Soil carbon storage in forests is vulnerable to climate extremes, such as warming and drought. Rising temperatures increase microbial activity, accelerating carbon cycling and potentially leading to increased carbon loss. Here’s what we know:
Key Factors Influencing Vulnerability:
- Temperature: Warmer temperatures increase microbial activity, leading to faster decomposition and carbon loss.
- Drought: Drought conditions limit microbial access to fresh carbon, increasing the contribution of older carbon to CO2 emissions.
- Forest Composition: Different tree species and forest types influence soil carbon dynamics, with varying responses to climate extremes.
Consequences of Climate Extremes:
- Carbon Loss: Climate extremes can lead to increased carbon loss from soils, potentially reducing soil carbon storage.
- Feedback Loops: Increased carbon loss can exacerbate climate change, creating a positive feedback loop.
- Ecosystem Resilience: Changes in soil carbon dynamics can impact ecosystem resilience and function.
Vulnerable Ecosystems:
- Tropical Forests: Tropical forests are particularly vulnerable due to their short carbon residence time and high sensitivity to climate change.
- Boreal and Temperate Forests: These forests have shifted from carbon sinks to carbon emitters due to increasing droughts, wildfires, and forest degradation.
- Tundra: Tundra ecosystems exhibit unique vulnerability, with mostly neutral effects but severe negative impacts from certain climate extremes ¹ ² ³.