Millions of Americans are once again in the grips of dangerous heat. Last week, Europe was blanketed by heat, making temperatures feel like late summer. India and Pakistan were hit with unrelenting heat in March.
Friederike Otto, senior lecturer in climate science at the Grantham Institute, Imperial College London, said heatwaves in Europe alone had increased in frequency by a factor of 100 or more, caused by human actions in pouring greenhouse gas emissions into the atmosphere.
High temperatures more recently scorched northern and central China even as heavy rains caused flooding in the country’s south. Weather stations around the world have been documenting record-breaking temperatures, and it is just the beginning of summer in the Northern Hemisphere.
Scientists actually were shocked back in March when heatwaves occurred at both of Earth’s poles, raising fears the “unprecedented” events could signal faster and abrupt climate breakdown.
The rapid rising of temperatures at the poles is a sign of the disruption in Earth’s climate systems, with the dangers being two-fold: heatwaves at the poles are a strong signal of the damage humanity is causing to our climate and the melting that could also trigger further cascading changes that will accelerate climate breakdown.
Global warming is making extreme heat more common worldwide, and scientists have been able to prove that these record-breaking temperatures are not a natural occurrence. For example, a team of researchers who studied this spring’s devastating heat in India found that climate change had made it 30 times as likely to occur.
Concurrent heat waves seem to be hitting certain groups of far-flung places with growing frequency of late, for reasons related to the La Nina current pattern, the jet stream, and other rivers of air that influence weather systems worldwide.
The La Nina phase is looking like it will last through winter, and is a “cold event.” During La Niña events, trade winds are even stronger than usual, pushing more warm water toward Asia. This, in turn, pushes the jet stream northward. This tends to lead to drought in the southern U.S. and heavy rains and flooding in the Pacific Northwest and Canada.
Studies have shown that parts of North America, Europe, and Asia are linked this way. Scientists are still trying to determine how these patterns might change as the planet warms further, but for now, it means simultaneous heat extremes will probably continue affecting these places where so much of the world’s economic activity is concentrated.
The thing is – simultaneous weather extremes in numerous locations aren’t just meteorological curiosities. Individual heatwaves can lead to illness and death, wildfires, and crop failures. Concurrent ones can threaten global food supplies.