Atmospheric rivers

If I asked you to name the deadliest single-event natural disaster to strike the western half of the United States in recorded history, what would you answer?

If I had to hazard a guess, most people are going to suggest the 1906 San Francisco earthquake.  This was a bad one, no doubt about it; an estimated three thousand people died, and most of the city was destroyed by the quake and the fires that followed it.  Another one that might come to mind is the eruption of Mount Saint Helens in 1980, but that one comes in a distant follower at fifty-seven casualties.

The worst natural disaster in the western United States -- by a significant margin -- is one a lot of people haven't heard of.  In the winter of 1861-1862, an atmospheric river event turned the entire Central Valley of California into an enormous lake, submerging once dry land under as much as ten meters of water.  Over a period of forty-five days, a hard-even-to-imagine three meters of rain fell in the Sierra Nevada Mountains and the surrounding area, draining down into the lowlands far too fast to run off.  Rivers overflowed their banks; some simply vanished under the expanding lake.  Although the middle part of the state bore the worst of it, devastating floods were recorded that year from northern Oregon all the way down to Los Angeles.

The exact death toll will probably never be known, but it's well over four thousand.  That's about one percent of the entire population of the state at the time.

A man named John Carr, writing in his memoir thirty years later, had this to say:

From November until the latter part of March there was a succession of storms and floods... The ground was covered with snow a foot deep, and on the mountains much deeper...  The water in the river ... seemed like some mighty uncontrollable monster of destruction broken away from its bonds, rushing uncontrollably on, and everywhere carrying ruin and destruction in its course.  When rising, the river seemed highest in the middle...  From the head settlement to the mouth of the Trinity River, for a distance of one hundred and fifty miles, everything was swept to destruction.  Not a bridge was left, or a mining-wheel or a sluice-box.  Parts of ranches and miners cabins met the same fate.  The labor of hundreds of men, and their savings of years, invested in bridges, mines and ranches, were all swept away.  In forty-eight hours the valley of the Trinity was left desolate.  The county never recovered from that disastrous flood.  Many of the mining-wheels and bridges were never rebuilt.

Many of the smaller towns never were, either.

Lithograph of K Street, Sacramento, California, in January of 1862 [Image is in the Public Domain]

What seems to have happened is that in rapid succession, a series of narrow plumes of moist tropical air were carried in off the Pacific.  These "atmospheric rivers" can carry an astonishing amount of water -- some of them have a greater flow rate than the Amazon River.  When they cross over land, sometimes they dissipate, raining out over a wide geographical area.  But the West Coast's odd geography -- two mountain ranges, the Coast Range/Cascades and the Sierra Nevada Mountains, running parallel to each other with a broad valley in between -- meant that as those plumes of moisture moved inland, they were forced upward in altitude (twice).  The drop in pressure and temperature as the air rose caused the water to condense, triggering a month-and-a-half-long rain event that drowned nearly the entire middle of the state.

The reason I bring this up is because the geological record indicates the Great Flood of 1861-62 was not a one-off.  These kinds of floods hit the region on the order of once every century or so.

Only now, the Central Valley is home to 6.5 million people.  And one of the predictions of our best models of climate change is that the warm-up will make atmospheric river events more common.

When people think of deadly disasters, they usually come up with obvious and violent ones like earthquakes and volcanoes.  Certainly, those can be horrific; the 1976 earthquake in Tangshan, China killed an estimated three hundred thousand people.  But the two most dangerous kinds of natural disasters, both in terms of human lives lost and property damage, are flooding and droughts -- two opposite sides of the climatic coin, and both of which are predicted to get dramatically worse if we don't somehow get a handle on the scale of fossil fuel burning.

I saw a quip making its way around social media a while back, that every disaster movie and horror flick starts with someone in charge ignoring a scientist.  There's some truth to that.  Unfortunately, we've not been very good at taking that message to heart.  We need to start listening -- and fast -- and learning from the lessons of the past.  Disasters like the Great California Flood will happen again, and now that we've stomped on the climatic accelerator, it will likely be sooner rather than later.

Let's hope we don't close our eyes to the potential for a catastrophe that will dwarf the one of 170 years ago by several orders of magnitude.

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Cliffs of ice and rivers in the sky

One of the most frustrating things is that instead of meeting the challenges we have and then moving forward, we seem to be fighting the same battles over and over and over.  It's like running on a treadmill, except instead of getting aerobic exercise, all you get is high blood pressure and an ulcer.

It will come as no surprise that I'm once again referring to anthropogenic climate change, which has such a mountain of evidence behind it that there is no argument any more.  Or there shouldn't be.  But all it takes is Some Guy On The Internet making a comment that amounts to "Nuh-uh, is not," and all of the science deniers give him a standing ovation and say, "See, we told you."

The latest in the long line of unqualified anti-science types acting as if their pronouncements somehow outweigh actual research is a tweet from Matt Thomas claiming that the eruption of Mt. Merapi in Indonesia in 2020 exceeded all of the human-generated carbon dioxide ever emitted.  Thomas said, "This volcano just spewed more CO2 than every car driven in history.  Climate change is natural.  Taxing us into poverty isn’t the answer."

Despite the fact that this isn't just false, it's false by several orders of magnitude, it immediately started a Greek chorus of "Climate change is a hoax!" from all the self-appointed climatologists on Twitter.  The tweet got over a hundred thousand likes, and the video link he provided got millions of views.  I've seen it posted on social media dozens of times myself, always to shouts of acclamation.  Very few people responded the way I did, which was to say, "You, sir, are a dangerous idiot."  It seems like a lot of the people who actually trust science have been wearied to the point of exhaustion, and we're just not taking the bait any more.

