Everyone knows that trees and other plants consume carbon dioxide, producing a byproduct of pure oxygen that leaves the surrounding air cleaner than it was before. Although widespread deforestation has had a devastating impact on the Earth’s atmosphere, a new study offers a glimmer of hope where all once seemed lost. A new Berkeley Lab study shows that plants around the globe are keeping atmospheric carbon levels steady, despite the increase in emissions in recent decades. But we can’t expect plants to clean up all the carbon, and researchers warn that the impressive work plants are doing may not be sustainable.
Measurements of carbon dioxide in the atmosphere show the amounts are climbing year after year, due to all the human activities that continue to emit the damaging greenhouse gas. The amount of carbon in the air steadily increased throughout the later part of the 20th century, but the levels plateaued around 1.9 parts per million (per year) from 2002 to 2014. Trevor Keenan, a researcher at Berkeley Lab’s Climate and Ecosystem Sciences Division, analyzed data from the Global Carbon Project and quickly realized that the numbers didn’t quite add up. He began looking for an explanation of the carbon offsetting: a mysterious carbon sink.
The world’s oceans absorb a great deal of carbon, but that didn’t account for enough carbon offset to explain the leveling out of atmospheric carbon. Keenan and his team instead looked to the land, where climate conditions change more drastically from one year to the next. The researchers used computer modeling of Earth’s carbon cycle, fueled by 30 years of satellite data, to identify the leafy saviors keeping the most devastating aspect of climate change at bay. Plants, Keenan found, are slowing the buildup of atmospheric carbon just by doing what plants do.
However, the Earth’s plants can’t scrub all the carbon dioxide humans are emitting into the atmosphere, and Keenan’s research suggests that the plateau of carbon levels may not last much longer. “It’s quite likely this is a temporary pause in the growth rate of CO2,” Keenan told Gizmodo. “As warming kicks back in, we’ll see the growth rate go up again.”
The study was recently published in the journal Nature.