https://sputnikglobe.com/20230823/tropical-treetops-are-getting-too-toasty-for-photosynthesis-study-says-1112830819.html
Tropical Treetops Are Getting Too Toasty for Photosynthesis, Study Says
Tropical Treetops Are Getting Too Toasty for Photosynthesis, Study Says
Sputnik International
A new study has found that an increasing number of leaves in Earth’s tropical regions are experiencing temperatures so high that photosynthesis, the process that turns carbon dioxide into life-giving oxygen, can no longer happen.
2023-08-23T20:44+0000
2023-08-23T20:44+0000
2023-08-23T20:43+0000
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Published on Wednesday in the journal Nature, the study found that the temperatures at the tops of rainforest canopies in several parts of the planet are getting dangerously close to the point where photosynthesis stops.The researchers found that at the tops of rainforest trees in Brazil, Puerto Rico and Australia, 1 in every 10,000 leaves reaches 46.7 degrees Celsius, the critical temperature in question, for at least one day per year.Moreover, the average temperature of those treetops is only about 4 degrees below the tipping point, threatening mass leaf dye-offs if global temperatures continue their rising trend.However, researchers have noted that much is uncertain. Christopher Still, an ecologist at Oregon State University in Corvallis, told US media they may be overestimating leaf vulnerability by “assuming that when leaves hit this critical temperature, they die.” He noted it as one possibility, adding that another variable may be the length of time for which the leaf is that hot.Their research also found variances in temperature depending on the kind of weather, with wetter periods corresponding to higher temperatures and dryer periods corresponding to lower temps, with the dry-period average being as low as 34 degrees Celsius. They also found temperature gaps between the highest treetops, which are directly exposed to the sun, and the expansive understory that lay beneath, where sunlight is sparser.Climatologists have warned that due to a man-made influence on the climate caused by vast emissions of carbon dioxide and other greenhouse gases, the Earth is rapidly warming at a pace not seen in hundreds of thousands of years. Estimates vary, but many predictions for the year 2100 expect the average global temperature to be at least 3 degrees Celsius higher than in 1880, when the industrial revolution was still beginning and emissions were low; they have already warmed by about 1 degree so far. While governments around the globe have made commitments to curbing carbon emissions, even the most ambitious agreements don’t aim to prevent more than a 1.5-degree temperature increase by the end of the century.
https://sputnikglobe.com/20230705/world-experiences-hottest-day-on-record-even-hotter-days-expected-ahead-1111681916.html
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photosynthesis; leaves too hot; climate change study; rainforest
photosynthesis; leaves too hot; climate change study; rainforest
Tropical Treetops Are Getting Too Toasty for Photosynthesis, Study Says
A new study has found that an increasing number of tree leaves in Earth’s tropical regions are experiencing temperatures so high that photosynthesis, the process that turns carbon dioxide into life-giving oxygen, can no longer happen inside them.
Published on Wednesday in the journal Nature,
the study found that the temperatures at the tops of rainforest canopies in several parts of the planet are getting dangerously close to the point where photosynthesis stops.
The researchers found that at the tops of rainforest trees in Brazil, Puerto Rico and Australia, 1 in every 10,000 leaves reaches 46.7 degrees Celsius, the critical temperature in question, for at least one day per year.
Moreover, the average temperature of those treetops is only about 4 degrees below the tipping point, threatening mass leaf dye-offs if global temperatures continue their rising trend.
“It’s pretty rare that these leaves will get that hot right now,” study co-author Christopher Doughty, an earth systems scientist at Northern Arizona University, told US media. “But it was actually surprising that any of them got to that point because it’s quite a bit above air temperature.”
However, researchers have noted that much is uncertain. Christopher Still, an ecologist at Oregon State University in Corvallis, told US media they may be overestimating leaf vulnerability by “assuming that when leaves hit this critical temperature, they die.” He noted it as one possibility, adding that another variable may be the length of time for which the leaf is that hot.
Their research also found variances in temperature depending on the kind of weather, with wetter periods corresponding to higher temperatures and dryer periods corresponding to lower temps, with the dry-period average being as low as 34 degrees Celsius. They also found temperature gaps between the highest treetops, which are directly exposed to the sun, and the expansive understory that lay beneath, where sunlight is sparser.
The scientists arrived at their conclusions first by gathering the raw data using a mixture of sensors taped under leaves and overhead data gathered by the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS), a sensor mounted on the International Space Station. Then, they built a computer model to project what might happen as temperatures continue to rise globally.
Climatologists have warned that due to a man-made influence on the climate caused by vast emissions of carbon dioxide and other greenhouse gases,
the Earth is rapidly warming at a pace not seen in hundreds of thousands of years.
Estimates vary, but many predictions for the year 2100 expect the average global temperature to be at least 3 degrees Celsius higher than in 1880, when the industrial revolution was still beginning and emissions were low; they have already warmed by about 1 degree so far. While governments around the globe have made commitments to curbing carbon emissions, even the most ambitious agreements don’t aim to prevent more than a 1.5-degree temperature increase by the end of the century.
