A British government report says global warming could have a disastrous effect on the world's economy, shrinking it by 20%.
Tackling the problem now would require 1% of global gross domestic product, the report by the economist, Sir Nicholas Stern, says.
BBC correspondents give the view on climate change from around the world.
NICK MILES, WASHINGTON
The latest global warming report is a huge contrast to Washington's current approach to global warming.
The Bush administration decided not to ratify the Kyoto protocol and that called for far more moderate cuts in carbon dioxide emissions than those suggested by the Stern report.
But recently there has been a subtle shift in public opinion about the environment.
Prominent public figures from both sides of the political divide have been taking a stand.
A film by former Democratic Party Vice-President, Al Gore, warned of the need for the US to address global warming.
An Inconvenient Truth was widely acclaimed and the Republican governor of California, Arnold Schwarzenegger, has recently introduced initiatives that will put a cap on carbon-dioxide emissions from the manufacturing plants and set targets for greener cars.
Those strategies were singled out for praise in Nicholas Stern's report.
There has been a parallel shift in public attitudes as well. Polls suggest that three-quarters of Americans feel that global warming is a serious problem and a majority of citizens feel environmental protection should take priority over economic growth.
But when the time comes to pay higher taxes to mitigate the problem, those lofty ideals may change and environmentalists point out that there is still considerable opposition within Congress to nationwide caps on greenhouse gases.
The car and energy lobbies are some of the most powerful in Washington.
DAMIAN GRAMMATICAS, DELHI
It is developing nations like India that are likely to be hit hardest by climate change. As global temperatures rise, so will sea levels.
Flooding will be a major problem. Glaciers in the Himalayas will melt, releasing more flood waters onto the Indian plains.
Then, as rivers shrink, there will be droughts. But while climate change is seen as a real threat to India, an even more pressing priority is driving forward economic development.
First, that means tackling poverty, improving life for some of the tens of millions who still live without access to electricity, to healthcare and education.
Second, there are growing numbers of Indians who want the luxuries of a developed lifestyle - cars, fridges, televisions. They will be the polluters of the future.
For now, the view from here is that it is developed countries that must help foot the bill if they want Indians to tackle climate change.
DAN GRIFFITHS, BEIJING
A hazy layer of smog often hangs over Beijing, a noxious mixture of emissions from cars, factories and power stations in the capital of the world's most populous nation.
And it is not just Beijing. China has some of the most polluted cities on the earth.
It is already the world's second largest producer of greenhouse gases. China produces more coal than any other nation, and oil consumption here has doubled in recent years.
The country's wealthy middle classes are buying cars in record numbers, adding to the problem.
And with the economy still booming, many analysts expect China's total emissions to overtake the US within a few decades.
The country's leaders say they are aware of the challenges presented by greenhouse gas emissions.
They have announced plans for China to generate 10% of its power from renewable sources and have promised to build more nuclear power reactors.
They ratified the Kyoto Protocol, but as a developing nation China is not required to reduce its emissions.
And there's the rub. China believes that emissions restrictions could slow economic growth.
The government is promising to do more for the environment, but so far the economy has always come first.
PETER BILES, JOHANNESBURG
Even before the publication of the Stern report, environmental groups had been warning of the dangers of climate change across Africa.
Global warming is said to be having a serious impact on the continent and research from an umbrella group of campaigners had predicted an "unprecedented" threat to food security.
In some parts of Africa - particularly in the countries of the Horn and the Sahel - food production is always at the mercy of the climate.
These arid and semi-arid regions are at risk of becoming even drier as a result of global warming.
Africa is, on average, 0.5C warmer than it was a century ago, but the latest research suggests that some places are more than 3C warmer than just 20 years ago.
In response to Nicholas Stern's findings, Oxfam says that for hundreds of millions of people living under the constant threat of drought or flood, urgent action on climate change is vital.
The agency says not only will this save money in the future but it will also save lives in the poorest countries today.
There is plenty of agreement on the fact that global warming and greenhouse emissions are caused by the rich industrial nations - but Africa is bearing the brunt of the problem and therefore needs help.
Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/in_depth/6099272.stm
Published: 2006/10/30 17:16:27 GMT
© BBC MMVI