30 THENEWYORKER,DECEMBER13, 2021
THECONTROLOFNATURE
A NEW LEAF
Could tinkering with photosynthesis prevent a global food crisis?BY ELIZABETH KOLBERT
ILLUSTRATION BY DERRICK SCHULTZ
T
his story begins about two billion
years ago, when the world, if not
young, exactly, was a lot more impres-
sionable. The planet spun faster, so the
sun rose every twenty-one hours. The
earliest continents were forming—Arc-
tica, for instance, which persists as bits
and pieces of Siberia. Most of the globe
was given over to oceans, and the oceans
teemed with microbes.
Some of these microbes—the group
known as cyanobacteria—had mastered
a peculiarly powerful form of alchemy.
They lived off sunlight, which they con-
verted into sugar. As a waste product,
they gave off oxygen. Cyanobacteria were
so plentiful, and so good at what they
did, that they changed the world. They
altered the oceans’ chemistry, and then
the atmosphere’s. Formerly in short sup-
ply, oxygen became abundant. Anything
that couldn’t tolerate it either died off
or retreated to some dark, airless corner.
One day, another organism—a sort
of proto-alga—devoured a cyanobacte-
rium. Instead of being destroyed, as you
might expect, the bacterium took up
residence, like Jonah in the whale. This
accommodation, unlikely as it was, sent
life in a new direction. The secret to
photosynthesis passed to the alga and
all its heirs.
A billion years went by. The planet’s
rotation slowed. The continents crashedtogether to form a supercontinent, Ro-
dinia, then drifted apart again. The alga’s
heirs diversified.
One side of the family stuck to the
water. Another branch set out to colo-
nize dry land. The first explorers stayed
small and low to the ground. (These
were probably related to liverworts.)
Eventually, they were joined by the an-
cestors of today’s ferns and mosses. There
was so much empty space—and hence
available light—that plants, as one bot-
anist has put it, found terrestrial life “ir-
resistible.” They spread out their fronds
and began to grow taller. The rise of
plants made possible the rise of plant-eat-
ing animals. During the Carboniferous
period, towering tree ferns and giant
club mosses covered the earth, and in-
sects with wingspans of more than two
feet flitted through them.
Some two hundred million years later,
in the early Cretaceous, plants with flow-
ers appeared on the scene. They were
so fabulously successful that they soon
took over. (Charles Darwin was deeply
troubled by the sudden appearance of
flowering plants in the fossil record, de-
scribing it as an “abominable mystery.”)
Later still, grasses and cacti evolved.
Through it all, plants continued to
make a living more or less the same way
they had since that ancient cyanobac-
terium took up with the alga. Photo-
synthesis remained remarkably stable
over thousands of millennia of natural
selection. It didn’t change when humans
began to domesticate plants, ten thou-
sand years ago, or, later, when they fig-
ured out how to irrigate, fertilize, and,
finally, hybridize them. It always worked
well enough to power the planet—that
is, until now.S
tephen Long is a professor of plant
biology and crop sciences at the Uni-
versity of Illinois Urbana-Champaign
and the director of a project called Re-
alizing Increased Photosynthetic Effi-
ciency, or RIPE. The premise of RIPE is
that, as remarkable as photosynthesis
may be, it needs to do better.
At seventy-one, Long is thin and
fit, with a craggy face and a voice so
soft it borders on a murmur. He grew
up in London in a working-class fam-
ily and attended what he describes as
“not the best” high school. (It’s since
It is often said that the world now needs a Second Green Revolution. been closed.) One of the teachers at