permaculture

[Lawrence London <lfljvenaura@gmail.com>]

When Will Climate Change Make the Earth Too Hot For Humans?
http://nymag.com/daily/intelligencer/2017/07/climate-change-earth-too-hot-for-humans.html

The Uninhabitable Earth

Famine, economic collapse, a sun that cooks us: What climate change could
wreak — sooner than you think.
By David Wallace-Wells

Fossils by Heartless Machine

In the jungles of Costa Rica, where humidity routinely tops 90 percent,
simply moving around outside when it’s over 105 degrees Fahrenheit would be
lethal. And the effect would be fast: Within a few hours, a human body
would be cooked to death from both inside and out.
July 9, 2017 9:00 pm
*I. *‘Doomsday’

*Peering beyond scientific reticence.*

It is, I promise, worse than you think. If your anxiety about global
warming is dominated by fears of sea-level rise, you are barely scratching
the surface of what terrors are possible, even within the lifetime of a
teenager today. And yet the swelling seas — and the cities they will drown
— have so dominated the picture of global warming, and so overwhelmed our
capacity for climate panic, that they have occluded our perception of other
threats, many much closer at hand. Rising oceans are bad, in fact very bad;
but fleeing the coastline will not be enough.

Indeed, absent a significant adjustment to how billions of humans conduct
their lives, parts of the Earth will likely become close to uninhabitable,
and other parts horrifically inhospitable, as soon as the end of this
century.

Even when we train our eyes on climate change, we are unable to comprehend
its scope. This past winter, a string of days 60 and 70 degrees warmer than
normal baked the North Pole, melting the permafrost that encased Norway’s
Svalbard seed vault — a global food bank nicknamed “Doomsday,” designed to
ensure that our agriculture survives any catastrophe, and which appeared to
have been flooded by climate change less than ten years after being built.

The Doomsday vault is fine, for now: The structure has been secured and the
seeds are safe. But treating the episode as a parable of impending flooding
missed the more important news. Until recently, permafrost was not a major
concern of climate scientists, because, as the name suggests, it was soil
that stayed permanently frozen. But Arctic permafrost contains 1.8 trillion
tons of carbon, more than twice as much as is currently suspended in the
Earth’s atmosphere. When it thaws and is released, that carbon may
evaporate as methane, which is 34 times as powerful a greenhouse-gas
warming blanket as carbon dioxide when judged on the timescale of a
century; when judged on the timescale of two decades, it is 86 times as
powerful. In other words, we have, trapped in Arctic permafrost, twice as
much carbon as is currently wrecking the atmosphere of the planet, all of
it scheduled to be released at a date that keeps getting moved up,
partially in the form of a gas that multiplies its warming power 86 times
over.

Maybe you know that already — there are alarming stories every day, like
last month’s satellite data showing
<https://www.carbonbrief.org/major-correction-to-satellite-data-shows-140-faster-warming-since-1998>the
globe warming, since 1998, more than twice as fast as scientists had
thought. Or the news from Antarctica this past May, when a crack
<http://www.newsweek.com/antarctica-ice-shelf-larsen-c-crack-grown-618676>in
an ice shelf grew 11 miles in six days, then kept going; the break now has
just three miles to go — by the time you read this, it may already have met
the open water, where it will drop into the sea one of the biggest icebergs
ever, a process known poetically as “calving.”

But no matter how well-informed you are, you are surely not alarmed enough.
Over the past decades, our culture has gone apocalyptic with zombie movies
and *Mad Max* dystopias
<http://www.vulture.com/2016/07/the-present-worse-than-fictional-dystopias.html>,
perhaps the collective result of displaced climate anxiety, and yet when it
comes to contemplating real-world warming dangers, we suffer from an
incredible failure of imagination. The reasons for that are many: the timid
language of scientific probabilities, which the climatologist James Hansen
once called “scientific reticence” in a paper chastising scientists for
editing their own observations so conscientiously that they failed to
communicate how dire the threat really was; the fact that the country is
dominated by a group of technocrats who believe any problem can be solved
and an opposing culture that doesn’t even see warming as a problem worth
addressing; the way that climate denialism has made scientists even more
cautious in offering speculative warnings; the simple speed of change and,
also, its slowness, such that we are only seeing effects now of warming
from decades past; our uncertainty about uncertainty, which the climate
writer Naomi Oreskes in particular has suggested stops us from preparing as
though anything worse than a median outcome were even possible; the way we
assume climate change will hit hardest elsewhere, not everywhere; the
smallness (two degrees) and largeness (1.8 trillion tons) and abstractness
(400 parts per million) of the numbers; the discomfort of considering a
problem that is very difficult, if not impossible, to solve; the altogether
incomprehensible scale of that problem, which amounts to the prospect of
our own annihilation; simple fear. But aversion arising from fear is a form
of denial, too.

