Wildfire and weather extremes: it’s not a coincidence, it’s climate change


Arguably on the heels of the West Coast Intense heat wave The most frightening part of the horrific wildfire has occurred in recent memories in modern history. Meanwhile, just a few hundred miles east, A. 60 degree temperature drop Wyoming and Colorado had just over 18 hours with an extremely rare late-summer dumping of up to 2 feet Snow.

This is not a coincidence, it is climate change.

Of this type Dystopian weather eventsAt the same time, this is often the case, as scientists have been warning for decades. While extreme weather is a part of the natural cycle, the speed and frequency of these recent extremes, scientists say, is evidence of an acceleration of climate effects, some of which were underestimated by climate computer models.

“This is another example where uncertainty is not our friend,” says Michael Mann, a distinguished professor of atmospheric science at Penn State. “As we learn more, we are finding that many climate change impacts, including these types of weather, are playing out faster and with greater magnitude than our models have predicted.”

On Wednesday, NOAA released its latest State of the Climate report, which found that the US faced four different billion-dollar disasters during the month of August: two hurricanes, vast forests, and an extraordinary Midwest derecho.

One such extreme event could strain emergency resources – a situation West Coast firefighters now find themselves in. However, in two dramatic cases this summer, the nation was hit together by concurrent disasters, some of which were no precedent in modern history. This is a concept scientists have called compound events, and these configurations in future projections are necessary to properly estimate risk, response, and resources.

The west encountered an extended heat wave in mid-August, which saw an increase in Death Valley 130 degreesThe hottest temperature ever measured reliably on Earth. Tinderbox conditions, along with a rare lightning outbreak caused by the heat, led to the first round of California’s major wildfires this season, spreading to one of the four largest fires in state history. A powerful almost at the same time derecho Due to billions of dollars of damage in Iowa and Illinois, and Hurricane Laura pledged as Category 4 in the Gulf Coast of Louisiana with 150 mph winds and 16 feet of hurricanes.

Just three weeks later, and here we are again. Experienced California this past weekend Even more intense heat waveAlong the southern part of the state, for the first time in record-keeping history, it hit 121 degrees west of the mountains. Primarily, the fire erupts due to the scorching heat and drying, and then intensifies as the weather cools early in the season – which is also bringing heavy snow to the Rocky – a breeze through the mountains and valleys of the Intermountain Brings the incident to the west.

In Washington State, an approximate 330,000 acres burnt Statewide on Monday, exceeding the total in each of the last 12 fire seasons. California has seen a record 2.3 million acres of burns so far this year – more than 3 times for a full season (typically July through November), and 7 times more than a normal year.

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NASA’s image shows smoke forests and scarlet forests in Western America

NASA


If it were just a season of fire, it could have chalked the peak up to a mere coincidence. But scientists say that this is part of a continuing upward trend, which has been elucidated by data and is well understood by science.

“There is little doubt that we have been witness to an acceleration of fire activity in the West – be it in reference to the burnt area, the number of large fires, the increase of fires and the direct and indirect effects of people,” explains Dr. John Abatzoglou, California Climate Professor at the University of Mered.

The acceleration has been dramatic. The fire season is now two to three months longer than it was a few decades ago in some parts of the West. Since the 1970s, California has experienced a five-fold increase in annual burn area and an eight-fold increase in summer wildfire limits. Since 2000, at least 17 of California’s top 20 largest wildlife have been burned.

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Growth of wild forest-lit areas in California from 1975 to 2015.

Williams, Abatzoglou et al., Earth’s future


Abatzoglou clarifies that there are several factors – not just climate change – that contribute to the increase in fire activity. These include the growing settlement of people in the lands affected by the fire and the legacy of fire suppression in many low-altitude forests, which led to a huge growth of trees and brush.

“We can focus on the bad luck of Lightning siege Around the San Francisco Bay Area, or crowd of Stupid human trick The major forest fires scorched, but a confluence of long-term and short-term environmental factors set the table for the 2020 fire season, ”he said.

