Regeneration trail: A farmer harvests berries from an acaí palm tree in the Amazon forest in Brazil. More diverse forests are often better at capturing carbon because they are more resilient to natural disasters, pests and diseases. — AFP
NEW YORK: Restoring and protecting forests has the potential to store the equivalent of the annual carbon emissions of 50,000 coal fired-plants, according to a new study.
Forests can play a central role in helping mitigate climate change, owing to their ability to pull carbon dioxide from the atmosphere and store it.
The study, published in Nature on Monday, provides a new estimate of how much CO2 could be sequestered by conserving existing forests and revitalising degraded ones.
Carbon storage could reach 226 gigatons, an amount that represents 30% of the world’s total excess carbon.
Investing in forests’ health isn’t an excuse to continue pumping greenhouse gasses into the atmosphere, particularly because the capacity of trees to survive and absorb carbon is significantly threatened by the impacts of an overheating planet.
If the world continues on its current emissions track, the ability of trees to absorb CO2 could drop 26% by 2050, according to a previous study.
“There cannot be a choice between nature and decarbonising, we absolutely must take steps to achieve both simultaneously,” said Tom Crowther, an ecologist at ETH Zurich and author of the new study.
To come up with the new estimate, researchers combined on-the-ground and satellite data to model the total potential forest biomass globally.
They incorporated information on soil, carbon, dead wood and litter to estimate the earth’s total carbon storage potential outside of urban and agricultural areas.
The findings indicate that the majority of that potential comes from allowing existing forests to recover, while the remaining comes from restoring forests in areas where they have been removed or fragmented.
But it’s not as simple as planting trees. Large-scale initiatives to do so often involve cultivating massive monoculture plantations, which can be more harmful than helpful as they disturb natural ecosystems and lead to biodiversity loss.
Tree plantations are also less productive at sequestering carbon. A recent study published in Frontiers in Forests and Global Change showed that mixed forests generally store 70% more carbon than their monoculture counterparts.
More diverse forests are often better at capturing carbon because they are more resilient to natural disasters, pests and diseases.
“I don’t want people to take this information to justify mass plantations, quick carbon offsetting, greenwashing or anything like that,” Crowther said.
How much forests can contribute to curbing climate change is a controversial area of research. The new study’s estimate that forests could capture 226 gigatons of CO2 is much too high, according to Carla Staver, an associate professor of ecology at Yale University.
She said the true potential probably falls closer to 25% of that amount. The reason for the discrepancy is because the study’s methodology relies too heavily on regenerating forests in ecosystems that thrive on having open spaces, like savannahs, she argued.
“When you increase the tree component of some of these ecosystems, it means that tree cover increases,” said Staver, who was not involved with the study.
“But it also makes it a much less friendly habitat for the types of biodiversity that depend on those ecosystems that historically lived in those places.”
Rather than focusing heavily on restoration, she said conserving existing forests could be more effective at reducing carbon emissions and have a “much more immediate impact”.
The CO2 storage potential associated with forest regeneration could take decades to years to be realised, given the amount of time needed for new trees to grow. — Bloomberg
