Drainage and degradation of coastal wetlands emit significant amounts of carbon dioxide directly to the atmosphere and lead to decreased carbon sequestration, a report by the World Bank said on Monday.

The report, written in partnership with the International Union for the Conservation of Nature (IUCN) and wetland specialists ESA PWA, calls for coastal wetlands to be protected and incentives for avoiding their degradation and improving their restoration to be included into carbon emission reduction strategies and in climate negotiations.

"For the first time we are getting a sense that greenhouse gas losses from drained and degraded coastal wetlands may be globally significant and that drained organic-rich soils continuously release carbon for decades. Emissions will increase with ongoing wetland losses." said Stephen Crooks, Climate Change Services Director at ESA PWA - the consulting firm which looked at 15 coastal deltas worldwide for the report.

The report highlights the current rates of degradation and loss of coastal wetlands which are up to four times that of tropical forests.

Destruction of about 20 percent of the worlds' mangroves, an area of 35,000 square kilometers in the last 25 years or four times the New York City metropolitan area, has led to the release of centuries of accumulated carbon.

This has also disturbed the natural protection against storm surges and other weather events.

Of the 15 coastal deltas studied for the report, seven were found to have released more than 500 million tons of CO2 each since the wetlands were drained, mostly in the past 100 years. By comparison, Mexico's carbon dioxide emissions for 2007 were just over 470 million tons.

"Protecting these coastal ecosystems and the blue carbon they store can be a win-win for communities," said Marea Hatziolos, Senior Coastal and Marine Specialist at the World Bank, who oversaw production of the report.

She said that shore line protection and increased fisheries productivity are among the co-benefits provided by healthy coastal wetlands - contributing to community resilience while sequestering CO2.

"If wetlands conservation can be linked to carbon markets, communities have a way to pay for conservation which will generate local and global benefits," she said.

According to the report, managing coastal ecosystems for the range of services they provide can complement existing approaches to nature-based solutions to reduce the effects of climate change. Such investments have the potential to link to REDD+ and other carbon financing mechanisms, provided that protocols on accounting, verification and reporting of net carbon uptake can be agreed.