REVIEW SUMMARY
◥
CLIMATE CHANGE
Biodiversity redistribution under
climate change: Impacts on
ecosystems and human well-being
Gretta T. Pecl,* Miguel B. Araújo,† Johann D. Bell, Julia Blanchard, Timothy C. Bonebrake,
I-Ching Chen, Timothy D. Clark, Robert K. Colwell, Finn Danielsen, Birgitta Evengård,
Lorena Falconi, Simon Ferrier, Stewart Frusher , Raquel A. Garcia, Roger B. Griffis,
Alistair J. Hobday, Charlene Janion-Scheepers, Marta A. Jarzyna, Sarah Jennings,
Jonathan Lenoir , Hlif I. Linnetved, Victoria Y. Martin, Phillipa C. McCormack,
Jan McDonald, Nicola J. Mitchell, Tero Mustonen, John M. Pandolfi, Nathalie Pettorelli,
Ekaterina Popova, Sharon A. Robinson, Brett R. Scheffers, Justine D. Shaw,
Cascade J. B. Sorte, Jan M. Strugnell, Jennifer M. Sunday, Mao-Ning Tuanmu,
Adriana Vergés, Cecilia Villanueva, Thomas Wernberg, Erik Wapstra, Stephen E. Williams
BACKGROUND: The success of human socie-
ties depends intimatelyonthelivingcompo-
nents of natural and managed systems. Although
the g eographical range limits of species are dy-
namic and fluctuate over time, climate change
is impelling a universal redistribution of life on
Earth. For mari ne, freshwater, and terrestrial
species alike, the first response to changing
climate is often a shift in location, to stay within
preferred environmental conditions. At the
cooler extremes of their distributions, species
are moving poleward, whereas range limits are
contracting at the warmer range edge, where
temperatures are no longer tolerable. On land,
species are also moving to cooler, higher eleva-
tions; in the ocean, they are moving to colder
water at greater depths. Because different species
respond at different rates and to varying degrees,
key interactions among species are often dis-
rupted, and new interactions develop. These
idiosyncrasies can result in novel biotic commu-
nities and rapid changes in ecosystem functioning,
with pervasive and sometimes unexpected conse-
quences that propagate through and affect both
biological and human communities.
ADVANCES: At a time when the world is antic-
ipating unprecedented increases in human pop-
ulation growth and demands, the ability of natural
ecosystems to deliver ecosystem services is being
challenged by the largest climate-driven global
redistribution of species since the Last Glacial
Maximum. We demonstrate the serious conse-
quences of this species redistribution for eco-
nomic development, livelihoods, food security,
human health, and culture,
and we document feed-
backs on climate itself. As
with other impacts of cli-
mate change, species range
shifts will leave “winners”
and “lose r s” in their wake,
radically reshaping the pattern of human well-
being between regions and different sectors
and potentially leading to substantial conflict.
The pervasive impacts of changes in species
distribution transcend single systems or di-
mensions, with feedbacks and linkages be-
tween multiple interacting scales and through
whole ecosystems, inclusive of humans. We ar-
gue that the negative effects of climate change
cannot be adequately anticipated or prepared
for unles s species responses are explicitly in-
cluded in decision-making and global strate-
gic frameworks.
OUTLOOK: Despite mounting evidence for the
pervasive and substantial impacts of a climate-
driven redistribution of Earth’s species, current
global goals, policies, and international agree-
ments fail to account for these effects. With the
predicted intensification of species movements
and their diverse societal and environmental im-
pacts, awarenes s of species “on the move” should
be incorporated into local, regional, and g lo b a l
assessments as standard practice. This will raise
hope that future targets—whether they be global
sustainability goals, plans for regional biodiver-
sity maintenance, or local fishing or forestry har-
vest strategies—can be achievable and that society
is prepared for a world of universal ecological
change. Human society has yet to appreciate the
implications of unprecedented species redistri-
bution for life on Earth, including for human
lives. Even if greenhouse gas emissions stopped
today, the responses required in human systems
to adapt to the most serious effects of climate-
driven species redistribution would be massive.
Meeting these challenges requires governance that
can anticipate and adapt to changing conditions,
as well as minimize negative consequences.
