Halting the conveyor

Today we have three stories that are absolutely horrifying in juxtaposition.

The first is a paper that came out a couple of days ago in Nature, describing a study by Jade Bowling (of Lancaster University) et al.  It is an analysis of a strange and sudden change in the topography of the Greenland Ice Sheet that happened in 2014 -- a two-square-kilometer part of the sheet dropped by as much as eighty-five meters.  The question, of course, is what happened to all the ice that used to be underneath it.  And what Bowling et al. found was that it had melted -- that the underside of the Greenland Ice Sheet is riddled with subglacial lakes and rivers.  In this case, downstream of the collapsed region, a flood burst through the surface, and within ten days ninety million cubic meters of fresh water gushed out as the cavity emptied.

We usually think of the melting of the polar ice sheets as a gradual process, something like the way ice cubes slowly melt in your glass of tea in summer.  But what this study shows is that the process proceeds quietly -- until it doesn't.  The tipping point between a gentle trickle and a massive flood can occur suddenly, and be due to factors that are largely out of sight.

The second came out in the same issue of Nature, and has to do with a study of the paleoclimate by a team led by Pedro DiNezio of Colorado University - Boulder.  DiNezio and his collaborators looked at the Atlantic Meridional Overturning Circulation (AMOC), sometimes called the "Atlantic Conveyor."  The AMOC is an enormous ocean current, of which the Gulf Stream is only a part, moving a greater volume of water per second than all of the rivers of the world put together.  It is driven by the combined effects of evaporation (making the water saltier) and cooling as the current flows northward; both of these result in the water becoming denser, and south of Iceland it becomes dense enough to sink.  This draws more warm water northward -- and is why Ireland and the United Kingdom, which are on the same latitude as Alberta, have mild climates.

[Image licensed under the Creative Commons R. Curry, Woods Hole Oceanographic Institution/Science/USGCRP., OCP07 Fig-6, CC BY 3.0]

But freshwater intrusion, like the one the prior study considered, lowers the density of the surface water, eventually making it too fresh to sink.  This can slow down -- or halt entirely -- the AMOC.

The focus of the effects has usually been on northeastern North America and northwestern Europe, where that heat transfer slowdown would be expected to trigger a dramatic cooling similar to the sudden crash that initiated the Younger Dryas 12,900 years ago, during which a warming climate was plunged back into the freezer for over a thousand years.  But what the DiNezio et al. study considered was what happens to all that excess heat.  Just because we here in upstate New York would probably be freezing our asses off doesn't mean the rest of the world would be.  The heat energy, of course, doesn't just go away.

And what they found is that when the AMOC slows down, that heat remains in the tropics -- triggering a spike in temperature and a drop in rainfall near the equator.  "This is bad news, because we have these very important ecosystems in the Amazon," said DiNezio.  "The Amazon rainforest contains almost two years of global carbon emissions, making it a major carbon sink on Earth.  Drought in this region could release vast amounts of carbon back into the atmosphere, forming a vicious loop that could make climate change worse."

But of course, no story about climate change would be complete without some breaking news describing how the Trump administration is determined to make it worse.  Lee Zeldin, head of the Environmental Protection Agency (which should have its name changed to the Big Oil Protection Agency, because under his leadership they couldn't give a flying rat's ass about protecting the environment), has just announced the overturning of a 2009 declaration stating that carbon dioxide and other greenhouse gases endanger human health and welfare.

His justification?  What do you think it was?

"It cost Americans a lot of money," Zeldin said.

The declaration was the foundation of climate change regulation in this country, and the impetus for rules limiting emissions from cars, airplanes, and power plants.  If the "endangerment finding," as the declaration is called, is overturned. it gives corporations carte blanche to ignore previous guidelines and mandates.

Zeldin, of course, thinks this is just hunky-dory.  "This will be the largest deregulatory action in the history of America," he crowed.

Because short-term profit is apparently more in need of attention than the long-term habitability of the planet.

