Researchers at the University of California, Riverside have made a groundbreaking discovery about methane, the potent greenhouse gas. While methane is known to trap heat in Earth’s atmosphere, the researchers found that it also creates cooling clouds that offset 30% of the heat. This cooling effect is due to the counterintuitive way that methane absorbs shortwave energy, which causes changes in clouds that have a slight cooling effect. This effect has not yet been incorporated into most climate models, which could have important implications for predicting future climate change.
The greenhouse effect is caused by gases like methane that trap heat from Earth’s surface, preventing it from radiating out into space. This makes the planet hotter, causing global warming. However, methane also absorbs shortwave energy from the sun, which should warm the planet. The researchers found that this shortwave absorption actually encourages changes in clouds that have a slight cooling effect. This means that methane not only warms the planet through the greenhouse effect but also cools it through cloud formation.
The recent study, published in Nature Geoscience, revealed that methane not only traps heat in the atmosphere but also creates cooling clouds that offset 30% of the heat. Moreover, the study found that methane absorbs incoming energy from the sun, known as shortwave energy, which should typically warm the planet. However, the shortwave absorption encourages changes in clouds that have a slight cooling effect. The study also found that methane decreases the amount of solar radiation reaching the Earth’s surface, leading to a decrease in evaporation and subsequently a decrease in precipitation. This creates a disruption in the climate system that has not been fully comprehended until now.
The research team used detailed computer models to simulate both longwave and shortwave methane effects, discovering these findings in the process. In the future, the research team plans to carry out further experiments to investigate the effects of varying levels of methane on the climate. This is an important area of research, as methane emissions have increased in recent years, with much coming from industrial sources, agricultural activities, and landfills. As the frozen ground beneath the Arctic continues to thaw, it is expected that methane emissions will increase.
According to Robert Allen, the lead researcher on the project and an assistant professor of Earth sciences at UCR, this discovery has important implications for understanding how methane and other greenhouse gases can impact the climate system. Shortwave absorption softens the overall warming and rain-increasing effects of methane but does not eradicate them altogether. This means that future climate models need to incorporate all known effects of greenhouse gases to more accurately predict future climate change.
Xueying Zhao, a UCR Earth and planetary sciences Ph.D. student and study co-author, said that methane emissions have become a major concern and that we need to better understand the effects that all this methane will have on our climate by incorporating all known effects into our climate models. Ryan Kramer, a researcher at NASA Goddard Space Flight Center and the University of Maryland, Baltimore County, echoed the need for further study. “We’re good at measuring the concentration of greenhouse gases like methane in the atmosphere. Now the goal is to say with as much confidence as possible what those numbers mean to us. Work like this gets us toward that goal,” he said.
This groundbreaking discovery highlights the importance of continued research into the effects of greenhouse gases on the climate system. While it is clear that greenhouse gases like methane contribute to global warming, this study shows that their effects are more complex than previously thought. By incorporating all known effects into climate models, researchers can more accurately predict future climate change and develop effective strategies to mitigate its impact.