In between scientific reticence and science fiction is science itself. This
article is the result of dozens of interviews and exchanges with
climatologists and researchers in related fields and reflects hundreds of
scientific papers on the subject of climate change. What follows is not a
series of predictions of what will happen — that will be determined in
large part by the much-less-certain science of human response. Instead, it
is a portrait of our best understanding of where the planet is heading
absent aggressive action. It is unlikely that all of these warming
scenarios will be fully realized, largely because the devastation along the
way will shake our complacency. But those scenarios, and not the present
climate, are the baseline. In fact, they are our schedule.

The present tense of climate change — the destruction we’ve already baked
into our future — is horrifying enough. Most people talk as if Miami and
Bangladesh still have a chance of surviving; most of the scientists I spoke
with assume we’ll lose them within the century, even if we stop burning
fossil fuel in the next decade. Two degrees of warming used to be
considered the threshold of catastrophe: tens of millions of climate
refugees unleashed upon an unprepared world. Now two degrees is our goal,
per the Paris climate accords, and experts give us only slim odds of
hitting it. The U.N. Intergovernmental Panel on Climate Change issues
serial reports, often called the “gold standard” of climate research; the
most recent one projects us to hit four degrees of warming by the beginning
of the next century, should we stay the present course. But that’s just a
median projection. The upper end of the probability curve runs as high as
eight degrees — and the authors still haven’t figured out how to deal with
that permafrost melt. The IPCC reports also don’t fully account for the
albedo effect (less ice means less reflected and more absorbed sunlight,
hence more warming); more cloud cover (which traps heat); or the dieback of
forests and other flora (which extract carbon from the atmosphere). Each of
these promises to accelerate warming, and the geological record shows that
temperature can shift as much as ten degrees or more in a single decade.
The last time the planet was even four degrees warmer, Peter Brannen points
out in *The Ends of the World*
<https://www.amazon.com/Ends-World-Apocalypses-Understand-Extinctions/dp/0062364804>,
his new history of the planet’s major extinction events, the oceans were
hundreds of feet higher.*

The Earth has experienced five mass extinctions before the one we are
living through now, each so complete a slate-wiping of the evolutionary
record it functioned as a resetting of the planetary clock, and many
climate scientists will tell you they are the best analog for the
ecological future we are diving headlong into. Unless you are a teenager,
you probably read in your high-school textbooks that these extinctions were
the result of asteroids. In fact, all but the one that killed the dinosaurs
were caused by climate change produced by greenhouse gas. The most
notorious was 252 million years ago; it began when carbon warmed the planet
by five degrees, accelerated when that warming triggered the release of
methane in the Arctic, and ended with 97 percent of all life on Earth dead.
We are currently adding carbon to the atmosphere at a considerably faster
rate; by most estimates, at least ten times faster. The rate is
accelerating. This is what Stephen Hawking had in mind when he said
<http://www.telegraph.co.uk/science/2017/05/02/tomorrows-world-returns-bbc-startling-warning-stephen-hawking/>,
this spring, that the species needs to colonize other planets in the next
century to survive, and what drove Elon Musk, last month, to unveil
<http://www.newsweek.com/elon-musk-mars-spacex-martian-city-625994>his
plans to build a Mars habitat in 40 to 100 years. These are nonspecialists,
of course, and probably as inclined to irrational panic as you or I. But
the many sober-minded scientists I interviewed over the past several months
— the most credentialed and tenured in the field, few of them inclined to
alarmism and many advisers to the IPCC who nevertheless criticize its
conservatism — have quietly reached an apocalyptic conclusion, too: No
plausible program of emissions reductions alone can prevent climate
disaster.
Related Stories
When Did Humans Doom the Earth for Good?
<http://nymag.com/scienceofus/2015/06/anthropocene-debate.html>

Over the past few decades, the term “Anthropocene” has climbed out of
academic discourse and into the popular imagination
<http://nymag.com/scienceofus/2015/06/anthropocene-debate.html> — a name
given to the geologic era we live in now, and a way to signal that it is a
new era, defined on the wall chart of deep history by human intervention.
One problem with the term is that it implies a conquest of nature (and even
echoes the biblical “dominion”). And however sanguine you might be about
the proposition that we have already ravaged the natural world, which we
surely have, it is another thing entirely to consider the possibility that
we have only provoked it, engineering first in ignorance and then in denial
a climate system that will now go to war with us for many centuries,
perhaps until it destroys us. That is what Wallace Smith Broecker, the
avuncular oceanographer who coined the term “global warming,” means when he
calls the planet an “angry beast.” You could also go with “war machine.”
Each day we arm it more.
II. Heat Death

*The bahraining of New York.*
In the sugar­cane region of El Salvador, as much as one-fifth of the
population has chronic kidney disease, the presumed result of dehydration
from working the fields they were able to comfortably harvest as recently
as two decades ago. Photo: Heartless Machine

Humans, like all mammals, are heat engines; surviving means having to
continually cool off, like panting dogs. For that, the temperature needs to
be low enough for the air to act as a kind of refrigerant, drawing heat off
the skin so the engine can keep pumping. At seven degrees of warming, that
would become impossible for large portions of the planet’s equatorial band,
and especially the tropics, where humidity adds to the problem; in the
jungles of Costa Rica, for instance, where humidity routinely tops 90
percent, simply moving around outside when it’s over 105 degrees Fahrenheit
would be lethal. And the effect would be fast: Within a few hours, a human
body would be cooked to death from both inside and out.

