Climate change could leave farmers with half the water needed to produce crops in the future, Government advisers have warned.

Higher temperatures, drier soils and more demand for food from a growing population will increase demand for the irrigation of crops, which are largely produced in drier areas of the UK, the Committee on Climate Change's adaptation team said.

Lower river levels as the country faces increasing weather extremes, such as reduced summer rainfall and drought, will also contribute to potentially significant shortfalls between the amount of water needed to grow crops and what can be supplied, it said.

Without changes to farming practices, the shortfall in a dry year could be up to 115 billion litres, almost half the 240bn litres a year used by agriculture, the experts warned. Current farming methods are also depleting fertile soils, they said.

Lord Krebs, who chairs the adaptation sub-committee of the Committee on Climate Change, said: "Our analysis shows we are putting future agricultural production at risk, jeopardising coastal habitats that provide vital flood defences, squeezing wildlife habitats and threatening billions of pounds worth of carbon stored in our peatlands.

"The Government should act now to develop and implement policies to ensure that we make the right land use choices to ensure we are resilient to climate change."

The report comes after the UK suffered the wettest autumn on record, followed by the coldest spring for more than 50 years, reducing wheat yields by around one third.