Coastal Wetlands May Get Climate Change Boost, Before Being Overwhelmed by Rising Seas
Though in the long-run rising sea levels and temperatures because of climate change certainly still pose a threat to coastal wetlands, researchers from the Smithsonian Institution and the US Geological Survey have concluded a two year study on the effect of CO2 levels on soil elevation in marshes which adds a new wrinkle to the effects we can expect to see as the Earth continues to warm:
Coastal wetlands must build upward through the accumulation of mineral and organic matter to maintain a constant elevation relative to water levels; otherwise, they will drown and disappear. Climate change, however, is causing acceleration in the rise of sea level, which would seemingly put wetlands at risk of excessive flooding.
"Our findings show that elevated CO2 stimulates plant productivity, particularly below ground, thereby boosting marsh surface elevation," said Adam Langley, the paper's lead author. Patrick Megonigal, the paper's corresponding author, added "We found that by stimulating root growth, thus raising a marsh's soil elevation, elevated CO2 may also increase the capacity for coastal wetlands to tolerate relative rises in sea level." (Science Codex)
Just to make it clear, the researchers also clearly say that this effect could easily be offset by rising sea levels in the longer term: Ultimately, rapidly rising seas could outstrip the positive effects of CO2 on the marshes that were observed.
The findings will be published in the Proceedings of the National Academy of Sciences this week. (At the time of this writing it didn't appear that a link was yet available...)