Climate-change skeptics point out that the planet has warmed and cooled
many times before, but the climate window that has allowed for human life
is very narrow, even by the standards of planetary history. At 11 or 12
degrees of warming, more than half the world’s population, as distributed
today, would die of direct heat. Things almost certainly won’t get that hot
this century, though models of unabated emissions do bring us that far
eventually. This century, and especially in the tropics, the pain points
will pinch much more quickly even than an increase of seven degrees. The
key factor is something called wet-bulb temperature, which is a term of
measurement as home-laboratory-kit as it sounds: the heat registered on a
thermometer wrapped in a damp sock as it’s swung around in the air (since
the moisture evaporates from a sock more quickly in dry air, this single
number reflects both heat and humidity). At present, most regions reach a
wet-bulb maximum of 26 or 27 degrees Celsius; the true red line for
habitability is 35 degrees. What is called heat stress comes much sooner.

Actually, we’re about there already. Since 1980, the planet has experienced
a 50-fold increase in the number of places experiencing dangerous or
extreme heat; a bigger increase is to come. The five warmest summers in
Europe since 1500 have all occurred since 2002, and soon, the IPCC warns,
simply being outdoors that time of year will be unhealthy for much of the
globe. Even if we meet the Paris goals of two degrees warming, cities like
Karachi and Kolkata will become close to uninhabitable, annually
encountering deadly heat waves like those that crippled them in 2015. At
four degrees, the deadly European heat wave of 2003, which killed as many
as 2,000 people a day, will be a normal summer. At six, according to an
assessment focused only on effects within the U.S. from the National
Oceanic and Atmospheric Administration, summer labor of any kind would
become impossible in the lower Mississippi Valley, and everybody in the
country east of the Rockies would be under more heat stress than anyone,
anywhere, in the world today. As Joseph Romm has put it in his
authoritative primer *Climate Change: What Everyone Needs to Know*
<https://www.amazon.com/Climate-Change-Everyone-Needs-Know%C2%AE/dp/0190250178>
*,* heat stress in New York City would exceed that of present-day Bahrain,
one of the planet’s hottest spots, and the temperature in Bahrain “would
induce hyperthermia in even sleeping humans.” The high-end IPCC estimate,
remember, is two degrees warmer still. By the end of the century, the World
Bank has estimated, the coolest months in tropical South America, Africa,
and the Pacific are likely to be warmer than the warmest months at the end
of the 20th century. Air-conditioning can help but will ultimately only add
to the carbon problem; plus, the climate-controlled malls of the Arab
emirates aside, it is not remotely plausible to wholesale air-condition all
the hottest parts of the world, many of them also the poorest. And indeed,
the crisis will be most dramatic across the Middle East and Persian Gulf,
where in 2015 the heat index registered temperatures as high as 163 degrees
Fahrenheit. As soon as several decades from now, the hajj will become
physically impossible for the 2 million Muslims who make the pilgrimage
each year.

It is not just the hajj, and it is not just Mecca; heat is already killing
us. In the sugarcane region of El Salvador, as much as one-fifth of the
population has chronic kidney disease, including over a quarter of the men,
the presumed result of dehydration from working the fields they were able
to comfortably harvest as recently as two decades ago. With dialysis, which
is expensive, those with kidney failure can expect to live five years;
without it, life expectancy is in the weeks. Of course, heat stress
promises to pummel us in places other than our kidneys, too. As I type that
sentence, in the California desert in mid-June, it is 121 degrees outside
my door. It is not a record high.
*III. The End of Food*

*Praying for cornfields in the tundra.*

Climates differ and plants vary, but the basic rule for staple cereal crops
grown at optimal temperature is that for every degree of warming, yields
decline by 10 percent. Some estimates run as high as 15 or even 17 percent.
Which means that if the planet is five degrees warmer at the end of the
century, we may have as many as 50 percent more people to feed and 50
percent less grain to give them. And proteins are worse: It takes 16
calories of grain to produce just a single calorie of hamburger meat,
butchered from a cow that spent its life polluting the climate with methane
farts.

