In India, the monsoon fails. In Europe, it rains without mercy. Is this more than a coincidence?

It was coursing down in Corsica, pouring in Prague and soaking in Salzburg. The umbrella-weather of Umbria was matched by rain in Spain and torrents in Turin. There was almost nowhere in central and southern Europe that escaped this summer's record downpour.

Majorca suffered its wettest August for more than a quarter of a century. In just one day violent storms dumped three times the average monthly rainfall for August on Palma and on neighbouring Ibiza five times the month's average fell over 24 hours.

Massive flooding in central Europe claimed more than 100 lives and caused billions of pounds of damage to some of the continent's most historic sites. Earlier this week, flooding killed at least 20 people in the south of France, which was hit by some of the most violent weather in living memory.

As the heavens opened this summer and thousands of Britons sat shivering in their holiday villas, another devastating phenomenon was taking place on the other side of the world with even greater consequences – only a third of the expected rainfall fell during this year's Indian monsoon.

Scientists now believe that these two events are related. The failure of the monsoon in India, which is so vital for crops, may have led directly to a breakdown in the normally settled summer weather of southern and central Europe.

Professor Brian Hoskins, a meteorologist from Reading University, said yesterday that there was now convincing evidence that the poor summer in Europe resulted from changes in atmospheric pressure caused by the failure of the Indian monsoon.

"We've looked back over the last 40 years and certainly the extreme events of the two seem to hang together," Professor Hoskins told the annual meeting of the British Association for the Advancement of Science at Leicester University.

"Don't go to the Mediterranean for your summer holiday before the Indian monsoon has started because that's when both kick in. It happens every year. The Indian monsoon starts and then the Mediterranean becomes settled," Professor Hoskins said.

Normally, as the monsoon season arrives, huge volumes of air begin to rise over the Indian subcontinent. These push north and west, allowing other columns of air to descend over the Mediterranean region, causing stable, high-pressure systems to develop, which repel unstable, rain-bearing weather. "The rising of air over India actually causes descent over the southern Mediterranean. That rising over India is much weaker this year so the descent over the southern Mediterranean is much weaker. So normally that descent gives high pressure and settled weather and this year that's not there, which has allowed low pressure systems to develop," Professor Hoskins said.

But that is just part of a bigger, global story with its beginnings over the southern Pacific Ocean where an El Niño – an unusual ocean current – is beginning to grow in strength. Meteorologists now believe El Niño is behind the failure of the Indian monsoon.

"There's been some very interesting events this summer. One is a developing El Niño in the Pacific, the second is almost a complete failure of the Indian monsoon, which is really going to be disastrous for India and its crops and the other is the flooding in Europe," Professor Hoskins told the Science Festival.

"I can relate those three events. Work we've done over the years has suggested that the settled summer weather over southern Europe is actually part of the Indian summer monsoon.

"What's happened this year is that the Indian summer monsoon is very weak and that has released this control over southern Europe and allowed these low-pressure systems to come in. This is a bit of a hypothesis at the moment but there is a lot in the data to suggest this," he said.

As much as it matters to European holidaymakers whether their summer is going to be wet or sunny, it matters far more for Indian farmers whose crops rely so heavily on a regular monsoon soaking.

Professor Hoskins said that scientists might soon be able to predict whether a monsoon failure is likely.

"Our ability to predict the Indian monsoon is crucial for those who live in India, and that's clearly the number one thing. The amazing thing about the Indian monsoon is not how much it varies but how little it varies," Professor Hoskins said.

"The typical variation of the rainfall in India is within 10 per cent. If it's plus 10 per cent then you get people drowning and if it's minus 10 per cent you get people dying from starvation. So what we are looking at in climate change is whether we are going to perturb that very subtle, seemingly stable system – although it is probably quite fragile as well.

"I think with the Indian monsoon we should be able to give some idea of its probability, although we can't do it with confidence now. I would think within the next five years or so we would get a more confident prediction of the probability distribution of the Indian monsoon and then we'd get an idea of the European situation beyond that," he said.

Freak weather has also been seen in China, where torrential rain has caused a risk of flooding on an unimaginably large scale, according to Professor Ian Cluckie, a flood engineer at the University of Bristol who has just returned from a trip to the regions worst affected. "If you were a Chinese meteorologist you wouldn't be talking about the failure of the monsoon, you'd be talking about one that has developed to a much greater extent. The Chinese flooding which is still going on is due to an extremely wet monsoon."

Although the link with the Chinese monsoon was not proved, it was part of a pattern. Flooding was rapidly becoming one of the most prevalent natural disasters everywhere in the world, he said. "Until the early 1980s, more people died in drought than flood. From the early 1980s, floods overtook droughts. About 140 million people around the world are affected by floods and 40 million people are affected directly by drought," Professor Cluckie said.

"You could interpret this as closely associated with climate change because it's exactly the period of increasing temperatures caused essentially by greenhouse gases," he added.

The climate scientists, however, are still unsure about the role played by increasing temperatures. "There is always the question, 'Is this global warming?' and we turn around and say, 'Well, we can't say this is global warming'," Professor Hoskins said.

But the signs are ominous. Computer models of a warmer world predict greater weather instability, with more extremes in temperatures and rainfall – which is just what happened this year in Europe and in India.