The message from Rio+20 is for practical action to deliver existing targets. Scientists must identify and overcome barriers to change.

A meeting in London this week will show whether science can not only diagnose our environmental crisis but also provide effective solutions.

Yet more failure to make much progress on climate change in Durban means that developing countries must exert stronger political pressure.

The Fukushima accident raised questions that must be addressed by developing countries considering nuclear energy.

The world still needs nuclear power — but it must be safer and more transparent.

Tackling recent controversies about climate change data requires a robust partnership between the natural and social sciences.

There were many regrets after the climate conference but it did reveal the new political setting within which climate change must be fought.

The hacked emails of climate researchers offer an opportunity to show how science is really done — instead of a rearguard defence of scientific 'objectivity'.