Pollyannaish plant physiologists will point out that the cereal-crop math
applies only to those regions already at peak growing temperature, and they
are right — theoretically, a warmer climate will make it easier to grow
corn in Greenland. But as the pathbreaking work by Rosamond Naylor and
David Battisti has shown, the tropics are already too hot to efficiently
grow grain, and those places where grain is produced today are already at
optimal growing temperature — which means even a small warming will push
them down the slope of declining productivity. And you can’t easily move
croplands north a few hundred miles, because yields in places like remote
Canada and Russia are limited by the quality of soil there; it takes many
centuries for the planet to produce optimally fertile dirt.

Drought might be an even bigger problem than heat, with some of the world’s
most arable land turning quickly to desert. Precipitation is notoriously
hard to model, yet predictions for later this century are basically
unanimous: unprecedented droughts nearly everywhere food is today produced.
By 2080, without dramatic reductions in emissions, southern Europe will be
in permanent extreme drought, much worse than the American dust bowl ever
was. The same will be true in Iraq and Syria and much of the rest of the
Middle East; some of the most densely populated parts of Australia, Africa,
and South America; and the breadbasket regions of China. None of these
places, which today supply much of the world’s food, will be reliable
sources of any. As for the original dust bowl: The droughts in the American
plains and Southwest would not just be worse than in the 1930s, a 2015 NASA
study predicted
<https://www.nasa.gov/press/2015/february/nasa-study-finds-carbon-emissions-could-dramatically-increase-risk-of-us>,
but worse than any droughts in a thousand years — and that includes those
that struck between 1100 and 1300, which “dried up all the rivers East of
the Sierra Nevada mountains” and may have been responsible for the death of
the Anasazi civilization.

Remember, we do not live in a world without hunger as it is. Far from it:
Most estimates put the number of undernourished at 800 million globally. In
case you haven’t heard, this spring has already brought an unprecedented
quadruple famine to Africa and the Middle East; the U.N. has warned that
separate starvation events in Somalia, South Sudan, Nigeria, and Yemen
could kill 20 million this year alone.
*IV. Climate Plagues*

*What happens when the bubonic ice melts?*

Rock, in the right spot, is a record of planetary history, eras as long as
millions of years flattened by the forces of geological time into strata
with amplitudes of just inches, or just an inch, or even less. Ice works
that way, too, as a climate ledger, but it is also frozen history, some of
which can be reanimated when unfrozen. There are now, trapped in Arctic
ice, diseases that have not circulated in the air for millions of years —
in some cases, since before humans were around to encounter them. Which
means our immune systems would have no idea how to fight back when those
prehistoric plagues emerge from the ice.

The Arctic also stores terrifying bugs from more recent times. In Alaska,
already, researchers have discovered remnants of the 1918 flu that infected
as many as 500 million and killed as many as 100 million — about 5 percent
of the world’s population and almost six times as many as had died in the
world war for which the pandemic served as a kind of gruesome capstone. As
the BBC reported
<http://www.bbc.com/earth/story/20170504-there-are-diseases-hidden-in-ice-and-they-are-waking-up>in
May, scientists suspect smallpox and the bubonic plague are trapped in
Siberian ice, too — an abridged history of devastating human sickness, left
out like egg salad in the Arctic sun.

Experts caution that many of these organisms won’t actually survive the
thaw and point to the fastidious lab conditions under which they have
already reanimated several of them — the 32,000-year-old “extremophile”
bacteria revived in 2005, an 8 million-year-old bug brought back to life in
2007, the 3.5 million–year–old one a Russian scientist self-injected
<https://www.youtube.com/watch?v=lv0_Cu0FcPA> just out of curiosity — to
suggest that those are necessary conditions for the return of such ancient
plagues. But already last year, a boy was killed and 20 others infected by
anthrax released when retreating permafrost exposed the frozen carcass of a
reindeer killed by the bacteria at least 75 years earlier; 2,000
present-day reindeer were infected, too, carrying and spreading the disease
beyond the tundra.

What concerns epidemiologists more than ancient diseases are existing
scourges relocated, rewired, or even re-evolved by warming. The first
effect is geographical. Before the early-modern period, when adventuring
sailboats accelerated the mixing of peoples and their bugs, human
provinciality was a guard against pandemic. Today, even with globalization
and the enormous intermingling of human populations, our ecosystems are
mostly stable, and this functions as another limit, but global warming will
scramble those ecosystems and help disease trespass those limits as surely
as Cortés did. You don’t worry much about dengue or malaria if you are
living in Maine or France. But as the tropics creep northward and
mosquitoes migrate with them, you will. You didn’t much worry about Zika a
couple of years ago, either.

