The current crisis in worldwide food prices reinforces the need for more productive agriculture. Emma Marris meets five ambitious scientists determined to stop the world from going hungry.

Carbon dioxide emissions and their associated warming could linger for millennia, according to some climate scientists. Mason Inman looks at why the fallout from burning fossil fuels could last far longer than expected.

Climate in the early Pleistocene varied with a period of 41 kyr and was related to variations in Earth's obliquity. About 900 kyr ago, variability increased and oscillated primarily at a period of approx100 kyr, suggesting that the link was then with the eccentricity of Earth's orbit.

Beijing conference tackles how to help developing countries.

Findings reignite debate over genetically modified crops.

The population cycles of rodents at northern latitudes have puzzled people for centuries, and their impact is manifest throughout the alpine ecosystem. Climate change is known to be able to drive animal population dynamics between stable and cyclic phases and has been suggested to cause the recent changes in cyclic dynamics of rodents and their predators.

The factors driving glacial changes in ocean overturning circulation are not well understood.

A re-evaluation of the relationship between Earth's orbital parameters, ice-sheet extent and ocean circulation sets further puzzles for those trying to disentangle cause from effect in long-term climatic changes.

The United Kingdom is on track to become the first country to have legally binding targets for cutting greenhouse gases.

Regular long-distance flying can easily triple an academic's carbon footprint. During the past year, I have 'spent' about nine tonnes of carbon, two-thirds of this on plane trips. Yet I am a good consumer otherwise. (Correspondence)