The annual summertime retreat of the Arctic icecap, greater this year than perhaps at any time during the 20th century. The nightmare of intensifying storms in some areas and extended drought in others, already taking place in developing countries of South Asia and sub-Saharan Africa.
It is against this backdrop of almost daily news of what scientists describe as signs of advancing global warming that the United Nations holds Monday what may be the largest high-level international meeting ever on climate change.
The conference, called by UN Secretary-General Ban Ki Moon, kicks off what many experts and officials say will be the high week of a turning-point year in the global political response to the challenge of a warming planet.
More than 80 heads of state or government are expected among the representatives of better than 150 countries attending the UN session. Then on Thursday, President Bush will convene at the White House a gathering of leaders from the world's top emitters of greenhouse gases.
In addition, the Clinton Global Initiative will host a forum in New York Wednesday, drawing business and international political leaders to promote grass-roots responses to global warming.
Over the past weekend, at a UN conference in Montreal, the governments of about 200 countries agreed to accelerate a treaty to phase out hydrochlorofluorocarbons.
Together, the meetings put climate change at the center of the global stage this week – and they will make it harder for leaders to drop the issue in the future, experts say. That may be especially true of Mr. Bush: He may be known internationally as the foot-dragging leader of a top emitter of fossil-fuel pollutants, but by endorsing Mr. Ban's meeting and then calling for his own at the White House, he will be seen as committing to a path of no return on climate-change action.
The Monday UN meeting "is looking to be quite an extraordinary event in what is turning out to be a remarkable year in the international response to climate change," says Richard Kinley, deputy executive director of the UN Framework Convention on Climate Change.
Typically, such international sessions draw environmental ministers, who may or may not attend with the full-fledged backing of their government. This time, many heads of state are involved, with the meeting coinciding with the opening of the UN General Assembly. Such high-level involvement suggests that the world has turned a corner in perception of the seriousness of the climate-change challenge, Mr. Kinley says.
"Increasingly, leaders are seeing this as an issue of national interest, and not just a question of responsibility. And the fact is that states are more apt to act when they see their interests at stake," he says.
Other factors this year, he says, include what many experts describe as a "conclusive" report from an international group of scientists and officials finding evidence of global warming to be "unequivocal." The Intergovernmental Panel on Climate Change concluded with what it termed near certainty that the warming taking place is the result of human activities.
"That doesn't mean we won't hear some unorthodox views" at the meeting, Kinley says. Czech Republic President Vaclav Klaus, for example, intends to portray the idea of man-made global warming as a "myth" that does not justify constrictive measures.
Yet other experts cite factors beyond scientific findings in global warming's rise to the international spotlight. David Sandalow, a specialist in the political dimensions of climate issues at the Brookings Institution in Washington, spoke at a forum earlier this year on the "new political climate" around climate change and listed factors such as: the business community's "astounding" rallying to the issue, the Democrats' taking control of Congress, increased Republican support for action – starting with California Gov. Arnold Schwarzenegger (R) – and even the documentary featuring Al Gore, "An Inconvenient Truth."
What UN experts hope for – and what Ban wants coming out of Monday's meeting – is fresh momentum for action at the UN climate-change conference set for Bali, Indonesia, in December. The Bali conference will take up the crucial question of what kind of agreement should replace the Kyoto Protocol on reducing greenhouse-gas emissions, which expires in 2012.
"What I want … is a strong political commitment at the leaders' level for the meeting in Bali," Ban told reporters last week. "There must be no vacuum" after expiration of the Kyoto accord, "so we must address the challenge boldly." That means reaching a replacement agreement by 2009 so national governments can act and implementation can begin in 2012, he says.
None of this means that the debates on climate change are over, or that global accord on measures for action will be easy to reach.
Many eyes will be focused on this week's White House meeting to gauge just how committed the United States is to action – and what kind of action the Bush administration will accept. Some experts worry that the administration will stick to a preference for voluntary goals in emissions cuts rather than reduction commitments, or that the Washington meeting signals a willingness on the part of the US to go outside the UN framework for addressing climate change.
Another potential stumbling block is the continuing disagreement between industrialized and developing countries over who should make the most substantial commitments to cutting greenhouse-gas emissions. It was the exclusion of developing countries from the Kyoto Protocol that in part led Bush to reject the agreement.
Major developing powers like China, India, and Brazil are still wary of any accord that would place the same burden on them as on developed economies, which they say have much higher per capita emission rates.
But these developing countries are also beginning to signal a seriousness about global warming and to address pollution and sustainable-development issues on their own, leading some experts to find hope that the divide can be narrowed. "Among a number of developing countries, we're seeing a growing realization that they have to take a new approach for their own well-being. And the leading example of that is China," says Kinley of the UN.
"That is not to say they have changed their position that the industrialized world should take the lead," he adds. But he says a door once shut tight has now been opened.
"What we hear more now is talk of incentives, of the right investment and technology flows into the developing countries, and that is bringing the two sides closer together," he says. "That's crucial, because it's clearly only through international cooperation that this challenge can be addressed."