ABC News Online,
The scientists' statement is appended below. To see the names of signatories go to - http://assets.wwf.org.uk/downloads/scientists__statement_16_sept.pdf
Forty of the world's leading scientists have signed an open letter calling on political leaders to take tougher action on climate change.
The scientists say this week's United Nations climate talks in New York must lay out a plan for an agreement to be delivered at the UN meeting in Copenhagen in December.
The joint statement calls for industrialised countries to cut emissions by at least 40 per cent below 1990 levels by 2020.
Ove Hoegh-Guldberg from the University of Queensland is part of the group and says it is vital politicians heed the advice from the world's scientific community.
"If you look at the commitment as we go towards Copenhagen they're falling woefully short of what we need to do in terms of avoiding dangerous climate change," he said.
"[We're] really saying, wake up, this is a lot more serious than we think.
"When you look at the science and you look at the potential impacts of runaway climate change, there isn't any room for this argy bargy. It's a really serious matter."
Scientists' statement on 40% emissions reduction target for developed countries
Copenhagen climate targets must be more ambitious
At the UN Climate Conference in Copenhagen this December, world leaders have the opportunity to agree a historic global climate deal. To avoid dangerous climate change, the deal must be based on the most up-to-date scientific understanding of the emissions reductions required, with obligations divided equitably between developed and developing countries. This means that developed countries must reduce greenhouse gas emissions by at least 40% below 1990 levels by 2020.
Copenhagen represents our best chance to avert the worst impacts of climate change on people, species and ecosystems. More than 120 countries, including the members of the G8, the EU, and key emerging economies such as China, South Africa and Mexico, agree that the rise in global temperature must stay well below 2°C. Beyond this point climate impacts will be more severe, with the risk of crossing 'tipping points' with dangerous and irreversible effects.
To stand a good chance of achieving this goal, the last Intergovernmental Panel on Climate Change report (2007) recommended that developed countries should reduce emissions by 25- 40% on 1990 levels by 2020. Yet more recent evidence shows that only reductions at the top end of this range will be sufficient to avoid the worst impacts of climate change.
Developed countries have so far committed to reduce greenhouse gas emissions by only 10- 16% by 2020, a level dangerously inconsistent with their commitment to the 2°C target. The latest scientific evidence clearly shows that these countries must increase their ambition and reduce emissions by 40% by 2020 to maintain a credible ambition of avoiding dangerous climate change.