It gets worse: In many cases, wildlife would have to go in one direction to find a liveable temperature but a different one to find the right amount of rainfall.

Harvard professor David Keith, author of "A Case for Climate Engineering," did not challenge the potential dangers for biodiversity, but told AFP he could not imagine the world's nations abruptly halting solar radiation management -- a scenario sometimes called "termination shock".

"A decision to suddenly terminate would have to be near unanimous," he told AFP. Any country who decided doing so was against its interest "could continue geoengineering unilaterally."

SOLAR ENGINEERING UNPROVEN

All this speculation assumes that solar engineering is feasible, which has yet to be proven. 

"If solar radiation management is unworkable, we need to know now," commented Ben Kravitz, a climate scientist at Pacific Northwest National Laboratory in Washington and an expert on geoengineering.

"What terrifies me is that people are gong to start relying on it, and then we find out later that it is not going to work and we are already locked in," he told AFP by email.

But that doesn't mean solar geoengineering should be taken off the table, he other scientists caution. 

Even the study authors agreed. "Given current emissions trajectories, it would be irresponsible not to study the potential benefits and costs of proposed climate engineering," they wrote. 

Keith and Harvard colleague Frank Keutsch plan to conduct preliminary atmospheric tests in the Arizona desert this fall, but any conclusions are years away, they said.

"It will be really hard to hit 1.5 C or 2 C without solar radiation, management," said Kravitz. "Not impossible, but very hard."

Source: AFP