DIMMING THE SUN

A thoughtful look at a high-tech effort at delaying global warming.

Technology writer Ramge, author of Who’s Afraid of AI?, points out that 2023 was the warmest year in 120,000 years, and even if greenhouse gas emissions stopped increasing today, worldwide temperatures would still rise a disastrous 5 degrees before 2100. In 1991, the Philippine Mount Pinatubo volcanic eruption spewed clouds of sulfur dioxide into the stratosphere, where it reacted with water to form a milky mist. The following year saw the earth cool by almost 1 degree Fahrenheit before the mist dissipated over the next few years. The eruption was mild by geological standards; more powerful outbursts probably triggered ice ages. A coterie of serious scientists and tech entrepreneurs are promoting the idea of geoengineering similar artificial clouds, claiming that “by spending a few billion dollars annually on sulfur in the stratosphere, human suffering…can be drastically reduced in the short term.” This doesn’t help in the long term, but may provide time to enact a permanent solution. Activists and many scientists denounce geoengineering as a pie-in-the-sky quick fix that is possibly dangerous and certain to be embraced by the fossil fuel industry to allow them to continue poisoning the atmosphere. So far, the industry has successfully discouraged research and even blocked individual ad hoc experiments. Ramge considers this shortsighted; a temporary fix may give lumbering governments time to get their act together. The author makes a sensible case for investigating geoengineering’s safety and efficacy. He defines its limited role and suggests guidelines for overseeing the project that mimic other successful international agreements. He concludes with a fictional scenario describing a miserably overheated world in 2038, when an international referendum approves a project to inject sulfur dioxide into the stratosphere that proceeds with mildly encouraging results.

Sober arguments for a still-controversial approach.