Efforts to accelerate action against the world's looming climate crisis begin in earnest this month, unfolding against a background of deepening scientific concern but entrenched political obstacles.
Two meetings could decide whether a key conference, taking place in Bali, Indonesia in December, will at last smash the logjam over how to step up cuts in greenhouse-gas emissions or be a landmark in fiascos.
The Bali meeting, gathering members of the UN Framework Convention on Climate Change (UNFCCC), will strive to set a roadmap for negotiating global pollution cuts that will be implemented after 2012, when the Kyoto Protocol runs out.
The clock is ticking fast. The next new treaty must be completed by 2009 or 2010 at the very latest, so that all signatories can ratify it in time.
So far, the post-2012 haggle has been messy, sometimes nightmarishly so.
Progress has often been tortoise-like as key players baulk and quibble or wait for others to declare their hand.
"It's not even a coalition of the willing," a UN source said on Friday, as a session in Vienna of Kyoto parties dragged into extra time.
For scientists, the "greenhouse effect" -- a warming of Earth's surface as solar heat is trapped by carbon gas from fossil fuels -- poses an ever grimmer peril.
In three reports this year, the UN's Intergovernmental Panel on Climate Change warned that by the end of the 21st century, the warmer world faced a heightened probability of water shortage, drought, flood and severe storms, boosting the risk of malnutrition, water-borne disease and homelessness.
Even though governments acknowledge the gravity of the threat, they seem unable to reach any consensus about how to tackle it.
Reducing greenhouse-gas emissions carries an economic price, for it entails a drive for greater energy efficiency and a switch to cleaner fuels. There is is little willingness for self-sacrifice if others are suspected to get an easier ride.
Roughly speaking, the post-2012 negotiations resemble a kaleidoscope image fractured into three parts.
In one part are the radicals, led by the EU, who want Kyoto's successor to set ambitious, unambiguous targets for cuts by industrialized countries.
They talk of a reduction of some 30 percent by 2020 compared to 1990 levels, a figure strongly opposed by other industrialized countries, notably Russia.
In another part are China and India, now major carbon polluters.
So far, they are sitting on their hands. They are waiting to see what the industrialized countries will offer while ruling out targeted pledges on their own pollution if to do so imperils their rise from poverty.
The third -- and possibly most intractable -- part of the kaleidoscope image is that of the US.
It, alone among the big polluters, opposes Kyoto (although it remains part of the UNFCCC, the main arena), citing the Protocol's mandatory caps and the fact that developing countries duck binding pledges of cuts.
So a big question is how to build a treaty with variable geometry, enabling the US to join the carbon cleanup club even if it still opposes Kyoto-style obligations espoused by the others.
In this context, two meetings are scheduled that seek to blow away the smoke obscuring the poker table.
The first will be in New York, where UN Secretary-General Ban Ki-moon will host a meeting of some 30 major countries on Sept. 24, which will be following by a General Assembly session devoted to climate change.
The other follows on Sept. 27 and Sept. 28 in Washington, when US Secretary of State Condoleezza Rice will chair a meeting of 16 countries that together account for some 90 percent of global emissions.
The US insists the Washington meeting simply aims to clarify matters so that at least everyone knows who is offering what, and any deal will feed into the UN process.
Even so, suspicions run deep among greens and in Europe that the US wants to subvert the mandatory Kyoto approach and replace it with a voluntary, technology-driven tack.
The Washington conference "is in spirit an attempt to block" the Kyoto process, an internal memo by a European government said.
It calls on EU members to be "perfectly united in the face of the American initiative."