Global warming to speed up if geoengineering is carried for decades and then stopped

A new research by atmospheric scientists at the University of Washington suggests that spraying reflective particles into the atmosphere to reflect sunlight and then stopping it, could exacerbate the problem of climate change.

Carrying out geoengineering for several decades and then stopping would cause warming at a rate that will greatly exceed than expected due to global warming, according to the study.

"The absolute temperature ends up being roughly the same as what it would have been, but the rate of change is so drastic, that ecosystems and organisms would have very little time to adapt to the changes," lead author Kelly McCusker, who did the work for her UW doctoral thesis, said.

The study looks at solar radiation management, a proposed method of geoengineering by spraying tiny sulfur-based particles into the upper atmosphere to reflect sunlight. This is similar to what happens after a major volcanic eruption, and many experts believe the technique is economically and technically feasible.

But continuous implementation over years depends on technical functioning, continuous funding, bureaucratic agreement and lack of negative side effects.

The UW team used a global climate model to show that if an business-as-usual emissions pathway is followed up until 2035, allowing temperatures to rise 1degree Celsius above the 1970-1999 mean, and then geoengineering is implemented for 25 years and suddenly stopped, global temperatures could rise by 4 degree Celsius in the following three decades, a rate more than double what it would have been otherwise, and one that exceeds historical temperature trends.

"The rate of standard projected global warming alone is going to be really detrimental to a lot of organisms, so if you increase that by a factor of 2 to 3, then those organisms are going to have an even harder time adapting or migrating," McCusker, now a postdoctoral researcher at the University of Victoria in Canada, added.

The study is published in Environmental Research Letters.