One regional geoengineering proposal for alleviating the extreme heat effects of global warming, the brightening of marine clouds to reflect more solar energy to space over different limited areas, could work in present-day conditions but may become ineffective in the future, according to new research.

The problem is that if the warming of the planet continues at its current pace, this geoengineering strategy not only stops working in computer simulations, but it could actually start increasing heat stress instead of relieving it. The study, published last week in the journal Nature Climate Change, is the first to demonstrate the potential diminishment and even reversal of benefits of a regional cloud brightening strategy as climate conditions change.

The research was led by graduate student Jessica Wan and colleagues at the Scripps Institution of Oceanography at the University of California San Diego, with co-authors at the U.S. National Science Foundation National Center for Atmospheric Research (NSF NCAR) and the School of Global Policy and Strategy at UC San Diego. It was funded by the NSF NCAR Innovator Program, which partners NSF NCAR scientists with external collaborators across the broad spectrum of human dimension and social science research areas.

The research team’s computer modeling shows that efforts to brighten marine clouds on a regional level would initially lower the risk of dangerous heat exposure by more than 50% across the Western U.S. By 2050, though, the strategy could start to backfire. A major avenue of ocean circulation, known as the Atlantic Meridional Overturning Circulation, or AMOC, would trigger different responses as heat builds, ultimately increasing heat risks in several regions around the world.

“This study is an excellent example of how much research is still needed to understand the impacts and risks of regional geoengineering proposals since it uses idealized assumptions in only one global model,” said NSF NCAR scientist Simone Tilmes, a co-author. “It is great to see that the support of the Innovator Program has made this work possible.” 

For more, see the Scripps news release.

See all News