Haigh is less convinced: “Who knows what the knock-on effects would be?” she says.

Solar radiation management is one of two broad categories of geoengineering techniques. The second is carbon dioxide removal, recently suggested as a possible complement to mitigation actions by Rajendra Pachauri, head of the Intergovernmental Panel on Climate Change.

Removing CO2 from the atmosphere would be a better long-term solution to global warming, as it would tackle not just global temperatures but other problems associated with high levels of greenhouse gases too, such as ocean acidification. But it would be very slow to affect the climate. On the other hand, the effects of reflecting sunlight could be seen within a few years.

Peter Irvine stressed that geoengineering should only be regarded as an emergency response: “It is no substitute for reductions in the emission of CO2,” he said.

Clive Cookson

The University of East Anglia has found an appropriate chairman for the independent review into leaked emails from its Climatic Research Unit, which sceptics say show unacceptable manipulation and suppression of data that do not support the cause of manmade global warming.

Sir Muir Russell has a distinguished background as a Scottish civil servant, including acting as the first Permanent Secretary to the Scottish Executive following devolution in 1999. He retired this year as principal and vice-chancellor of Glasgow University.

Russell (left) has no known links with climate change research and should be acceptable to both sides of the increasingly polarised debate over global warming.

The terms of reference for the inquiry seem to cover the main allegations of misconduct made by sceptics, including data manipulation/suppression and failure to comply with Freedom of Information requests. Russell will be free to amend the university’s terms of reference and devise his own working methods to investigate fully any alleged misconduct by CRU academics.

UEA wants Russell to complete his work by the spring. That will leave several months in which sceptics will be able to make hay with the allegations.

We had an example today when Saudi Arabia’s chief climate negotiator, Mohammad Al-Sabban told BBC News that the CRU email issue would have a “huge impact” on next week’s UN climate summit.

“It appears from the details of the scandal that there is no relationship whatsoever between human activities and climate change,” said Al-Sabban – who obviously has a vested interest in arguing that the vast volumes of oil pumped from beneath the Saudi sands are not contributing to global warming.

Meanwhile the CRU keeps the flag flying on an emergency website that promises: “Normal service will be resumed as soon as possible.” Its home page defiantly displays a graph of global temperatures over the past 150 years, which climate scientists believe shows the impact of manmade warming.

Clive Cookson

A visit to Purdue, a state university in the cornfields of Indiana almost three hours drive from Chicago, shows the strength in depth of the US academic system.

I’m just back from my third visit, courtesy of Purdue’s imaginative Science Journalism Laureates programme. On each occasion I have been struck by the intellectual quality of the academic staff – faculty, as they are known in America – and the curiosity of the students.

For research as a whole, Purdue is not in the same league as Harvard or Stanford but in some fields it is world class. One is palaeoclimatology, the study of past climate and what it can tell us about the likely course of global warming in future.

Matt Huber left me fascinated but deeply depressed by his latest conclusions about the climate’s response to rising and falling levels of carbon dioxide over the past 50m years. He and his Purdue colleagues have discovered that climate is more sensitive to CO2 than previously suspected – which is of course extremely bad news for efforts to control manmade global warming. I’ll use his insights soon for an FT article on climate history.

Another Purdue scientist with thought-provoking views is David Waters. He showed us how misguided some of the big clinical trials of vitamins and nutritional supplements have been – particularly the $175m US trial to see whether selenium pills can cut men’s risk of prostate cancer, which was stopped last year because it was, if anything, increasing the incidence of disease.

The problem, according to Waters, was that the trial took all comers in the chosen age group, rather than focussing on those – a minority in the US – who are actually deficient in selenium. From that base he built a devastating critique of the “either-or-ness” of public health medicine, and the search for things that are “good for you”.

Part of the rationale for the laureates programme is to interact with Purdue people – and part to discuss issues in science journalism. This year’s set-piece theme was “science journalism in the age of Twitter” in the form of what Americans call a “town hall meeting” with Purdue staff.

Each of the 12 journalists present had to kick off proceedings with a 100-word statement. One managed to do so within the 140-character (about 25 words) Twitter limit.

Opinions about the future of science journalism varied from optimism through “we’ve seen it all before” to utter gloom.

Clive Cookson

Europe’s hardware and DIY stores are preparing for a last rush this weekend to buy old-style 100W incandescent light bulbs. From Tuesday they will be not be available anywhere in the EU – victims of the battle against global warming. Lower wattage incandescent bulbs will be phased out over the next three years.

Their disappearance at the behest of Brussels has provoked protests from a wide range of traditionalists, who dislike the light emitted by new low-energy bulbs, besides the predictable howls from Eurosceptics and climate change deniers.

