by Simon Mansfield
Sydney, Australia (SPX) Dec 06, 2023
A groundbreaking study, led by Prof. Li and his team, has leveraged high-resolution satellite data to investigate the local temperature responses to actual land cover changes (LCCs) across various latitudes. Traditionally, research in this area was hindered by the coarse resolution of available data, which often necessitated the use of a space-for-time substitution to hypothesize potential effects of afforestation and deforestation.
By generating a high-resolution temperature dataset and adopting a more holistic space-and-time approach, Prof. Li's team was able to encompass all forms of realistic LCCs. Their extensive analysis of satellite observations uncovered changes in 529,128 1-km pixels from 2006 to 2015. Notably, the study expanded beyond the commonly examined afforestation and deforestation (accounting for 46.28% of the changes), to include transitions within non-forest vegetation types (18.62%) and changes involving non-vegetation types (35.10%).
The findings reveal a nuanced picture of temperature changes: a global average increase of 0.08 K in areas with LCCs, yet with significant variations across latitudes, ranging from -0.05 K to 0.18 K. These temperature effects contributed to as much as 44.6% of the overall concurrent warming, underscoring the substantial impact of LCC biophysical processes.
The study further identified distinct regional patterns. In the northern mid-latitudes, expansions of cropland predominantly drove cooling effects, while forest-related LCCs induced warming in other regions. Contrary to previous assumptions of symmetry in potential effects, the actual effects exhibited notable asymmetries: LCCs with warming impacts were more frequent and intense than those leading to cooling. This asymmetry was attributed to a combination of uneven changes in transition types and driving variables.
These insights challenge the notion that reversing a specific LCC would counterbalance its temperature impact. As such, the study offers a new perspective on land management and climate adaptation strategies, emphasizing the need for nuanced approaches in response to diverse LCC scenarios.