Low clouds, which reflect incoming solar radiation and reduce outgoing thermal radiation, have helped to cool the Earth, but their effect cannot be relied upon to continue indefinitely, according to research conducted by scientists at the Department of Energy’s Lawrence Livermore National Laboratory in California. “As the Earth’s surface warms, the net radiative effect of clouds also changes, contributing a feedback to the climate system. If these cloud changes enhance the radiative cooling of the Earth, they act as a negative, dampening feedback on warming. Otherwise, they act as a positive, amplifying feedback on warming,” a LLNL press release explains.
According to the research, “the strength of the cloud feedback simulated by a climate model exhibits large fluctuations depending on the time period. Despite having a positive cloud feedback in response to long-term projected global warming, the model exhibits a strong negative cloud feedback over the last 30 years. At the heart of this difference are low-level clouds in the tropics, which strongly cool the planet by reflecting solar radiation to space.”
