Slowing Atlantic Current Could Intensify California Storms

A significant Atlantic Ocean current is slowing, potentially impacting weather patterns far beyond the Atlantic. New research suggests this change could strengthen powerful storms along the California coast. It could also reduce snowfall over Greenland.

The Atlantic Meridional Overturning Circulation (AMOC) is a vast system of ocean currents. It transports warm tropical water northward. This process helps maintain mild temperatures in regions like Europe. The water then cools, becomes denser, and flows southward along the ocean floor.

Researchers at the University of California, Riverside, found that a weakening AMOC could alter ocean temperatures. These changes would affect how much moisture the atmosphere can hold. The study also indicates that high-altitude winds, which guide storms, could strengthen across the Northern Hemisphere.

Stronger winds would direct more moisture toward the West Coast of North America. This would increase the intensity of atmospheric rivers. Atmospheric rivers are long, narrow bands of water vapor. They transport moisture from tropical regions to higher latitudes. These systems provide a large portion of California's water supply.

However, stronger atmospheric rivers also pose a risk of severe flooding and widespread damage. Climate modeling projects more atmospheric rivers along the eastern coast of South America and near Antarctica. Conversely, Greenland would experience fewer storms, leading to less snowfall and slower ice accumulation.

These projected changes are based on a high greenhouse gas emissions scenario. In this scenario, the AMOC continues to weaken throughout the century. Reducing greenhouse gas emissions could limit these effects on the AMOC and future rainfall patterns.