The worst predicted impacts of climate change are starting to
happen — and much faster than climate scientists expected
Walruses, like these in
Alaska, are being forced ashore in record numbers. Corey Accardo/NOAA/AP
Historians may look to 2015 as the year when shit really started
hitting the fan. Some snapshots: In just the past few months, record-setting
heat waves in Pakistan and India each killed more than 1,000 people. In
Washington State’s Olympic National Park, the rainforest caught fire for the
first time in living memory. London reached 98 degrees Fahrenheit during the
hottest July day ever recorded in the U.K.; The Guardian briefly
had to pause its live blog of the heat wave because its computer servers
overheated. In California, suffering from its worst drought in a millennium, a
50-acre brush fire swelled seventyfold in a matter of hours, jumping across the
I-15 freeway during rush-hour traffic. Then, a few days later, the region was
pounded by intense, virtually unheard-of summer rains. Puerto Rico is under its
strictest water rationing in history as a monster El Niño forms in the tropical
Pacific Ocean, shifting weather patterns worldwide.
Eric Rignot, a climate scientist at NASA and the University of
California-Irvine and a co-author on Hansen's study, said their new research
doesn't necessarily change the worst-case scenario on sea-level rise, it just
makes it much more pressing to think about and discuss, especially among world
leaders. In particular, says Rignot, the new research shows a two-degree
Celsius rise in global temperature — the previously agreed upon
"safe" level of climate change — "would be a catastrophe
for sea-level rise."
Hansen's new study also shows how complicated and unpredictable
climate change can be. Even as global ocean temperatures rise to their highest
levels in recorded history, some parts of the ocean, near where ice is melting
exceptionally fast, are actually cooling, slowing ocean circulation currents
and sending weather patterns into a frenzy. Sure enough, a persistently
cold patch of ocean is starting to show up just south of Greenland, exactly
where previous experimental predictions of a sudden surge of freshwater from
melting ice expected it to be. Michael Mann, another prominent climate
scientist, recently said of the unexpectedly sudden Atlantic slowdown,
"This is yet another example of where observations suggest that climate
model predictions may be too conservative when it comes to the pace at which
certain aspects of climate change are proceeding."
Since storm systems and jet streams in the United States and
Europe partially draw their energy from the difference in ocean temperatures,
the implication of one patch of ocean cooling while the rest of the ocean warms
is profound. Storms will get stronger, and sea-level rise will accelerate.
Scientists like Hansen only expect extreme weather to get worse in the years to
come, though Mann said it was still "unclear" whether recent severe
winters on the East Coast are connected to the phenomenon.
And yet, these aren't even the most disturbing changes happening
to the Earth's biosphere that climate scientists are discovering this year. For
that, you have to look not at the rising sea levels but to what is
actually happening within the oceans themselves.
Water temperatures this year in the North Pacific have never been
this high for this long over such a large area — and it is already having
a profound effect on marine life.
Eighty-year-old Roger
Thomas runs whale-watching trips out of San Francisco. On an excursion earlier
this year, Thomas spotted 25 humpbacks and three blue whales. During a survey
on July 4th, federal officials spotted 115 whales in a single hour near the
Farallon Islands — enough to issue a boating warning. Humpbacks are
occasionally seen offshore in California, but rarely so close to the coast or
in such numbers. Why are they coming so close to shore? Exceptionally warm
water has concentrated the krill and anchovies they feed on into a narrow band
of relatively cool coastal water. The whales are having a heyday. "It's
unbelievable," Thomas told a local paper. "Whales are all over
the place."
Last fall, in northern Alaska, in the same part of the Arctic
where Shell is planning to drill for oil, federal scientists discovered 35,000
walruses congregating on a single beach. It was the largest-ever documented
"haul out" of walruses, and a sign that sea ice, their favored
habitat, is becoming harder and harder to find.
Marine life is moving north, adapting in real time to the warming
ocean. Great white sharks have been sighted breeding near Monterey Bay,
California, the farthest north that's ever been known to occur. A blue marlin
was caught last summer near Catalina Island — 1,000 miles north of its
typical range. Across California, there have been sightings of non-native
animals moving north, such as Mexican red crabs.
