This coming Sunday is World Environment Day. So what is the state of the planet in 2011?

This time last year, engineers in the USA were still battling to stop the largest oil spill of its kind in the Gulf of Mexico.

A year on, engineers are trying to prevent a different kind of ocean leak – a radiation leak.

Following the nuclear meltdown at Fukishima in Japan, scientists are struggling to stop contaminated water from reaching the sea.

But for many environmentalists the key challenge remains climate change.

According to the International Energy Agency, carbon emissionsreached a record level last year. The Intergovernmental Panel on Climate Change is aiming forgreenhouse emissions to peak by 2020, but there are growing doubts about whether the necessary curbswill be implemented.

A recent report by the charity Oxfam highlights the impact global warming will have on food security. Food prices could almost double in the next twenty years, with climate change the main cause.

But there is one good piece of news for conservationists, relating todeforestation. According to the think-tank Chatham House, global illegal logging has fallen by nearly a quarter since 2002.

That fits nicely with the theme for this year's World Environment Day: "Forests - Nature At Your Service".