Water, water everywhere... but not where Californians need it

Predictions about the effects of global warming on water this week suggest that California will have lots of it - but it will not be where farms will need it, and it will be full of salt.

Just as US energy secretary Stephen Chu warned that a lack of water could kill off California's agricultural industry, a Canadian scientist is predicting that global warming could swamp some coastal regions more than others, leading to higher levels of water around California's coast than previously expected.

Chu gave a chilling interview in the LA Times this week in which he warned that rapidly dwindling snow runoff from the western Sierra mountain range could herald the end of Californian agriculture, creating a dustbowl in the state by the end of the century. "I don't actually see how they can keep their cities going," he added.

His concerns over water scarcity echo those of a US Climate Change Science Program report released last May. It suggested western states would be hit hard by drought as the climate altered.

Chu argued a huge increase in renewable energy capacity, the roll out of a carbon cap-and-trade scheme and wide reaching public education initiatives were needed to help avert the problem.

There will nevertheless will be more water surround the coast of the US than previously expected thanks to the melting of Antarctic ice, postulates Toronto scientist Jerry Mitrovica in a paper to be published in the journal Science today. The sea level rise will not be evenly distributed, the report will suggest, thanks to factors including the shifting gravitational effect of the Antarctic ice sheet as it melts. Sea levels in some areas could rise by 30 per cent more than previously thought, according to the document, which will warn that the US coastline could be particularly badly hit.

Insurance companies have previously expressed concern about rising sea levels. Reinsurance giant Munich Re last month predicted more natural disasters in the coming years, and spokespeople warned that coastal areas would be particularly vulnerable.