Climate and water

As floods devastated central Europe and Asia this summer, climate scientists found themselves in great demand from journalists struggling to explain the connections between recent catastrophic weather and expected long-term changes in climate.

The problem for climate scientists lies in determining whether recent events fall outside natural variability: a single summer of excessive rainfall could be just the 100-year or even 1000-year flood. But it is clear that water and climate are — and always have been — intricately linked. Changes in climate are likely to bring changes to the hydrological cycle — the most important feedback cycle in the Earth's climate system.

The oceans play the central role in this feedback loop via heat storage and transport around the globe. Atmospheric water vapour produces rainfall, and acts as the most important greenhouse gas. But through the formation of clouds, water vapour also leads to the reflection of sunlight back into space. And over geological time-scales, the waxing and waning of ice sheets changes the reflection of the sun's light back into space, and largely determines the sea level.

This web focus encompasses a specially commissioned Insight on Climate and Water, together with a selection of recent articles handpicked from the pages of Nature, all of which illuminate the connections between climate and water in ice, oceans and atmosphere.