Warmer winters mean less carbon dioxide could be stored in the world’s highest places

Climate change is causing winter temperatures to rise faster than summer temperatures, especially in high-altitude regions. This “asymmetric” warming could change microbial activity more than expected, causing problems for the vast amounts of carbon stored in soil.

Earth’s soils store more carbon than any other ecosystem other than the oceans. Can store more If only I could manage it better. However, soil carbon is threatened by climate change. Researchers predict that as temperatures rise, the amount of soil carbon lost to the atmosphere as a greenhouse gas will increase, primarily due to changes in the behavior of soil microorganisms. However, the magnitude of this warming feedback remains uncertain.

Ninglin Researchers from Lanzhou University in China heated soil in experimental grasslands on the Tibetan Plateau to test how different warming patterns affected microbial activity. Some of the soils were kept at ambient temperature, while other soils were exposed to a 2°C “symmetrical” warming throughout the year. The third group was exposed to warming of 2.5–2.8 °C during winter and 0.5–0.8 °C during other seasons. This is a more realistic simulation of actual warming patterns.

After applying this treatment for 10 years from 2011 to 2020, the researchers tested samples taken from different soils for microbial activity. They focused specifically on two metrics: growth rate and a measure of how organisms use carbon, known as carbon-use efficiency. this is, shown to be a major determinant The amount of organic carbon stored in the soil.

“When microbes eat carbon, they can do one of two things with it: they can break it down for energy and breathe the carbon as CO2, or they can use it in a new body. It is used to create the structure of Daniel Russ at the Natural Resources Defense Council, a New York-based environmental nonprofit. A higher growth rate means that the microorganisms are using more carbon, and a higher carbon use efficiency means that more carbon is stored in body structures rather than being respired as CO2. He says it means to be made in.

Ling and colleagues found that both warming patterns significantly reduced microbial activity. Soils under symmetrical warming had 31 percent lower growth rates and 22 percent lower carbon use efficiency compared to soils exposed to ambient temperatures. Under asymmetric warming, this effect was even stronger, with growth rates reduced by 58 percent and carbon use efficiency reduced by 81 percent compared to soils exposed to ambient temperatures. They attributed the difference to factors such as changes in nutrients available to the microbes.

“Their findings suggest that soil carbon stocks are likely to decline, reducing the carbon sequestration capacity of terrestrial ecosystems and reducing the effectiveness of soils for nature-based solutions to climate change.” “We are doing so.” Luo Yiqi At Cornell University in New York.

Russ says the fact that current models don’t account for asymmetric warming means they’re likely underestimating soil carbon loss due to climate change. However, he said this finding may only apply to soils in extremely cold ecosystems, and further research is needed to understand exactly what these changes in microbial activity mean for carbon. states. For example, despite significant changes in microbial activity, the total amount of carbon stored in the soil did not change over the course of the experiment.