SAN JOSE, Calif. — Scientists are calling for tests to find ways to cool the planet — the first step toward exploration of the controversial field of geoengineering, which aims to change the climate by blocking the sun’s rays.
It might be necessary if society can’t agree on how to stop carbon emissions that are heating up Earth, a panel of experts said at the weekend meeting of the American Association for the Advancement of Science.
The call for small-scale tests represents a profound shift in thinking among the scientific community, which has resisted conversations about deliberate, large-scale manipulation of the planet.
“We have to know through research … what the benefits and risks might be,” said climate scientist Alan Robock of Rutgers University.
Scientists say the proposals to study sun-blocking ideas are spurred by this sobering reality: Even if we completely stopped carbon emissions today, the Earth will continue warming over the next several decades.
A geoengineering test, opposed by some environmentalists, could involve wafting tiny sea-salt particles toward low-lying clouds off California’s Central Coast to try to fend off sunlight. They argue that it’s dangerous to tinker with the environment rather than stop the problem at its source.
Another might measure the cooling haze-inducing effect of emissions from cargo ships traveling from the Port of Oakland to Asia, the scientists said.
The scientists’ recommendations followed last week’s release of two reports on geoengineering by the National Research Council of the Academy of Sciences. The council recommended a research agenda for how to offset the release of billions of tons of carbon dioxide a year caused by the burning of fossil fuels.
The reports were funded largely by the Central Intelligence Agency, Robock said. That suggests that intelligence experts view climate control as a potential tool of international conflict, he said.
Some countries might try to create clouds and send them toward an enemy, for example. Or there may be disputes over the “right” temperature; for example, if Indonesia wants cooling to avoid sea level rise and Russia wants warming to increase agricultural production.
At present, the only geoengineering studies involve computer modeling. But it’s time to do real-world testing, Saturday’s panelists said.
“Current research is not sufficient to allow us to decide if it could be useful,” said Lynn Russell, a professor of atmospheric chemistry at the University of California, San Diego. “We just don’t have enough information to make this decision at this point.”
Some environmental groups oppose geoengineering tests because they believe they would suggest that there’s an easy technological fix to carbon emissions.
“Research into geoengineering is a distraction from the hard work of reducing carbon emissions,” said Richard Heinberg of the Santa Rosa-based Post Carbon Institute.
“If something goes wrong, we may not be able to undo or control the damage,” said Heinberg, who is particularly opposed to efforts to block sunlight. “The metaphor ‘playing with fire’ hardly begins to communicate the level of risk we are talking about.”
Scientists said at the conference that they’re also interested in researching ways to trap carbon in the atmosphere and remove it. However, they said, this approach would take longer to be effective.
“We’re at the beginning of an important moment in human history: the trial separation of humanity and nature,” said science ethicist Stephen Gardiner of the University of Washington.
“I recommend modest steps in this direction, with trepidation.”