Solar geoengineering ‘highly risky’ strategy to combat global warming

Original article.

Mimicking the effect of volcanoes to curb global warming impacts is a “highly risky” strategy that could backfire disastrously, a study suggests.

Climate experts conducted sophisticated computer simulations of what would happen if millions of droplet particles, or aerosols, were injected into the atmosphere to block the sun’s rays.

They found that adopting the geoengineering approach in the northern hemisphere would reduce tropical cyclone activity responsible for devastating storms such as Hurricane Katrina.

But at the same time, it risked triggering widespread drought in the Sahel, the region of Africa just south of the Sahara desert.

Aerosols injected into the sky over the southern hemisphere would potentially boost North Atlantic tropical cyclone activity, increasing the likelihood of destructive hurricanes.

The approach, based on the effects of volcanic eruptions which naturally fire aerosols into the atmosphere, has been promoted by some experts as a “quick fix” to reduce the rate of global warming.

Climate scientist Dr Anthony Jones, from the University of Exeter, who led the new research, said: “Our results confirm that regional solar geoengineering is a highly risky strategy which could simultaneously benefit one region to the detriment of another.

“It is vital that policymakers take solar geoengineering seriously and act swiftly to install effective regulation.”

A blanket of aerosols high in the atmosphere would reflect some of the sun’s energy back into space, thereby cooling the Earth’s surface.
But many experts have warned of the potential dangers caused by knock-on effects on climate and weather.

Aerosol injection is one of the more radical ideas touted to achieve the aspirational global warming target agreed by world leaders at the 2015 climate talks in Paris.
This would peg end-of-the-century warming to 1.5C above pre-industrial revolution levels.

The new findings are published in the journal Nature communications.

Commenting on the research Professor John Shepherd, Research Fellow in Earth System Science at the University of Southampton, said: “This is not a technique that is ready to use in the near future: reducing CO2 (carbon dioxide) emissions and planning our adaptation to climate change must remain the top priorities for climate policy.”

US expert Dr Peter Irvine, from Harvard University, said: “Deploying stratospheric aerosol geoengineering in only one hemisphere is pretty certainly a bad idea and this work helps reinforce that view.”