http://news.bbc.co.uk/2/hi/science/nature/8492450.stm

Fifty-five countries have submitted pledges for curbing greenhouse gas emissions to the UN climate convention.

Governments were asked to do so before 31 January by the "Copenhagen Accord", the document produced at December's UN climate summit in the Danish capital.
In some cases the pledges are weaker than those made before the summit.
The UN's top climate official, Yvo de Boer, said the pledges would invigorate the UN process, but several environment groups say they do not go far enough.
Submissions have come from major developed and developing countries, and collectively account for about three-quarters of the world's emissions from energy use.
But few of the smaller, more vulnerable nations have sent in their figures.
"The commitment to confront climate change at the highest level is beyond doubt," said Mr de Boer, executive secretary of the UN climate convention (UNFCCC).
"Greater ambition is required to meet the scale of the challenge. But I see these pledges as clear signals of willingness to move negotiations towards a successful conclusion."
Basic instincts
Earlier, UK Prime Minister Gordon Brown had urged governments to send their pledges to the UNFCCC by the 31 January deadline.
"If those countries which agreed the accord in Copenhagen inscribe into it the commitments they made in the run-up to the conference - and I believe it is very much in the global interest that they should do so - the international community will have taken the first steps towards a historic transformation in the trajectory of global emissions," he wrote in an open letter.

The 55 countries sending in pledges include EU member states, US and Japan, as well as the four Basic bloc countries (Brazil, China, India and South Africa) that were the principal architects of the Copenhagen Accord.
Most of them re-iterate pledges made before December's summit; but some are weaker.
The US previously pledged a cut of 17% from 2005 levels by 2020 (equivalent to 3% from the conventional baseline of 1990).
But its current submission promises a cut "in the range of 17%, in conformity with anticipated US energy and climate legislation, recognising that the final target will be reported to the Secretariat in light of enacted legislation".
Canada will also amend its target of 17% to make it align "with the final economy-wide emissions target of the US in enacted legislation".
Australia, the EU and Norway are all currently going for the weak end of the ranges they had previously proposed - 20% rather than 30% in the EU's case - while New Zealand promises no cuts at all in the absence of a comprehensive global deal.
Among developing countries, China re-affirms that its 2020 target is a cut of 40-45% in carbon intensity and that this is to be regarded as voluntary, while India has retreated from a firm pledge to improve its energy intensity to a position where it promises to "endeavour reduce its emissions intensity" by 2020.
'Greenwash' concerns
Although some US-based environment groups applauded the fact that the Obama administration had sent its figures in, many other campaigners were dismissive of the exercise and the numbers.
"Supporters of the accord have failed to make emissions pledges which are strong enough to avert dangerous climate change," said Bernhard Obermayr of Greenpeace.
"It is the start of the Copenhagen 'greenwash'. The accord is no substitute for the fair, ambitious and legally binding treaty demanded by millions of people who are concerned about climate change or are being affected by its impacts."
Only three members of the Association of Small Island States (Aosis) - the Maldives, the Marshall Islands and Singapore - have submitted pledges to the UNFCCC.
Meanwhile, a report from the International Institute for Environment and Development (IIED) raises questions over the accord's financial targets of raising $10bn per year for the developing world over the next three years, rising to $100bn per year by 2020.
"It is far from clear where the funding will come from, if it is genuinely new and additional, and how it will be allocated and channelled," said Saleemul Huq, the IIED's senior climate change fellow and one of the report's authors.