Bill McKibben
New research: the Antarctic current--one of earth's most crucial systems--is
“on a trajectory that looks headed towards collapse,” and not on a scale of
centuries, or even century. On a scale of decades and years.
Truly 'Uncharted Territory.'
Sadly, Trump's arrest was not the biggest news story of the week
Bill McKibben
Last Thursday’s big news story was the indictment of Donald Trump, with
banner headlines in all the papers that still print on paper. The phrase I saw
most often was “uncharted territory,” (and occasionally “unchartered
territory”), which is somewhat true: we’ve never had a former president,
much less one seeking election, under indictment. But, truth be told, it seems
like these waters were fairly easy to predict. It’s been obvious for many years
that Trump disregarded rules and laws, acted on whims and appetites, and
was a greedy skinflint; him ending up in trouble for tax evasion to cover up an
affair with a porn star seems unlikely only in its details.
The truly novel story came out a few hours earlier on Thursday, with the
publication of Nature. The magazine is one of the world’s two pre-eminent
scientific journals, and it emerges weekly from its London base with the
latest in carefully peer-reviewed research. This week it carried one of the
most important installments in the most important saga of our time, the rapid
decline of the planet’s physical health. It was in the form of a dispatch from
the Antarctic, where researchers found, to quote their title, clear evidence of
“Abyssal ocean overturning slowdown and warming driven by Antarctic
meltwater.”
One understands why that was not quite as easy to put into headlines as
Trump’s arrest. But translated from the scientific, it’s the rough equivalent of
“South Pole to Planet Earth: Drop Dead.” As the Guardian explained, in the
best summary of the research I’ve seen, the study shows that “melting ice
around Antarctica will cause a rapid slowdown of a major global deep ocean
current by 2050 that could alter the world’s climate for centuries and
accelerate sea level rise.”
If greenhouse gas emissions continue at today’s levels, the current in the
deepest parts of the ocean could slow down by 40% in only three decades.
This, the scientists said, could generate a cascade of impacts that could
push up sea levels, alter weather patterns and starve marine life of a vital
source of nutrients.
Basically, as melting ice pours fresh water into the ocean around Antarctica,
it dilutes the salinity of the sea; that reduces its density and it’s no longer
heavy enough to sink, pushing out the water that’s already there. The
decomposing organisms that have dropped to the sea floor thus remain
locked there, as the whole vast conveyor belt begins to slow. This
phenomenon has already been observed in the Arctic, where melting water
pouring off Greenland and from melting sea ice has slowed the Arctic
Meridional Overturning Current, or AMOC; the Australian scientists behind
this new study have confirmed that the same thing is underway in the
antipodes. The water that once flowed north, carrying nutrients to the
Pacific, Atlantic and Indian oceans will stagnate in place. Other studies have
predicted additional problems as these currents decline, including moving
rainfall bands by a thousand kilometers from their present position. As one
scientist put it, the Antarctic current is “on a trajectory that looks headed
towards collapse,” and not on a scale of centuries, or even century. On a
scale of decades and years. We’re as far from 2050 as we are from Bill
Clinton denying he’d had “sexual relations” with “that woman,” which is to say
not very far (and also reminder that embarrassing presidents are not in
themselves a new phenomenon, even if Trump took it to an entirely new and
endlessly more dangerous level).
The scale of the systems we’re now affecting is almost incomprehensible—
the flow of the Arctic current is a hundred times larger than the Amazon river.
And the speed is incomprehensible. “In the past, these circulations have
taken more than 1,000 years or so to change, but this is happening over just
a few decades,” one of the study’s author’s said. “It’s way faster than we
thought these circulations could slow down.”
But that’s because we’ve built a new planet, one with a markedly different
atmosphere. Which changes everything. Even before the epochal news from
the Antarctic, the earth’s oceans had been sending distressing signals this
spring. In late March, scientists reported that the temperature of ocean
waters around the planet was rising abruptly, reaching record levels in recent
weeks.
Around mid-March, ocean-temperature monitoring data shows that average
surface water temperatures surpassed 21 degrees Celsius (about 70 degrees
Fahrenheit) around the globe, excluding polar waters, for the first time since
at least 1981, when the data set originated. That is warmer than what
scientists observed at this time of year in 2016, when a strong El Niño drove
the planet to record warmth.This time those records are being set in the
latter phases of a La Nina cold cycle—though it’s becoming clear that a new
El Nino is in the process of forming and should be here by late summer or
early fall. The chances are growing that it will be an extremely strong version
of the Pacific warm current, and if so it will drive the climate crisis into a new
gear—Jim Hansen, the planet’s greatest climatologist, has suggested we
could see temperatures pass, at least for a time, the 1.5 degree temperature
mark. In political terms, this means probably the last spurt in aroused global
fear, translating into the last chance for widescale emissions reductions,
during the period when we still have some hope of really limiting temperature
rise. After that, we may well be in territory where only truly terrifying
interventions like solar geoengineering will suffice.
“The longer we go on with higher rates of greenhouse gas emissions, the
more changes we commit ourselves to,” said one of the Aussie scientists who
brought us this week’s grim and vital news. That’s been true for decades
now; the question as always is if we’ll react to the latest warning. The crime
that history will remember Trump for is almost certainly withdrawing from the
Paris climate accord. But they got Al Capone on his taxes too."
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