Climate change co
biodiversity loss
Current Address: 1 Senior Research Fellow, Univers
Evolution & Environment
Reprinted From: htt
Christopher Trisos
T he impacts of climate change on species
and ecosystems are already evident.
Poleward shifts in the geographic
distributions of species, catastrophic forest
fires and mass bleaching of coral reefs all
bear the fingerprints of climate change.
But what will the world’s biodiversity look
like in the future?
Projections indicate that unless emissions
are rapidly reduced the climate crisis will
get substantially worse. Up to 50% of species
are forecast to lose most of their suitable
climate conditions by 2100 under the
highest greenhouse gas emissions scenario.
But we still lack answers to some basic
questions. When will species be exposed
to potentially dangerous climate conditions?
Will this occur in the next decade or
only later in the century? Will the exposure
of species accumulate gradually, one species
at a time? Or should we expect abrupt
jumps as the climate limits of multiple species
are exceeded?
Our understanding of when and how
abruptly climate driven disruptions of biodiversity
will occur is limited because biodiversity
forecasts typically focus on individual
snapshots of the future. We took a
different route. We used annual projections
of temperature and precipitation from 1850
to 2100 across more than 30,000 marine and
terrestrial species to estimate the timing of
species exposure to potentially dangerous
climate conditions.
Based on these projections, we estimate
that climate change could cause sudden biodiversity
losses. These could occur much
sooner this century than had been expected.
This new analysis indicates that a high
percentage of species in local ecosystems
could be exposed to potentially dangerous
climate conditions simultaneously.
Rather than slowly sliding down a climate
change slope, many ecosystems face a cliff
edge.
Risk of abrupt biodiversity loss early this
century
Abrupt biodiversity loss due to marine
heatwaves that bleach coral reefs is already
under way in tropical oceans. The risk of climate
change causing sudden collapses of
ocean ecosystems is p
further in the 2030s an
greenhouse gas emiss
of abrupt biodiversity
spread onto land, affe
and more temperate
2050s.
These dire projection
perature models to fin
each species can survi
know. Once tempera
species has never ex
have very limited evid
to survive.
It’s possible some sp
with very short gener
able to adapt. For
generation times – su
mammals – it may be
tions before unpreced
occur. When this happ
ity to evolve out of t
limited.
Why it matters
Abrupt losses of biod
change represent a sig
man well-being. In m
percentage of people
diate natural environ
security and income.
local ecosystems wo
their ability to earn a
themselves, potential
poverty.
For instance, marine e
do-Pacific, Caribbean
Africa are at high risk
as early as the 2030s.
of people across these
caught fish as an esse
Eco-tourism revenues
also a major source of
In Latin America, As
parts of the Andes,
and Congo forests ar
risk from 2050 under a
nario.
Sudden loss of anima
negatively affect the fo
in these regions. It co
long-term ability of tr
up carbon if the birds a
important for dispersin
Grassroots Vol 20 No 2 June 2020