I wish I had a hopeful note to end on, but I don't.  The whole thing puts me in mind of a comment from a student in my Environmental Science class, maybe fifteen years ago.  The question I put to them was, "At what point do you think that the majority of Americans will be motivated to address climate change in a meaningful way?"

Her answer was, "It won't happen until average Americans are directly and harshly impacted by it.  When there's no food on the shelves in the grocery stores.  When the rivers dry up.  When the sea level rises enough to flood major coastal cities.  Until then, it's easier to pretend nothing's wrong."

Another student, aghast, said, "But won't it be too late at that point?"

She responded simply, "Of course it will."

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Meltdown

With the insane weather we've had this summer -- and which is showing no signs of calming down -- it's easy to forget about another inevitable outcome of anthropogenic climate change: sea level rise.

Part of the issue, of course, is that humans have a regrettable tendency only to pay attention to what's right in front of their faces, like the current worldwide extreme heat wave.  It's why researchers found in 2014 that public concern about climate change decreases during the winter, an attitude Stephen Colbert summed up as "I just had dinner, so there's no such thing as world hunger."

And sea level rise is so gradual you really do have to have a long baseline even to notice it.  It's only in extremely low-lying places like Louisiana's Isle de Jean-Charles that people have been forced to notice -- and that only because the place looks very likely to cease to exist entirely in the next ten years.

Another reason the (well justified) panic over climate change has mostly focused on extreme high temperatures on land and hot sea surfaces fueling bigger storms is that climatologists thought we had something of a buffer, ice-melt-wise, in the Greenland Ice Sheet.  The Greenland Ice Sheet, they thought, had been unmelted for millions of years, which not only kept all that water locked up in solid form on land, but also helped stabilize the Arctic climate.

Note my use of the past tense.

[Image licensed under the Creative Commons Christine Zenino from Chicago, US, Greenland Glaciers outside of Ammassalik (5562580093), CC BY 2.0]

New research, based on an ice core that had been collected in the 1960s but then lost for nearly sixty years, showed something terrifying: four hundred thousand years ago, nearly the entire Greenland Ice Sheet melted, raising the sea level by several meters -- at a time when the carbon dioxide concentration was lower than it is today.  Using something called a luminescence signal -- a highly-sensitive technique that measures the last time flakes of feldspar or quartz were exposed to light, and therefore were on the surface -- the researchers found what they are calling "bulletproof" evidence that layers thought to be continuously buried deep in the Greenland ice were exposed between 420,000 and 370,000 years ago.

If this happened today -- and the indications are that if we don't curb climate change fast, it will -- the results will be nothing short of catastrophic.

"If we melt just portions of the Greenland ice sheet, the sea level rises dramatically," said Tammy Rittenour, climatologist at Utah State University.  "Forward modeling the rates of melt, and the response to high carbon dioxide, we are looking at meters of sea level rise, probably tens of meters.  And then look at the elevation of New York City, Boston, Miami, Amsterdam. Look at India and Africa -- most global population centers are near sea level."

Considering that the average elevation of the state of Delaware is twenty meters -- and that Louisiana and Florida tie at thirty-three meters -- this should scare the absolute shit out of everyone.  (And like Rittenour said -- even in those low-elevation states, most of the population is still along the coast -- so even a meter or two rise would be catastrophic.)

And, typical of privileged people in industrialized countries, I've focused on where I live.  If you look at the top ten cities threatened by climate change, only one (Miami, Florida) is in the United States.  Two are in India (Kolkata and Mumbai), two are in Vietnam (Ho Chi Minh City and Hai Phong), two are in China (Guangzhou and Shanghai), and one each in Bangladesh (Dhaka), Myanmar (Rangoon), and Thailand (Bangkok).  Just counting the urban population of these ten cities puts almost seventeen million people with the choice of relocating or drowning.

You think the refugee problem is bad now?  

And I'm not just talking about the dreaded "caravans of foreign refugees" the right-wingers here in the U.S. like to bring out every time there's focus on the fact that their entire platform lately has consisted of denying rights to people they don't like.  If the sea level rises even by a meter or two, every coastal city in the United States is in trouble -- so we're gonna have an internal refugee problem the likes of which we've never seen before.

