Many coastal wetlands likely to disappear this century

December 01, 2010

Many coastal wetlands worldwide -- including several on the U.S. Atlantic coast -- may be more sensitive than previously thought to climate change and sea-level rise projections for the 21st century.

U.S. Geological Survey scientists made this conclusion from an international research modeling effort published today in the journal Geophysical Research Letters, a publication of the American Geophysical Union. Scientists identified conditions under which coastal wetlands could survive rising sea level.

Using a rapid sea-level rise scenario, most coastal wetlands worldwide will disappear near the end of the 21st century. In contrast, under the slow sea-level rise projection, wetlands with low sediment availability and low tidal ranges are vulnerable and may drown. However, in the slow sea-level rise projection, wetlands with higher sediment availability would be more likely to survive.

Several coastal marshes along the east coast of the United States, for example, have limited sediment supplies and are likely to disappear this century. Vulnerable east coast marshes include the Plum Island Estuary (the largest estuary in New England) and coastal wetlands in North Carolina's Albemarle-Pamlico Sound (the second-largest estuary in the United States).

"Accurate information about the adaptability of coastal wetlands to accelerations in sea-level rise, such as that reported in this study, helps narrow the uncertainties associated with their disappearance," said USGS scientist Glenn Guntenspergen, an author of this report. "This research is essential for allowing decision makers to best manage local tradeoffs between economic and conservation concerns."

"Previous assessments of coastal wetland responses to sea-level rise have been constrained because they did not consider the ability of wetlands to naturally modify their physical environment for adaptation," said USGS scientist Matt Kirwan, an author of this report. "Failure to incorporate the interactions of inundation, vegetation and sedimentation in wetlands limits the usefulness of past assessments."

USGS scientists specifically identified the sediment levels and tidal ranges (difference between high and low tide) necessary for marshes to survive sea-level rise. As water floods a wetland and flows through its vegetation, sediment is carried from upstream and deposited on the wetland's surface, allowing it to gain elevation. High tidal ranges allow for better sediment delivery, and the higher sediment concentrations in the water allow wetlands to build more elevation.

Coastal wetlands provide critical services such as absorbing energy from coastal storms, preserving shorelines, protecting human populations and infrastructure, supporting commercial seafood harvests, absorbing pollutants and serving as critical habitat for migratory bird populations. These resources and services will be threatened as sea-level rise inundates wetlands.

The rapid sea-level rise scenario used as the basis for this study is accredited to Stefan Rahmstorf at Potsdam University, one of the contributing authors of the Intergovernmental Panel on Climate Change Fourth Assessment Report. The slow sea-level rise projection is from the A1B scenario of the Intergovernmental Panel on Climate Change Fourth Assessment Report.
-end-
The study, "Limits on the Adaptability of Coastal Marshes to Rising Sea-Level," can be found at http://dx.doi.org/10.1029/2010GL045489. Any journalists who are not registered with AGU and cannot view this article can contact USGS to have a copy emailed to them.

Photos accompanying this release can be found at http://gallery.usgs.gov/tags/NR2010_12_01

The USGS provides science for a changing world. Visit USGS.gov, and follow us on Twitter @USGS and our other social media channels.

Subscribe to our news releases via e-mail, RSS or Twitter.

US Geological Survey

Related Climate Change Articles from Brightsurf:

Are climate scientists being too cautious when linking extreme weather to climate change?
Climate science has focused on avoiding false alarms when linking extreme events to climate change.

Mysterious climate change
New research findings underline the crucial role that sea ice throughout the Southern Ocean played for atmospheric CO2 in times of rapid climate change in the past.

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.

Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.

Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.

Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.

A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.

Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).

Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.

Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.

Read More: Climate Change News and Climate Change Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.