Despite their green intentions, buyers of blended biofuel may not be getting quite what they are paying for.

A controversial nuclear club is taking shape.

If a link with cancer wasn't bad enough, radiation may be bad for your heart too.

Three of the most controversial ingredients in politics - race, gender and age - are conspiring to make this year's US presidential election one of the most engrossing ever. But there is another factor that many Americans will hopefully be taking just as seriously because of its future impact on everyone's lives: how the candidates plan to deal with climate change.

Carbon dioxide is the devil molecule of our time. Yet a pioneering band of researchers would like us to see it differently - as a valuable resource. They are developing a collection of technologies to retrieve some of the CO2 that would otherwise pollute the atmosphere, using its carbon atoms to form hydrocarbons. Feb 27, 2008

Greasy hair may not help you to attract the object of your affection, but it might reduce the amount of ozone you breathe in. Lakshmi Pandrangi and Glenn Morrison from the University of Missouri in Rolla exposed eight washed and eight unwashed hair samples to ozone for 24 hours. They found that, on average, unwashed hair. absorbs around seven times as much ozone as freshly washed hair

Carbon neutrality has never been more highly prized. Half of New Zealand's greenhouse gas emissions come from the guts of sheep and cows; Norway spews ever more gases from its North Sea oil platforms; Iceland has soaring emissions thanks to its aluminium smelters. But all have promised to cut their emissions to zero by becoming founding members of the Climate Neutral Network, set up by the UN Environment Programme at a meeting in Monaco last week. Feb 27, 2008

We should not wait to cut back on burning fossil fuels until we have developed greener technology to supply our energy needs, despite what many economists are advising their respective governments. Such a waiting game may have deadly consequences. Feb 27, 2008

Climate change is the biggest science issue in the world, and the biggest science issue in the upcoming US election. Who is the front runner? If you look at the parties, it's a no-brainer: the Democrats snatched control of both houses of Congress in 2006, and have so far made good on their promises to fight climate change. Feb 27, 2008

One of the outstanding phenomena of the 20th century was the huge migrations of population it witnessed. It is natural to think first of the effects of war, exacerbated by nationalism and beliefs about ethnicity. A major example is the forced displacement of millions of people in Europe and the Middle East in 1945 and afterwards. But these movements are dwarfed by the migration of rural dwellers to urban areas, a process with origins in the industrial revolution but which in the past 60 years has turned from a stream to a tsunami. (Commentary)