In many cases, water stress is more about politics, economics, behaviour and governance than absolute water scarcity. Better planning is needed, to allocate water where societal need is greatest, and to allow trade-offs between alternative uses.

I've always been torn between the pure and the social sciences.

Human activity is having a major impact on the planet. We consume or have diverted a large proportion of the productivity of the land and oceans. Our hunger for land crowds out fellow species. Our waste products pollute the waters, warm the atmosphere and acidify the oceans.

Global actions require local and national participation. International cooperation and action requires community perspectives and legitimacy if it is to be effective.