We always want to restore forests and make things greener because we know that plants play a vital role in pulling excess carbon out of the atmosphere as well as helping absorb excess carbon emissions. But the question is, can they stay that way for a long time?
At some point plants will be full of carbon and as the time goes, they can barely help reducing the impact of climate change. When does that happen? Scientists still don’t have the answer until now.
Since the Industrial Revolution began in the early 20th century, the amount of carbon in the atmosphere caused by human activity has rapidly increased. Study authors used computer models to conclude that photosynthesis has increased by 30 percent.
A study author, Lucas Cernusak and his colleagues used data from a 2017 Nature study that measured carbonyl sulfide found in ice cores and air samples. So plants don’t only take carbon dioxide, they take in carbonyl sulfide during their natural carbon cycle, and that is frequently used to measure photosynthesis on a global scale.
“Terrestrial plants are removing about 29 percent of our emissions that would otherwise contribute to growth of the atmospheric CO2 concentration. What our model analysis showed is that the role of terrestrial photosynthesis in driving this land carbon sink is larger than estimated in most other models,” said Cernusak.
Carbon sink is an amount of carbon taken in by plants versus the amount they might naturally emit through deforestation or respiration. On the other hand, some scientists don’t prefer using carbonyl sulfide as a method to measure photosynthesis.
Kerrie Sendall, a biologist from Georgia Southern University said that due to plant absorption of carbonyl sulfide can vary by the amount of light they get, the study could be overestimated. But Sendall agrees that there’s no fixed methods of measuring global photosynthesis since the results always vary.
Read also: What To Talk About Scotland’s Rainforests
Carbon as plant fertilizer
Even though there are no certain answers about the rate of photosynthesis and plants’ long-term reliability for mitigating the climate change, scientists agree that excess carbon is acting like a fertilizer for plants, boosting their growth.
“There’s evidence that trees are leafier, and that there’s more wood. The wood is really where more most of the carbon is absorbed in the mass of the plant,” said Cernusak.
Researchers at the Oak Ride National Laboratory have observed that when plants are exposed to increasing levels of CO2, the size of pores on a leaf increase. Additionally, in Sendall’s own experimental research, she has exposed plants to double the amount of carbon dioxide they were used to.
Sendall said that under those conditions, the makeup of the plants’ leaf tissues became different. The heavily carbon-exposed plants became tougher to eat for herbivores and larvae can’t thrive or grow on them.
So what does that make?
It’s still an assumption that when the levels of carbon keep rising in the atmosphere, plants won’t be able to keep up.
“The response of the land carbon sink to increasing atmospheric CO2 remains the largest uncertainty in global carbon cycle modeling to date, and this is a huge contributor to uncertainty in climate change projections,” states Oak Ride National Laboratory on their website.
The biggest contributors to the excess carbon are fossil fuel emissions and land clearing for ranching or agriculture. If we don’t do anything to minimize that, scientists believe that we can reach a point where everything changes significantly.
“More of the CO2 we emit will stay in the air, CO2 concentrations will rise quickly, and climate change will occur more rapidly,” said Danielle Way, an ecophysiologist from Western University.
Is there any way to not let this happen?
Humanity owes a lot to science, including in this case. Scientists from the University of Illinois and the Department of Agriculture have been experimenting with ways to genetically modify plants to store up even more carbon.
There’s an enzyme called rubisco that’s responsible for capturing CO2 for photosynthesis in plants, and scientists want to make it more efficient.
Tests were run and scientists found that the engineered, modified crops can absorb carbon by about 40 percent. Results are promising, though it’s going to take more than a decade to fully implement those plants.
So far, the scientists have been testing on common plants such as tobacco and they still don’t know whether the rubisco in trees could also be modified like crops. Considering that trees capture carbon more, researchers need to run tests more so that excess carbon can get absorbed more.
In September of 2018 environmental groups met in San Francisco to devise a plan to save forests, a natural asset they say is the “forgotten climate solution.”
“I think policy makers should respond to our findings by acknowledging that the terrestrial biosphere is functioning for the moment as an efficient carbon sink. Take immediate measures to protect forests so that they can continue functioning in this way, and get to work immediately to de-carbonize our energy production,” said Cernusak.
What’s your take on this? Do you think trees and plants won’t last long? Do you think trees will always do a good job in capturing and absorbing carbon? Tell us what you think in the comments below.