▪
RESEARCH
Pecl et al., Science 355, 1389 (2017) 31 March 2017 1of1
The list of author affiliations is available in the full article online.
*Corresponding author. Email: gretta.pecl@utas.edu.au
†All authors after the first author are listed alphabetically.
Cite this article as G. T. Pecl et al., Science 355,eaai9214
(2017). DOI: 10.1126/science.aai9214
As the global climate changes, human well-being, ecosystem function, and even climate
itself are inc reasin gly affected b y the shifting geography of life. Climate-driven changes in species
distributions, or range shifts, affect human well-being both directly (for example, through emerging
diseases and changes in food supply) and indirectly (b y degr ading ecosystem health). Some range shifts
even cr eate feedbacks (positive or neg ative) on the climate system, altering the pace of climate change.
ON OUR WEBSITE
◥
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REVIEW
◥
CLIMATE CHANGE
Biodiversity redistribution under
climate change: Impacts on
ecosystems and human well-being
Gretta T. Pecl,
1,2
* Miguel B. Araújo,
3,4,5
† Johann D. Bell,
6,7
Julia Blanchard,
1,2
Timothy C. Bonebrake,
8
I-Ching Chen,
9
Timothy D. Clark,
1,10
Robert K. Colwell,
5,11,12,13
Finn Danielsen,
14
Birgitta Evengård,
15
Lorena Falconi,
16
Simon Ferrier,
17
Stewart Frusher,
1,2
Raquel A. Garcia,
18,19
Roger B. Griffis,
20
Alistair J. Hobday,
2,21
Charlene Janion-Scheepers,
22
Marta A. Jarzyna,
23
Sarah Jennings,
2,24
Jonathan Lenoir,
25
Hlif I. Linnetved,
26
Victoria Y. Martin,
27
Phillipa C. McCormack,
28
Jan McDonald,
2,28
Nicola J. Mitchell,
29
Tero Mustonen,
30
John M. Pandolfi,
31
Nathalie Pettorelli,
32
Ekaterina Popova,
33
Sharon A. Robinson,
34
Brett R. Scheffers,
35
Justine D. Shaw,
36
Cascade J. B. Sorte,
37
Jan M. Strugnell,
38,39
Jennifer M. Sunday,
40
Mao-Ning Tuanmu,
41
Adriana Vergés,
42
Cecilia Villanueva,
1,2
Thomas Wernberg,
29,43
Erik Wapstra,
44
Stephen E. Williams
16
Distributions of Earth’s species are changing at accelerating rates, increasingly driven by human-
mediated climate change. Such changes are alr eady altering the composition of ecological
communities, but bey ond conservation of natural systems, how and why does this matter? We
re view evidence that climate-driv en species redistribution at regional to global scales affects
ecosystem functioning, human well-being, and the dynamics of climate change itself . Production
of natural resources required fo r food security , patterns of disease transmission, and processes
of carbon sequestration are all altered b y changes in species distribution. Consideration of
these effects of biodiv ersity redistribution is critical yet lacking in most mitigation and
adaptation strategies, including the United Nation’s Sus tain ab le Deve lo pme nt Goals.
T
he history of life on Earth is closely asso-
ciated with environmental change on multi-
ple spatial and temporal scales (1). A critical
component of this association is the capacity
for species to shift their distributions in re-
sponse to tectonic, oceanographic, or climatic events
(2). Observed and projected climatic changes for
the 21st century, most notably globa l warmin g,
arecomparableinmagnitudetothelargestglobal
changes in the past 65 million years (3, 4). The
combined rate and magnitude of climate change
is already resulting in a global-scale biological re-
sponse. Marine, freshwater, and terrestrial orga-
nisms are altering distributions to stay within their
preferred environmental conditions (5–8), and spe-
cies are likely changing distributions more rapidly
than they have in the past (9). Unlike the intro-
duction of non-native species, which tends to be
idiosyncratic and usually depends on human-
mediated transport, climate-driven redistribution is
ubiquitous, follows repeated patterns, and is poised
to influence a greater proportion of Earth’sbiota.
This redistribution of the planet’s living organisms
is a substantial challenge for human society.