As it happens, Zika may also be a good model
<http://nymag.com/scienceofus/2016/02/zika-virus-gmo-mosquitoes.html> of
the second worrying effect — disease mutation. One reason you hadn’t heard
about Zika until recently is that it had been trapped in Uganda; another is
that it did not, until recently, appear to cause birth defects. Scientists
still don’t entirely understand what happened, or what they missed. But
there are things we do know for sure about how climate affects some
diseases: Malaria, for instance, thrives in hotter regions not just because
the mosquitoes that carry it do, too, but because for every degree increase
in temperature, the parasite reproduces ten times faster. Which is one
reason that the World Bank estimates that by 2050, 5.2 billion people will
be reckoning with it.
*V. Unbreathable Air*

*A rolling death smog that suffocates millions.*
By the end of the century, the coolest months in tropical South America,
Africa, and the Pacific are likely to be warmer than the warmest months at
the end of the 20th century. Photo: Heartless Machine

Our lungs need oxygen, but that is only a fraction of what we breathe. The
fraction of carbon dioxide is growing: It just crossed 400 parts per
million, and high-end estimates extrapolating from current trends suggest
it will hit 1,000 ppm by 2100. At that concentration, compared to the air
we breathe now, human cognitive ability declines by 21 percent.

Other stuff in the hotter air is even scarier, with small increases in
pollution capable of shortening life spans by ten years. The warmer the
planet gets, the more ozone forms, and by mid-century, Americans will
likely suffer a 70 percent increase in unhealthy ozone smog, the National
Center for Atmospheric Research has projected. By 2090, as many as 2
billion people globally will be breathing air above the WHO “safe” level;
one paper last month showed that, among other effects, a pregnant mother’s
exposure to ozone raises the child’s risk of autism (as much as tenfold,
combined with other environmental factors). Which does make you think again
about the autism epidemic in West Hollywood.

Already, more than 10,000 people die each day from the small particles
emitted from fossil-fuel burning; each year, 339,000 people die from
wildfire smoke, in part because climate change has extended forest-fire
season (in the U.S., it’s increased by 78 days since 1970). By 2050,
according to the U.S. Forest Service
<https://www.usda.gov/oce/climate_change/effects_2012/FS_Climate1114%20opt.pdf>,
wildfires will be twice as destructive as they are today; in some places,
the area burned could grow fivefold. What worries people even more is the
effect that would have on emissions, especially when the fires ravage
forests arising out of peat. Peatland fires in Indonesia in 1997, for
instance, added to the global CO2 release by up to 40 percent, and more
burning only means more warming only means more burning. There is also the
terrifying possibility that rain forests like the Amazon, which in 2010
suffered its second “hundred-year drought” in the space of five years,
could dry out enough to become vulnerable to these kinds of devastating,
rolling forest fires — which would not only expel enormous amounts of
carbon into the atmosphere but also shrink the size of the forest. That is
especially bad because the Amazon alone provides 20 percent of our oxygen.

Then there are the more familiar forms of pollution. In 2013, melting
Arctic ice remodeled Asian weather patterns, depriving industrial China of
the natural ventilation systems it had come to depend on, which blanketed
much of the country’s north in an unbreathable smog. Literally
unbreathable. A metric called the Air Quality Index categorizes the risks
and tops out at the 301-to-500 range, warning of “serious aggravation of
heart or lung disease and premature mortality in persons with
cardiopulmonary disease and the elderly” and, for all others, “serious risk
of respiratory effects”; at that level, “everyone should avoid all outdoor
exertion.” The Chinese “airpocalypse” of 2013 peaked at what would have
been an Air Quality Index of over 800. That year, smog was responsible for
a third of all deaths in the country.
*VI. Perpetual War*

*The violence baked into heat.*

Climatologists are very careful when talking about Syria. They want you to
know that while climate change did produce a drought that contributed to
civil war, it is not exactly fair to saythat the conflict is the result of
warming; next door, for instance, Lebanon suffered the same crop failures.
But researchers like Marshall Burke and Solomon Hsiang have managed to
quantify some of the non-obvious relationships between temperature and
violence: For every half-degree of warming, they say, societies will see
between a 10 and 20 percent increase in the likelihood of armed conflict.
In climate science, nothing is simple, but the arithmetic is harrowing: A
planet five degrees warmer would have at least half again as many wars as
we do today. Overall, social conflict could more than double this century.

This is one reason that, as nearly every climate scientist I spoke to
pointed out, the U.S. military is obsessed with climate change: The
drowning of all American Navy bases by sea-level rise is trouble enough,
but being the world’s policeman is quite a bit harder when the crime rate
doubles. Of course, it’s not just Syria where climate has contributed to
conflict. Some speculate that the elevated level of strife across the
Middle East over the past generation reflects the pressures of global
warming — a hypothesis all the more cruel considering that warming began
accelerating when the industrialized world extracted and then burned the
region’s oil.