I too prefer the slightly warmer glow of an incandescent bulb. Whatever the manufacturers say – and I agree that there has been a huge improvement in energy-saving bulbs over the past couple of years – they do not quite match traditional lamps in the speed with which they come on or, more importantly, in the quality of their illumination.

Indeed I was tempted to join the hoarders who have laid in dozens of old-style bulbs. But, for a firm believer in the battle against global warming, that would have been outrageous hypocrisy. The phase-out is not just a token gesture, as some people seem to believe – it will cut European emissions of carbon dioxide by millions of tonnes a year.

Creating a huge market for low-energy bulbs gives manufacturers the incentive to spend money on research and development to improve their quality further. Today’s energy-saving bulbs are mainly what the industry calls compact fluorescent lamps or CFLs, as well as some (slightly less efficient) halogen bulbs. Given two or three more years of technical improvement CFLs really will match incandescent bulbs.

But the great hope for the near future is the light emitting diode or LED. This is far more versatile – and energy efficient – than the CFL and will produce instant illumination in any colour you want, from stark white to a warm mock-incandescent glow.

LEDs for domestic lighting are just coming onto the market and within a few years they will be ubiquitous. Then only the most nostalgic will be yearning for the incandescent bulbs of the past.

Clive Cookson

Hydrofluorocarbons or HFCs were introduced to save the ozone layer in the upper atmosphere from destruction. When the world agreed in 1987 to phase out chlorofluorocarbons (CFCs) through the Montreal Protocol, the chemical industry came up with HFCs as a replacement in applications such as refrigeration, air conditioning and making insulating foams.

While HFCs do not initiate ozone-destroying chemical reactions in the upper atmosphere, like CFCs, they turn out to be extremely powerful greenhouse gases – and now the environmental movement is rightly alarmed that growing use of HFCs could seriously exacerbate global warming.

Individual HFC molecules have a greenhouse effect many hundreds of times greater than carbon dioxide. At present they are present in the atmosphere only in small traces, so their total contribution to global warming is less than 1 per cent that of carbon dioxide.

But projections for the future see a huge increase in HFC use over the next few years, mainly for refrigeration and air conditioning in the developing world. A recent study by scientists at the US National Oceanic and Atmospheric Administration (NOAA) showed that, without restrictions, annual HFC emissions could heat the atmosphere by as much as 8bn tonnes of carbon dioxide by 2050.

So pressure is building for HFCs to be phased out too. The Environmental Investigation Agency (EIA), a green NGO, is leading a campaign for them to be banned under the Montreal Protocol, whose member countries are meeting in Geneva later this week.

The move has support from Achim Steiner, executive director of the UN Environment Programme, who said: “Action to freeze and then reduce this group of gases could buy the world the equivalent of a decade’s worth of carbon dioxide emissions.”

Campaigners point out that it may be easier to use the existing machinery of the Montreal Protocol, which regulates chemicals very similar to HFCs, than to try to include HFCs in climate change treaties which concentrate on carbon dioxide.

Clive Cookson

To St James’s Palace for a press briefing at the end of the Nobel Laureate Symposium on Climate Change, hosted by the Prince of Wales.

The symposium, attended by 20 Nobel Prize winners and dozens of climate experts, produced a strong closing declaration in keeping with its strangely compelling motto, “The fierce urgency of now”.

The declaration made three demands of world leaders:

1. “An effective and just global agreement” on fighting global warming. This would require a commitment at December’s UN conference in Copenhagen to achieve a peak in global emissions of greenhouse gases before 2015 and a 50 per cent cut by 2050. Given that developing country emissions will continue rise, such an agreement requires industrialised nations to aim for a 25-40 per cent reduction by 2020.

2. Deliver a low-carbon infrastructure – including “smart grids” to connect renewable power sources over large areas – through an unprecedented partnership between governments and business.

3. Protect and restore tropical forests. (This is a pet cause of Prince Charles; as he says, without a solution to rainforest protection there is no solution to tackling climate change.)

It would be easy for a cynic to attack the Nobel Laureate symposium for the way it appeals to snobbery – scientific snobbery by inviting so many laureates and playing up their participation for all it’s worth in publicising the event, and royal snobbery by arranging for a prince to hold it in his palace.

Of course some Nobel laureates are indeed knowledgeable about climate science and involved in the fight against global warming – notably Steven Chu, the US energy secretary. It is not clear what some of the other Nobel attendees contributed, though the idea that laureates as a body constitute some sort of eminent high court of science is an interesting one.

In the end, however, I agree so strongly with the aims of the symposium and its closing declaration that I give it my wholehearted support (for what it is worth). Let us hope governments take the same attitude.

The world of research

The science blog is no longer updated but it remains open as an archive.

Clive Cookson, the FT's science editor, picks out the research that everyone should know about, in fields from astronomy to zoology. He also discusses key policy issues, from R&D funding to science education. He'll cover the weird and wonderful, as well as the serious side of science.