Despite agreements to curb greenhouse gas
emissions, the climate will continue to change for
at leas t the next severa l hundred years, given the
inertia of the oceanic and atmospheric circulation
systems (10), and species will continue to respond,
often with unpredictable consequences. Since 1880,
there has been an average warming of 0.85°C glob-
ally (10), resulting in well-documented shifts in spe-
cies distributions with far-reaching implications
for human societies, yet governments have agreed
to accept more than double this amount of warm-
ing in the future (e.g., the 2°C target from the Paris
Conference of Parties 21). Moreover , current glob-
al commitments will only limit warming to 2.7° to
3.7°C, more than three to four times the warming
already experienced (11). To date, all key internation-
al discussions and agreem ents regarding climate
change have focused on the direct socioeconomic
implications of emissions reduction and on funding
mechanisms; shifting natural ecosystems have not
yet been considered in detail.
Here we review the consequences of climate-
driven species redistribution for economic devel-
opment and the provision of ecosystem services,
including livelihoods, food security, and culture,
as well as for feedbacks on the climate itself (Fig.
1andtableS1).Westartbyexaminingtheimpacts
of climate-driven species redistribution on eco-
system health, human well-being, and the climate
system, before highlighting the governance chal-
lenges these impacts individually and collectively
RESEARCH
Pecl et al., Science 355, eaai9214 (2017) 31 March 2017 1of9
1
Institute for Marine and Antarctic Studies, Hobart, Tasmania 7001, Australia.
2
Centre for Marine Socioecology, Hobart, Tasmania 7001, Australia.
3
Department of Biogeography and Global
Change, Museo Nacional de Ciencias Naturales, Consejo Superior de Investigaciones Científicas, 28006 Madrid, Spain.
4
Centro de Investigação em Biodiversidade e Recursos Geneticos,
Universidade de Évora, 7000-890 Évora, Portugal.
5
Department of Biology, Center for Macroecology, Evolution and Climate, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen
O, Denmark.
6
Australian National Centre for Ocean Resources and Security, University of Wollongong, New South Wales 2522, Australia.
7
Betty and Gordon Moore Center for Science and
Oceans, Conservation International, Arlington, VA 22202, USA.
8
School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China.
9
Department of Life Sciences, National Cheng
Kung University, Tainan 701, Taiwan, Republic of China.
10
Commonwealth Scientific and Industrial Research Organization (CSIRO) Agriculture and Food, Hobart, Tasmania 7000, Australia.
11
Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA.
12
University of Colorado Museum of Natural History, Boulder, CO 80309, USA.
13
Departmento de Ecologia, Universidade Federal de Goiás, CP 131, 74.001-970 Goiânia, Goiás, Brazil.
14
NORDECO, Copenhagen DK-1159, Denmark.
15
Division of Infectious Diseases, Department
of Clinical Microbiology, Umea University, 90187 Umea, Sweden.
16
College of Marine and Environmental Science, James Cook University, Townsville, Queensland 4811, Australia.
17
CSIRO Land and
Water, Canberra, Australian Capital Territory 2601, Australia.
18
Centre for Statistics in Ecology, the Environment and Conservation, Department of Statistical Sciences, University of Cape Town,
Rondebosch 7701, Cape Town, South Africa.
19
Centre for Invasion Biology, Department of Botany and Zoology, Faculty of Science, Stellenbosch University, Matieland 7602, South Africa.
20
National Oceanic and Atmospheric Administration (NOAA) Fisheries Service, Silver Spring, MD 20912, USA.
21
CSIRO Oceans and Atmosphere, Hobart, Tasmania 7000, Australia.
22
Monash
University, School of Biological Sciences, Clayton, Victoria 3800, Australia.
23
Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520, USA.
24
Tasmanian School of
Business and Economics, University of Tasmania, Hobart, Tasmania 7001, Australia.
25
EDYSAN (FRE 3498 CNRS-UPJV), Université de Picardie Jules Verne, 80037 Amiens Cedex 1, France.
26
Institute of Food and Resource Economics, Faculty of Science, University of Copenhagen, Rolighedsvej 25, DK-1958 Frederiksberg C, Denmark.
