The protocol is designed to reduce emissions of greenhouse gasses from industrial nations, which are held to be warming the earth and causing such extremes as droughts, floods, storms, and rising sea levels.
Controversy has raged about the protocol since it was drawn up in 1997. Supporters see the accord as a first step towards avoiding an environmental catastrophe, opponents see it as an unfair yoke placed upon economic activity for scientifically unproven reasons.
For a growing number of people around the world, the issue is no longer a matter of debate. It's a question of life or death. One of them is Beiataake Orea, whose homeland, the island-chain country of Kiribati in the South Pacific, is threatened by rising ocean waters.
Standing amid the debris of flooded village houses last week, she expressed fear at the rising sea levels. "It worries us a lot; yes we are worrying, I am afraid of the future, I don't know what will happen to Kiribati," she said.
The driving force behind the Kyoto Protocol has been the European Union, whose then-15 members voluntary pledged a hefty 8 percent cut in greenhouse-gas emissions compared to 1990 levels. That's well beyond the 5.2 percent demanded by the protocol.
The trouble is, things are not going too well. The reduction period does not start until 2008, but based on present indications, those targets will be hard to meet. Overall emissions among the EU members are down by 2.9 percent compared with the reference year 1990, but many individual countries are well above the limit. Economically expanding Spain, for instance, is 25 percent above its target.
Richard Tarasofsky of the London-based Royal Institute of International Affairs said that if the EU can meet its target, that will strengthen the hand of the protocol supporters. If it does not, then "other countries will lose faith" in the process.
The Kyoto Protocol is a binding document that has the force of law. It's not clear what will happen if ratifying countries fail in their obligations.
Negotiations on a second, deeper round of post-Kyoto emission cuts, for the years after 2012, are supposed to get under way this year. Scientists estimate that much bigger reductions are necessary to achieve long-term climate stability. Brussels-based ecologist Mahi Sideridou of the Greenpeace organization said time is short.
"Which is why it's extremely urgent that we move beyond the [present] Kyoto Protocol and we look ahead, and see what needs to be done, and what the next steps are to be able to deal with this huge problem," Sideridou said.
One of the most difficult aspects of Kyoto, however, is that it does not impose binding limits on nations classed as "developing." These include China, India, and Brazil -- big nations where industrialization is now proceeding rapidly, and where pollution is rising.
"This is actually one of the biggest arguments the United States used when they decided to withdraw from the Kyoto Protocol [in 2001]; one of their arguments was that they did not want to damage the competitiveness of their industry, the second one was that they felt it was unfair for industrialized countries to take on commitments to reduce their emissions when the developing nations were not taking these commitments," Sideridou said.
The United States -- by far the biggest single emitter of greenhouse gasses -- also has doubts about the reliability of the scientific data underpinning Kyoto. But despite rejecting the protocol, it says it has been active in furthering research.
White House spokesman Scott McClellan said: "There's a lot we're still learning about the science of climate change. This administration is working to advance that science and to learn more about climate change itself and its effect on the world. And we're working very closely with our international partners on these issues as well. We've made some unprecedented commitments to furthering the research.”
There's no easy way out of the dilemma posed by the nonparticipation of developing nations, such as China and India. There's no indication that they will be willing to join the second round of greenhouse emission cuts, because they say the industrial world has caused the problem historically, and should now repair the climate damage themselves.
But without developing countries like China and India participating, there's a danger the industrialized Kyoto signatories will refuse to go further.
Environmentalists say it's up to the developed nations to pioneer the systems of pollution control and pass on these technologies to the poorer countries. And they note that the developing giants India and China are already taking some steps towards cleaner and renewable energy sources.
All the debate, however, seems far away from the immediate problems of people like Pacific islanders, whose homes are sinking. As Kiribati President Anote Tong put it: "The international community was shocked by the effect of the tsunami that occurred in the Indian Ocean. We are very much like that except it is more gradual, at least the victims of the tsunami had the luxury of having it happen in one very fast instant. We are facing a gradual dying process and I do think they [members of the international community] need to come in and provide opportunities and options for us."
Of the Central Asian countries, Kyrgyzstan, Turkmenistan, and Uzbekistan have ratified or acceded to the Kyoto Protocol. Accession gives the same status as ratification. Tajikistan has not signed. Kazakhstan and Afghanistan have signed but not yet ratified it. The Caucasian republics of Georgia, Armenia, and Azerbaijan have all ratified or acceded, as has Moldova, Romania, Ukraine, and Russia. Belarus and Iran have neither signed nor ratified the protocol.