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| Salmon on the brink of dying out. Michael Quinton/Newscom |
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No species may be as
uniquely endangered as the one most associated with the Pacific Northwest,
the salmon. Every two weeks, Bill Peterson, an oceanographer and senior
scientist at the National Oceanic and Atmospheric
Administration's Northwest Fisheries Science Center in Oregon, takes to
the sea to collect data he uses to forecast the return of salmon. What
he's been seeing this year is deeply troubling.
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Salmon are crucial to their coastal ecosystem like perhaps few
other species on the planet. A significant portion of the nitrogen in West
Coast forests has been traced back to salmon, which can travel hundreds of
miles upstream to lay their eggs. The largest trees on Earth simply wouldn't
exist without salmon.
But their situation is precarious. This year, officials in
California are bringing salmon downstream in convoys of trucks, because river
levels are too low and the temperatures too warm for them to have a reasonable
chance of surviving. One species, the winter-run Chinook salmon, is at a
particularly increased risk of decline in the next few years, should the warm
water persist offshore.
"You talk to fishermen, and they all say: 'We've never seen
anything like this before,'” says Peterson. "So when you have no
experience with something like this, it gets like, 'What the hell's going
on?' "
Atmospheric scientists increasingly believe that the exceptionally
warm waters over the past months are the early indications of a phase shift in
the Pacific Decadal Oscillation, a cyclical warming of the North Pacific that
happens a few times each century. Positive phases of the PDO have been known to
last for 15 to 20 years, during which global warming can increase at double the
rate as during negative phases of the PDO. It also makes big El Niños, like
this year's, more likely. The nature of PDO phase shifts is unpredictable
— climate scientists simply haven't yet figured out precisely what's
behind them and why they happen when they do. It's not a permanent change
— the ocean's temperature will likely drop from these record highs, at
least temporarily, sometime over the next few years — but the impact on
marine species will be lasting, and scientists have pointed to the PDO as a
global-warming preview.
"The climate [change] models predict this gentle, slow
increase in temperature," says Peterson, "but the main problem we've
had for the last few years is the variability is so high. As scientists, we
can't keep up with it, and neither can the animals." Peterson likens it to
a boxer getting pummeled round after round: "At some point, you knock
them down, and the fight is over."
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| Pavement-melting heat waves in India. Harish Tyagi/EPA/Corbis |
Attendant with this weird wildlife behavior is a stunning drop in
the number of plankton — the basis of the ocean's food chain. In July,
another major study concluded that acidifying oceans are likely to have a
"quite traumatic" impact on plankton diversity, with some species
dying out while others flourish. As the oceans absorb carbon dioxide from the
atmosphere, it's converted into carbonic acid — and the pH of seawater
declines. According to lead author Stephanie Dutkiewicz of MIT, that trend
means "the whole food chain is going to be different."
The Hansen study may have gotten more attention, but the
Dutkiewicz study, and others like it, could have even more dire implications
for our future. The rapid changes Dutkiewicz and her colleagues are observing have
shocked some of their fellow scientists into thinking that yes, actually, we're
heading toward the worst-case scenario. Unlike a prediction of massive
sea-level rise just decades away, the warming and acidifying oceans
represent a problem that seems to have kick-started a mass extinction on the
same time scale.
Jacquelyn Gill is a paleoecologist at the University of Maine. She
knows a lot about extinction, and her work is more relevant than ever.
Essentially, she's trying to save the species that are alive right now by
learning more about what killed off the ones that aren't. The ancient data she
studies shows "really compelling evidence that there can be events of
abrupt climate change that can happen well within human life spans. We're
talking less than a decade."
For the past year or two, a persistent change in winds over the
North Pacific has given rise to what meteorologists and oceanographers are
calling "the blob" — a highly anomalous patch of warm water
between Hawaii, Alaska and Baja California that's thrown the marine ecosystem
into a tailspin. Amid warmer temperatures, plankton numbers have plummeted, and
the myriad species that depend on them have migrated or seen their own numbers
dwindle.
Significant northward surges of warm water have happened before,
even frequently. El Niño, for example, does this on a predictable basis. But
what's happening this year appears to be something new. Some climate scientists
think that the wind shift is linked to the rapid decline in Arctic sea ice over
the past few years, which separate research has shown makes weather patterns
more likely to get stuck.
