Make clear dire scenarios to prod climate action: Stern

Gelu Sulugiuc, Reuters 12 Mar 09;

COPENHAGEN (Reuters) - Scientists must make clear the disastrous effects of climate change so the world takes action now to cut carbon emissions, leading economist Nicholas Stern said on Thursday.

"You have to tell people very clearly and strongly just how difficult (a temperature rise of) four, five, six or seven degrees Celsius is," he said.

"Billions of people would have to move and there would be very severe conflict," said Stern, a professor at the London School of Economics and a former British Treasury economist.

"That's a story that must be told to persuade people it's a very bad idea to go anywhere near five degrees. This is not a black swan, this is a big probability of a devastating outcome," he told a gathering of 2,000 scientists at the Congress on Climate Change in Copenhagen.

"The costs of delay are very big," he said.

Stern, in a 2006 report, warned inaction on greenhouse gas emissions could cause economic pain equal to that of the Great Depression of the 1930s.

Above two degrees warming, hundreds of millions of people would face reduced water supplies, and above three degrees food production worldwide would be very likely to decrease, a U.N. panel of climate scientists said in 2007.

Professor John Schellnhuber of the Potsdam Institute for Climate Impact Research, speaking before Stern, said a warming of five degrees would mean the planet could support less than 1 billion people.

Reaching a new global climate deal in December in Copenhagen, to succeed the Kyoto protocol, depends largely on whether developing countries agree to steps to help solve a problem they say rich countries created.

Stern said rich countries should agree to cut their greenhouse gas emissions by 80 percent by 2050 to bring emissions in the world as a whole down by 50 percent over the same period.

"For 1 or 2 percent of global GDP we can hold concentrations of (atmospheric carbon) below 500 parts per million, then go down from there," Stern said. "This would bring the probability of five degrees warming to only 2 or 3 percent. That sounds like a pretty good deal to me. We can make a very powerful insurance case."

Stern said developing countries were not yet ready to agree to fixed carbon targets, but that rich countries could convince them by sharing green technologies, starting global carbon trading and helping poorer countries to stop deforestation and adapt to the more immediate consequences of climate change.

"China and India are potential deal-breakers. But we can get there. I am more optimistic than I was two years ago, he said."

(Editing by Janet Lawrence)

Scientists must raise climate alarm: Lord Stern
Marlowe Hood Yahoo News 12 Mar 09;

COPENHAGEN (AFP) – The economic impact of global warming has been grossly underestimated and scientists must warn that inaction will spell disaster, top economist and climate change expert Nicholas Stern said on Thursday.

Stern told 2,000 climate scientists meeting here that they had failed to clearly tell humanity what it faces if global temperatures reach the upper range of forecasts made by the UN's Intergovernmental Panel for Climate Change (IPCC).

"There has been lots of scientific information on 2.0 and 3.0 degrees Celsius (3.6 and 5.4 degrees Fahrenheit), but you have to tell people loudly and clearly just how difficult 4.0 or 5.0 would be," he said.

The IPPC's 2007 report for policymakers predicted an increase by 2100 of 1.1 to 6.4 C (2.0 to 11.5 F) compared to a century earlier.

New findings show that these projections were vastly understated, scientists here said.

"Recent observations confirm that, given high rates of observed emissions, the worst-case IPCC scenario trajectories -- or even worse -- are being realised," the three-day conference, organised by top universities worldwide and the Danish government, concluded Thursday in a closing statement.

Stern, whose 2006 Stern Review has become the benchmark for calculating the economic cost of tackling climate change, conceded that his report had also fallen short in assessing the potential consequences of global warming.

Greenhouse gas emissions are growing faster, and the planet's capacity to absorb them is weaker, than was understood only a few years ago.

"The costs of delay are very deep," he told the conference in Copenhagen, which will host critical United Nations climate talks in December.

"Climate change is not like a WTO negotiation where, if it falls apart, you can pick it up five years later be more or less in the same position. If you wait, you will be in a significantly worse position."

Even smaller increases in temperatures, the IPCC has said, could unleash a devastating maelstrom of violent storms, drought, expanding disease and hunger over the coming decades.

A "five degree world" -- well within the range of IPCC predictions -- would cause an almost unimaginable level of disruption and suffering.

The last time Earth was four or five degree hotter than it is now, some 30 million years ago, alligator-like creatures navigated swampy primeval forests at the North Pole.

"Sea levels, in the long run, would rise by 50 meters. You would have to redraw the map of Europe," and every other continent, said John Schellnhuber, director of the Postdam Institute for Climate Impact Research in Germany.

"The carrying capacity of the planet would fall to one billion people or less," Schellnhuber told the conference.

"This is not a 'black swan'," said Stern, invoking a term used by philosophers to describe an event beyond the realm of normal expectation.

"This is not a small probability of a rather unattractive outcome. This is a big probability of a very bad outcome."

Faced with this unacceptable scenario, decision makers and the people they govern should be willing to buy some insurance, he said.

"Would you pay one-to-two percent of GDP for this kind of risk reduction, thinking about the cost of inaction? I think people will understand," he said.

Katherine Richardson, head of the Danish government's Commission on Climate Change Policy and a co-organiser of the meeting, agreed that scientists had not done a perfect job in getting the message out.