People, we have got to figure this out.

We've had enough time to process it all, to come to the conclusion that yes, it's real, and no, it's not a "natural warm-up."  I'll end with a quote from British science historian James Burke's brilliant (and prescient) documentary After the Warming, which aired all the way back in 1989: "People spend money to insure their homes, their health, and their lives against far less likely occurrences.  That's all legislation to stop climate change turns out to be: planetary insurance...  Our attitude thus far has been like the guy in the old joke, have you heard it?  A man falls off the top of a twenty-story building, and someone on the seventeenth floor sticks his head out of the window and asks the guy how he's doing.  The man shrugs as he falls and says, 'So far, so good.'"

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The rising waters

2020 has become some kind of nihilist joke.  How many versions of the "2020 Apocalypse Bingo Card" have you heard?  And it does seem like things are just piling on.  Right now, we have a major category-3 hurricane bearing down on southern Louisiana -- that just got hit by a totally different tropical storm three days ago.  We're in the middle of a pandemic that is showing no signs of letting up.  There are record-setting wildfires in California.  The economy is giving serious signs of tanking in a big way.  Protests against police brutality seem to erupt every other day.  Last, we're in the middle of the Republican National Convention, where the platform seems to be, "Look how fucked up everything has gotten in the last four years!  Give us another four and we'll do the same thing again but even bigger this time!"

In a situation like this, I'm always reluctant to add to the doom and gloom.  But I would be remiss in not pointing out that all of the above is small potatoes, really.  A lot of us, in fact, are concerned at how the current chaos has distracted us from a far, far bigger problem.  We are facing an unprecedented climate catastrophe, not in a hundred years, not in fifty years, but right now. and three papers in the past two weeks have added to what was already a clarion call to action.

Let's start with the deep oceans.  The abyssal region of the Earth's oceans is supposed to be one of the most stable ecosystems on Earth.  Saline, completely pitch dark, crushing pressures, and always at just shy of four degrees Celsius -- the temperature at which water is its densest.  No change, no matter what's happening up above.

But last week a paper in Nature Climate Change looked into the deeps of the ocean, and found something terrifying.  The anthropogenic climate change signature is showing up in a place that is supposed to be about as insulated from human effects as you could imagine.

A team led by oceanographer Yona Silvy of the Université Sorbonne wrote the following:

[U]sing 11 climate models, we define when anthropogenic temperature and salinity changes are expected to emerge from natural variability in the ocean interior along density surfaces.  The models predict that in 2020, 20–55% of the Atlantic, Pacific and Indian basins have an emergent anthropogenic signal; reaching 40–65% in 2050 and 55–80% in 2080.  The well-ventilated Southern Ocean water masses emerge very rapidly, as early as the 1980–1990s, while the Northern Hemisphere water masses emerge in the 2010–2030s.  Our results highlight the importance of maintaining and augmenting an ocean observing system capable of detecting and monitoring persistent anthropogenic changes.

Perhaps this should have been unsurprising, considering that 93% of the anthropogenic heating the Earth is experiencing is being absorbed by bodies of water.  But the idea that this absorption isn't limited to the surface -- that we're actually impacting the deepest parts of the world's oceans -- is seriously scary to anyone who knows anything about the environment and climate models.

Scientists have long been concerned about the tipping point -- the point that climatic catastrophe becomes inevitable no matter what we do.  A second study out of Ohio State University has shown conclusively that we've passed that point with respect to one of the Earth's systems, the melting of the Greenland Ice Sheet.

What the researchers found was that up until about the year 2000, the glaciers in Greenland were pretty well in balance.  The amount of ice loss during the summer was nearly equal to the amount of ice gain from snowfall during the winter.  But around 2000, the situation changed, and since then Greenland has lost a staggering 50 gigatons (50 billion tons) more ice than it gained.

"Glacier retreat has knocked the dynamics of the whole ice sheet into a constant state of loss," said Ian Howat, who co-authored the paper.  "Even if the climate were to stay the same or even get a little colder, the ice sheet would still be losing mass."

