In 1965, leading scientists of the day produced a report for President Lyndon B. Johnson on the rampant pollution of the environment. It included a section that summed up their understanding of climate change.
"Through his worldwide industrial civilization, Man is unwittingly conducting a vast geophysical experiment," wrote longtime University of California, San Diego oceanographer Roger Revelle. "The climatic changes that may be produced," he warned, "could be deleterious from the point of view of human beings."
What Revelle suggested next kicked off a debate that continues to this day: Can humans avert the worst effects of climate change with a vast geoengineering experiment?
Revelle thought so. One solution, he proposed, would be to reflect more of the sun's energy away from the Earth "by spreading very small reflecting particles" over large swaths of the ocean.
Over the intervening decades, the idea of geoengineering Earth's climate has only grown more controversial.
Most climate experts agree that the best way to keep global temperatures in check is to rapidly reduce emissions of carbon dioxide and other greenhouse gases by transitioning to clean energy sources. But scientists and policymakers are deeply divided over which forms of geoengineering also deserve serious consideration _ and when the world might want to use them.
The United Nations Environment Assembly recently shelved a resolution to commission a report on the subject, because even studying it is contentious. (The U.S. helped block the proposal.)
Many questions revolve around scientific uncertainties and economic arguments. But the debate also taps into thorny philosophical questions:
Is intentionally altering the climate a defensible last-ditch effort to stave off climate damages _ or a dangerous act of hubris?
And do we betray future generations by contemplating such drastic measures, or by failing to pursue them?