27
School of Environment, Science and
Engineering, Southern Cross University, Lismore, New South Wales 2480, Australia.
28
Faculty of Law, University of Tasmania, Hobart, Tasmania 7001, Australia.
29
School of Biological Sciences,
The University of Western Australia, Crawley, Western Australia 6009, Australia.
30
Snowchange Cooperative, University of Eastern Finland, Joensuu, FIN 80100 Finland.
31
School of Biological
Sciences, Autralian Research Council (ARC) Centre of Excellence for Coral Reef Studies, The University of Queensland, Brisbane, Queensland 4072, Australia.
32
Institute of Zoology, Zoological
Society of London, Regent’s Park, NW1 4RY London, UK.
33
National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK.
34
Centre
for Sustainable Ecosystem Solutions, School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia.
35
Department of Wildlife Ecology and Conservation,
Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, USA.
36
Centre for Biodiversity and Conservation Science, School of Biological Sciences, The University of
Queensland, St Lucia, Queensland 4072, Australia.
37
Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
38
Centre for Sustainable Tropical Fisheries
and Aquaculture, College of Science and Engineering, James Cook University, Townsville, 4811 Queensland, Australia.
39
Department of Ecology, Environment and Evolution, School of Life
Sciences, La Trobe University, Melbourne, Victoria 3086, Australia.
40
Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
41
Biodiversity
Research Center, Academia Sinica, Taipei 115, Taiwan, Republic of China.
42
Centre for Marine Bio-Innovation and Evolution and Ecology Research Centre, School of Biological, Earth and
Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.
43
Oceans Institute, The University of Western Australia, Perth, Western Australia 6009,
Australia.
44
School of Biological Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia.
*Corresponding author. Email: gretta.pecl@utas.edu.au †All authors after the first author are listed alphabetically.
on April 18, 2017http://science.sciencemag.org/Downloaded from
create. Critically, the pervasive effects of changes
in species distribution trans c end si n gle systems
or dimensions, with feedbacks and linkages among
multiple interacting spatial and temporal scales
and through entire ecosystems, inclusive of hu-
mans (Figs. 2 and 3). We conclude by considering
species redistribution in the context of Earth sys-
tems and sustainable development. Our Review
suggests that the negative effects of climate change
cannot be adequately mitigated or minimized un-
less species responses are explicitly included in
decision-making and strategic frameworks.
Biological responses and
ecosystem health
Species are affected by climate in many ways, in-
cluding range shifts, changes in relative abun-
dance within species ranges, and subtler changes
in activity timing and microhabitat use (12, 13). The
geographic distribution of any species depends
upon its environmental tolerance, dispersal con-
straints, and biological interactions with other
species (14). As climate changes, species must
either tolerate the change, move, adapt, or face
extinction (15). Surviving species may thus have
increased capacity to live in new locations or de-
creased ability to persist where they are currently
situat ed (13).
Shifts in species distributions acro ss latitude,
elevation, and with depth in the ocean have been
extensively documented (Fig. 1). Meta-analyses
show that, on average, terrestrial taxa move pole-
ward by 17 km per decade (5)andmarinetaxaby
72 km per decade (6, 16). Just as terrestrial species
on mountainsides are moving upslope to escape
warming lowlands (17), some fish species are driv-
en deeper as the sea surface warms (18).
The distributional responses of some species
lag behind climate change (6, 8). Such lags can arise
from a range of factors, including species-specific
physiological, behavioral, ecological, and evolution-
ary responses (12). Lack of adequate habitat con-
nectivity and access to microhabitats and associated
microclimates are expected to be critical in increas-
ing exposure to macroclimatic warming and ex-
treme heat events, thus delaying shifts of some
species (19). Furthermore, distribution shifts are
often heterogeneous across geographic gradients
when factors other than temperature drive species
redistribution. For example, precipitation changes
or inter sp eci fi c interactions can cause downward
elevation shifts as climate warms (20). Although
species may adapt to changing climates, either
through phenotypic plasticity or natural selection
(21), all species have limits to their capacity for
adaptive response to changing environments (12),
andtheselimitsareunlikelytoincreaseforspe-
cies already experiencing warm temperatures close
to their tolerance limits (22).
