From deadly floods in Louisiana to an "explosive" wildfire in California, the impacts of the climate change are being felt across the United States this week.
Neither extreme weather event can be exclusively blamed on global warming. But record-breaking heat, warmer oceans, and drier brush—all linked to man-made climate change—are certainly contributing factors.
"Climate change is never going to announce itself by name. But this is what we should expect it to look like," declared Jonah Engel Bromwich at the New York Times, referring to the flooding in southern Louisiana, which has been called the worst natural disaster to strike the U.S. since Superstorm Sandy.
In fact, current analyses suggest that—as was the case in 2012—greenhouse gas emissions and resultant climate change at the very least increased the severity of the storm that brought on the flooding.
InsideClimate News reported Wednesday:
Of the two factors that made Louisiana's storm so devastating, one (increased moisture in the air) wears the fingerprints of man-made climate change from mostly fossil-fuel burning, while the other (how slowly the storm was moving) is not so easily explained.
"This storm is a good example of why we care about a changing climate," said Katharine Hayhoe, a climate scientist at Texas Tech University, "because Louisiana is a place that is already at risk of flooding and climate change is taking the risk that we already face, and it's exacerbating" the threat.
[...] "With such a warm year, you're going to see much higher-than-average sea surface temperatures," Hayhoe said. Those water temperatures, in this case the Gulf of Mexico where the storm system formed on Aug. 7, mean the air above it has more than its usual share of water vapor, Hayhoe explained.
Added Weather Underground's Bob Henson and Jeff Masters in a blog post on Monday:
The storm system carried near-record amounts of atmospheric moisture, drawn from the Gulf of Mexico and northwest Atlantic, where sea-surface temperatures are well above average. Climate change has already been shown to increase the amounts of rain falling in the most intense events across many parts of the world, and extreme rainfall events like this week's Louisiana storm are expected to grow increasingly common in the coming years.
Indeed, wrote Gulf Coast mother and activist Cherri Foytlin on Thursday, "This type of storm is far from normal—but it could become normal if we don't act now."
"Across the region, tens of thousands of people have been evacuated, thousands of homes damaged, and at at least eleven people killed," wrote Foylin, who serves as state director of climate action group Bold Louisiana. "This fills my heart with both a deep sadness and deep anger—at the fossil fuel companies driving this ongoing crisis, and at an [Obama] administration that continues to sell them the right to do so."
As evidence, Foytlin pointed to the looming auction of "an area the size of Virginia for offshore drilling in the Gulf of Mexico"—and called for President Barack Obama to call off the auction "and stop treating the Gulf Coast like a sacrifice zone."
Meanwhile, on the West Coast, the Blue Cut fire now covers close to 50 square miles, threatening more than 34,000 structures and forcing the evacuation of more than 82,500 people.
California Gov. Jerry Brown has declared a state of emergency for the fast-moving wildfire, which was only 4 percent contained as of early Thursday morning.
Higher spring and summer temperatures and earlier spring snow-melt typically cause soils to be drier for longer, increasing the likelihood of drought and a longer wildfire season, particularly in the western United States.
These hot, dry conditions also increase the likelihood that, once wildfires are started by lightning strikes or human error, they will be more intense and long-burning.
"Climate change has exacerbated naturally occurring droughts, and therefore fuel conditions," Robert Field, a research scientist at NASA's Goddard Institute for Space Studies," told Climate Central earlier this year.
And the New York Times reported Wednesday:
Richard Minnich, a professor in the department of earth sciences at the University of California, Riverside, said it was not so much the long-term drought, but the weather of the day — coupled with a prevailing fire management strategy in which, he said, small fires are knocked down quickly but larger ones can grow more out of control — that had driven the fire.
The low humidity, Mr. Minnich said, had dried out shrubs and bushes — known as chaparral — making them as flammable as a carpet.
“It’s got a reputation for burning explosively,” he said of the chaparral, adding, “As soon as it’s blowing up like that, the capacity to stop the fire goes to zero.”
Furthermore, a new Yale-led study conducted with collaborators from Harvard showed just this week that "a surge in major wildfire events in the U.S. West as a consequence of climate change will expose tens of millions of Americans to high levels of air pollution in the coming decades."
As an observer noted on Twitter, with more than 80,000 people currently under evacuation orders in California and 30,000 more displaced in Louisiana, "one might say there are over 100k climate refugee[s] in the US right now."