Climate chaos: Extreme heat, wildfires and record-setting storms suggest a frightening future is already here
2020 has been quite a rollercoaster year.
It seems the main problem is there is more heat available. There is also a "vapor pressure deficit," something I didn't know of before.
And it's not just in California. The Midwest and Gulf Coast states are affected as well.
Things are looking pretty grim.
From the historic heat wave and wildfires in the West, to the massive derecho that tore through the middle of the nation, to the record-breaking pace of this year's hurricane season, the unprecedented and concurrent extreme conditions resemble the chaotic climate future scientists have been warning us about for decades — only it's happening right now.
While climate catastrophes are typically spaced out in time and geographic location, right now the U.S. is dealing with multiple disasters. The Midwest is cleaning up from a devastating derecho that caused nearly $4 billion in damage to homes and crops, as nearly a quarter-million people in the West are under evacuation orders or warnings from fires that have burned over 1 million acres, and at the same time residents along the Gulf Coast are bracing for back-to-back landfalls of a tropical storm and hurricane.
"This current stretch of natural catastrophe events in the United States are essentially a snapshot of what scientists and emergency managers have long feared," says meteorologist Steven Bowen, the head of Catastrophe Insight at AON, an international risk mitigation firm.
2020 has been quite a rollercoaster year.
To be sure, these events are not all related to each other, but the one thing they do have in common is that climate change makes each one more likely. The simple explanation is that there's more energy in the system and that energy is expended in the form of more extreme heat, fire, wind and rain.
Daniel Swain is a well-known climate scientist who specializes in studying the link between climate change and weather in the West at the University of California, Los Angeles. In a blog post he described how even someone like him, well-versed in climate disaster, is shocked by the current situation: "I'm essentially at a loss for words to describe the scope of the lightning-sparked fire outbreak that has rapidly evolved in northern California – even in the context of the extraordinary fires of recent years. It's truly astonishing."
While it's not rare for tropical moisture to invade California, it is infrequent, and extremely unfortunate that it happened during one of the worst western U.S. heat waves in recent history, not to mention an ongoing short- and long-term drought. Researchers believe that in the year 2000 the western U.S. entered a megadrought, one of the worst in the past 1,200 years.
This is why climate scientists often say that climate change "loads the dice" for extreme weather. The cause of the fires is not climate change, but many of the factors which set the stage and made conditions ripe for fire ignition and spread are a direct result of a warming climate.
On August 16, Death Valley reached 130 degrees Fahrenheit, the highest temperature ever reliably measured on Earth. It was just a small part of a monster heat wave which broke hundreds of heat records over a two-week span. The link between heat waves and climate change is straightforward, and multiple studies have shown that a warmer climate is making heat waves more likely and more intense.
It seems the main problem is there is more heat available. There is also a "vapor pressure deficit," something I didn't know of before.
"Basically there is more heat available: Earth's energy balance is out of whack," says Trenberth. That extra heat energy, trapped in the atmosphere by excess greenhouse gases from the burning of fossil fuels, must be used up in some way.
Trenberth explains, if the land was wet the heat would be used first to evaporate water, keeping air temperatures moderate. But when the air and ground are bone dry, as is typical of the dry season in California — especially in summers like this — the excess heat energy is expended by drying out the brush and warming and drying the air.
This long-term drying out of the air has created a "vapor pressure deficit" — or in simpler terms, a moisture deficit. According to a 2019 study, this is a leading reason for the intensified summer fire seasons in California, presently at record levels.
"Vapor pressure deficit" (gap between how much moisture *could* be in the air vs. how much is *actually* there) is key determinant of wildfire risk, and is increasing in a warming climate. This week, VPD in California reached highest Aug. levels in at least 40 yrs.
And it's not just in California. The Midwest and Gulf Coast states are affected as well.
Midwest derecho
A derecho is a particularly fierce and long-lasting line of thunderstorms, often causing winds over 75 mph. While these weather events are common during summer, the event that took place August 10 in Iowa and Illinois seemed otherworldly.
The squall line plowed a path 800 miles long and 40 miles wide through communities and corn fields, damaging 43% of Iowa's corn and soybean crop and causing nearly $4 billion in damage. Winds are estimated to have reached up to 140 mph, with hurricane-force winds lasting 40 to 50 minutes.
Hurricane season
Having two tropical systems like Marco and Laura in late August, the beginning of the peak of hurricane season, is not abnormal, even if the storms are very close to one another. But what is abnormal is the record-setting pace of the current hurricane season. So far the Atlantic season has tallied 14 named storms, 10 days ahead of record pace. That's two more than the average number for an entire season, which runs through the end of November. Seasonal forecasters are predicting up to 25 named systems this year, which would place second behind 2005.
Things are looking pretty grim.