Climate Change and the New Age of Extinction
People easily forget “last of” stories about individual species, but the loss of nature also threatens our existence.
The
first documented extinction of 2019 occurred on New Year’s Day, with
the death of a Hawaiian tree snail named George. George, who was about
an inch long, had a grayish body, grayish tentacles, and a conical shell
striped in beige and brown.
He was born in captivity, in Honolulu, and had spent his unassuming life oozing around his terrarium, consuming fungi. Researchers with Hawaii’s forestry department had tried to find a partner for him—George was a hermaphrodite, but he needed a mate in order to reproduce—and when they couldn’t they concluded that he was the last of his kind, Achatinella apexfulva. A few days after he went, presumably gently, into that good night, the department posted a eulogy under the heading “farewell to a beloved snail . . . and a species.” “Unfortunately, he is survived by none,” it observed.
George’s passing prompted a spate of headlines, and then, it seems safe to say, was forgotten. Americans have, by now, grown inured to “last of” stories, which appear with the unsurprising regularity of seasonal dessert recipes. (George the snail was named for Lonesome George, a Pinta Island tortoise from the Galápagos, also the last of his kind, who died in 2012.)
In February, the Australian government declared a ratlike creature known as the Bramble Cay melomys to be extinct. The melomys, found on a single low-lying island between Australia and Papua New Guinea, appears to have been done in by climate change, which has shrunk its habitat and brought ever more damaging flooding. Then, in April, Chinese state media reported that the last known female Yangtze giant softshell turtle had died. “Her species might die with her,” the Washington Post noted.
He was born in captivity, in Honolulu, and had spent his unassuming life oozing around his terrarium, consuming fungi. Researchers with Hawaii’s forestry department had tried to find a partner for him—George was a hermaphrodite, but he needed a mate in order to reproduce—and when they couldn’t they concluded that he was the last of his kind, Achatinella apexfulva. A few days after he went, presumably gently, into that good night, the department posted a eulogy under the heading “farewell to a beloved snail . . . and a species.” “Unfortunately, he is survived by none,” it observed.
George’s passing prompted a spate of headlines, and then, it seems safe to say, was forgotten. Americans have, by now, grown inured to “last of” stories, which appear with the unsurprising regularity of seasonal dessert recipes. (George the snail was named for Lonesome George, a Pinta Island tortoise from the Galápagos, also the last of his kind, who died in 2012.)
In February, the Australian government declared a ratlike creature known as the Bramble Cay melomys to be extinct. The melomys, found on a single low-lying island between Australia and Papua New Guinea, appears to have been done in by climate change, which has shrunk its habitat and brought ever more damaging flooding. Then, in April, Chinese state media reported that the last known female Yangtze giant softshell turtle had died. “Her species might die with her,” the Washington Post noted.
Last week, an international group of scientists issued what the Times
called “the most exhaustive look yet at the decline in biodiversity.”
The findings were grim. On the order of a million species are now facing
extinction, “many within decades.” “What’s at stake here is a liveable
world,” Robert Watson, the chairman of the group, Intergovernmental
Science-Policy Platform on Biodiversity and Ecosystem Services, told Science.
The U.N.-backed I.P.B.E.S.
is to flora and fauna what the Intergovernmental Panel on Climate
Change is to the atmosphere. Based in Bonn, it is funded by a hundred
and thirty-two member nations, including the United States. More than
three hundred experts contributed to its latest assessment, which runs
to more than fifteen hundred pages.
The authors trace two
diverging trend lines: one upward-sloping, for people, and one sloping
downward, for everything else. During the past fifty years, the planet’s
human population has doubled. In that same period, the size of the
global economy has quadrupled, and global trade has grown tenfold. If
hundreds of millions of people around the world are still mired in
poverty, there are many more people living in prosperity today than ever
before.
To keep nearly eight billion people fed, not to mention
housed, clothed, and hooked on YouTube, humans have transformed most of
the earth’s surface. Seventy-five per cent of the land is “significantly
altered,” the I.P.B.E.S. noted in a summary of its report, which was
released last week in Paris. In addition, “66 per cent of the ocean area
is experiencing increasing cumulative impacts, and over 85 per cent of
wetlands (area) has been lost.” Approximately half the world’s coral
cover is gone. In the past ten years alone, at least seventy-five
million acres of “primary or recovering forest” have been destroyed.
Habitat
destruction and overfishing are, for now, the main causes of
biodiversity declines, according to the I.P.B.E.S., but climate change
is emerging as a “direct driver” and is “increasingly exacerbating the
impact of other drivers.” Its effects, the report notes, “are
accelerating.” Watson wrote last week, in the Guardian,
that “we cannot solve the threats of human-induced climate change and
loss of biodiversity in isolation. We either solve both or we solve
neither.”
How long can the two trend lines continue to head in
opposite directions? This is the key question raised by the report, and
it may turn out to be the key question of the century. Many documented
species have already disappeared—to take the example of Hawaiian tree
snails, Achatinella apexfulva is just one of hundreds
of species that have been lost—and probably even more vanished before
they could be identified. Many others, like the Yangtze giant softshell
turtle, are functionally extinct.
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So
far, it could be argued, the casualties haven’t slowed us down. The
I.P.B.E.S. report cautions, however, against assuming that this pattern
will continue. Nature, it succinctly observes, “is essential for human
existence.” The report points to pollinators as one group of organisms
that humans can’t readily do without. Ninety per cent of flowering
plants and seventy-five per cent of all types of food crops rely on
pollination by animals—birds, bats, and (mostly) insects. Cash crops
including coffee, cocoa, and almonds are pollinator-dependent. In many
regions, important pollinators, like native bees, are in decline. It’s
not clear exactly why, but probably one of the major factors is an
increasing reliance on synthetic pesticides, which don’t distinguish
between insects that are useful and those that are unwanted. These
chemicals are supposed to prevent crop failures; the danger is that they
may end up causing them.
As
much as six hundred billion dollars’ worth of annual agricultural
production “is at risk as a result of pollinator loss,” the I.P.B.E.S.
warned. In an earlier report, on
pollinators and the food supply, the group predicted that “total
pollinator loss” would decrease production of the most important
dependent crops “by more than 90 per cent.”
We would, it seems, be
well advised to shift course, if only for our own, species-centric
reasons. And, according to the I.P.B.E.S., there is still time for
“transformative changes” in the “production and consumption of energy,
food, feed, fibre and water.” Regrettably, though, all signs point to
more of the same. In 2018, carbon-dioxide emissions from the energy
sector rose to a new high of thirty-six billion tons. Also in 2018,
nearly thirty million acres of tropical forest were lost—an area the
size of Pennsylvania. As the Web site InsideClimate News noted, this
destruction occurred “even as more corporations and countries made
commitments to preserve tropical forests.” As long as we continue to
tear through the biosphere, expect the losses to continue to mount. ♦
This article appears in the print edition of the May 20, 2019, issue, with the headline “Last Chances.”