A similar shift in the behavior of the jet stream has also
contributed to the California drought and severe polar vortex winters in the
Northeast over the past two years. An amplified jet-stream pattern has produced
an unusual doldrum off the West Coast that's persisted for most of the past 18
months. Daniel Swain, a Stanford University meteorologist, has called it the
"Ridiculously Resilient Ridge" — weather patterns just aren't
supposed to last this long.
What's increasingly uncontroversial among scientists is that in
many ecosystems, the impacts of the current off-the-charts temperatures in the
North Pacific will linger for years, or longer. The largest ocean on Earth, the
Pacific is exhibiting cyclical variability to greater extremes than other ocean
basins. While the North Pacific is currently the most dramatic area of change
in the world's oceans, it's not alone: Globally, 2014 was a record-setting year
for ocean temperatures, and 2015 is on pace to beat it soundly, boosted by the
El Niño in the Pacific. Six percent of the world's reefs could disappear before
the end of the decade, perhaps permanently, thanks to warming waters.
Since warmer oceans expand in volume, it's also leading to a surge
in sea-level rise. One recent study showed a slowdown in Atlantic Ocean
currents, perhaps linked to glacial melt from Greenland, that caused a
four-inch rise in sea levels along the Northeast coast in just two years, from 2009
to 2010. To be sure, it seems like this sudden and unpredicted surge was only
temporary, but scientists who studied the surge estimated it to be a
1-in-850-year event, and it's been blamed on accelerated beach erosion
"almost as significant as some hurricane events."
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| Biblical floods in Turkey. Ali Atmaca/Anadolu Agency/Getty |
Possibly worse than
rising ocean temperatures is the acidification of the
waters. Acidification has a direct effect on mollusks and other marine
animals with hard outer bodies: A striking study last year showed that,
along the West Coast, the shells of tiny snails are already dissolving,
with as-yet-unknown consequences on the ecosystem. One of the study's
authors, Nina Bednaršek, told Science magazine that the
snails' shells, pitted by the acidifying ocean,
resembled "cauliflower" or "sandpaper." A similarly
striking study by more than a dozen of the world's top ocean scientists
this July said that the current pace of increasing carbon emissions would
force an "effectively irreversible" change on ocean ecosystems
during this century. In as little as a decade, the study
suggested, chemical changes will rise significantly above background
levels in nearly half ofthe world's oceans.
"I used to think it was kind of hard to make things in the
ocean go extinct," James Barry of the Monterey Bay Aquarium Research Institute
in California told the Seattle Times in 2013. "But
this change we're seeing is happening so fast it's almost
instantaneous."
Thanks to the pressure we're putting on the planet's ecosystem
— warming, acidification and good old-fashioned pollution — the
oceans are set up for several decades of rapid change. Here's what could happen
next.
The combination of excessive nutrients from agricultural runoff,
abnormal wind patterns and the warming oceans is already creating seasonal dead
zones in coastal regions when algae blooms suck up most of the available
oxygen. The appearance of low-oxygen regions has doubled in frequency every 10
years since 1960 and should continue to grow over the coming decades at an even
greater rate.
So far, dead zones have remained mostly close to the coasts, but
in the 21st century, deep-ocean dead zones could become common. These
low-oxygen regions could gradually expand in size — potentially thousands
of miles across — which would force fish, whales, pretty much everything
upward. If this were to occur, large sections of the temperate deep oceans
would suffer should the oxygen-free layer grow so pronounced that it
stratifies, pushing surface ocean warming into overdrive and hindering
upwelling of cooler, nutrient-rich deeper water.
Enhanced evaporation from the warmer oceans will create heavier
downpours, perhaps destabilizing the root systems of forests, and accelerated
runoff will pour more excess nutrients into coastal areas, further enhancing
dead zones. In the past year, downpours have broken records in Long Island,
Phoenix, Detroit, Baltimore, Houston and Pensacola, Florida.
Evidence for the above scenario comes in large part from our best
understanding of what happened 250 million years ago, during the "Great
Dying," when more than 90 percent of all oceanic species perished after a
pulse of carbon dioxide and methane from land-based sources began a period of
profound climate change. The conditions that triggered "Great Dying"
took hundreds of thousands of years to develop. But humans have been emitting
carbon dioxide at a much quicker rate, so the current mass extinction only took
100 years or so to kick-start.
