A recent study published in Nature suggests that the warming climate is causing tundra environments to release trapped carbon, potentially transforming them from carbon sinks into carbon sources. The study, conducted by over 70 scientists using open-top chambers (OTCs) to simulate warming effects on tundra sites worldwide, found that experimental warming led to a 1.4 degrees Celsius increase in air temperature and a 0.4 degrees increase in soil temperature. This resulted in a 1.6 percent drop in soil moisture and a 30 percent increase in ecosystem respiration during the growing season, leading to more carbon being released due to increased metabolic activity in soil and plants.
The team found that the increase in ecosystem respiration varied depending on local soil conditions, such as nitrogen and pH levels, resulting in geographic differences in the response to warming. This highlights the importance of understanding the links between soil conditions and respiration in response to warming, as it can help improve climate models. The study, led by Sybryn Maes from Umeå University, represents the first assessment of ecosystem respiration response to experimental warming across a broad environmental gradient in the tundra, incorporating a comprehensive set of environmental drivers.
In addition to providing insights into how tundra ecosystems are responding to climate change, the study also offers a broader perspective on Arctic and alpine regions by predicting increases in respiration across the entire tundra area. Professor Matti Kummu of Aalto University notes that some areas, particularly parts of Siberia and Canada, exhibit greater sensitivity to warming, indicating a potential for increased respiration across the whole Arctic and alpine tundra. However, he emphasizes the need for more in situ data on local soil conditions to address uncertainties and refine predictions.
Understanding how ecosystems shift in response to climate change and how these changes feed back into the climate is crucial for accurately predicting future changes. These findings serve as an important baseline for improved climate models, but the researchers plan to further refine them by analyzing how the experimental sites change over time and extending the scope of the study to include new sites. Associate Professor Ellen Dorrepaal of Umeå University highlights the significance of the study in providing detailed information on variation in the sensitivity of tundra ecosystems to warming, emphasizing the importance of continued research in this area.
