http://news.bbc.co.uk/2/hi/science_and_environment/10122639.stm

The new head of the UN's climate convention has called for ambition and transparency in UN climate talks.

Christiana Figueres also told the BBC that the process used to hammer out a deal at December's Copenhagen summit was "not the most satisfactory".
The Costa Rican diplomat, who has been involved in UN climate negotiations since 1995, said she was "very honoured" to take up the post.
"It's time to make more effort, it's time to be more ambitious," she said.
Speaking to the BBC's One Planet programme, Ms Figueres added: "It is time to be more transparent and it's time to be more inclusive."
Little accord
The immediate challenge facing the new executive secretary will be to rebuild political and public support for UN negotiations, following the perceived failure to deliver a binding agreement at the Copenhagen summit.
A weaker deal - the Copenhagen Accord - was thrashed out by a select group of countries as the summit came to a stuttering end.
Admitting those accord talks were "not transparent and not inclusive enough," Ms Figueres denied that Copenhagen had been a failure, stressing climate change was now "at the top of every political agenda in every country".
The next big summit being organised by the UN Framework Convention on Climate Change (UNFCCC) will be held in Mexico at the end of the year.
Kim Carstensen, leader of the Global Climate Initiative with WWF, offered Ms Figueres the environment group's congratulations.
"She promises to be an inspiring leader who can keep a high level political dialogue going in order to secure the first critical elements of a climate treaty in Mexico," he said.
"Her background should allow her to foster trust between countries and to push for an ambitious climate deal."
Asked if it was time for the UN to look at ways to control the climate other than by enforcing tough cuts in carbon emissions, Ms Figueres re-iterated that emissions will remain the focus of her efforts.
But she did suggest it was wrong to devote all political attention to curbing harmful gases, saying efforts to help countries adapt to a changing climate had become "relegated to the side, and need to come to the centre and front".
She will take over from outgoing executive secretary Yvo de Boer in July, after the annual two weeks of negotiations between officials in Bonn.