Humans warmed Earth. Can’t we just cool it? Here are some ideas.

Even if they did work, critics worry they could backfire spectacularly. Ask scientists and you’ll get a range of answers: “Probably not.” “Maybe?” and “Are you insane?” And yet ideas for geoengineering – literally engineering ways to either lower carbon dioxide levels or temporarily cool the planet while they come down – are increasingly being floated as a climate stopgap, even though they seem more like movie plot lines than serious suggestions. The ideas sound outlandish, and even if they do work, critics worry they could backfire spectacularly. But amid the climate crisis, these moonshot ideas have gained attention from experts and investors. Geoengineering: This climate change fix could save the world — or doom it There’s a big catch: None of these ideas would allow humanity to keep burning fossil fuels without consequence. Here’s a look at a few ideas for how humans could help cool the planet: Carbon capture: Efforts underway to suck carbon dioxide out of the air Carbon dioxide (CO2) is the main culprit in climate change. The technology already exists, and at least one version is fast becoming noncontroversial. On the controversial side are projects that capture CO2 from oil and natural gas wells and from industrial processes, then pump it back underground to make it easier to bring up more oil and gas – which doesn’t do enough to actually stop fossil fuel use, critics say. Because there are subsidies for this technology, it effectively pays polluters to pollute, they say. The less controversial approach involves constructing huge fanlike machines that suck in air, pull out carbon dioxide via chemical processes and then store it underground. The plant is a pilot project demonstrating that the technology can work on a large scale, but experts say far more and bigger plants would be necessary to make a real difference. About 500 billion tons of carbon dioxide would need to be removed to return to preindustrial levels of carbon dioxide in the atmosphere, according to researchers at the Massachusetts Institute of Technology. Solar geoengineering: Use sulfur to create reflective clouds Solar geoengineering involves launching sulfur dioxide or other materials into the stratosphere so they reflect some of the sun’s energy back to space, artificially cooling the Earth. It’s exactly what some volcanic eruptions do: spew huge amounts of dust and sulfur dioxide high enough that the material goes into the stratosphere where rain and other weather systems can’t quickly wash it out of the air. Though the proposal wouldn’t reduce the amount of greenhouse gases in the atmosphere, it could buy time, said Wake Smith, a lecturer at the Yale School of the Environment and author of “Pandora’s Toolbox: The Hopes and Hazards of Climate Intervention.” “It’s a very immature technology, a very controversial technology, and so we shouldn’t put too much faith in it yet. But if we heated the Earth too much, there is at least one tool that looks like it would help.” Already two startups are working in the area, though neither has gotten very far. In 2022, a company called Make Sunsets began doing small launches, deploying biodegradable balloons full of helium and sulfur dioxide that burst in the stratosphere. Marine cloud brightening: Create reflective clouds over the ocean Clouds are white and reflect sunlight, which lowers the amount of heat added to the atmosphere. “If we can make clouds last a bit longer, particularly over the oceans because no one really wants more clouds over land, and maybe make them whiter than gray, that would reflect more solar energy,” said Hugh Hunt, a professor of engineering at the Centre for Climate Repair at the University of Cambridge in England. “The good thing about all this is that you can spray this stuff from boats, where it doesn’t feel quite so scary as going 20 kilometers up with planes spraying sulfuric acid. You’re just spraying saltwater from the boat,” said Shaun Fitzgerald, director of research at Cambridge’s Center for Climate Repair. The downside is that the method works only in small areas, like cooling a reef, rather than being scalable to large portions of the planet. “You stop spraying your saltwater and the effect on the clouds will stop within a day,” he said. In April, a test of this technology was begun in San Francisco Bay by scientists at the University of Washington – and quickly shut down by local officials who worried there were possible health and environmental risks. A bubble curtain for glaciers: Slow melting by insulating the ice The world’s glaciers are melting, a problem because of their potential to significantly raise sea levels. (Even newer research says the nightmare scenario is unlikely, for now.) Glaciers melt because warmer, deep, dense saline water from the ocean is being pushed under them, known as seawater intrusion. One idea is to stop the warmer ocean water from reaching the base of the glaciers using a curtain of air bubbled up from the bottom, which would act as insulation and cause the warmer water to curl around and return to sea rather than under the glacier. “We’re testing methods to pump air along a pipe with holes in it to create a bubble curtain to disrupt the flow of water,” Fitzgerald said. Ocean fertilization: Trap CO2 in dead algae The idea here is to fertilize the oceans with iron to stimulate algae and plankton blooms, which would pull CO2 out of the water and into their bodies. About 30% of the world’s oceans have low iron levels, which keeps the growth of microscopic ocean plants and animals such as algae and plankton down. When these blooms die off, they would fall to the ocean floor and store the CO2 there. But it’s not clear that the CO2 would stay put, or how well the technology would work. – This Summarize was created by Neural News AI (V1). Source: https://www.usatoday.com/story/graphics/2024/09/07/reverse-global-warming-geoengineering/73748917007/