Britain faces a severe increase in damaging storms and floods after scientists found climate change could have a “much worse” impact on winter weather than previously thought.

Experts have been warning for years that global warming will bring warmer and wetter winters because warmer air holds more water. However, scientists at the Met Office have now identified another way that rising greenhouse gas emissions could “severely” affect Britain with increased flooding and more storm damage.

An Atlantic weather pattern known as the North Atlantic oscillation, measured as the pressure difference between the high in the islands of the Azores in the mid-Atlantic to the low in Iceland, already plays a key role in determining winters in Britain and northern Europe. When it is positive, it brings wetter and stormier weather. A negative oscillation brings drier and colder conditions.

To date, the impact of rising emissions on the weather pattern has been largely unknown. Some computer models suggested climate change would increase the oscillation, others decrease it, and some projected no change. The range of uncertainty was huge.

But a study by a Met Office team has narrowed that range, and found that rising emissions mean “unprecedented” highs in the oscillation by the end of this century. “That would be expected to severely increase flooding and storminess in the UK and western Europe,” said Doug Smith, one of the study’s authors. The research did not estimate precisely how much more flooding and how many more storms would occur.

However, Smith said: “This shows that the impacts of climate change could be more intense than we presently think. I suspect that over the coming five years or so, we might start to really realise that the impacts of climate change could be much worse than we currently think.”

The team narrowed the uncertainty about how rising greenhouse gas emissions would affect the Atlantic weather pattern by running climate models to better understand how water vapour changes the oscillation.

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The prospect of more storms and floods is based on the assumption that emissions remain high this century, with global average temperatures rising by about 4C.

They have already risen by 1.3C above pre-industrial levels. Countries’ climate plans have Earth on track for about 2.8C of warming this century, which would bring “catastrophic” impacts on weather, food production and ecosystems.

The sliver of good news is that it is not too late to stop the oscillation bringing more floods and storms, provided the world curbs its emissions. The study found that in a “middle of the road” emissions scenario, where temperatures rise by 2.7C, the weather pattern would decrease rather than increase. “That scenario would avoid these impacts,” said Smith.