According to a study from the University of Arizona, rising global temperatures will cause plant vegetation to heat up faster than the surrounding air. Researchers found that plant canopy temperatures could rise by approximately 0.11°C more than air temperatures by the end of the 21st century, increasing pressure on ecosystems and reducing the ability of plants to absorb carbon dioxide.
Why Plant Canopies Heat Up Faster Than Air
Leaves absorb direct solar radiation, causing them to reach temperatures higher than the surrounding air. When conditions turn hot and dry, plants limit transpiration to conserve water. This defensive mechanism cuts off their natural cooling process, leading to even higher surface temperatures.
Many climate models currently rely exclusively on air temperature rather than the actual temperature of the plants themselves. According to University of Arizona researchers, this oversight means standard models routinely underestimate the thermal stress placed on vegetation worldwide.
Impacts on Global Ecosystems and Carbon Storage
The growing temperature gap between plants and air will affect approximately 81% of vegetated areas globally. Arid and tropical ecosystems face the most severe risks from this emerging trend.
Lead author Julia Green, Assistant Professor in the university’s Department of Environmental Science, explained the direct biological consequences of these rising thermal thresholds. “Plant surface temperature has a first-order impact on plant photosynthesis, transpiration, respiration and other important processes,” Green noted. She added that relying on air temperature alone causes researchers to underestimate real-world temperature effects on plants.
As these surface temperatures climb, photosynthesis slows down. This reduction weakens the capacity of global forests to store carbon, potentially accelerating the timeline of climate change.
Did you know? Tropical and arid regions will experience the most pronounced divergence between air and plant surface temperatures as global warming continues.
Improving Climate Models for Future Protection
Scientists argue that shifting toward more accurate climate models will help protect vulnerable ecosystems and improve regional climate planning. Better data collection supports targeted efforts to reduce carbon dioxide emissions in the future by accounting for the true physiological stress experienced by plant life.
Without updates to account for canopy heating, current projections miss a critical feedback loop in the global carbon cycle.
Frequently Asked Questions
Why do plants heat up faster than the air?
Plants absorb direct solar radiation. Under hot and dry conditions, they restrict transpiration to conserve water, limiting their natural cooling and causing surface temperatures to rise above ambient air temperatures.
Which regions are most affected by the temperature gap?
According to the University of Arizona study, arid and tropical ecosystems will experience the most severe impacts, with temperature differences increasing across roughly 81% of vegetated areas.
How does this affect carbon storage?
Higher plant temperatures reduce photosynthesis and weaken the capacity of forests to absorb and store carbon dioxide, which can speed up climate change.
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