Weather warning

Britain's Chief Scientist told an American audience in Seattle how dangerous he believes global warming to be.

We already know he thinks it's a more serious threat to national security than al-Qaeda. Now strategic planners working for the Pentagon have produced their own report on the risk climate change poses to global stability.

Growing evidence suggests the planet is being pushed to a tipping point that could alter the weather radically, not in centuries - but in a decade. If that happens it could cause mayhem in countries overwhelmed and destabilised by huge temperature shifts.

Ben Geoghegan reported.

BEN GEOGHEGAN:
Since 9/11, nothing has been as important for America as the war on terrorism. But Britain's chief scientist has been arguing that there is a more pressing problem which the Bush administration hasn't done enough to address. Sir David King thinks global warming is the biggest danger facing the world today, more serious even than the threat from Al-Qaeda. He has accused the US Government of failing to take up the challenge of climate change.

DANIEL LASHOF:
National Resources Defense Council
David King is absolutely correct to say that the United States is not addressing global warming in a serious way. The Bush administration not only walked away from the Kyoto protocol, but it has opposed any meaningful standards to reduce carbon dioxide pollution that causes global warming.

BEN GEOGHEGAN:
Tonight in Seattle, Sir David will repeat what most scientists accept - that human activity is making the Earth warmer and that big cuts in greenhouse gases are needed.

DOCTOR RICHARD WOOD:
Hadley Centre for Climate Prediction
The climate models predict that, over the next 50 years, we are likely to see a rise in global average temperatures of maybe one or one-and-a-half degrees, which is more than the global warming we have already seen. The impacts of that on all sorts of systems, such as sea level rise, such as extreme events like heat waves and extreme rainfall events - floods - possibly wind events, like storms. There are really wide-ranging impacts on the climate system of the whole world.

BEN GEOGHEGAN:
President Bush has decided not to impose mandatory limits on carbon dioxide production because of the harm they might do to American industry. The US believes the emissions targets in the Kyoto agreement on climate change are arbitrary and expensive.

PRESIDENT GEORGE BUSH:
I will not commit our nation to an unsound international treaty that will throw millions of our citizens out of work.

BEN GEOGHEGAN:
So the policy up until now has been to given individual states the freedom to regulate themselves. The Government is also investing heavily in technology as a way of coming up with solutions that don't hurt the economy. But environmentalists are hoping that new research for the Department of Defence might soon bring about a different approach. Inside the Pentagon is a unit with the job of identifying future threats to the United States. It reports directly to the Secretary of Defence. It recently hired experts to look into some of the implications climate change might have for national security. Newsnight has obtained a copy of their unpublished report. It warns that a dire climate scenario might be unfolding, and it's one which needs to be considered immediately.

PETER SCHWARTZ:
Report Author
This is very much in the spirit of thinking the unthinkable. The report that we put together for the Pentagon is an extreme scenario, in the sense that most climatologists would say that this is low probability, in the sense of it happening soon, and as pervasively. But it is the Pentagon's job to think about many cases, the worst-case scenario. What are the extreme continue conditions that could put pressures on US national security?

BEN GEOGHEGAN:
Rather than looking at gradual change over centuries, the Pentagon has been finding out about what might happen if the climate in the northern hemisphere suddenly lurched into a big freeze. There is growing evidence to suggest this might happen, in which case Britain would become just as cold as Siberia.

DOCTOR MERIC SROKOSZ:
Rapid Climate Change Programme, Natural Environment Research Council
Paradoxically, we could actually get colder locally while the rest of the world is warming because of the effects on the oceans circulation. We have evidence from ice-core data in Greenland and sediments at the bottom of the sea that show such changes have occurred in the past, and they have occurred on fairly short timescales, like 10- 20 years which is quite rapid for climate change.

BEN GEOGHEGAN:
The eastern United States and northern Europe are warmed by a huge Atlantic current flowing north from the tropics. It's called the great conveyor. As the warm current moves north, it cool, sinks and begins to head south again. The problem is that as the Earth heats up and the Arctic glaciers melt, more fresh water is poured into the sea. That makes it less salty and less dense, and so less likely to sink. One possibility is that the circulation of the current could slow down, or stop altogether.

PETER SCHWARTZ:
The only real question is, when, and exactly with what effects, where. That is, I think that it is likely that, if the climate is changing - and I think the evidence is very strong that it is - that when it changes, it will change suddenly. It will snap. Following a period of warming, we will get a dramatic cooling. What we don't really know is whether this will take 10 years, 20 years or 50 years. The evidence is mounting that it's fairly soon. That's why there is an interest in considering what the consequences might be in the near future.

BEN GEOGHEGAN:
The report says that if the ocean's conveyor does stop, average temperatures in North America could fall by up to 5 degrees and by even more in some parts of Europe. Average rainfall in this region would fall by 30% leading to massive droughts in key agricultural areas. Winds would increase by 15% provoking widespread dust storms and soil loss. The Pentagon study claims that climate change could mean human life would come to be defined by war. Different regions would fight for diminishing resources.

PETER SCHWARTZ:
Around the world, we could see conflict induced by the search for particularly food and water, in some cases access to energy, and as a result either friends or allies, or others, may need our assistance in military ways to cope with the kind of stresses that they are having to confront.

BEN GEOGHEGAN:
On the River Clyde this week, a ship was being prepared for a joint British, American expedition to the Atlantic. Scientists will monitor changes in the strength and temperature of ocean currents to see if the conveyor is indeed about to turn itself off.

DOCTOR STEWART CUNNINGHAM:
Chief Scientist, Rapid Climate Change Monitoring Programme
What we are going out to measure is the temperature and speed of the warm water flowing north in the Gulf stream, and then the same speed and temperature of the cold water which turns southwards from the high Arctic regions. It's the balance of the temperature and speeds of those two main currents that will tell us about the state and strength of the Atlantic circulation.

BEN GEOGHEGAN:
This expedition shows that the whole idea of abrupt climate change is not something that's only talked about by the policy wonks in the back rooms of the Pentagon. It is a real and potential consequence of global warming and something which scientists at least are treating with increasingly seriousness. But the Pentagon's paper says that this whole issue should be taken beyond the level of scientific debate because of its potential implications for national security, and so some groups are hoping that it will now trigger a change in policy at the White House.

FILM CLIP:
Meteorologists are at a loss to explain what is causing this weather...

BEN GEOGHEGAN:
Hollywood has already decided that climate change can be made to look as scary as terrorism. This film was released in Britain in May and there are some unmistakable references to 9/11.

FILM CLIP:
Lower Manhattan is virtually inaccessible. A wall of water coming towards New York City!

DANIEL LASHOF:
National Resources Defense Council
Global warming is a problem that the Pentagon should take seriously, and it's very welcome that they have commissioned a thoughtful study of the risks that global warming poses to the United States. I think that coming from the Pentagon, a lot of people will take this seriously that might not otherwise pay attention.

BEN GEOGHEGAN:
It's possible to argue that rapid climate change has nothing to do with human behaviour, and so there is no point in trying to stop it, but environmentalists say the Pentagon's research provides as good a case for a policy of pre- emption as anything else.

This transcript was produced from the teletext subtitles that are generated live for Newsnight. It has been checked against the programme as broadcast, however Newsnight can accept no responsibility for any factual inaccuracies. We will be happy to correct serious errors.