Here's What to Understand About How Climate Change Slows and Intensifies Global Heat Waves
A new study published in Science Advances reveals alarming trends in the behavior of global heat waves, highlighting how climate change is exacerbating their impact on human populations around the world.
The research, led by climate scientists Wei Zhang of Utah State University and Gabriel Lau of Princeton University, indicates that since 1979, heat waves have been moving across the planet at a slower pace, resulting in prolonged periods of extreme heat and higher temperatures over larger geographical areas. The study found that global heat waves are now moving 20% more slowly than they did four decades ago, leading to a 67% increase in their frequency.
Moreover, the intensity of heat waves has also escalated, with temperatures during these events reaching unprecedented levels. The study reveals that the highest temperatures recorded within heat waves are now warmer than they were 40 years ago, and the area covered by a heat dome has expanded significantly.
An analysis of heat wave duration shows a disturbing trend, with events lasting longer than they did in previous decades. Between 1979 and 1983, the average duration of a heat wave was eight days, but by the period from 2016 to 2020, this had increased to 12 days.
Eurasia has been particularly hard hit by prolonged heat waves, while Africa has experienced a slowdown in the movement of these events. Conversely, North America and Australia have witnessed significant increases in both the magnitude and spatial extent of heat waves.
The implications of these findings are profound, as longer-lasting heat waves pose greater risks to human health and well-being. As the co-authors of the study explain, prolonged exposure to extreme heat can have serious consequences, with heat-related illnesses and fatalities becoming more prevalent.
The researchers conducted computer simulations to understand the underlying factors driving these changes in heat wave behavior. Their analysis attributes the worsening heat waves to heat-trapping emissions stemming from the burning of fossil fuels such as coal, oil, and natural gas. By simulating a world without greenhouse gas emissions, the study demonstrates that the observed trends cannot be replicated in the absence of human-induced climate change.
Furthermore, the study explores shifts in atmospheric circulation patterns that contribute to the propagation of heat waves. Weakening atmospheric waves, including the jet stream, are failing to swiftly transport heat waves across continents, resulting in their prolonged presence in affected regions.