Theidiosyncrasiesofspeciesresponsestocli-
mate change can result in discordant range shifts,
leading to novel biotic communities as species sep-
arate or come into contact in new ways (23). In turn,
altered biotic interactions hinder or facilitate fur-
ther range shifts, often with cascading effects (24).
Changes in predati on dynamics, herbivory, host-
plant associations, competition, and mutualisms
can all have substantial impacts at the commu-
nity level (16, 25). A case in point involves the ex-
pected effects of crabs invading the continental shelf
habitat of Antarctic seafloor echinoderms and
m
ollusks—species that have evolved in the absence
Pecl et al., Science 355, eaai9214 (2017) 31 March 2017 2of9
Human/cultural/social Ecosystem Governance Climate feedbacks
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
3
17
16
18
19
20
21
6
25
22
26
28
23
24
27
29
30
Fig. 1. Climate-driven changes in the distribution of life on Earth are affecting ecosystem health, human well-being, and the dynamics of cli-
mate change, challenging local and regional systems of governance. Examples of documented and predicted climate-driven changes in the
distribution of species throughout marine, terrestrial, and freshwater systems of the globe in tropical, temperate, and polar regions are shown. Details of
the impacts associated with each of these changes in distribution are provided in table S1, according to the numbered key, and the links to specific
Sustainable Development Goals are given in table S2.
RESEARCH | REVIEW
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of skeleton-crushing predators (26). The commu-
nity impacts of shifting species can be of the same
or greater magnitude as the introduction of non-
native species (16), itself recognized as one of
the primary drivers of biodiversity loss (27).
When species range shifts occur in foundation
or habitat-forming species, they can have perva-
sive effects that propagate through entire commu-
nities (28). In some cases, the impacts are so severe
that species redistribution alters ecosystem pro-
ductivity and carbon storage. For example, climate-
driven range expansion of mangroves worldwide,
at the expense of saltmarsh habitat, is changing
local rates of carbon sequestration (29). The loss of
kelp-forest ecosystems in Australia and their re-
placement by seaweed turfs have been linked to
increases in herbivory by the influx of tropical
fishes, exacer bated by increases in water temper-
ature beyond the kelp’s physiological tolerance
limits (30, 31). Diverse disruptions from the
redistribution of species include effects on ter-
restrial productivity (32), impacts on marine com-
munity assembly (33), and threats to the health
of freshwater systems from widespread cyano-
bacteria blooms (34).
The effects on ecosystem functioning and con-
dition arising from species turnover and changes
in the diversity of species within entire commun-
ities are less well under stood. The redistribution
of species may alter the community composition
in space and time (beta diversity), the number of
species co-occurring at any given location (alpha
diversity), and/or the number of species found with-
in a larger region (gamma diversity) (35). The di-
versity and composition of functional traits within
communities may also change as a result of spe-
cies range shifts (36), although changes in function-
al traits may occur through alterations in relative
abundance or community composition, without
changes in species richness. Increasingly, evidence
indicates that spec ies diversity, which under lies
functional diversity, has apositiveeffectonthe
mean level and stability of ecosystem functioning
at local and regional scales (37). It therefore ap-
pears likely that any changes in diversity resulting
from the redistribution of species will have indirect
consequences for ecosystem condition.
Extinction risk from climate change has been
widely discus sed and contest ed (38–40), and pre-
dictions of extinction risk for the 21st century are
considerable (41). In some cases, upslope migra-
tion allows mountain-dwelling species to track
suitable climate, but topography and range loss
can sometimes trap species in isolated and even-
tually unsuitable habitats (42). The American pika
(Ochotona princeps) has been extirpated or severe-
ly diminished in some localities, signaling climate-
induced extinction or at least local extirpation (43).
Complicated synergistic drivers or “extinction debt”—
a process in which functional extin ction precedes
physical extinction—may make climate-induced
extinction seem a distant threat. However , the dis-
appearance of the Bramble Cay melomys (Melomys
rubicola), an Australian rodent declared extinct due
to sea level rise (44), sh ows that anthropogenic cli-
mate change has already caused irreversible spe-
cies loss.
