The Guardian
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Oliver Milman
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Andrew Witherspoon
| Rita Liu |
Alvin Chang
Earth is already becoming unlivable. Will governments act to stop this
disaster from getting worse?The enormous, unprecedented pain and turmoil caused by the climate
crisis is often discussed alongside what can seem like surprisingly small
temperature increases – 1.5C or 2C hotter than it was in the era just before the
car replaced the horse and cart.
These temperature thresholds will again be the focus of upcoming UN climate
talks at the COP26 summit in Scotland as countries variously dawdle or scramble
to avert climate catastrophe. But the single digit numbers obscure huge
ramifications at stake. “We have built a civilization based on a world that
doesn’t exist anymore,” as Katharine Hayhoe, a climate scientist at Texas Tech
University and chief scientist at the Nature Conservancy, puts it.
The world has already heated up by around 1.2C, on average, since the
preindustrial era, pushing humanity beyond almost all historical boundaries.
Cranking up the temperature of the entire globe this much within little more
than a century is, in fact, extraordinary, with the oceans alone absorbing the
heat equivalent
of five Hiroshima atomic bombs dropping into the water every second.
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Until now, human civilization has operated within a narrow, stable band of
temperature. Through the burning of fossil fuels, we have now unmoored
ourselves from our past, as if we have transplanted ourselves onto another
planet. The last time it was hotter than now
was at least
125,000 years ago, while the atmosphere has more heat-trapping carbon dioxide
in it than any time in the past two million years, perhaps more.
Since 1970, the Earth’s temperature has raced upwards faster than in any
comparable period. The oceans have heated up at a rate not seen in at least
11,000 years. “We are conducting an unprecedented experiment with our planet,”
said Hayhoe. “The temperature has only moved a few tenths of a degree for us
until now, just small wiggles in the road. But now we are hitting a curve
we’ve never seen before.”
No one is entirely sure how this horrifying experiment will end but humans
like defined goals and so, in the
2015 Paris climate agreement, nearly 200 countries agreed to limit the global temperature rise to “well
below” 2C, with an aspirational goal to keep it to 1.5C. The latter target was
fought for by smaller, poorer nations, aware that an existential threat of
unlivable heatwaves, floods and drought hinged upon this ostensibly small
increment. “The difference between 1.5C and 2C is a death sentence for the
Maldives,” said Ibrahim Mohamed Solih, president of the country, to world
leaders at the United Nations in September.
There is no huge chasm after a 1.49C rise, we are tumbling down a painful,
worsening rocky slope rather than about to suddenly hit a sheer cliff edge –
but by most standards the world’s governments are currently failing to avert a
grim fate. “We are on a catastrophic path,” said António Guterres, secretary
general of the UN. “We can either save our world or condemn humanity to a
hellish future.”
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This year has provided bitter evidence that even current levels of warming are
disastrous, with astounding floods in
Germany
and
China, Hades-like fires from
Canada
to
California
to
Greece
and rain, rather than snow,
falling for the first time
at the summit of a rapidly melting Greenland. “No amount of global warming can
be considered safe and people are already dying from climate change,” said
Amanda Maycock, an expert in climate dynamics at the University of Leeds.
A “heat dome” that pulverized previous temperature records in the US’s Pacific
northwest in June,
killing
hundreds of people as well as a billion sea creatures
roasted alive in their shells off the coast, would’ve been “virtually impossible” if human activity hadn’t heated the
planet, scientists have calculated, while the German floods were made
nine times more likely
by the climate crisis. “The fingerprint of climate change on recent extreme
weather is quite clear,” said Michael Wehner, who specializes in climate
attribution at Lawrence Berkeley National Laboratory. “But even I am surprised
by the number and scale of weather disasters in 2021.”
After a Covid-induced blip last year, greenhouse gas emissions have roared back
in 2021, further dampening slim hopes that the world will keep within the 1.5C
limit. “There’s a high chance we will get to 1.5C in the next decade,” said
Joeri Rogelj, a climate scientist at Imperial College London.
For humans, a comfortably livable planet starts to spiral away the more it heats
up. At 1.5C, about 14% of the world’s population will be hit by severe heatwaves
once every five years. with this number jumping to more than a third of the global population at 2C.
Beyond 1.5C, the heat in tropical regions of the world will
push societies to the limits, with stifling humidity preventing sweat from evaporating and making it
difficult for people to cool down. Extreme heatwaves could make
parts of the Middle East
too hot for humans to endure, scientists have found, with rising temperatures
also posing enormous risks for
China
and
India.
A severe heatwave historically expected once a decade will happen every other
year
at 2C. “Something our great-grandparents maybe experienced once a lifetime will
become a regular event,” said Rogelj. Globally, an extra 4.9 million people will
die each year from extreme heat should the average temperature race beyond this
point,
scientists have estimated.
At
2C warming, 99% of the world’s coral reefs also start to dissolve away, essentially
ending warm-water corals. Nearly one in 10 vertebrate animals and almost one in
five plants will lose half of their habitat. Ecosystems spanning corals,
wetlands, alpine areas and the Arctic “are set to die off” at this level of
heating, according to Rogelj.
