Climate variability

Climate variability is driving a global decline in forest resilience

Forests cover almost a third of the Earth’s land surface. Not only do they play a fundamental role in the global carbon cycle by absorbing a third of anthropogenic carbon emissions and mitigating climate change, but they also provide a series of ecosystem services that contribute to the well-being of society, such as regulation of water flows, soil protection and biodiversity conservation.

The persistence and functionality of forest ecosystems strongly depends on their ability to resist and recover from natural and anthropogenic disturbances. This capacity is defined as their resilience. Experimental evidence of sudden increases in tree mortality in different biomes across much of the Americas and Europe raises concerns about variation in forest resilience, but not enough is known about how it evolves in response to climate change.

In a new study conducted by the JRC and published in Naturethe researchers integrated satellite vegetation indices with machine learning techniques to show how forest resilience changed between 2000 and 2020.

The results show that the resilience of tropical, arid and temperate forests decreased during this period. These changes are associated with reduced water availability and increasing climate variability. In contrast, boreal forests show divergent local patterns with an average trend of increasing resilience, likely benefiting from warming and CO2 fertilization, which may still at present outweigh the adverse effects of climate change. climate change. These patterns appear consistently across both managed and intact forests, supporting the existence of common large-scale climatic drivers.

The authors estimate that, overall, about 23% of undisturbed intact forests may already have reached a critical threshold, with resilience continuing to decline. This decline could have critical consequences for key ecosystem services provided by forests, such as carbon storage. Observed trends in forest resilience need to be considered in the design of land-based mitigation and adaptation plans as well as conservation and restoration activities.