Notwithstanding the rich body of evidence from
the response to climate change of species and eco-
systems in the fossil record (45), understanding
more recent, persistent responses to climate change
usually requires several decades of data to rigor-
ously assess pre- and postclimate change trends
at the level of species and ecosystems (46). Such
long-term data sets for biological systems are rare,
and recent trends of declining funding under-
mine the viability of monitoring programs required
to document and respond to climate change.
Human well-being
The well-being of human societies is tied to the
capacity of natural and altered ecosystems to prod-
uce a wide range of goods and services. Human
well-being, survival, and geographical distribu-
tion have always depended on the ability to re-
spond to envi ronmental change. The emergence
of early humans was likely conditioned by a ca-
pacity to switch prey and diets as changing climat-
ic conditions made new resources available (47).
However, recent technological changes in agricul-
ture, forestry, and fisheries have weakened the di-
rectlinkbetweenhumanmigrationandsurvival.
Now, human societies rely more on technological
and behav ioral innovation to accommodate hu-
man demography, trade and economics, and food
production to changing species distribution pat-
terns. The redistributions of species are expected
to affect the availability and distribution of goods
and services for human well-being in a number of
ways, and the relative immobility of many human
societies, largely imposed by jurisdictional borders,
has limited capacity to respond to environmental
change by migration.
Redistributions of species are likely to drive ma-
jorchangesinthesupplyoffoodandotherproducts.
For example, the relative abundance of skipjack
tuna in the tropical Pacific, which underpins gov-
ernment revenue and food security for many small
island states, is expected to beco me pro gre s si v ely
greater in eastern areas of the western and central
Pacific Ocean, helping to offset the projected ubiq-
uitous decline in the supply of fish from degraded
coral reefs in that region (48). Conversely, it is es-
timated that an average of 34% of European forest
lands, currently covered with valuable timber trees,
such as Norway spruce, will be suitable only for
Mediterranean oak forest vegetation by 2100, re-
sulting in much lower economic returns for forest
owners and the timber industry (49).
The indirect effects of climate change on food
webs are also expected to compound the direct ef-
fects on crops. For example, the distribution and
abundanceofvertebratespeciesthatcontrolcrop
pests are predicted to decline in European states,
where agriculture makes important contributions
to the gross domestic product (50). Shifts in the
spatial distribution of agriculture will be required
to counter the impact of these combined direct
and indirect effects of changing climate. Geograph-
ic shifts in natural resource endowments and in
systems supporting agriculture, forestry, fisheries,
and aquaculture will result in winners and losers,
with many of the negative effects likely to occur in
developing countries (51). A prime example is the
projectedeffectofclimatechangeonthesupplyof
coffee, with principal coffee-growing regions ex-
pected to shift (52).
Species range shifts are also affecting the in-
trinsic and economic values of recreation and tour-
ism, in both negative and positive ways (53). The
buildup of jellyfish due to warmer temperatures in
a Mediterranean lag oon has had a negative effect
on local economies linked to recreation, tourism,
and fishing (54). In southeast Australia, a range-
extending sea urchin has overgrazed macroalgae,
resulting in localized loss of up to 150 ass ociated
taxa and contributing to reduced catch limits for
popular recreational fisheries species dependent
on large seaweed (55). Impacts have been positive
in some contexts, such as the recent emergence
of highly prized species in recreational fishing
areas (53).
Indirect effects from changes in species distri-
butions that underpin society and culture can be
dramatic. In the Arctic, chan ges in distribut ions
of fish, wild reindeer , and caribou are affecting the
food security, traditional knowledge systems, and
endemic cosmologies of indigenous societies (Figs.
1and2)(7). In partial response, the Skolt Sámi in
Finland have introduced adaptation measures to
aid survival of Atlantic salmon stocks faced with
war mi ng water s and to maintain their spiritual
re
lationship with the species. These measures in-
clude increasing the catch of pike to reduce pre-
dation pressure on salmon. In the East Siberian
tundra, faced with melting permafrost, the Chukchi
people are struggling to maintain their tradi-
tional nomadic reindeer-herding practices (56)
(Fig. 2). Citizen-recording of climate-induced changes
to complement assessments based on scientific
sampling and remote sensing forms part of their
strategy to maintain traditional practices.
