The deal was a compromise on major technical issues that have hamstrung Kyoto since it was born in 1997 as a weapon to reduce emissions of carbon-rich "greenhouse" gases blamed for dangerously warming the planet.
Kyoto's declared target is a global cut of 5.2 per cent of these gases by 38 industrial nations in a timeframe of 2008-12 compared with 1990 levels.
The defection of the Americans in March after Mr Bush branded Kyoto as too costly for the American economy cast a dark shadow over its future.
Australia, Canada and Japan were the most vocal of those countries which doubted the point of an anti-pollution pact that excluded the world's biggest polluter.
But the EU - arguably the most environmentally sensitive region in the world - decided otherwise.
In an unusual show of resolve, it embarked on a campaign of diplomatic arm-twisting, supported by influential environment groups, and finally won over the doubters by offering a range of concessions.
The biggest by far was on "sinks". These are forests and agricultural lands that soak up airborne carbon dioxide by photosynthesis.
Big farming and forested countries fought hard to have these sinks generously calculated as an asset that could be offset against national targets for gas emissions.
For more than 3 1/2 years the EU said the use of "sinks" should be limited because it could be impossible to police them and the scientific evidence about their benefit was confused.
In the end, the EU abandoned virtually every position on this issue, opening up a potentially large loophole in Kyoto's effectiveness.
The Worldwide Fund for Nature calculates that the overall emissions cut will now be just 1.8 per cent instead of 5.2 and may even be as low as zero, depending on how crops and grazing land are evaluated.
EU leaders admitted that the deal fell far short of their hopes, but said a failure would have given Mr Bush time to float rival proposals that would have destroyed Kyoto.
"I prefer an imperfect agreement that is living to an imperfect agreement that doesn't exist," said Belgian Deputy Environment Minister Olivier Deleuze, whose country is president of the EU.
The chief advantage, they believed, was that they had secured a good model with tough penalty clauses which would be used in further commitment periods after 2012 to make bigger and deeper reductions.
Many challenges, however, lie down the road, especially technical decisions needed to make Kyoto's fancy mechanisms work.
But, as the Daily Telegraph in London reported, even if the agreement is much watered down, it still establishes rules for cutting emissions and sets rules for carbon trading, based on the highly successful system for trading permits to emit acid rain pioneered in the US Clean Air Act.
A cap on company emissions is set and those able to make savings may sell emission rights to companies that need them. Every now and then the Government raises the price of permits by buying some on the commodity markets. This creates a market in saving pollution.
The Telegraph says many Kyoto negotiating experts believed that once carbon trading became a reality (domestically or internationally), the emission savings resulting would vastly outstrip the reduction targets in the Kyoto arrangement.
What is unclear at present is whether Japan and Russia will share the EU's enthusiasm for ratifying Kyoto in time for the 10th anniversary next year of the Rio summit.
Canada says it hopes to ratify a modified version of the agreement next year.
Japan, desperate to coax its American ally back into the club, may delay ratification and thus implementation of the landmark accord.
In previous negotiating rounds, New Zealand was attacked in the EU for aligning itself with many Australian positions on "sinks".
But this time it won praise for submitting an innovative idea, even though it did not make headway in the hectic negotiations. Under this, countries would gain emissions credits for planting new forests, not for their present ones, thus encouraging reforestation of degraded land.
New Zealand further broke ranks with Australia by refusing to join Canberra's stonewalling over funds for developing countries.
It joined a 20-country group, including the EU, Canada, Iceland, Norway and Switzerland, that pledged to give these nations $US410 million a year from 2005 to help them cope with climate change.
SOME FACTS AND FIGURES
What was the Kyoto accord intended to do?
Born in 1997, it was a stepping-stone - to which about 85 states were party - intended to lead to a pact binding each country to reduce greenhouse emissions.
What are these emissions?
Greenhouse gases, mainly carbon dioxide (COinf2) but also methane and nitrous oxide, are increasing because of human activities. Gases occur naturally in the atmosphere, forming a blanket round the earth and trapping warmth from the sun, so we do not freeze to death. But the blanket is becoming thicker, trapping too much warmth and causing global warming. Burning fossil fuels - coal, gas oil and gas - produces COinf2. Farm animals emit methane, and chopping down trees(deforestation) also contributes because forests soak up COinf2.
What was Kyoto's target?
A cut of 5.2 per cent in these gases compared with 1990 levels by 38 industrialised countries by 2008-2012.
What might the reduced Kyoto Protocol achieve now?
At least the accord is still alive, because of the European Union-brokered deal, but in a lesser form. It is also minus the world's biggest polluter, the United States. And there have been concessions that are causing some doubts about whether the target cuts in emissions may be achieved at all in the short term. But its supporters say keeping the global warming accord alive has humiliated the US and may still lead to greater reductions in emissions in the future.
www.nzherald.co.nz/climate
Intergovernmental Panel on Climate Change (IPCC)
United Nations Environment Program
World Meteorological Organisation
Framework Convention on Climate Change
Executive summary: Climate change impacts on NZ
IPCC Summary: Climate Change 2001