What accounts for the relationship between climate and conflict? Some of it
comes down to agriculture and economics; a lot has to do with forced
migration, already at a record high, with at least 65 million displaced
people wandering the planet right now. But there is also the simple fact of
individual irritability. Heat increases municipal crime rates, and swearing
on social media, and the likelihood that a major-league pitcher, coming to
the mound after his teammate has been hit by a pitch, will hit an opposing
batter in retaliation. And the arrival of air-conditioning in the developed
world, in the middle of the past century, did little to solve the problem
of the summer crime wave.
VII. Permanent Economic Collapse

*Dismal capitalism in a half-poorer world.*

The murmuring mantra of global neoliberalism, which prevailed between the
end of the Cold War and the onset of the Great Recession, is that economic
growth would save us from anything and everything.
But in the aftermath of the 2008 crash, a growing number of historians
studying what they call “fossil capitalism” have begun to suggest that the
entire history of swift economic growth, which began somewhat suddenly in
the 18th century, is not the result of innovation or trade or the dynamics
of global capitalism but simply our discovery of fossil fuels and all their
raw power — a onetime injection of new “value” into a system that had
previously been characterized by global subsistence living. Before fossil
fuels, nobody lived better than their parents or grandparents or ancestors
from 500 years before, except in the immediate aftermath of a great plague
like the Black Death, which allowed the lucky survivors to gobble up the
resources liberated by mass graves. After we’ve burned all the fossil
fuels, these scholars suggest, perhaps we will return to a “steady state”
global economy. Of course, that onetime injection has a devastating
long-term cost: climate change.

The most exciting research on the economics of warming has also come from
Hsiang and his colleagues, who are not historians of fossil capitalism but
who offer some very bleak analysis of their own: Every degree Celsius of
warming costs, on average, 1.2 percent of GDP (an enormous number,
considering we count growth in the low single digits as “strong”). This is
the sterling work in the field, and their median projection is for a 23
percent loss in per capita earning globally by the end of this century
(resulting from changes in agriculture, crime, storms, energy, mortality,
and labor).
Tracing the shape of the probability curve is even scarier: There is a 12
percent chance that climate change will reduce global output by more than
50 percent by 2100, they say, and a 51 percent chance that it lowers per
capita GDP by 20 percent or more by then, unless emissions decline. By
comparison, the Great Recession lowered global GDP by about 6 percent, in a
onetime shock; Hsiang and his colleagues estimate a one-in-eight chance of
an ongoing and irreversible effect by the end of the century that is eight
times worse.

The scale of that economic devastation is hard to comprehend, but you can
start by imagining what the world would look like today with an economy
half as big, which would produce only half as much value, generating only
half as much to offer the workers of the world. It makes the grounding of
flights out of heat-stricken Phoenix last month seem like pathetically
small economic potatoes. And, among other things, it makes the idea of
postponing government action on reducing emissions and relying solely on
growth and technology to solve the problem an absurd business calculation.
Every round-trip ticket on flights from New York to London, keep in mind,
costs the Arctic three more square meters of ice.
*VIII. Poisoned Oceans*

*Sulfide burps off the skeleton coast.*

That the sea will become a killer is a given. Barring a radical reduction
of emissions, we will see at least four feet of sea-level rise and possibly
ten by the end of the century. A third of the world’s major cities are on
the coast, not to mention its power plants, ports, navy bases, farmlands,
fisheries, river deltas, marshlands, and rice-paddy empires, and even those
above ten feet will flood much more easily, and much more regularly, if the
water gets that high. At least 600 million people live within ten meters of
sea level today.

But the drowning of those homelands is just the start. At present, more
than a third of the world’s carbon is sucked up by the oceans — thank God,
or else we’d have that much more warming already. But the result is what’s
called “ocean acidification,” which, on its own, may add a half a degree to
warming this century. It is also already burning through the planet’s water
basins — you may remember these as the place where life arose in the first
place. You have probably heard of “coral bleaching” — that is, coral dying
— which is very bad news, because reefs support as much as a quarter of all
marine life and supply food for half a billion people. Ocean acidification
will fry fish populations directly, too, though scientists aren’t yet sure
how to predict the effects on the stuff we haul out of the ocean to eat;
they do know that in acid waters, oysters and mussels will struggle to grow
their shells, and that when the pH of human blood drops as much as the
oceans’ pH has over the past generation, it induces seizures, comas, and
sudden death.

