Unexpected Warming From Land Radiative Management

[Geoengineering News]

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024GL112433

Authors

Yu Cheng, Kaighin A. McColl

First published: 19 November 2024

https://doi.org/10.1029/2024GL112433

Abstract

“Land radiative management” (LRM)—deliberately increasing surface albedo to decrease temperatures—has been proposed as a form of geoengineering to mitigate the effects of regional warming. Here, we show that, contrary to expectations, LRM causes temperatures to increase in surrounding regions. The basic reason for the increase is unintended impacts on precipitation. Precipitation is suppressed over the LRM region, but this effect also extends to nearby areas unprotected by LRM. The reduction in precipitation and soil moisture in these regions leads to higher temperatures than would be expected in the absence of LRM. The resulting warming outside the LRM region is comparable to the cooling achieved inside it. This implies that, if wealthy regions unilaterally adopt LRM to cool, their neighbors may experience warming, worsening heat inequality.

Key Points

Land radiative management (LRM) causes temperatures to unexpectedly increase in surrounding regions

LRM decreases precipitation over its immediate surroundings, which dries the land surface and increases temperatures

The unilateral adoption of LRM by affluent regions will exacerbate heat inequality between wealthy and poor neighborhoods

Plain Language Summary

Land radiative management (LRM), which involves artificially increasing Earth's surface albedo to mitigate regional warming, has been recognized by the Intergovernmental Panel on Climate Change as a potential solution to combat the adverse effects of climate change. Examples of LRM approaches include the adoption of white roofs and pavements. Our study challenges conventional wisdom by demonstrating that LRM can actually cause temperatures to increase, rather than decrease as intended, due to its unintended impacts on rainfall. LRM suppresses rainfall in surrounding regions, causing them to experience higher temperatures than they would in the absence of LRM. The implications of our findings are significant, as the unilateral adoption of LRM by affluent regions will exacerbate heat inequality between wealthy and poor neighborhoods.

Source: AGU