Climate change is an existential threat to humanity. Year after year,
we are seeing an increase in both the severity and number of extreme weather events. Droughts,
wildfires, famine, and flooding are on the rise. Migration is surging, generating more
climate refugees every year. But we live on a planet that is 71% water. And the largest
chunk of fresh water exists as ice in Antarctica, a continent directly affected by climate change.
This is Unveiled, and today we’re answering the extraordinary question:
What would happen if Antarctica Melted?
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Our climate is in a sustained period of global warming. While it undergoes cyclical variations,
cooling and warming, current warming is taking place at an unprecedented rate. There’s a strong
scientific consensus that this is due to human activities. In a normal global system,
sunlight reflected off the earth’s surface escapes back into space. But
when carbon dioxide and other greenhouse gasses are released into the atmosphere,
they act like a blanket over the earth, absorbing sunlight and reflecting back solar radiation.
Greenhouse gasses can then stay in the atmosphere for decades or centuries. As they accumulate,
the ‘blanket’ gets thicker, preventing more and more heat from escaping.
The burning of fossil fuels releases billions of metric tons of greenhouse
gasses into the atmosphere every year. And those particles have
led to incredible changes over a relatively short period of time.
Scientists began keeping accurate records of global temperature around 1880. In the
century that followed, temperatures rose less than a tenth of a degree Celsius every decade.
That rate of rise has doubled in the last 40 years, though. We are seeing the results in
real time. The top five hottest years ever recorded, for example, are all post 2015.
That rise has had a direct impact on global ice, especially in polar regions - the Arctic in the
north and the Antarctic in the south. The Antarctic Ice Sheet is tremendous:
at almost 5.4 million square miles, it’s about the same size as the continental United States
and Mexico combined. Together, the Antarctic Ice Sheet and the Greenland Ice Sheet (in the Arctic)
account for 99% of the world’s land ice (and 68% of freshwater on the planet). That ice is at risk,
though. According to the Ocean Conservancy, 95% of the oldest, thickest Arctic ice has melted
away since 1985. That begs the question: how much total ice has Antarctica already lost, as well?
NASA has the answers. In 1997, the box office was dominated by ‘Titanic,’ a film about an
iceberg destroying the exemplar of human invention. In an example of cruel irony,
however, human-induced climate change has melted over 12 trillion tons from
Antarctica’s ice shelves since then, according to a 2022 study.
The ice sheets in Antarctica lose 150 billion tons of ice mass every year.
Again, we can witness that loss in real-time. Ice or glacier calving is when giant chunks of
ice break off from the polar sheets. Calvings are booming, dramatic losses of ice shelves,
birthing icebergs destined to die slow, melting deaths. In the last 25 years,
the Antarctic Ice Sheets have lost around 23,000 square miles of ice to calving. That’s an area
larger than the nation of Taiwan. The amount of ice that Greenland and Antarcica have lost
since the 1990s accounts for over one third, or approximately 0.7 inches, of sea level rise.
In April 2023, scientists published a terrifying new paper in Nature. After
analyzing the beds of former ice streams, they discovered the rate at which ice retreated at
the end of the last Ice Age: from 180 to 2,000 feet per day. Somewhat thankfully,
neither polar ice cap is melting at that rate right now, though the current rates do appear
to be accelerating. The Eurasian Ice sheet is certainly melting rapidly, and Antarctica is
melting as fast as 160 feet per day - only just off of last Ice Age levels. That retreat acts
like a runaway train, gaining momentum all the time. And, as that momentum continues,
it reveals more and more surface area to the warming ocean, once again accelerating
the melt. Some describe this as a tipping point, and one that we’re very, very close to passing.
Increasing temperatures put the pedal to the metal when it comes to the melt rate. If current
projections of temperature increases hold, that rate could eventually reach a pace that
would cause a rapid collapse of Antarctica’s glaciers. The lead author of the 2023 study,
Christine Batchelor, addressed this worrisome point directly. “If temperatures continue to
rise,” she says, “then we might have the ice being melted and thinned from above
as well as from below.” According to Batchelor, if the ice sheet did melt at
2,000 feet for a year, we probably wouldn’t have any ice left. As another glaciologist,
Eric Rignot put it, “This is not a model. This is a real observation. And it is frankly scary.”
