The redistribution of rainfall predicted by climate change modeling is playing out in real life, a new study by Lawrence Livermore National Laboratory has found.
The research, published Monday in the journal Proceedings of the National Academy of Sciences, is the first study to find the signal of climate change in global precipitation shifts across land and sea. According to The Australian, large-scale studies to date have overlooked the 77 percent of global rainfall that occurs over the oceans.
The initial change has resulted in wet areas, such as the tropics, becoming wetter, while drier regions such as deserts have become more arid. The effect is expected to worsen as climate change continues to worsen.
According to the study, greenhouse gasses affect the distribution of precipitation through two mechanisms. Increasing temperatures that are expected to make wet regions wetter and dry regions drier (thermodynamic changes) and changes in atmospheric circulation patterns will push storm tracks and subtropical dry zones toward the poles.
“Both these changes are occurring simultaneously in global precipitation and this behavior cannot be explained by natural variability alone,” said lead author Kate Marvel. “External influences such as the increase in greenhouse gases are responsible for the changes.”
The study also found that ozone depletion had played a significant role in the movement of atmospheric circulation patterns toward the poles.
Marvel and colleagues reviewed more than 30 years of data, including NASA satellite information and rain gauge measurements, in an effort to overcome the complications of the local nature of rainfall patterns and natural precipitation phenomena such as El Nino.
The paper says new rainfall patterns are one of the most significant potential consequences of climate change because water is the most important natural resource and many societal and natural impacts of climate change will depend on the response to changes to the hydrological cycle.