Extreme weather events alter carbon uptake by plants
By Summit Voice
FRISCO — Scientists often think about climate change in terms of how larger, ongoing atmosphere changes affect ecosystems on land and in the ocean, but a new study by German researchers shows that it works both ways.
In a classic climate feedback loop, the researchers determined that extreme weather events like like storms, heavy precipitation, as well as droughts and heat waves, prevent the uptake of 3 gigatons of carbon by global vegetation.
A team of scientists under the lead of Markus Reichstein, Director of the Max Planck Institute for Biogeochemistry in Jena, Germany, investigated the effect of extremes on the carbon cycle from the terrestrial ecosystem perspective for the first time. The study was published Aug.14 in Nature.
Combining statistical analyses with observational data to concluded that extreme droughts in particular result in a strong reduction in the carbon sequestration of forests, grass- and croplands.
This reduction in the regional and global carbon uptake has the potential to influence the global climate. Especially large scale events like the heat wave in western and southern Europe in the year 2003 provide the evidence that such extremes events have a much stronger and long lasting impact on the carbon cycle than expected so far.
One part of the question is the response of arable ecosystems: Plants take up carbon dioxide, soils are an important storage for the carbon produced by plants, which they release driven by increasing temperature.
However, in the case of croplands the researchers observed a complex interplay of these natural processes with the human management either increasing or reducing the impacts of an event.
“In general the timing of an event in the course of the development of crops clearly influences the magnitude of the impact on the carbon cycle,” said Martin Wattenbach from the GFZ German Research Centre for Geosciences, who contributed to part of the study.
“Extreme temperatures in spring can foster growth, prevent pollination, or have no effect at all, depending on when they appear in the cropping cycle and the type of crop,” Wattenbach said. “Rice yields are reduced when temperatures rise above 37°C, but only in the short period of pollination in spring,” he added.
Farmers can use irrigation to mitigate extremes like droughts and heat waves, but they are limited by the amount of water available at the time of the event and their technical resources.
Filed under: climate and weather, Environment, global warming Tagged: | carbon cycle, climate change, extreme weather, global carbon cycle, global warming, greenhouse gases, Max Planck Institute for Biogeochemistry