* Climate change inaction cost around 100 bln euros by 2020
* Vulnerable sectors include agriculture, fisheries, tourism
BRUSSELS, April 19 (Reuters) - The European Union must take measures to prevent the destruction of crops and property by extreme weather or face instability and deeper social divisions as a result of potential climate change, a European Commission document said.
The discussion paper, seen by Reuters, calls for a pre-emptive, EU-wide strategy, taking account of factors such as disruption to energy and food supplies.
While most scientists agree that the planet has been warming, there is a high degree of uncertainty over the pace of temperature rises in the future. The EU paper said uncertainty about the exact nature of climate change was no reason for inaction.
“Failing to act or delaying action may put pressure on EU cohesion. Climate change impacts are also expected to widen social differences across the EU,” the document said. “It is therefore opportune to launch an adaptation strategy covering the whole of the EU.”
Over the decade 2002-2011, the temperature of the European land area was on average 1.3 degrees above the pre-industrial level, the paper said.
Southern EU nations such as Spain, Greece and Cyprus, have experienced severe droughts, while increased rain in the north has led to flooding in Britain and Denmark.
While scientists have said they are virtually certain of the link between human activity and a more extreme climate, the precise impact is complex.
In some places, growing seasons have got longer, while in others, yields from traditional grain crops have shrunk.
Measures such as better flood defences, improved water management and more resilient transport and building infrastructure could save 6 euros for every euro spent, the Commission paper said.
It estimated the cost of not adapting to extreme weather at a minimum of 100 billion euros ($131 billion) a year in 2020 and 250 billion euros in 2050 for the European Union as a whole.
Between 1980 and 2011, direct economic losses from flooding totalled more than 90 billion euros. The bill is expected to keep rising, with an annual cost from river floods of 20 billion euros by the 2020s and 46 billion by the 2050s, the paper said.
There is also a heavy human toll. Across the European Union more than 2,500 people were killed by floods between 1980 and 2011.
The paper is expected to be published in the coming weeks. The Commission does not comment on unpublished documents. ($1 = 0.7644 euros) (Reporting by Barbara Lewis; additional reporting by Charlie Dunmore; editing by Jane Baird)