Sun Mao has been trying to stop the dolphin decline

He is looking for one of the world's rarest mammals - the Mekong Irrawaddy dolphin.

Older people in this part of northern Cambodia talk of how they used to take the dolphins for granted.

Little effort was needed to see them in their dozens. Now, scientists say, there are less than 100 remaining.

National heritage

With a practised eye, Sun Mao spots a group of five dolphins, collectively known as a pod.

They briefly break the surface as they come up for air - grey-brown, bullet-headed and exhaling with an old man's rasp.

Officials say the city's air will be clean enough for the Olympics

Just a month before the start of the Beijing Olympics, the city is still failing to meet international air quality standards, the BBC has found.

When Beijing bid for the Olympics in 2001, it said its air would meet World Health Organization (WHO) standards.

The BBC put this to the test using a hand-held detector to test for airborne particles known as PM10.

We found that the city's air failed to meet the WHO's air quality guidelines for PM10 on six days out of seven.

These particles are caused by traffic, construction work and factory emissions. They are responsible for much of this city's pollution.

At first sight, the G8 agreement on climate change promises much.

Leaders are "committed to avoiding the most serious consequences of climate change", and determined to stabilise greenhouse gases in the atmosphere at levels that would avoid "dangerous climate change".

In fact, this is exactly what leaders of nearly 200 countries signed up to in the original UN Framework Convention on Climate Change (UNFCCC), agreed at the 1992 Earth Summit. So if re-stating a 16-year-old commitment is progress, then this is clearly a success.

The question ever since Rio has been what to do about it. But the reality of negotiations within groups such as the G8 is that every party needs to emerge with bits of language that they can point to and say "I won".

There have been deep divisions over how to curb global emissions

World leaders say they will aim to set a global target of cutting carbon emissions by at least 50% by 2050 in an effort to tackle global warming.

It strengthens last year's G8 pledge to "seriously consider" the cuts.

But the US has refused to set any interim targets for cutting emissions - and environmentalists have criticised the progress at talks as "pathetic".

Five of the world's biggest emerging economies said the G8 should increase its targets to more than 80% by 2050.

China, India, Mexico, Brazil and South Africa - who will join talks on Wednesday - also urged developed countries to commit to an interim target of a 25-40% cut below 1990 levels by 2020.

The UK is to slow its adoption of biofuels amid fears they raise food prices and harm the environment, the transport secretary has said.

Ruth Kelly said biofuels had potential to cut carbon emissions but there were "increasing questions" about them.

"Uncontrolled" growing of fuel crops could destroy rainforest, she told MPs.

A government-commissioned report recommends ministers "amend not abandon" biofuel policies. The Tories said policy had to change "right now".

Biofuel crops such as jatropha could be good for Africa, the EU believes

When biofuels sprang to political prominence a few years ago - endorsed by Tony Blair among others - the world was rapidly running out of options for a liquid fuel that could keep the wheels of transport turning after the oil ran out.

Hydrogen had been the bright-eyed new kid on the block. But as the practical difficulties and economic realities raised their ugly heads, the new kid was quickly revealed as an unpleasant, drug-addled hoodie.

Fuel cells with a low tolerance for pollution or vibration, a finite supply of already expensive platinum for catalysts, a range smaller than a Tour de France cyclist could achieve in a day, high leakage from pipes… the closer one looked, the spottier the hoodie's face appeared.

Research into hydrogen continues, and rightly so - the least promising kids can turn into prime ministers.