Should scientists artificially cool the planet to stave off climate catastrophe? Here’s everything you need to know:
What is geoengineering?
Some climate scientists are coming to believe it’s humanity’s only hope for slowing or stopping disastrous changes in the climate. As runaway carbon dioxide emissions contribute to melting ice caps, widespread flooding, prolonged heat waves and droughts, apocalyptic wildfires, and devastating hurricanes, researchers are exploring planetary-scale interventions in Earth’s natural systems as a way of counteracting climate change. Geoengineering has been debated since the 1960s, when U.S. scientists suggested floating billions of white, golf ball–like objects in the oceans to reflect sunlight. Interfering in natural processes was widely considered naïve and dangerous until recently, but as the window to curb global warming shrinks, proposals to reflect sunlight, shade Earth’s surface, accelerate carbon absorption in the oceans, and remove CO2 from the air are being taken more seriously. In October, SilverLining, a nonprofit, gave $3 million toward climate-engineering research. “I liken geoengineering to chemotherapy,” said Michael Gerrard, a professor of environmental and climate law at Columbia University. “If all else is failing, you try it.”
What are the most plausible proposals?
SilverLining’s grant recipients are researching whether humans can blast sunlight-reflecting aerosol particles into the stratosphere, mimicking the cooling effect of volcanic ash clouds. In 1991, Mount Pinatubo in the Philippines erupted, spewing sulphate particles into the atmosphere that caused global temperatures to drop 0.6 degrees Celsius over the next two years.
Solar-radiation management would involve sending fleets of airplanes up about 65,000 feet, where they’d spray sulfate aerosols into the upper atmosphere, or perhaps even diamond dust. A research team at Harvard University projects that if high-altitude tankers had the capacity to make 60,000 particle dumps by 2035, it would shave off 0.3 degrees Celsius of warming.
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