That isn’t all that ocean acidification can do. Carbon absorption can
initiate a feedback loop in which underoxygenated waters breed different
kinds of microbes that turn the water still more “anoxic,” first in deep
ocean “dead zones,” then gradually up toward the surface. There, the small
fish die out, unable to breathe, which means oxygen-eating bacteria thrive,
and the feedback loop doubles back. This process, in which dead zones grow
like cancers, choking off marine life and wiping out fisheries, is already
quite advanced in parts of the Gulf of Mexico and just off Namibia, where
hydrogen sulfide is bubbling out of the sea along a thousand-mile stretch
of land known as the “Skeleton Coast.” The name originally referred to the
detritus of the whaling industry, but today it’s more apt than ever.
Hydrogen sulfide is so toxic that evolution has trained us to recognize the
tiniest, safest traces of it, which is why our noses are so exquisitely
skilled at registering flatulence. Hydrogen sulfide is also the thing that
finally did us in that time 97 percent of all life on Earth died, once all
the feedback loops had been triggered and the circulating jet streams of a
warmed ocean ground to a halt — it’s the planet’s preferred gas for a
natural holocaust. Gradually, the ocean’s dead zones spread, killing off
marine species that had dominated the oceans for hundreds of millions of
years, and the gas the inert waters gave off into the atmosphere poisoned
everything on land. Plants, too. It was millions of years before the oceans
recovered.
*IX. The Great Filter*

*Our present eeriness cannot last.*

So why can’t we see it? In his recent book-length essay *The Great
Derangement*
<https://www.amazon.com/Great-Derangement-Climate-Unthinkable-Lectures/dp/022632303X>
*,* the Indian novelist Amitav Ghosh wonders why global warming and natural
disaster haven’t become major subjects of contemporary fiction — why we
don’t seem able to imagine climate catastrophe, and why we haven’t yet had
a spate of novels in the genre he basically imagines into half-existence
and names “the environmental uncanny.” “Consider, for example, the stories
that congeal around questions like, ‘Where were you when the Berlin Wall
fell?’ or ‘Where were you on 9/11?’ ” he writes. “Will it ever be possible
to ask, in the same vein, ‘Where were you at 400 ppm?’ or ‘Where were you
when the Larsen B ice shelf broke up?’ ” His answer: Probably not, because
the dilemmas and dramas of climate change are simply incompatible with the
kinds of stories we tell ourselves about ourselves, especially in novels,
which tend to emphasize the journey of an individual conscience rather than
the poisonous miasma of social fate.

Surely this blindness will not last — the world we are about to inhabit
will not permit it. In a six-degree-warmer world, the Earth’s ecosystem
will boil with so many natural disasters that we will just start calling
them “weather”: a constant swarm of out-of-control typhoons and tornadoes
and floods and droughts, the planet assaulted regularly with climate events
that not so long ago destroyed whole civilizations. The strongest
hurricanes will come more often, and we’ll have to invent new categories
with which to describe them; tornadoes will grow longer and wider and
strike much more frequently, and hail rocks will quadruple in size. Humans
used to watch the weather to prophesy the future; going forward, we will
see in its wrath the vengeance of the past. Early naturalists talked often
about “deep time” — the perception they had, contemplating the grandeur of
this valley or that rock basin, of the profound slowness of nature. What
lies in store for us is more like what the Victorian anthropologists
identified as “dreamtime,” or “everywhen”: the semi-mythical experience,
described by Aboriginal Australians, of encountering, in the present
moment, an out-of-time past, when ancestors, heroes, and demigods crowded
an epic stage. You can find it already watching footage of an iceberg
collapsing into the sea — a feeling of history happening all at once.

It is. Many people perceive climate change as a sort of moral and economic
debt, accumulated since the beginning of the Industrial Revolution and now
come due after several centuries — a helpful perspective, in a way, since
it is the carbon-burning processes that began in 18th-century England that
lit the fuse of everything that followed. But more than half of the carbon
humanity has exhaled into the atmosphere in its entire history has been
emitted in just the past three decades; since the end of World War II, the
figure is 85 percent. Which means that, in the length of a single
generation, global warming has brought us to the brink of planetary
catastrophe, and that the story of the industrial world’s kamikaze mission
is also the story of a single lifetime. My father’s, for instance: born in
1938, among his first memories the news of Pearl Harbor and the mythic Air
Force of the propaganda films that followed, films that doubled as
advertisements for imperial-American industrial might; and among his last
memories the coverage of the desperate signing of the Paris climate accords
on cable news, ten weeks before he died of lung cancer last July. Or my
mother’s: born in 1945, to German Jews fleeing the smokestacks through
which their relatives were incinerated, now enjoying her 72nd year in an
American commodity paradise, a paradise supported by the supply chains of
an industrialized developing world. She has been smoking for 57 of those
years, unfiltered.

