The ocean is Earth’s climate hero.
For decades, ocean waters have helped hold back the juggernaut of global warming, absorbing at least a third of the carbon dioxide emitted by human activities since the Industrial Revolution began.
Now, the world may ask the ocean to do even more. That would require tinkering with the chemistry and biology of the ocean to increase how much carbon it takes up.
Such an approach is worth considering because the window for limiting warming by reducing carbon emissions alone is closing fast, climate simulations suggest. Forestalling the worst impacts of climate change by 2100 will require actively pulling carbon back out of the atmosphere — at a scale possible only with the ocean’s help, some scientists say.
Earth is on track to warm by about 3.2 degrees Celsius by the end of the century, relative to preindustrial times, according to the Intergovernmental Panel on Climate Change. Even if all nations meet their current emission-reduction pledges, the world would still warm by about 2.7 degrees (SN: 10/26/21).
That’s higher than the target of 1.5 to 2 degrees set by the 2015 Paris Agreement, an international climate treaty signed by 195 parties. In fact, Earth’s average temperature is likely to surpass the 1.5-degree benchmark as soon as the mid-2030s (SN: 12/15/23). Each uptick in the thermostat increases the risk of devastating consequences, including deadly heat waves, more intense storms and inundations of coastal cities due to melting ice and rising seas.
Technologies that remove carbon from the atmosphere could help turn the thermostat back down by the end of the century. “The latest IPCC report notes that to meet the [Paris Agreement] climate goals, we have to employ carbon dioxide removal technologies,” says geochemist Gabriella Kitch of the U.S….
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