"Most of us have been trained as scientists to not get our hands dirty by talking to politicians. But we now realise that what we are dealing with is so complicated and urgent that we have to help to make sure the results are understood," she told AFP.

Climate change leading the world into catastrophe, claims Lord Stern
Climate change could cost trillions of pounds and lead to worldwide social unrest and decades of war, warned one of Britain's leading economists as he accused politicians of underestimating the scale of the problem.
Richard Alleyne, The Telegraph 12 Mar 09;

Lord Stern, whose report on the social and economic costs of global warming acted as a wake up call to the world in 2006, said the effects were worse than he originally thought and that the consequences could be "devastating".

He said that increases of average temperature of four, five or even six degrees by the end of the century were becoming an increasing possibility and would produce conditions not seen on Earth for more than 30 million years.

That could mean massive rises in sea level, whole areas devastated by hurricanes and others turned to inhabitable desert, he claimed - the results of which would force billions of people to leave their homelands.

He told the emergency climate summit in Copenhagen that politicians continued to underestimate the impact and that scientists needed to double their efforts to get them to understand.

"Much of Southern Europe would look like the Sahara," he said on the final day of the conference organised to bring the science up to date for a political summit in December. That forthcoming conference will hammer out a new Kyoto-style worldwide agreement on reducing emissions.

"Many of the major rivers of the world, serving billions of people would dry up in the dry seasons or re-route.

"What would be the implication? Hundreds of millions of people would have to move, probably billions. What would be the implication of that? Extended conflict, social disruption, war essentially, over much of the world for many decades."

Lord Stern, the World Bank's former chief economist, was credited with shifting the debate about climate change from an environmental focus to the economic impacts two years ago.

His Stern Review made headlines after it calculated that countries needed to spend one per cent of their GDP to stop greenhouse gases rising to dangerous levels. Failure to do this would lead to damage costing much more, the report warned - at least five per cent and perhaps more than 20 per cent of global GDP.

He now believes that he underestimated his findings and that countries need to spend at least 50 per cent more again to tackle the problem.

"Looking back the Stern review underestimates the risks and underestimated the damage from inaction," he said.

"For the reasons the scientists have been telling us over the last two or three years emissions are growing faster than we thought.

"The absorbing capacity of the Planet is less than we thought. The stocks (of emissions) are building up faster than we thought. The kinds of temperatures that could arise from those higher stocks and concentrations of greenhouse gases have higher probabilities than we thought.

"Some of the consequences seem to be coming through faster and more worryingly than we thought.

"For all those reasons I think the damages were underestimated in the Stern Review and the costs of inaction were even bigger than we argued then.

"I described it then as being pretty risky and I argued that the costs of inaction are vastly higher than the costs of action. I think that is still, I would make that argument still more strongly now."

"Do the politicians understand just how difficult it could be? Just how devastating four, five, six degrees centigrade could be. I think not yet."

Global warming 'will be worse than expected' warns Stern
Economist says his 2006 groundbreaking report underestimated risk and accuses governments of not being ready for consequences of 6C temperature rise
David Adam, guardian.co.uk 12 Mar 09;

Politicians have failed to take on board the severe consequences of failing to cut world carbon emissions, Nicholas Stern, the economist who warned the government of the high cost of climate change, said today.

Stern told a meeting of climate change scientists in Copenhagen that the effects of global warming would be worse than he predicted in his seminal 2006 report on the economics of the problem. He said policy-makers needed to think more about the likely impact of severe temperature rises of 6C or more.

Speaking after a keynote speech at the conference, Stern said: "Do the politicians understand just how difficult it could be? Just how devastating 4, 5, 6 degrees centigrade would be? I think not yet. Looking back, the Stern review underestimated the risks and underestimated the damage from inaction."

His remarks echo concerns by other scientists at the meeting. Privately, many climate experts and officials say that the European target of limiting world temperature rise to 2C above pre-industrial levels is no longer realistic.

Steven Sherwood, a climate researcher at Yale university, will tell the conference later today that warming of 4C or more this century looks "increasingly likely".

Bob Watson, a former head of the Intergovernmental Panel on Climate Change (IPCC) and chief scientist at the environment department, has already warned that governments need to prepare for a 4C rise.

The 2007 report of the IPCC said that average temperatures could rise by up to 6C this century if no action were taken to curb greenhouse gas emissions. Many scientists say this could be an underestimate, because world emissions have grown faster than expected.

According to the 2006 Stern report, a rise of 4C would put between seven million and 300 million more people at risk of coastal flooding each year, there would be a 30-50% reduction in water availability in southern Africa and the Mediterranean, agricultural yields would decline by 15%-35% in Africa, and 20%-50% of animal and plant species would face extinction. Yesterday, scientists announced at the conference that a 4C rise would lead to the loss of 85% of the Amazon rainforest.

A 5C rise would mean that major cities such as New York, London and Tokyo would be threatened by a rise in sea levels and increases in ocean acidity would severely disrupt marine ecosystems and fisheries. An increase of more than 5C — equivalent to the amount of warming that occurred between the last ice age and today — is, according to the Stern report, "likely to lead to major disruption and large-scale movement of population". It said the effects would be "catastrophic" and "far outside human experience".