A new study is giving the deniers of human-based climate change effects pause. Researchers found that trees are shedding their leaves earlier as the globe’s heat rises. Thereby reversing the past beliefs that rising weather is prolonging the growing seasons and plant fertility.
What is the Climate impact of global warming
A common notion was that the warmer temperature boosts carbon dioxide capture by plants, increasing photosynthesis and allowing the leaves to persist until late autumn. Scientists previously believed that global warming would stimulate the deciduous trees to lose their leaves 2-3 weeks later than usual.
But the recent discovery reverses the past assumptions.
A new theory on climate impact
The current study conducted by a team of Ecosystem ecologists has some interesting findings. Constantin Zohner revealed that enhanced plant productivity during the growing seasons resulted from elevated carbon dioxide, temperature, and light cause earlier leaf senescence.
Zohner’s team concluded the study after conducting experiments on six European deciduous tree species: English oak, silver birch, European larch, European horse chestnut, European beech, and rowan. After harvesting the information, they related the data with that collected in the last six decades.
According to Constantin Zohner, this mechanism is like a human who starts eating earlier and gets full first. He said his study contradicts the previous models, which suggest that the temperature will get warmer. Autumns will be delayed, and growing seasons will be longer.
Perhaps, rising carbon dioxide levels allow the plants to capture more. Still, we can not expect them to process more carbon dioxide because we produce more. In simpler words, plants’ wood and roots stop storing carbon dioxide after a specific value, hindering the further uptake, resulting in earlier senescence.
What is Senescence
Senescence is a phenomenon in which the leaves of deciduous plants(which shed leaves in fall) turn yellow, orange, red. Then they fall off as they have lost their ability to absorb carbon dioxide. Zohner said that the warming climate would cause the leaves to shed three to six days earlier by the end of this century.
Zohner’s research is based on a study comparing red maples and sugar maples to changing seasons. Red maples start turning yellow several days earlier than sugar maples. He has been studying them for over 20 years in the forest around his university, growing nearby.
“The research project started because there were some anomalies and unexplained observations,” Zohner said. “For example, we had discovered that the time during which both species lose their leaves was getting shorter and shorter.”
He added: “We took samples from all over New England and gradually we found out what was happening: the climate change models predicted this change very accurately.”
According to Zohner, it will be less energy-intensive to adapt the new phenology than adjusting the trees. For example, it is necessary to remove some of their leaves during autumn as they reach for sunlight below the canopy, creating a big problem for power lines.
“There are some other modifications that need to happen as well,” Zohner said. “But those changes don’t have an effect on society – we just have to do them.”
For his future research, Zohner plans to investigate whether or not low-level ozone emissions created by vehicles and power plants emit harmful compounds into the air, which permanently damage the leaves and bark of deciduous trees.
“These phenomena can show us how trees cope with climate change in general,” he said.
Though the study involved the trees from central Europe, it raised serious concerns targeting the forests worldwide. Forests that act as sinks to absorb the excess carbon dioxide became the new global warming victims, a significant threat to the world in the 21st century.