By Richard Black
Environment correspondent, BBC News website
Adapting to impacts of climate change will cost $75-100bn (£47-63bn) per year in the developing world from 2010, a World Bank study concludes.
The bank released preliminary findings from its new global study at the latest round of UN climate talks in Bangkok.
The figures assume that temperatures rise by 2C (3.6F) in the next 40 years.
How to finance adaptation, and how much money will be available, is a major theme in the talks that are supposed to produce a new global treaty this year.
The major costs would come from improving coastal protection and protecting transport links, the bank says.
Developing countries say that as western nations grew prosperous largely through burning fossil fuels, they have a duty to finance protection around the world.
The principle is accepted by some developed countries, and a number of proposals are on the table.