By Nina Chestney

LONDON (Reuters) - Extreme floods like those swamping parts of Britain in recent months could become more frequent in Europe by 2050, more than quadrupling financial losses, if climate change worsens and more people live in vulnerable areas, research showed on Sunday.

The study said instances of very extreme floods, which now occur about once every 50 years, could shorten to about every 30 years, while cases of extreme damage now occurring once every 16 years could shorten to once every 10 years.

With shorter cycles of extreme floods and damage, the European's current average losses of 4.9 billion euros a year could reach 23.5 billion euros by 2050, a rise of almost 380 percent, said the study in the journal Nature Climate Change.

Scientists at several universities and research centers in Europe and Australia used climate change models, economic data and river discharge data to form their conclusions.

"Due to climate change and GDP growth, by 2050 a one-in-fifty-years-flood might be one in 30 years so the frequency of such losses increases dramatically - almost doubling," said co-author Brenden Jongman, researcher at the IVM Institute for Environmental Studies at VU University Amsterdam.

Extreme damage can more than double the average damage rate used in the study's calculations. In June last year, extensive flooding resulted in 12 billion euros ($16 billion) of losses in nine countries across central and eastern Europe, according to reinsurance company Munich Re.

RISING COSTS

The study said investment in flood protection measures could help reduce the magnitude of overall flood losses in the future.

By investing around 1.75 billion euros in such measures, Europe's annual flood losses could be reduced by around 7 billion euros, or around 30 percent, by 2050, it estimated.

Rising costs from flood damage are due to several factors such as changes in climate, land use, population and wealth.

The European Environment Agency said last year that costs from flooding were also rising in part because more housing was being built in flood-prone areas.

Better reporting of floods has also contributed to the rising overall cost of these inundations.

A U.N. panel of climate scientists has said the Earth is set for more heat waves, floods, droughts and rising sea levels from melting ice sheets that could swamp coasts as greenhouse gases built up in the atmosphere.

Other bodies, such as the European Environment Agency, have said it is likely that rising temperatures in Europe will change rainfall patterns, leading to more frequent and heavy floods in many regions.

Britain is currently experiencing its wettest winter on record, resulting in the worst floods for the country in 50 years.

Accountancy firm Deloitte said on Friday there were nearly 200,000 insurance claims in Britain in the last three months of 2013 due to storms and floods - the highest number of such claims over a fourth-quarter financial period for 10 years.

It has also estimated that the cost of repairing the damage caused could reach 1 billion pounds ($1.66 billion). Insurance companies such as Aviva and Swiss Re have urged for more action and investment to manage flooding.

The paper is available at: http://dx.doi.org/10.1038/nclimate2124 ($1 = 0.7317 euros)

(Editing by Tom Heneghan)