[Image licensed under the Creative Commons Christine Zenino from Chicago, US, Greenland Glaciers outside of Ammassalik (5562580093), CC BY 2.0]

The polar bears aren't the only ones who should be concerned.  Greenland is second only to Antarctica in its potential effect on sea level rise.  If the Greenland Ice Sheet melts -- which is has sometimes done during warm periods in Earth's climate -- it would raise the sea levels by six meters.  Everywhere under six meters of elevation would be under water.

So wave goodbye at New Orleans, Antwerp, Charleston, Boston, a good chunk of New York City and Long Island, and most of Florida, Delaware, the Netherlands, and Bangladesh.

If that's not bad enough, a paper in The Cryosphere last week, authored by a team from three universities -- Leeds, Edinburgh, and University College London -- considered the situation worldwide, and found that in the past twenty-three years, the Earth lost 28 trillion tons of ice.

"To put that in context, every centimeter of sea-level rise means about a million people will be displaced from their low-lying homelands," said Andy Shepherd, director of Leeds University's Centre for Polar Observation and Modelling, in an interview with The Guardian.  "In the past researchers have studied individual areas – such as the Antarctic or Greenland – where ice is melting.  But this is the first time anyone has looked at all the ice that is disappearing from the entire planet...  What we have found has stunned us.  There can be little doubt that the vast majority of Earth's ice loss is a direct consequence of climate warming."

It's easy to focus on what's right in front of your face and forget about the big picture.  This would be okay if the big picture wasn't so deeply horrifying.  I hate to be another purveyor of pessimism, but we have got to start taking this seriously.  I'm as upset about the pandemic and the global political chaos as the next guy, but this isn't a time to be distracted away from a much bigger issue -- the long-term habitability of the planet.

Let's keep our eyes on the ball, here.

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This week's Skeptophilia book recommendation of the week is a brilliant retrospective of how we've come to our understanding of one of the fastest-moving scientific fields: genetics.

In Siddhartha Mukherjee's wonderful book The Gene: An Intimate History, we're taken from the first bit of research that suggested how inheritance took place: Gregor Mendel's famous study of pea plants that established a "unit of heredity" (he called them "factors" rather than "genes" or "alleles," but he got the basic idea spot on).  From there, he looks at how our understanding of heredity was refined -- how DNA was identified as the chemical that housed genetic information, to how that information is encoded and translated, to cutting-edge research in gene modification techniques like CRISPR-Cas9.  Along each step, he paints a very human picture of researchers striving to understand, many of them with inadequate tools and resources, finally leading up to today's fine-grained picture of how heredity works.

It's wonderful reading for anyone interested in genetics and the history of science.

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

The terrible cost of inaction

I try not to be a one-issue voter, but it would be very hard for me to support a candidate for state or federal office who is not explicitly in favor of addressing the causes of anthropogenic climate change.

The jury is still out, of course, as to whether we might already be too late to avoid some of the worst repercussions.  The temperature is climbing at a rate not seen since the globally-catastrophic Paleocene-Eocene Thermal Maximum 55-some-odd million years ago, and it's possible that the rate of the increase we're seeing now is actually higher.

And yet our politicians sit on their hands.  "The scientists are still uncertain" -- despite the fact that the ones harping on all the doubt are the mouthpieces of the fossil fuel industry, who are scared stiff that there'll be an administration that actually takes climate change seriously.  "It's a natural warm-up" -- despite mountains of evidence that this alteration in the climate is caused by man-made greenhouse gases like carbon and methane.  "It'd cost too much to fix" -- despite the fact that the cost of not doing anything is projected to run into the trillions of dollars.  (More on that in a moment.)  And -- most maddening of all -- "it was cold in January so the world isn't warming" -- which you hear from politicians who evidently failed ninth-grade earth science and never figured out the difference between "weather" and "climate."

