Among their latest findings: carbon dioxide and methane levels in the atmosphere -- the so-called greenhouse gases that are responsible for global warming -- are higher now than they have been for millennia.
"Present carbon dioxide levels [in the atmosphere] are now beyond about a 650,000-year high, so we're into uncharted territory certainly in this recent climactic epoch," said John Coll, a climate-change scientist at the Environmental Research Institute in Scotland.
Greenland's ice sheet is currently melting twice as fast as it was just a decade ago. Combined with the melting Antarctic ice cap, some scientists warn that this could raise sea levels by several meters within the century.
If that happens, entire island nations will disappear and much of the world's coastlines will be reshaped -- with the survival of major cities threatened.
Pragmatic Solutions Needed
In short, scientists caution that dramatic effects of climate change could be felt very soon unless the world gets serious about reining in greenhouse gases.
British Prime Minister Tony Blair's message today was that he accepts the warnings. And he signaled that he intends to lead a global effort to prevent these dire scenarios from happening. But he said pragmatic long-term solutions are needed, which are not being addressed by the current Kyoto Protocol on climate change.
Under the Kyoto Protocol, which runs out in 2012, over 50 industrialized countries have pledged to cut their combined greenhouse-gas emissions by 5 percent.
The United States, which produces one-quarter of the world's greenhouse gases, has not ratified the treaty, citing economic reasons. Major developing countries like China, the second-biggest producer of greenhouse gases, and India are also not covered by Kyoto.
Blair said today that Britain is on track to meet its Kyoto targets. But he argued that without the involvement of the world's largest countries, any climate pact is meaningless.
"We will meet our Kyoto targets, in fact we will double our Kyoto targets," he said. "But there is one very obvious truth about climate change. Without the participation of America and the emerging economies of China and India, there isn't going to be a solution."
Blair said a new agreement must be drafted that addresses U.S. concerns as well as the goals of developing countries that are trying to catch up economically with the West.
"What is necessary is to get an international agreement that has got a framework with a stabilization goal in it, so that we set a very clear objective for everyone to aim at, and then you have to develop the science, the technology, and the changes in behavior necessary in order to meet that goal," Blair said.
Kyoto Targets Not Met
John Coll welcomes Blair's statement but said it won't be easy. He noted that even the modest Kyoto targets are in danger of not being met.
"Even trying to meet some of the Kyoto targets has created lots of legislative problems for some of the industrialized and developed countries," Coll said. "Obviously, the big problem for politicians is how do you square the circle, if you will, on this economic-development paradigm and reigning in people's lifestyles in line with trying to curb emissions. Obviously, a large part of it relates to energy and transport policy, so I think at the political level it becomes quite difficult for the policymakers."
An added difficulty is that scientists' dire predictions are all based on theoretical models. We know the world has experienced periods of rapid cooling and warming over the millennia. But no one can be certain at what point such changes are triggered, although according to Cole, most scientists believe a certain tipping point -- beyond which changes become irreversible -- exists.
"The very real concern is that nobody really knows what the critical thresholds and tipping points are," he said. "But [it certainly has been the case] in past sudden climate transitions that once a certain temperatures threshold is reached, things can start to go out of kilter in a more linear fashion. So at that point you might start to get a lot of [contributing] feedback into the climate system and accelerate the warming. So I think that's what a lot of the reports have expressed a concern about."
Blair said he hopes the July summit of the Group of Eight major industrialized countries in St. Petersburg, which will also include nonmembers like China and India, can be a good place to start discussing a new global environmental accord.