A new study that endeavored to link realtime weather events to climate change suggests an accumulation of greenhouse gases may underlie the precursor for the next El Nino weather event with this year's California drought and polar vortex.
A new study to be reported in the next issue of Geophysical Research Letters suggests for the first time that both the California drought and the polar vortex, two extreme weather outcomes from this past winter season, are linked to the same underlying cause: climate change as a result of warming with the accumulation of greenhouse gases. The recent winter was accompanied by severe dry conditions in the West and unusually severe winter conditions in the Midwest and Eastern Seaboard. All of California is officially in a state of drought, but the other areas have finally escaped their relentless wintery conditions.
The new study, headed by scientists at Utah State University, identified a weather “dipole,” or combination of a strong Western high pressure ridge with a deep Great Lakes region low pressure trough. The dipole is related to cold water along the China coast–a recently found precursor to El Nino, a cyclic weather pattern over the Pacific Ocean that influences weather worldwide. This El Nino precursor, in turn, is thought to be a result of an accumulation of heat-trapping greenhouse gases in the atmosphere, the study others propose.
“It’s like a complex game of weather dominos that starts with cold water off China and ends with a devastating drought and memorable winter in the United States,” said study author Simon Wang, a Utah State University climate scientist.
Wang and colleagues examined the colder water near China and how it triggers westerly winds in the tropical Pacific. These winds persist and push warm water the central Pacific where El Nino forms every several years. Wang drew a connection between this El Nino precursor and the unusual weather patterns in the U.S. He modeled the patterns with and without gases from the burning of fossil fuels and with them, his model produced patterns very similar to what have been observed.
The study has created both praise and criticisms in the field of climatology, and a consensus on how accurate the findings are is still pending.