Biophysical impacts of earth greening can substantially mitigate regional land surface temperature warming

Vegetation change can alter surface energy balance and subsequently affect the local climate. This biophysical impact has been well studied for forestation cases, but the sign and magnitude for persistent earth greening remain controversial. Based on long-term remote sensing observations, we quantify the unidirectional impact of vegetation greening on radiometric surface temperature over 2001-2018. Here, we show a global negative temperature response with large spatial and seasonal variability. Snow cover, vegetation greenness, and shortwave radiation are the major driving factors of the temperature sensitivity by regulating the relative dominance of radiative and non radiative processes. Combined with the observed greening trend, we find a global cooling of -0.018 K/decade, which slows down 4.6 +/- 3.2% of the global warming. Regionally, this cooling effect can offset 39.4 +/- 13.9% and 19.0 +/- 8.2% of the corresponding warming in India and China. These results highlight the necessity of considering this vegetation-related biophysical climate effect when informing local climate adaptation strategies.

Automated summary

Vegetation greening has a unidirectional negative impact on radiometric surface temperature, with significant spatial and seasonal variability. Snow cover, vegetation greenness, and shortwave radiation are the main driving factors of this temperature response. Globally, the observed greening trend leads to a cooling effect that slows down a percentage of global warming, while regionally, it can offset a considerable portion of warming in India and China. These findings emphasize the importance of considering vegetation-related biophysical climate effects in local climate adaptation strategies.