The Penn State Department of Geography will host Laifang Li, assistant professor of meteorology and atmospheric science at Penn State, as part of its spring 2025 Coffee Hour lecture series. Li's talk, "Changing Atmosphere Cools the Subpolar North Atlantic Throughout the Past Century," will explore why a region of the North Atlantic has been cooling for decades despite global warming.
The talk will take place from 3:30 to 4:30 p.m. on Friday, Feb. 7, in 112 Walker Building on the University Park campus and will also be accessible via Zoom.
"For more than a century, an area of the North Atlantic, known as the 'cold blob' or 'warming hole,' has been cooling, which contradicts the broader trend of rising global temperatures," Li said. "Many scientists have suggested this cooling is caused by a slowing of the Atlantic Meridional Overturning Circulation (AMOC), a system of ocean currents that transports warm water from the tropics to the North Atlantic."
However, Li's research presents an alternative explanation, arguing that changes in wind patterns and storm activity have had a far greater impact than previously thought. Using historical weather data and climate models, Li found that shifts in atmospheric conditions, specifically, a long-term increase in strong winds and storminess, have been driving the cooling. These winds increase heat loss from the ocean to the atmosphere and disrupt ocean currents in ways that reinforce the cooling effect. Her findings suggest that the role of AMOC in controlling ocean temperatures may be overstated in many climate models and that scientists may need to reconsider how they use past ocean temperatures to estimate changes in ocean circulation.
Li earned her doctorate in climate dynamics from Duke University in 2014. She conducted postdoctoral research at the Woods Hole Oceanographic Institution, focusing on ocean salinity and the global water cycle. She joined Penn State as an assistant professor in 2020.
