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People breathe out carbon dioxide, trees breathe in carbon dioxide. It’s one of the first things children learn about the carbon cycle, the paths carbon takes as it moves among the living and nonliving things that make up the planet. That might be part of the reason trees and forests have long been a focal point of the carbon sequestration conversation. Dozens of companies have committed to planting and protecting trees as part of their efforts to counteract greenhouse gas emissions, and by 2030 the Trillion Trees Campaign is aiming to increase the number of trees in the world by one third.
Tree planting sounds great and makes for striking photo-ops of CEOs and presidents turning soil with golden shovels—and there’s compelling evidence that both new trees and existing forests can help bring down the concentration of carbon dioxide in the atmosphere. But trees’ and forests’ role in global warming is more complex than it may seem. Anyone hoping to harness the power of trees in the fight against global warming needs to appreciate that complexity.
Forest protection and tree planting projects predate the idea of net-zero: The Trillion Trees Campaign is a continuation of the Billion Trees Campaign of the early 2000s, which was inspired by the Green Belt Movement that started in Kenya in the 1970s. The current number comes from a much-cited 2015 paper that calculated that planting an additional 1.2 trillion trees would absorb the equivalent of 10 years of carbon emissions. A later 2019 paper calculated that 1 trillion trees could fit on about 2.2 million acres of available land, though its definition of “available” has been contested.
Remembering Basic Science
How would trees pull off this feat? In a word, photosynthesis. Carbon dioxide (CO2) and water (H2O) are the ingredients for this recipe; light serves as the energy that helps…
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Source : time
