“It’s possibly the worst thing that could be done to address climate change, but we actually need to take it seriously.” That’s how Peter Frumhoff, director of science and policy at the Union of Concerned Scientists, described solar geoengineering, the controversial idea of reflecting away more of the sun’s rays to slow global warming.
Geoengineering has long been on the fringes of climate science. Critics have argued that tinkering with the planet at such a large scale is far too risky, and could have disastrous consequences. But with global temperatures continuing to rise, a growing number of scientists are supporting research in the contentious field. Geoengineering, they argue, might be the only hope of avoiding a climate catastrophe.
Last month, Harvard University made headlines when it launched a new solar geoengineering research program. Researchers there hope to conduct their first real-world experiment in 2018, when they’ll release tiny reflective particles into the stratosphere from a hot-air balloon, and then measure its effectiveness at reducing solar radiation below. The $20 million project is expected to be the largest geoengineering experiment ever done.
“To me, solar geoengineering is terrifying,” Daniel Schrag, a professor of environmental science and engineering at Harvard, conceded in a video released with the announcement of the new research program. “We’re talking about an engineering project that could affect every living thing on this planet. The possibility that something could go wrong is really scary.”
But, Schrag said, it could take decades or longer for the world’s energy system to shift from fossil fuels to renewables – and by then climate impacts could be devastating. “The evidence is becoming clearer and clearer that not doing geoengineering and letting climate change proceed might be worse, as an alternative,” he said.
Schrag isn’t alone. In 2015, the U.S. National Academy of Science warned against the risks of geoengineering but, for the first time, recommended more research to determine its potential. Earlier this year, scientific advisers to the U.S. government urged more funding for geoengineering research to provide “insight into the science needed to understand potential pathways for climate intervention or geoengineering, and the possible consequences, both intended and unintended.”
Over the years, a number of climate engineering schemes have been proposed for the Arctic, to slow the melting of sea ice and glaciers. One idea was to cover the landscape with massive white tarps that would reflect the sun’s heat. Another suggested damming the entire Bering Strait, to stop the flow of warmer water from the south.
Last December, a team from Arizona State University published a proposal to build wind turbines in the Arctic to pump water onto sea ice, to thicken and preserve it. The plan, which was published in the American Geophysical Union’s journal Earth’s Future, would require 10 million windmills and cost a staggering $500 billion, leading some to call it the Manhattan Project of climate change.
Steve Desch, a co-author of the proposal and a professor of astrophysics at Arizona State University, said he felt compelled into action after attending a climatology conference several years ago. “I realized that the climate science community has basically one answer [for climate change]: stop CO2 emissions, which, of course, is the correct answer,” he said. “But I also became aware of how urgent the need is in the Arctic, and though we probably will reduce CO2 – we have to – it won’t be fast enough to preserve the sea ice.”
Geoengineering might seem like a quick fix, but the risks are enormous. Light-reflecting sulfate aerosol – a material often suggested for solar geoengineering – has been shown to damage the ozone layer, which protects the planet from harmful ultraviolet radiation. Sulfates have also been linked with acid rain. And modifying the atmosphere in one part of the world can have unintended consequences elsewhere.
The 1991 eruption of Mount Pinatubo in the Philippines, for example, spewed more than 15 million metric tons of sulphur dioxide into the stratosphere, and for the next two years temperatures in the northern hemisphere dropped by about 0.6C (1F). But precipitation also declined dramatically, causing drought in some parts of the world.
“What little research that’s been done on geoengineering has been done on computer models,” said the Union of Concerned Scientists’ Frumhoff. He’s quick to point out that geoengineering is no substitute for reducing emissions, and that currently there isn’t nearly enough scientific understanding, oversight or public support to make geoengineering a plausible alternative. But, Frumhoff said, we simply can’t ignore the subject any longer.
“We are at a point where we’ve dallied so long with addressing the climate problem, where even very aggressive reductions in greenhouse emissions may well not be sufficient to limit dangerous climate change,” he noted.
One of the thorniest questions is around regulation: Currently, there is no international oversight of geoengineering. Creating a decision-making body won’t be easy, said Janos Pasztor, director of the Carnegie Climate Geoengineering Governance Project. “How do you decide, as an international community, to go for the global good but at the same time have impacts in a particular region?” he asked. “And if you decided, how do you set up mechanisms for compensating that region?”
Pasztor pointed to the Intergovernmental Panel on Climate Change as an example of how governance for geoengineering might work. “The scientists have been talking about climate engineering and that’s great – we have to be science based – but so far there has been no discussion at the policy level,” he said. “We need to start having that discussion now.”
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