British agriculture could collapse by the end of the century if a climate “tipping point” is reached, a Met Office event has been told.

Under a worst case scenario, the collapse of the Atlantic’s system of ocean currents would lead to a “profound drying” that would wipe out crop farming, said Prof Tim Lenton.

Prof Lenton, of the University of Exeter, told the event at Glasgow’s Cop26 climate change conference that there had not been enough funding to know about the impacts of the most unlikely but also the most extreme impacts of climate change.

But he said the potential collapse of the Atlantic meridional overturning circulation (AMOC) currents, which bring wetter and warmer conditions to the UK, had been relatively well-studied.

While the most likely effects of climate change involve Britain having hotter summers and more intense rainfall, the AMOC collapsing would cause dryer weather.

This would “eliminate arable farming, but that’ll be the least of our worries because the drying is so extreme that it poses huge water supply challenges in the south-east of England,” Prof Lenton said.

“We also well know that the winter storms that will batter across the UK and across western Europe under that scenario of an Atlantic meridional overturning circulation currents collapse are quite striking,” he added. “The regional sea level in the North Atlantic region goes up by up to a metre in some locations.

“I could elaborate further, but that’s one where we really can paint a fairly grim picture.”

The Met Office says that while the currents are  likely to weaken over the next century, total collapse before 2100 is “very unlikely”.

The currents depend on cold salty water sinking in the North Atlantic, and scientists fear warming from greenhouse gases and more freshwater from melting glaciers could disrupt that. Experts are “currently not able to confidently define a level of global warming at which the currents would be at risk of crossing a tipping point”.