Alaska's glaciers are melting at an accelerating pace, losing roughly 60 billion tons of ice each year. About 4,000 kilometers to the south, in California and Nevada, records for heat and dryness are being shattered, creating favorable conditions for wildfire events. One major factor contributing to climate change in both regions is the northward shift of winter storm tracks across the North Pacific Ocean. These storms transport heat and moisture from Earth's warmer regions toward the pole; when their tracks shift northward, more heat and moisture reach Alaska, while natural ventilation of the southwestern United States is reduced, driving temperatures upward.
In a new study published today in Nature, Dr. Rei Chemke of the Weizmann Institute of Science's Earth and Planetary Sciences Department and Dr. Janni Yuval of Google Research show that the storms' northward shift is occurring much faster than climate models have predicted. Moreover, using a new metric based on sea-level pressure - a parameter measured consistently for decades - the researchers found that this shift is not part of natural climate variability but rather a clear consequence of climate change.
""The fact that models fail to capture the effect of climate change on the northward shift of storm tracks suggests that changes may be more dramatic than we expect"
The findings add to a series of Chemke's previous studies pointing to a troubling pattern: Earth's storm tracks are changing rapidly, and climate models don't always account for that. "Our preparedness for future climatic change relies on the ability of models to make accurate predictions," Chemke says. "The fact that models fail to capture the effect of climate change on the recent northward shift of storm tracks - and its consequences for western North America - suggests that changes in this region may be even more dramatic than we currently expect."
