Engineering Earth: Altering the sky to cool the planet

Scientists claim they need little more than a year to force down global temperatures

The pressure to control climate change is building quickly, and the Catholic Church is joining a campaign to fight global warming. This year Pope Francis is expected to issue an encyclical, or teaching document, that focuses on humanity’s impact on the natural world. Yet even encouraging the planet’s 1.1 billion Catholics to be more environmentally conscious may not work quickly enough prevent widespread disruptions caused by global warming. That’s why a group of leading U.S. scientists is recommending direct research into climate engineering on a planetary scale. Such a tool could be humanity’s ultimate Hail Mary, said Marcia McNutt, who led the team of 16 elite scientists. “The jury is still out in terms of how it can be controlled spatially and temporally.”

The scholars agree the main weapon against global warming should be a coordinated move away from fossil fuel dependence to reduce carbon dioxide emissions, the root of global warming. But that process could take decades and trillions of dollars “before you see any climate benefit, but with these solar geoengineering proposals, the Earth would start getting cooler the next year,” said Ken Caldeira, who is part of the group and a climate scientist at the Carnegie department of global ecology.

The scientists released two reports: “Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration” and “Climate Intervention: Reflecting Sunlight to Cool Earth.” Both were co-authored by the 16 scientists, who have deep connections to Washington, from former federal advisory roles to oversight of critical research with millions of dollars of public and private funding. While the papers are not official U.S. government policy, they were requested and supported by key parts of the government, including the Department of Energy, NASA and the intelligence community.

Stephen Cole, a NASA spokesman, said the agency wants to know what would be needed to create “an observing system that would be able to quantify and monitor the impact of geoengineering on the Earth system.”

Department of Energy spokesman Andrew Gumbiner said its interest in geoengineering stems from wanting “to better understand the effects of climate change on U.S. national security."

Many methods of engineering Earth are under consideration. Because of the relative ease and low cost, humanity’s first strike against the weather would likely be aimed at the sun. The effects of climate engineering are not fully understood, and that, according to the scientists, is part of the problem of relying on it as a tool of last resort.

Research suggests humanity has the technical know-how to force average global temperatures down by almost 10 degrees Fahrenheit. Microscopic particles are the key to that bold claim. According to the report, airborne particles could be used to increase the planet’s reflectivity and thereby lower the amount of sunlight and heat that Earth absorbs. The process is called albedo modification. According to the theory, if aerosolized particles injected into the stratosphere spread around the world and reduce the amount of the sun’s energy warming the planet. 

That’s what happened naturally and on a planetary scale in 1991 when Mount Pinatubo in the Philippines erupted, spewing 17 million tons of sulfur dioxide into the stratosphere. Global temperatures dropped by almost a degree for more than a year until the planet could shake off the sulfur cloud and temperatures rose.

Were humans to deploy this method to engineer Earth, planes could be used to pump the skies full of particles.

“Cooling the Earth with solar geoengineering just requires a few people with a few billion dollars. It appears very easy,” said Caldeira, “which is why it is so interesting and potentially dangerous.” 

Dangerous because governments, corporations and powerful individuals may be persuaded to take desperate steps during desperate times. A group of world leaders meeting at the Vatican issued a joint statement in April that read, “The poor and excluded face dire threats from climate disruptions, including the increased frequency of droughts, extreme storms, heat waves and rising sea levels.” The most severe pain caused by global warming is likely to be felt in developing economies.

“The more likely scenario is a scenario where India or China or other tropical countries have massive crop failures due to heat stress and they feel they need to deploy some sort of geoengineering scheme to cool the planet quickly so that we can feed our people,” said Caldeira.

It could disrupt rainfall patterns or cool the planet on average while causing temperatures in some parts of the globe. In the process, it could set the stage for a redistribution of wealth as changing climate opens and closes access to global resources.

“I used to think that a climate catastrophe would be something just produced by the climate system, but I now see if there is going to be a catastrophe, it is going to be because of the interaction between climate systems and social institutions,” said Caldeira. For this reason, he and his colleagues say direct research into climate engineering is needed right now, if for no other reason than to prepare for the consequences of desperate actions in an unknown future.


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