And it's not like the numbers aren't out there to confirm Thomas's dangerous idiocy.  Anyone with a computer and access to scientific databases on the internet can check his figures, and see that he's not just in left field, he's so far away he couldn't see left field with a powerful telescope.  In an average year, all the volcanic activity in the world releases about 0.3 gigatons of carbon dioxide; the carbon dioxide released in one year from vehicular exhaust is ten times higher than that.  (Note that this is all the emissions from all the volcanoes in a year, as compared to vehicular emissions in a year; Thomas was claiming that one volcano exceeded the emissions of all the automobiles ever created.  I guess if you're gonna lie, you may as well make it a doozy.)

So instead of trusting Some Guy On The Internet, let's look at what the actual science is saying.  How's that for a novel idea?

Just last week there were three studies that in a sane world, would alarm the hell out of everyone, but for some reason, have barely caused a blip on the radar.

First from the University of Tsukuba (Japan), we have a study showing that a scary meteorological phenomenon called an atmospheric river is predicted to spike in frequency, especially in east Asia.  Atmospheric rivers are pretty much what they sound like; narrow, fast-moving bands of extremely humid air, that undergo what's called adiabatic cooling when they run into land that has a higher elevation.  This forces the air upward, causing the volume to expand and the temperature to drop -- and all of that moisture condenses as rain or snow.

We're not talking insignificant amounts of water, here.  An atmospheric river, propelled by a typhoon a thousand kilometers to the east, struck Henan Province in China last year.  The amount of rainfall they received is, honestly, hard to imagine.  In three days the city of Zhengzhou got sixty centimeters of rainfall -- about equal to its average annual precipitation.  In some places in the region, the rainfall rate exceeded twenty centimeters per hour.  Over three hundred people died in the floods, and the damage was estimated at twelve billion dollars.

And this phenomenon isn't limited to east Asia.  Want it brought home to you, Americans?  This same phenomenon has been known to strike other places with strong on-shore air currents driving into lowland areas bounded by steep climbs in elevation -- like the Central Valley of California.

The second study is from the Alfred Wegener Institute in Germany, and found that current models support that Greenland -- one of the world's largest repositories of land-bound ice -- has a delayed response to warming.  Meaning that even if everyone suddenly wised up and cut greenhouse emissions and the temperature stabilized, the Greenland Ice Cap would continue to melt.

For centuries.

The response of Some Guy On The Internet to this was a viral YouTube video showing an ice cube melting in a cup of water, wherein the water level in the cup did not change, captioned,  "A little science lesson for the IDIOTS at the global warming conference," once again to rousing applause, despite the fact that this particular SGOTI neglected the fact that the meltwater that matters is from ice that starts out on land.

That almost no one raised this objection makes me despair for the state of science education in American public schools.

Scariest of all was the study presented at the annual meeting of the American Geophysical Union warning that the Thwaites Glacier -- an on-land mass of ice about the size of Florida -- is in imminent danger of collapse.  And I do mean imminent; we're not talking "by 2100."

The prediction is that the collapse could come some time in the next three to five years.

The leading edge of Thwaites Glacier [Image is in the Public Domain courtesy of NASA]

What's going on is that Thwaites is held back by a floating ice shelf, the bottom of which is caught against the top of an undersea mountain.  The recent study looked at the rate of warm water infiltration and melting on the underside of that ice sheet, and found that the area of ice that's caught -- the part that's providing the friction holding the whole thing in place --  has decreased drastically.  It's like putting a chuck underneath the tire of a car in neutral sitting on an incline.  It doesn't move -- until you remove the chuck.  After that, the car rolls forward, and continues to accelerate.

If the ice sheet holding Thwaites back buckles, the entire glacier will start to slide.  Dumping this much ice into the ocean will raise sea levels by something on the order of sixty centimeters, inundating coastlines and low-lying areas and displacing millions of people.

Although the studies have improved in terms of detail, none of this is new information.  Scientists have been sounding the alarm for decades.  Increasingly they're taking the role of Cassandra -- the figure from Greek myth who was blessed with the ability to see the future, but cursed to have no one believe her.  The situation isn't helped by deliberate anti-science propaganda from the corporations who stand to lose financially if fossil fuels are phased out, and "news" services who are funded by those same corporations.

And, of course, by a populace who has been brainwashed to pay more attention to Some Guy On The Internet than to the hard data and sophisticated models generated by trained scientists.  But wearing blinders only works for so long.

Once you're up to your neck in sea water, it will be a little hard to argue that the scientists have been lying all along.

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Since reading the classic book by Desmond Morris, The Naked Ape, when I was a freshman in college, I've been fascinated by the idea of looking at human behavior as if we were just another animal -- anthropology, as it were, through the eyes of an alien species.  When you do that, a lot of our sense of specialness and separateness simply evaporates.

The latest in this effort to analyze our behavior from an outside perspective is Pascal Boyer's Human Cultures Through the Scientific Lens: Essays in Evolutionary Cognitive Anthropology.  Why do we engage in rituals?  Why is religion nearly universal to all human cultures -- as is sports?  Where did the concept of a taboo come from, and why is it so often attached to something that -- if you think about it -- is just plain weird?

Boyer's essays challenge us to consider ourselves dispassionately, and really think about what we do.  It's a provocative, fascinating, controversial, and challenging book, and if you're curious about the phenomenon of culture, you should put it on your reading list.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]