Trees help keep our planet as healthy as possible. They clean the air humans breathe, slowing climate change by absorbing roughly a quarter of all human-driven carbon dioxide emissions. However, it’s unlikely that trees can slow global warming for much longer, a new study suggests, due to deforestation, high fossil fuel usage which causes soil acidification, calcium deficiencies and much more. All these are the reasons why trees may stop being as generous as they are today.
A team led by Stanford University’s scientists and the Autonomous University of Barcelona believe that trees can continue to slow global warming by absorbing the carbon dioxide humans emit, but that doesn’t mean that carbon dioxide emissions shouldn’t be curtailed. A new study published in the journal Nature Climate Change suggests that trees can absorb only a portion of carbon dioxide, and that it’s unclear whether they can continue to do so into the next century.
“Keeping fossil fuels in the ground is the best way to limit further warming,” study lead author César Terrer, a postdoctoral scholar in Earth system science in Stanford’s School of Earth, Energy & Environmental Sciences said in a statement. “But stopping deforestation and preserving forests so they can grow more is our next-best solution.”
Carbon dioxide, which is the most prominent greenhouse gas in Earth’s atmosphere, is food for plants and trees which convert it into the oxygen we breathe throughout the process we know as photosynthesis. When it binds with nitrogen and phosphorus, it helps plants grow. However, as the carbon dioxide emissions rise, trees may not have enough extra nitrogen and phosphorus to balance their CO2 concentrations.
“Planting or restoring trees is like putting money in the bank,” said co-author Rob Jackson, the Michelle and Kevin Douglas Provostial Professor in Earth System Science at Stanford. “Extra growth from carbon dioxide is the interest we gain on our balance. We need to know how high the interest rate will be on our carbon investment.”
The team used statistics, machine learning, different models and satellite data to confirm how much soil nutrients trees will need to be able to absorb the growing carbon dioxide. Trees can slow the global warming only if there are enough soil nutrients. Additionally, the data sets of soil nutrients suggests that the trees and plants could grow even more if the atmospheric concentration of the gas doubled in the future.
The team suggests that the carbon dioxide levels could increase the plant biomass by 12% by the end of the century, allowing the trees to absorb more carbon dioxide.
“We have already witnessed indiscriminate logging in pristine tropical forests, which are the largest reservoirs of biomass in the planet,” said Terrer, who also has a secondary affiliation with the Institut de Ciencia i Tecnologia Ambientals, Universitat Autonoma de Barcelona. “We stand to lose a tremendously important tool to limit global warming.”