Across the planet, people are set to be strafed by cascading storms, heatwaves,
flooding and drought. Around 216 million people, mostly from developing
countries, will be forced to flee these impacts by 2050 unless radical action is
taken, the World Bank has
estimated. As much as $23tn is on track to be
wiped from the global economy, potentially upending many more.
Some of the most dire impacts revolve around water – both the lack of it and
inundation by it. Enormous floods, often fueled by abnormally heavy rainfall,
have become a regular occurrence recently, not only in Germany and China but
also from the US, where the Mississippi River spent most of 2019 in a state of
flood, to the UK, which was hit by floods in 2020 after storms delivered the
equivalent of one month of rain in 48 hours, to Sudan, where flooding wiped out
more than 110,000 homes last year.
Meanwhile, in the past 20 years the aggregated level of
terrestrial water available to humanity has dropped at a rate of 1cm per year,
with more than five billion people
expected to have an inadequate water supply within the next three decades.
At 3C of warming, sea level rise from melting glaciers and ocean heat will also
provide torrents of unwelcome water to coastal cities, with places such as
Miami, Shanghai and Bangladesh in danger of
becoming
largely marine environments. The frequency of heavy precipitation events, the
sort that soaked Germany and China, will start to climb, nearly doubling the
historical norm once it heats up by 2C.
Virtually all of North America and Europe will be at heightened risk of
wildfires at 3C of heating, with places like California already stuck in a
debilitating cycle of “heat, drought and fire”,
according
to scientists. The magnitude of the disastrous “Black Summer” bushfire season in
Australia in 2019-20 will be four times more likely to reoccur
at 2C of heating, and will be fairly
commonplace
at 3C.
A disquieting unknown for climate scientists is the knock-on impacts as epochal
norms continue to fall. Record wildfires in California last year, for example,
resulted in a million children missing a significant amount of time in school.
What if permafrost melting or flooding cuts off critical roads used by supply
chains? What if storms knock out the world’s leading computer chip factory? What
happens once half of the world is
exposed
to disease-carrying mosquitos?
“We’ve never seen the climate change this fast so we don’t understand the
non-linear effects,” said Hayhoe. “There are tipping points in our human-built
systems that we don’t think about enough. More carbon means worse impacts which
means more unpleasant surprises.”
There are few less pleasant impacts in life than famine and the climate crisis
is beginning to take a toll on food production. In August, the UN said that
Madagascar was on the brink of the world’s first “climate change famine”, with
tens of thousands of people at risk following four years with barely any rain.
Globally, extreme crop drought events that previously occurred once a decade on
average will more than double in their frequency at 2C of temperature rise.
Heat the world a bit more than this and
a third of all the world’s food production will be at risk by the end of the century as crops start to wilt and fail in the heat.
Many different aspects of the climate crisis will destabilize food production,
such as dropping levels of groundwater and shrinking snowpacks, another critical
source of irrigation, in places such as the Himalayas. Crop yields decline the
hotter it gets, while more extreme floods and storms risk ruining vast tracts of
farmland.
Despite the rapid advance of renewable energy and, more recently, electric
vehicles, countries still remain umbilically connected to fossil fuels,
subsidizing oil, coal and gas to the tune of around $11m
every single minute. The air pollution alone from burning these fuels
kills
nearly nine million people each year globally. Decades of time has been
squandered – US president Lyndon Johnson was
warned
of the climate crisis by scientists when Joe Biden was still in college and yet
industry denial and government inertia means the world
is set
for a 2.7C increase in temperature this century, even if all emissions reduction
pledges are met.
By the end of this year the world will have burned through 86%
of the carbon “budget”
that would allow us just a coin flip’s chance of staying below 1.5C. The Glasgow
COP talks will somehow have to bridge this yawning gap, with scientists warning
the world will have to cut emissions in half this decade before zeroing them out
by 2050.
“2.7C would be very bad,” said Wehner, who explained that extreme rainfall would
be up to a quarter heavier than now, and heatwaves potentially 6C hotter in many
countries. Maycock added that much of the planet will become “uninhabitable” at
this level of heating. “We would not want to live in that world,” she said.
A scenario approaching some sort of apocalypse would comfortably arrive should
the world heat up by 4C or more, and although this is considered unlikely due to
the belated action by governments, it should provide little comfort.
Every decision – every oil drilling lease, every acre of the Amazon rainforest
torched for livestock pasture, every new gas-guzzling SUV that rolls onto the
road – will decide how far we tumble down the hill. In Glasgow, governments will
be challenged to show they will fight every fraction of temperature rise, or
else,
in the words of Greta Thunberg, this pivotal gathering is at risk of being dismissed as “blah, blah, blah”.
“We’ve run down the clock but it’s never too late,” said Rogelj. “1.7C is better
than 1.9C which is better than 3C. Cutting emissions tomorrow is better than the
day after, because we can always avoid worse happening. The action is far too
slow at the moment, but we can still act.”
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