The trouble with climate change is that so many of its knock-on effects are cumulative. Each
effect builds upon the other, working together to make things much worse for life on earth.
Another 2023 study, again published in Nature and this time from a team of Australian researchers,
focused on the effects of ice melt on the deep ocean. It was found that the increase of ocean
volume could lead to a 40% slowdown of deep ocean currents by 2050. This, the researchers say,
could lead to centuries of altered climate. Slower ocean currents would cause a cascade of negative
impacts from rising sea levels, worsening weather, and the starvation of ocean life.
One of the co-authors, Matt England, of the Climate Change Research Centre at the
University of New South Wales, discussed the study in an interview with The Guardian. At
our current trajectory, the entire deep ocean current could rapidly collapse. In the past,
changes of these currents took centuries, not decades, to unfold. England says that: “We are
talking about the possible long-term extinction of an iconic water mass.” That extinction could
spread to oceanic life. When animals and plants die in the ocean, they sink to the ocean floor and
circulate across the world in deep ocean currents. Upswells return the nutrients they provide to
phytoplankton, the keystone of the entire food chain. It would take a cooling climate and
centuries of waiting to resuscitate the ocean’s food supply if the deep ocean current collapses.
Without that volume of phytoplankton, the oceans will also see diminished capacity to absorb
and sequester CO2, further accelerating global warming. Again, all of these problems are linked.
So what happens if these cascading effects ever do lead to the complete melting of all of
Antarctica’s ice? If Antarctica melts completely, we are looking at a sea level rise of 60 meters,
or approximately 200 feet. Since Antarcica is melting at a slower rate than Greenland,
if Antarctica melts, it means Greenland will have done so,
as well. That’s 70 meters (or 230 feet) of total sea level rise.
In that scenario, the map of the world would be drastically different. Every
single coastal city on earth - every single one - would be underwater. Virtually all of
the state of Florida would be taken by the ocean. Rivers would turn into massive inland
seas. The UK and Ireland would turn into small archipelagos. China would be utterly decimated,
with all of its major population centers drowned in the Pacific. Australia would
look something like a donut with a giant inland sea in the middle.
But there is some good news. Current models do not project the total destruction of Antarcica’s
Ice happening anytime soon. Science Magazine published a large and thorough assessment of
climate tipping points in 2022. They focused on the most vulnerable section of Antarctica,
its Western Ice Sheet. The study concluded that the tipping point for the West Antarctic
Ice Sheet is likely around 1.5°C of global warming, a target we are very likely to hit
by the 2030s. When that tipping point is reached, this particular sheet is on the
fast track for collapse. But we would still have some time to turn things around. Once the tipping
point is reached, the range of total collapse is estimated to be anywhere between 500 and
13,000 years, and most likely somewhere in the neighborhood of 2,000 years, total.
Fortunately, after decades of warnings, some real progress has been made in combating climate
change. In August 2022, the Biden administration passed the Inflation Reduction Act. It includes
the largest investment in climate resilience in American history, devoting hundreds of
billions of dollars to reducing greenhouse gas emissions. A mixture of federal investment in
electric vehicles and tax credits for green energy projects have already had an impact.
Recent analyses are now increasing projections of greenhouse gas reductions by anywhere between
5 and 9% on top of initial projections. According to the former economic advisor for Barack Obama,
Steve Rattner, we are already seeing better-than-predicted effects from the Inflation
Reduction Act. As of May 2023, more than 300 post-IRA green power generation projects had
been announced, more than doubling the number of projects in the same period year-over-year.
The US, Rattner says, is on the cusp of a green revolution; renewable energy is projected to grow
by a factor of ten by 2050. So there is a real possibility that the US could meet its Paris
Climate Agreement emission goals by the same year. If further action is taken, the chances are good.
Nevertheless, climate change is a daisy chain of disaster. Global warming causes one unwanted
effect that leads to another that leads to another. Knock-on problems feed into the next
and the next, working in tandem to eventually affect every corner of the planet. Ultimately,
if Antarctica ever did fully melt away, then it wouldn’t be an isolated incident;
it would be proof of just how much wider trouble we were in. The time
hasn’t passed to stem the time and turn things around, but the clock is ticking.
What do you think? Is there anything we missed? Let us know in the comments, check out these other
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