In rainforests, trees and plants grow more densely than anywhere else on the planet, and this enormous mass of plants Acts like a giant sponge Which absorbs carbon dioxide that threatens the climate2 outside the atmosphere.
But at some point, rainforest trees will no longer be able to photosynthesize. If it is too hot, the leaves will not be able to handle this the operation, Which includes the conversion of the sun and carbon dioxide2 To energy.
According to a study in nature It fails when the average temperature reaches 46.7 degrees.
I must choose
The researchers behind the study used measurements from the International Space Station (ISS) to show that under extreme heat, tropical tree leaves are approaching the maximum heat they can withstand.
If their temperature rises further, they die.
Researchers warn that the collapse of rainforests would be a disaster for Earth’s climate systems and biodiversity.
Says biologist and professor Dag O. Hessen says rainforest foliage “has to make a choice” when the temperature rises.
He says: They have to choose between hunger or thirst.
When there are very high temperatures, the leaves close their openings to reduce or avoid evaporation – that is, to dry out. But this prevents the leaves from absorbing carbon dioxide2 – That is, nutrition, explains Hessen.
He also notes that there is a fear that the combination of declining forest area and drought could push large parts of the Amazon to a tipping point, turning into savanna.
– Serious consequences
Indeed, today there are places in the rainforest where the temperature is sometimes warmer than 46.7 degrees at the top of tree crowns, he writes. Live sciences:
In total, 0.01% of all leaves exceed this critical temperature each year.
Although it’s a small number, it has serious consequences, said Joshua B. Fisher, a professor of environmental sciences at Chapman University in California, when the study was presented.
– It will not increase from 0.01 to 0.02. He explained that it will likely increase much faster.
The largest in the world
Rainforests are important to our planet. It covers approximately six percent of the Earth’s surface and is home to half of the world’s animal and plant species. It is also an important storage room for the world’s fresh water supply Videnskap.dk.
a company2-One is converted into carbon which becomes part of tree trunks, plants and soil Rainforest Trust.
– That’s why rainforests are considered one of the largest “carbon stores” on Earth, explains Professor Hessen.
According to the study published in the journal Nature, the worst scenario is for the global temperature to rise by 4 degrees. Then there is the risk of “total leaf dieback”.
This is a factor when scientists study the danger of the so-called tipping point where rainforests disappear and turn into savannas.
It would have very serious consequences for species diversity, ecology and climate, the NTB wrote. If large areas of rainforest disappeared, huge amounts of carbon, which was stored in trees, would end up in the atmosphere as carbon dioxide.2.
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