1436 17 DECEMBER 2021 • VOL 374 ISSUE 6574 science.org SCIENCEPHOTO: FLORIAN GAERTNER/GETTY IMAGESHope dims for climate target
The world’s nations gathered in early
November for U.N. climate talks in Glasgow,
U.K., to keep alive the hope of limiting
global warming to 1.5°C above preindustrial
levels. It’s an ambitious goal, with the world
already at 1.2°C and the global economy still
overwhelmingly reliant on fossil fuels. After
2 weeks of discussion, it was clear that—
although rapid change has begun—the 1.5°C
target is on life support.
The recent, rapid adoption of renewable
energy has likely averted the worst-case
warming scenarios of 4°C or more that
seemed probable 10 years ago. And for the
first time, there is a path toward limit-
ing warming to just below 2°C, as long as
nations keep their Glasgow pledges. But
it would take far more ambitious action—
halving present emissions within 10 years—
to reach the 1.5°C goal.
Other progress in Glasgow included a
deal on the rules for carbon markets and
reporting emissions. But given that U.N.
agreements are not binding, the true fate
of carbon emissions will come down to ac-
tion at the national level.
To keep the pressure on, the U.N. talks
are now encouraging countries to offer
revised emissions reduction pledges every
year, including at the next meeting, in
Sharm el-Sheikh, Egypt, in November 2022.
— Pa u l Vo o s e nAlzheimer’s drug prompts outrage
Under normal circumstances, U.S. approval
of the first drug designed to interfere with
the biology underlying Alzheimer’s dis-
ease would be cause for celebration. But
aducanumab, cleared by the Food and DrugBREAKDOWNS OF THE YEAR
What went wrong in
the world of science2021 BREAKTHROUGH OF THE YEAR^
This coal-fired power plant in Boxberg, Germany,
won’t be powered off until 2038.Administration (FDA) in June, was not the
drug many researchers were hoping for.
Its bizarre path to market stoked divisions
between scientists, sowed confusion among
doctors and patients, and prompted many
to question the integrity of the U.S. drug
regulatory system.
The drug, an intravenously delivered
antibody developed by Biogen and marketed
as Aduhelm, clears sticky plaques of the
protein beta amyloid, thought to cause dam-
age in the brains of people with Alzheimer’s
disease. But only one of two large clinical
trials showed the drug was better at slowing
cognitive decline than a placebo. (One pos-
sible explanation is that removing amyloid
plaques isn’t sufficient to reverse a cascade
of harmful brain changes already underway
by the time Alzheimer’s symptoms emerge.)
In November 2020, an independent
advisory committee to FDA recommended
overwhelmingly against approving the drug.
But 7 months later, the agency stunned
scientists by greenlighting aducanumab
under an accelerated approval pathway. That
process relies on a “surrogate endpoint”—
here, beta amyloid reduction—rather than a
demonstration of clinical benefit.
Reaction was swift. Three of 10 advisory
committee members resigned in June. One
of them, Aaron Kesselheim of Harvard
Medical School, called the move “probably
the worst drug approval decision in recent
U.S. history.” Journalists dug into the close
relationship between Biogen executives
and FDA officials, reporting back-channel
communications and unofficial meetings.
Investigations into the approval process by
the inspector general of the Department
of Health and Human Services and by two
committees in the U.S. House of Representa-
tives are ongoing.Some physicians have said they will not
prescribe the drug, and medical centers,
including the Cleveland Clinic and Mount
Sinai, have announced they won’t admin-
ister it. Biogen told investors in September
that sales of the $56,000-a-year drug had
been slower than anticipated. The com-
pany announced in November that it was
investigating the death of a 75-year-old
woman who took aducanumab and devel-
oped brain swelling, a known side effect.
Even supporters of the drug say the tur-
bulent rollout has harmed the field. “All of
this is confusing and scary for people and
families who are facing this devastating
and fatal disease,” Maria Carrillo, chief sci-
entific officer of the Alzheimer’s Associa-
tion, which advocated for approval, said at
a conference last month. —Kelly ServickScientists under fi re
Scientists have long come under attack
for their work. But this year, political rifts
over the COVID-19 pandemic sparked
unprecedented public hostility toward
scientists, including online and offline
intimidation, protests, and death threats.
Those involved in public health suf-
fered the highest profile harassment. U.S.
National Institute of Allergy and Infectious
Diseases Director Anthony Fauci, for ex-
ample, needed a full-time security detail as
early as April 2020. Chris Whitty, England’s
chief medical officer, faced harassment in
public and regular demonstrations outside
his house before the U.K. government took
protective measures. Health workers and
officials around the world have reported
physical and online attacks—and many
have quit their jobs as a result.
Researchers who criticized unproven
treatments for COVID-19 also faced abuse.
Marcus Lacerda, a clinical researcher who
led a large trial in Manaus, Brazil, showing
no benefits from high-dose hydroxychlo-
roquine, received death threats. Scientific
integrity consultant Elisabeth Bik faced
online intimidation—and legal threats—
after raising concerns about ethical and
methodological problems in French micro-
biologist Didier Raoult’s hydroxychloro-
quine research.
Such threats have had a chilling effect
on scientists: A Nature survey of 321
researchers who spoke to the media about
the pandemic found that more than half
have had their credibility attacked, and
15% had received death threats. Many said
the experiences left them unwilling to give
future interviews. —Cathleen O’Grady