Climate Tools Seek to Bend Nature’s Path

The solution to global warming, Olaf Schuiling says, lies beneath our feet.

For Dr. Schuiling, a retired geochemist, climate salvation would come in the form of olivine, a green-tinted mineral found in abundance around the world. When exposed to the elements, it slowly takes carbon dioxide from the atmosphere.

Olivine has been doing this naturally for billions of years, but Dr. Schuiling wants to speed up the process by spreading it on fields and beaches and using it for dikes, pathways, even sandboxes. Sprinkle enough of the crushed rock around, he says, and it will eventually remove enough CO₂ to slow the rise in global temperatures.

“Let the earth help us to save the earth,” said Dr. Schuiling, who has been pursuing the idea single-mindedly for several decades and at 82 is still writing papers on the subject from his cluttered office at the University of Utrecht.

Once considered the stuff of wild-eyed fantasies, such ideas for countering climate change — known as geoengineering solutions, because they intentionally manipulate nature — are now being discussed seriously by scientists. The National Academy of Sciences is expected to issue a report on geoengineering later this year.

That does not mean that such measures, which are considered controversial across the political spectrum, are likely to be adopted anytime soon. But the effects of climate change may become so severe that geoengineering solutions could attract even more serious consideration. Some scientists say significant research should begin now.

Dr. Schuiling’s idea is one of several intended to reduce levels of CO₂, the main greenhouse gas, so the atmosphere will trap less heat. Other approaches, potentially faster and more doable but riskier, would create the equivalent of a sunshade around the planet by scattering reflective droplets in the stratosphere or spraying seawater to create more clouds over the oceans. Less sunlight reaching the earth’s surface would mean less heat to be trapped, resulting in a quick lowering of temperatures.

No one can say for sure whether geoengineering of any kind would work. And many of the approaches are seen as highly impractical. Dr. Schuiling’s, for example, would take decades to have even a small impact, and the processes of mining, grinding and transporting the billions of tons of olivine needed would produce enormous carbon emissions of their own.

Beyond the practicalities, many people view the idea of geoengineering as abhorrent — a last-gasp, Frankenstein-like approach to climate change that would distract the world from the goal of eliminating the emissions that are causing the problem in the first place. The climate is a vastly complex system, so manipulating temperatures may also have consequences, like changes in rainfall, that could be catastrophic or benefit one region at the expense of another.

Critics also worry that geoengineering could be used unilaterally by one nation, creating another source of geopolitical worries, or could aggravate tensions between rich and poor nations over who causes and who suffers from climate change. Even conducting research on some of these ideas, they say, risks opening a Pandora’s box.

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