In other words, although climate change does not cause heat waves or fires, it sets the stage so that when conditions begin to ripen, such as summer and fall 2020, heat waves are more intense and fires are more severe. Is jealous of

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Climate central


This summer has been extremely hot and dry in the West. According to NOAA, Arizona, California, Colorado, Nevada, New Mexico and Utah each had their warmest August on record. Research has found that heat waves are now larger, becoming more intense and permanent than they were decades ago. Especially in California, extreme heat waves – like in recent weeks – are now 3 to 4 degrees Fahrenheit due to climate change. By 2080, the same study found that such heat waves would accelerate from 3 to 5 degrees.

This week’s NOAA report also found that the same general area in the west also experienced one of its best August on record. This short-term drought and hot pattern is mainly due to natural cycles in the weather, and has the greatest impact on the amount of area burned from season to season as it determines how dry the forests and brush are.

“Across the West American forests, we find that the climatic measures of fuel drying out reflect year-over-year variability in the burned area – highlighting that the climate is very hot during dry-summer summers. Enabling and preventing widespread fire activity. In the cool-wet summer, “Abzoglu explains.

But for a long time, human-climate change is slowly drying up the atmosphere and fuel. “Observed change in fuel dryness [plus the] “The number of days of high fire danger in the American West has increased especially in the last half century,” says Abatzoglou.

Warmer weather in the West has warmed to 2 to 3 degrees Fahrenheit since the 1970s. This excess heat has increased the evaporation of moisture from the surface. While there is also some increase in atmospheric humidity, it has not increased nearly as rapidly. This caused prolonged “moisture loss” and has accelerated the rate of leaf drying. This is part of the reason that, according to research, the West has entered one of the worst megadroughts In the last 1,200 years.

A recent study, co-authored by Abzoglu, found a direct link with Almost all Growth in summer forest-fire zone during the period 1972–2018 induced by moisture deficiency. Just to illustrate how effective moisture loss is, as now Unprecedented wildfires Out of control, the majority of Western America has deficit deficits at record levels

one more A recent study Since the 1980s it was found that since the 1980s, the frequency of autumn days with extreme fire conditions has doubled from a combination of low rain and warm temperatures.

But many scientists believe that sports contribute more to this extreme weather than the direct effects of warming and drying. One of those mechanisms is the indirect effect of global warming on the most influential weather-maker on day-to-day conditions: the jet stream.

The speed and orientation of the jet stream – a river of rapidly flowing air streams in the atmosphere – determines the track, intensity, and forward speed of most storm systems and also tells how cold or hot the weather is. The characteristics of a jet stream at any given time are largely determined by the placement of hot and cold air masses and the strength of the gradient between them. Because the Arctic has been three times warmer than the rest of the world, climate scientists know that human-caused climate change is throwing the jet stream off-kilter. But how and to what extent is not fully understood.

Many climate scientists believe that a hot Arctic is slowing down the jet stream during certain times of the year, resulting in a more wavy jet stream. As shown below, a wavy jet stream can drive warm air northward into the Arctic and drive cold air southward. This is exactly what happened during the Holocaust Mid-west floods in 2019 And we have this kind of pattern right now, leading to record low temperatures and very early snowfall in the Rocky and Plains. A wavy jet stream is a normal part of nature, but climate change can make it more amplified, resulting in more extremes.

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Mann explains, “I think it’s a triple fume – heat and drought, which favor climate change, and the added added component is the slow, wavy jet stream.” But they state that the wavy jet stream is not well resolved by the current model, thus they reduce the peak of weather events aggravated by climate change.

As a result, when scientists dig into the causes of an extreme event, Mann says studies reduce the effects of human-caused climate change. “If anything, climate change studies are likely to underline the role that climate change is playing with these persistent extreme weather events,” he said.

For future fire seasons, Abjoglu says that we should expect the peak fire season of 2020 to be the rule rather than the exception.

He added, “However, the extent of fire siege going on in the West is the highest. The alignment of material to such fire seasons is becoming more favorable as a result of climate change and land-use practices.” “We should expect similar years to move forward, adapt and prepare.”

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