Or the scientists’. Some of the men who first identified a changing climate
(and given the generation, those who became famous were men) are still
alive; a few are even still working. Wally Broecker is 84 years old and
drives to work at the Lamont-Doherty observatory across the Hudson every
day from the Upper West Side. Like most of those who first raised the
alarm, he believes that no amount of emissions reduction alone can
meaningfully help avoid disaster. Instead, he puts his faith in carbon
capture — untested technology to extract carbon dioxide from the
atmosphere, which Broecker estimates will cost at least several trillion
dollars — and various forms of “geoengineering,” the catchall name for a
variety of moon-shot technologies far-fetched enough that many climate
scientists prefer to regard them as dreams, or nightmares, from science
fiction. He is especially focused on what’s called the aerosol approach —
dispersing so much sulfur dioxide into the atmosphere that when it converts
to sulfuric acid, it will cloud a fifth of the horizon and reflect back 2
percent of the sun’s rays, buying the planet at least a little wiggle room,
heat-wise. “Of course, that would make our sunsets very red, would bleach
the sky, would make more acid rain,” he says. “But you have to look at the
magnitude of the problem. You got to watch that you don’t say the giant
problem shouldn’t be solved because the solution causes some smaller
problems.” He won’t be around to see that, he told me. “But in your
lifetime …”

Jim Hansen is another member of this godfather generation. Born in 1941, he
became a climatologist at the University of Iowa, developed the
groundbreaking “Zero Model” for projecting climate change, and later became
the head of climate research at NASA, only to leave under pressure when,
while still a federal employee, he filed a lawsuit against the federal
government charging inaction on warming (along the way he got arrested a
few times for protesting, too). The lawsuit, which is brought by a
collective called Our Children’s Trust and is often described as “kids
versus climate change,” is built on an appeal to the equal-protection
clause, namely, that in failing to take action on warming, the government
is violating it by imposing massive costs on future generations; it is
scheduled to be heard this winter in Oregon district court. Hansen has
recently given up on solving the climate problem with a carbon tax, which
had been his preferred approach, and has set about calculating the total
cost of extracting carbon from the atmosphere instead.

Hansen began his career studying Venus, which was once a very Earth-like
planet with plenty of life-supporting water before runaway climate change
rapidly transformed it into an arid and uninhabitable sphere enveloped in
an unbreathable gas; he switched to studying our planet by 30, wondering
why he should be squinting across the solar system to explore rapid
environmental change when he could see it all around him on the planet he
was standing on. “When we wrote our first paper on this, in 1981,” he told
me, “I remember saying to one of my co-authors, ‘This is going to be very
interesting. Sometime during our careers, we’re going to see these things
beginning to happen.’ ”

Several of the scientists I spoke with proposed global warming as the
solution to Fermi’s famous paradox, which asks, If the universe is so big,
then why haven’t we encountered any other intelligent life in it? The
answer, they suggested, is that the natural life span of a civilization may
be only several thousand years, and the life span of an industrial
civilization perhaps only several hundred. In a universe that is many
billions of years old, with star systems separated as much by time as by
space, civilizations might emerge and develop and burn themselves up simply
too fast to ever find one another. Peter Ward, a charismatic paleontologist
among those responsible for discovering that the planet’s mass extinctions
were caused by greenhouse gas, calls this the “Great Filter”:
“Civilizations rise, but there’s an environmental filter that causes them
to die off again and disappear fairly quickly,” he told me. “If you look at
planet Earth, the filtering we’ve had in the past has been in these mass
extinctions.” The mass extinction we are now living through has only just
begun; so much more dying is coming.

And yet, improbably, Ward is an optimist. So are Broecker and Hansen and
many of the other scientists I spoke to. We have not developed much of a
religion of meaning around climate change that might comfort us, or give us
purpose, in the face of possible annihilation. But climate scientists have
a strange kind of faith: We will find a way to forestall radical warming,
they say, because we must.

It is not easy to know how much to be reassured by that bleak certainty,
and how much to wonder whether it is another form of delusion; for global
warming to work as parable, of course, someone needs to survive to tell the
story. The scientists know that to even meet the Paris goals, by 2050,
carbon emissions from energy and industry, which are still rising, will
have to fall by half each decade; emissions from land use (deforestation,
cow farts, etc.) will have to zero out; and we will need to have invented
technologies to extract, annually, twice as much carbon from the atmosphere
as the entire planet’s plants now do. Nevertheless, by and large, the
scientists have an enormous confidence in the ingenuity of humans — a
confidence perhaps bolstered by their appreciation for climate change,
which is, after all, a human invention, too. They point to the Apollo
project, the hole in the ozone we patched in the 1980s, the passing of the
fear of mutually assured destruction. Now we’ve found a way to engineer our
own doomsday, and surely we will find a way to engineer our way out of it,
one way or another. The planet is not used to being provoked like this, and
climate systems designed to give feedback over centuries or millennia
prevent us — even those who may be watching closely — from fully imagining
the damage done already to the planet. But when we do truly see the world
we’ve made, they say, we will also find a way to make it livable. For them,
the alternative is simply unimaginable.

**This article appears in the July 10, 2017, issue of *New York *Magazine.*

**This article has been updated to clarify a reference to Peter Brannen’s *The
Ends of the World*.*