Human health is also likely to be seriously af-
fected by changes in the distribution and viru-
lence of animal-borne pathogens, which already
account for 70% of emerging infections (57, 58).
Movement of mosquitoes in response to global
warming is a threat to health in many countries
through predicted increases in the number of known
and potentially new diseases (Fig. 3). Malaria, the
most prevalent mosquito-borne disease, has long
been a risk for almost half of the world’spopu-
lation, with more than 200 million cases recorded
in 2014 (59). Malaria is expected to reach new areas
with the poleward and elevational migration of
Anopheles mosquito vectors (60). Climate-related
transmission of malaria can result in epidemics
due to lack of immunity among local residents (59)
and will challenge health systems at national and
international scales, diverting public- and private-
sector resources from other uses.
The winners and losers arising from the redis-
tributions of species will reshape patterns of hu-
man well-being among regions and sectors of
industry and communities (61). Those regions
with the strongest climate drivers, with the most-
sensitivespecies,andwherehumanshavetheleast
capacity to respond will be among the most af-
fected. Developing nations, particularly those near
the equator , are likely to experience greater climate-
related local extinctions due to poleward and
Pecl et al., Science 355, eaai9214 (2017) 31 March 2017 3of9
RESEARCH | REVIEW
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elevational range shifts (62)andwillfacegreater
economic constraints. In some cases, species re-
distribution will also lead to substantial conflict—
the recent expansion of mackerel into Icelandic
waters is a case in point (Fig.
1 and table S1). The mackerel
fishery in Iceland increased
from 1700 metric tons in 2006
to 120,000 metric tons in 2010,
resulting in “mackerel wars”
between Iceland and compet-
ing countries that have tradi-
tionally been allocated mackerel
quotas (63). Likewise, with up-
slope shift of climate zones in
the Italian Alps, intensified
conflict is anticipated between
recreation and biodiversity sec-
tors. For example, climate-driven
contractions in the most val-
uable habitat for high-elevation
threatened bird species and for
ski trails are predicted to in-
crease, along with an increase
in the degree of overlap be-
tween the bird habitat and the
areas most suitable for future
ski trail construction (64).
Climate feedbacks
Species redistributions are ex-
pected to influence climate
feedbacks via changes in al-
bedo, biologically driven se-
questration of carbon from
the atmosphere to the deep
sea (the “biological pump”),
and the release of greenhouse
gases (65). For instance, ter-
restrial plants affect albedo via
leaf area and color and regu-
late the global carbon cycle
through CO
2
atmosphere-land
exchanges. Similarly, CO
2
atmosphere-ocean exchanges
are biologically modulated by
CO
2
-fixing photosynthetic phy-
toplankton and by the biolog-
ical pump that exports carbon
into deep ocean reservoirs (66).
The climate-d riven shifts in
species distributions most like-
ly to affect biosphere feedbacks
involve redistribution of vege-
tation on land (Figs. 2 and 4)
and phytoplankton in the ocean.
Decreased albedo, arising from
the combined effect of earlier
snowmelt and increasing shrub
density at high latitudes, al-
ready contributes to increased
net radiation and atmospher-
ic heating, amplifying high-
latitude warming (67). Thus,
continued warming will de-
crease the albedo in the Arc-
tic, not only through a decline
in snow cover but also through a northward shift
of coniferous trees (Fig. 2). Pearson et al.(68)
projected that by 2050, vegetation in the Arctic
will mostly shift from tundra (dominated by
lichens and mosses with high albedo) to boreal
forest (dominated by coniferous trees with low
albedo). Additionally, the greenhouse effect may
be amplified by top-of-atmosphere radiative
Pecl et al., Science 355, eaai9214 (2017) 31 March 2017 4of9
Fig. 2. Species on the move drive greening of the Arctic. Changes in species distribution can lead to climate
feedbacks, changes in ecosystem services, and impacts on human societies, with feedbacks and linkages between each
of these dimensions, illustrated here through climate-driven changes in Arctic vegetation. See Fig. 4 for a more com-
prehensive description of the direct and indirect climate feedbacks. See also (10, 68, 69, 75, 106–110).
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