We had two more pieces of research recently published that highlight how dire the situation has become.  In the first, a team led by Eric Rignot of the University of California - Irvine showed that the rate of ice loss from Greenland -- which has the world's second-largest on-land ice sheet -- has increased sixfold in the last fifty years.  Between 1980 and 1990, an estimated 51 billion tons of ice melted from the Greenland Ice Sheet; between 2010 and 2018 -- a two-year shorter time span -- 286 billion tons melted.  Of the rise in sea level attributable to Greenland ice melt, over half of it has occurred in the last eight years.

[Image licensed under the Creative Commons Christine Zenino from Chicago, US, Greenland Ice Sheet, CC BY 2.0]

In an interview in the Washington Post, Rignot was unequivocal:

The 1980s marked the transition time when the Earth’s climate started to drift significantly from its natural variability as a result of man-made emissions of greenhouse gases...  The entire periphery of Greenland is affected.  I am particularly concerned about the northern regions, which host the largest amount of potential sea-level rise and are already changing fast. 

In Antarctica, some big sleeping giants in East Antarctica are waking up, in addition to a large part of West Antarctica being significantly affected. None of this is good news.  We ought to prepare ourselves for what is coming up and take action as soon as possible to avoid the most drastic scenarios.

The second study, led by climatologist Dmitry Yumashev of Lancaster University, looked at it from the perspective of the only thing that seems to motivate most politicians -- money.  The authors write:

Arctic feedbacks accelerate climate change through carbon releases from thawing permafrost and higher solar absorption from reductions in the surface albedo, following loss of sea ice and land snow.  Here, we include dynamic emulators of complex physical models in the integrated assessment model PAGE-ICE to explore nonlinear transitions in the Arctic feedbacks and their subsequent impacts on the global climate and economy under the Paris Agreement scenarios.  The permafrost feedback is increasingly positive in warmer climates, while the albedo feedback weakens as the ice and snow melt.  Combined, these two factors lead to significant increases in the mean discounted economic effect of climate change: +4.0% ($24.8 trillion) under the 1.5 °C scenario, +5.5% ($33.8 trillion) under the 2 °C scenario, and +4.8% ($66.9 trillion) under mitigation levels consistent with the current national pledges.

Catch that?  Under the best case scenario, the economic cost by 2100 is projected at almost twenty-five trillion dollars.  That's "trillion," with a "t."  And the current Paris Agreement pledges don't even meet that.  If all the signatories meet their pledged targets for carbon emission, the cost is projected to be well over twice that.

Oh, and the United States, one of the top carbon emitters in the world, withdrew from the Paris Agreement in June of 2017 under an explicit directive from Donald Trump, using the excuse that the mandated targets would be "too expensive" and "economically disastrous for the United States."

You want to see economic disaster, Mr. Trump?  You ain't seen nothing yet.  Wait till rising sea levels start inundating coastal cities, requiring massive relocation.  And from the Rignot et al. study referenced above, the wait may not even be that long.

"It’s disheartening that we have this in front of us," Yumashev said in an interview with The Guardian.  "We have the technology and policy instruments to limit the warming but we are not moving fast enough."

Disheartening?  I'd call it "alarming," myself.

I know I've rung the changes on this topic many times, but I feel duty-bound to keep bringing it up because our leaders are still not doing anything.  There's been some lip-service to addressing climate change, but the propaganda machine that is bound and determined to label any recommendations for mitigation as left-wing ultra-green economically unfeasible claptrap has worked all too well.  So don't expect this to be the last time you hear about it here -- and, hopefully, elsewhere.  We'll keep yelling until the politicians wake up or get voted out of office.

It's too important an issue to do otherwise.

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This week's Skeptophilia book recommendation is a classic, and is pure fun: Man Meets Dog by the eminent Austrian zoologist and ethologist Konrad Lorenz.  In it, he looks at every facet of the human/canine relationship, and -- if you're like me -- you'll more than once burst out laughing and say, "Yeah, my dog does that all the time!"

It must be said that (as the book was originally written in 1949) some of what he says about the origins of dogs has been superseded by better information from genetic analysis that was unavailable in Lorenz's time, but most of the rest of his Doggy Psychological Treatise still stands.  And in any case, you'll learn something about how and why your pooches behave the way they do -- and along the way, a bit about human behavior, too.

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