Plants Are "Leaking" - A Threat That Could Worsen Global Warming

Scientists have discovered that plants are releasing more carbon than expected, a process dubbed “leaking,” which could accelerate global warming. This unexpected carbon release challenges previous climate models and raises concerns about its long-term impact on the environment. Understanding this phenomenon is crucial in addressing climate change and developing effective strategies for carbon management.

Rising temperatures force plants to lose more water, reducing their ability to absorb carbon. This shift could transform plants into carbon sources, intensifying climate change.

Plants play a vital role in maintaining Earth's climate, but new research indicates that increasing temperatures may disrupt this balance. Scientists have found that plants release more water than previously thought, which could significantly impact climate predictions.

Dr. Sean Michaletz, an assistant professor at the University of British Columbia and a Sloan Research Fellow in botany, investigates how plants respond to heat. His research challenges traditional beliefs about plant water loss and could reshape climate models.

Plants are essential to life on Earth. Through photosynthesis, they absorb carbon dioxide and release oxygen and water vapor. Since carbon dioxide is a primary driver of global warming, understanding how temperature affects this process is crucial for climate predictions.

It was once believed that plants primarily lose water through small pores that close in extreme heat. However, research now shows that as temperatures rise, plants also lose significant amounts of water through their waxy outer layer, which cannot close. The thinner the waxy layer, the more water is lost.

This means that during extreme heat, plants continue losing water but struggle to absorb carbon dioxide, reducing their ability to perform photosynthesis. If temperatures become too high, plants may even release more carbon than they absorb, worsening climate change.

Preliminary calculations suggest that a medium-sized leaf exposed to 50°C could lose about one-third of a teaspoon of water daily through its waxy layer. On a larger scale, entire forests could experience drastic shifts in water and carbon cycles - effects that may not be fully accounted for in current climate models.

Another study of 200 plant species in Vancouver revealed that photosynthesis begins to fail between 40°C and 51°C. During the 2021 heat dome, temperatures reached 49.6°C, pushing plants to their limits.

Research suggests that plants may survive up to 60°C, beyond which their proteins break down, leading to cellular damage and death. Only a few desert and tropical species have been observed surviving at such extreme temperatures.

Scientists worldwide are trying to determine the tipping point at which vegetation emits more carbon dioxide than it absorbs. Current estimates suggest this could occur around 30°C, though factors such as microclimates and water availability introduce uncertainties.

With global temperatures already averaging 16°C, understanding these thresholds is critical for predicting climate change feedback loops and the future of ecosystems.

Research at Biosphere 2, a closed ecological experiment, offers insights into how extreme temperatures affect plant survival. Originally designed to test human self-sufficiency, the project faced unexpected challenges such as carbon dioxide buildup and psychological stress among participants.

Plants have adapted to climate shifts for millions of years, but they are still subject to physical limits. While some species are more heat-tolerant, the exact point at which plants reach their survival threshold remains uncertain. Recent findings suggest we may be approaching that limit sooner than expected.

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Source: scitechdaily‍