THE world has little chance of avoiding at least two degrees of global warming this century - the projected threshold for unpredictable and accelerated climate changes - if the emissions targets proposed by rich nations are locked in at next week's Copenhagen summit, an analysis has found.
A report by German-based consultants Climate Analytics says wealthy countries will arrive in Denmark with proposals that would lead to a joint cut in greenhouse gas emissions of between 13 and 20 per cent below 1990 levels by 2020. Australia's contribution is a 5 to 25 per cent cut, with the final figure dependent on the level of international agreement reached.
The industrialised world target is well below the 25 to 40 per cent range that the Intergovernmental Panel on Climate Change found would be necessary for a 50/50 chance of keeping the temperature rise near two degrees.
Factor in climate policies proposed by major developing nations, including China, and global emissions could increase 35 per cent between 1990 and 2020 - a rise that is said to lock in the inundation of island countries such as Tuvalu, the Maldives and Kiribati.
Scientists have warned that global emissions must peak between 2015 and 2020 to avoid the worst impacts of climate change.
The analysis will add weight to a push by the US and the G77 bloc of developing countries for the Copenhagen talks to set aside proposed 2020 emissions targets, and instead aim for a climate treaty to expire in 2017. This would allow 2020 targets to be reassessed and potentially toughened up mid-decade.
Climate Institute chief executive John Connor, who commissioned the analysis, said it showed that signing up to inadequate 2020 emissions targets would lead to a global warming of 3 degrees, which would destroy the world's coral reefs.
Attempting to reduce emissions after 2020 would require abrupt annual cuts of between 4 and 6 per cent a year until 2050, he said. The rate of change was likely to cause severe economic disruption.
''Inadequate climate action in the short-term also risks tripling current rates of global warming,'' already being seen in Australia in intense droughts, bushfires and heatwaves.
The release of the analysis is timed to coincide with politicians and officials from 192 countries arriving in Denmark for the two-week conference to discuss a climate agreement to replace the current phase of the Kyoto Protocol, which expires in 2012.
World leaders have said the gap between rich and poor nations is too great for a new treaty to be signed this year.
Many countries have already introduced domestic climate change policies. China has announced it will reduce its ''carbon intensity'' by 40 to 45 per cent by 2020, almost cutting in half the carbon dioxide emitted for every yuan of GDP. Under current economic projections, it would still lead to China's emissions growing 40 per cent by 1990.
India has proposed a 25 per cent carbon intensity target.
Saudi Arabia's lead climate negotiator, Mohammed al-Sabban, told the BBC that leaked emails from a British climate research unit last month would have a ''huge impact'' on the Copenhagen talks.
He said the emails cast doubt upon man's influence on global warming and could deter countries from offering emissions cuts at the conference.
Saudi Arabia, one of the world's biggest oil producers, has long taken a sceptical view of climate change.
Senior British civil servant Sir Muir Russell has been appointed to investigate suggestions that the emails, stolen from the University of East Anglia's climate research unit, suggested senior scientists were involved in manipulation or suppression of data and failing to comply with freedom of information requests. The head of the unit, Phil Jones, said he would stand down during the inquiry.