With all these stressors working against it, a hypoxic feedback
loop could wind up destroying some of the oceans' most species-rich ecosystems
within our lifetime. A recent study by Sarah Moffitt of the University of
California-Davis said it could take the ocean thousands of years to recover.
"Looking forward for my kid, people in the future are not going to have
the same ocean that I have today," Moffitt said.
As you might expect, having tickets to the front row of a global
environmental catastrophe is taking an increasingly emotional toll on
scientists, and in some cases pushing them toward advocacy. Of the two dozen or
so scientists I interviewed for this piece, virtually all drifted into
apocalyptic language at some point.
For Simone Alin, an oceanographer focusing on ocean acidification
at NOAA's Pacific Marine Environmental Laboratory in Seattle, the changes she's
seeing hit close to home. The Puget Sound is a natural laboratory for the
coming decades of rapid change because its waters are naturally more acidified
than most of the world's marine ecosystems.
The local oyster industry here is already seeing serious impacts
from acidifying waters and is going to great lengths to avoid a total collapse.
Alin calls oysters, which are non-native, the canary in the coal mine for the
Puget Sound: "A canary is also not native to a coal mine, but that doesn't
mean it's not a good indicator of change."
Though she works on fundamental oceanic changes every day, the
Dutkiewicz study on the impending large-scale changes to plankton caught her
off-guard: "This was alarming to me because if the basis of the food web
changes, then . . . everything could change, right?"
Alin's frank discussion of the looming oceanic apocalypse is
perhaps a product of studying unfathomable change every day. But four years
ago, the birth of her twins "heightened the whole issue," she says.
"I was worried enough about these problems before having kids that I maybe
wondered whether it was a good idea. Now, it just makes me feel
crushed."
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| Katharine Hayhoe speaks about climate change to students and faculty at Wayland Baptist University in 2011. Geoffrey McAllister/Chicago Tribune/MCT/Getty |
Katharine Hayhoe, a
climate scientist and evangelical Christian, moved from Canada to Texas
with her husband, a pastor, precisely because of its vulnerability to
climate change. There, she engages with the evangelical community
on science — almost as a missionary would. But she's already planning
her exit strategy: "If we continue on our current pathway, Canada
will be home for us long term. But the majority of people don't have an exit
strategy. . . . So that's who I'm here trying to help."
James Hansen, the dean of climate scientists, retired from NASA in
2013 to become a climate activist. But for all the gloom of the report he just
put his name to, Hansen is actually somewhat hopeful. That's because he knows
that climate change has a straightforward solution: End fossil-fuel use as
quickly as possible. If tomorrow, the leaders of the United States and China
would agree to a sufficiently strong, coordinated carbon tax that's also
applied to imports, the rest of the world would have no choice but to sign up.
This idea has already been pitched to Congress several times, with tepid
bipartisan support. Even though a carbon tax is probably a long shot, for
Hansen, even the slim possibility that bold action like this might happen is
enough for him to devote the rest of his life to working to achieve it. On a
conference call with reporters in July, Hansen said a potential joint
U.S.-China carbon tax is more important than whatever happens at the United
Nations climate talks in Paris.
One group Hansen is helping is Our Children's Trust, a legal
advocacy organization that's filed a number of novel challenges on behalf of
minors under the idea that climate change is a violation of intergenerational
equity — children, the group argues, are lawfully entitled to inherit a
healthy planet.
A separate challenge to U.S. law is being brought by a former EPA
scientist arguing that carbon dioxide isn't just a pollutant (which, under the
Clean Air Act, can dissipate on its own), it's also a toxic substance. In
general, these substances have exceptionally long life spans in the
environment, cause an unreasonable risk, and therefore require remediation. In
this case, remediation may involve planting vast numbers of trees or restoring
wetlands to bury excess carbon underground.
Even if these novel challenges succeed, it will take years before
a bend in the curve is noticeable. But maybe that's enough. When all feels
lost, saving a few species will feel like a
triumph.
From The Archives Issue 1241: August
13, 2015
