For Wetland Plants, Sea Level Rise Stamps Out Benefits of Higher CO2
The following is an excerpt from a news story by Columbia’s Mailman School of Public Health.
Wetlands across the globe are in danger of drowning from rising seas. But for decades, scientists held out hope that another aspect of climate change—rising carbon dioxide (CO2)—could trigger extra plant growth, enabling coastal wetlands to grow fast enough to outpace sea level rise. That helpful side effect is disappearing, they discovered in a new study in the journal Science Advances.
“In some ways, this is a race,” said co-author Lew Ziska, professor of Environmental Health Sciences at Columbia University Mailman School of Public Health and a plant physiologist. “A race between what CO2 can do and what sea level can do.”
Ziska, who began as a post-doc the second year of this study, has seen in his lifetime the shift in perception, from climate change as an issue for our grandchildren, to a matter of concern now. ”[S]ea-level rise threatens one of the globe’s largest carbon sinks, marsh and wetlands — another facet of how wide-ranging, pervasive climate change is affecting the world around us,” he said.
“Too much water is a stress, an environmental stress, for plant response to high CO2,” said Chunwu Zhu, lead author. Zhu, a biologist with the Chinese Academy of Sciences, conducted the study while on a fellowship with the Smithsonian Environmental Research Center.
The study took place at the Smithsonian’s Global Change Research Wetland on the western shore of Maryland. The wetland is home to several futuristic experiments, where scientists simulate the climate of 2100. For this study, the researchers relied on an experiment that started in 1987—currently the world’s longest-running field experiment on how rising CO2 impacts plants. Inside 15 open-top chambers, scientists have been raising CO2 concentrations by an additional 340 parts per million, roughly doubling atmospheric CO2 levels of 1987.