That Heat Dome? Yeah, It’s Climate Change.
and Dr. Mann is a professor of atmospheric science and the director of the Earth System Science Center at Penn State. He is the author of : The Fight to Take Back Our Planet Ms. Hassol is the director of the nonprofit organization Climate Communication. She publishes the series with the American Association for the Advancement of Sciences SciLine on the connections between extreme weather and climate change. In the old days, we could escape the summer heat by heading north to the Adirondacks in the East or to the cool, forested Pacific Northwest in the West. But this is your grandparents climate. And though were only one week into official summer, the characteristically cool Pacific Northwest has turned into a caldron of triple-digit temperatures, with Portland, Ore., and Seattle reaching record highs of 115 and 108 degrees, respectively. Thats unseasonably hot for Phoenix. The western United States is currently under the influence of an epic heat dome, an expansive region of high atmospheric pressure characterized by heat, drought and heightened fire danger. Its being called a event, which means you might have expected to witness it once during your lifetime if you happen to be Methuselah of biblical fame. All bets are off when one accounts for human-caused warming. It no longer makes sense to talk about a once-in-a-century or once-in-a-millennium event as if were just rolling an ordinary pair of dice, because weve loaded the dice through fossil fuel burning and other human activities that generate carbon pollution and warm the planet. Its as if snake eyes, which should occur randomly only once every 36 times you roll a pair of dice, were coming up once every four times. Might a heat dome have developed out West this past week without climate change? Sure. Might it have been as extreme as what were witnessing without climate change? Almost surely not. If we step back a bit, we see a disturbing pattern. With this latest heat wave, Canada observed : 116 degrees in British Columbia. Less than a year ago, the United States set its own record the highest temperature reliably recorded on the entire planet, in fact with a 130 degree in Death Valley in Southern California. Yes, the dice have been loaded, and not in our favor. If climate change were a casino, wed be hemorrhaging cash. Wildfires, heat waves, floods and superstorms, many exacerbated by climate change, nearly $100 billion in 2020. As the climate advocate so poignantly put it, Our house is on fire. Weve long known that a warming climate would yield more extremely hot weather. The science is clear on how human-caused climate change is already affecting heat waves: Global warming has caused them to be hotter, larger, longer and more frequent. What were once very rare events are becoming more common. Heat waves now occur as they did in the 1960s on average at least six times a year in the United States in the 2010s. Record-breaking hot months are occurring than would be expected without global warming. And heat waves have become larger, affecting in the Northern Hemisphere than they did in 1980; including ocean areas, heat waves grew 50 percent. These changes matter because extreme heat is the deadliest form of extreme weather in the United States, on average than hurricanes and floods combined over the past 30 years. Recent research projects that in the Pacific Northwest by 2100 unless aggressive action is taken to reduce heat-trapping greenhouse gas emissions. Some still refuse to acknowledge the dire warning that Mother Nature is sending us. They say the science is to take action. But uncertainty, if anything, is a reason for taking even more significant action to reduce carbon emissions. Uncertainty is not our friend. And the current heat dome is an excellent example of why. The heat wave afflicting the Pacific Northwest is characterized by what is known as an omega block pattern, because of the shape the sharply curving jet stream makes, like the Greek letter omega (). This omega curve is part of a pattern of pronounced north-south wiggles made by the jet stream as it traverses the Northern Hemisphere. It is an example of a phenomenon known as wave resonance, which scientists (including one of us) have shown is by the considerable warming of the Arctic. By decreasing the contrast in temperature between the cold pole and warm subtropics, the amplified warming of the Arctic causes the jet stream to slow down and, under the right circumstances, like the ones , settle into a very wiggly and rather stable configuration. That, in turn, allows very deep high pressure centers, like the current heat dome, to remain locked in place over a region, as it is over the Pacific Northwest. Those climate models that the critics claim are alarmist of reproducing this phenomenon. That means that the models do not account for this critical factor behind many of the persistent and damaging weather extremes weve seen in recent years, including the heat dome. But there is a way out of this nightmare of ever-worsening weather extremes, and its one that will serve us well in many other ways, too. A rapid transition to clean energy can stabilize the climate, improve our health, provide good-paying jobs, grow the economy and ensure our childrens future. The choice is ours. is a professor of atmospheric science, the director of the Earth System Science Center at Pennsylvania State University and the author of : The Fight to Take Back Our Planet is the director of the nonprofit organization Climate Communication. She publishes the series with the American Association for the Advancement of Sciences SciLine on the connections between extreme weather and climate change.