Emperor penguins increasingly threatened by climate change

Date:
August 3, 2021
Source:
Woods Hole Oceanographic Institution
Summary:
A new study provides valuable new data that highlights how species
extinction risk is accelerating due to rapid climate change and
an increase in extreme climate events, such as glacial calving
and sea ice loss.



FULL STORY ==========================================================================
A new study published today in Global Change Biology provides valuable
new data that highlights how species extinction risk is accelerating
due to rapid climate change and an increase in extreme climate events,
such as glacial calving and sea ice loss. The study, led by Stephanie Jenouvrier, associate scientist, and seabird ecologist at Woods Hole Oceanographic Institution, and co-authored by an international team of scientists, policy experts, ecologists, and climate scientists, provided pivotal research and projections tailored for use by the U.S Fish &
Wildlife Service (USFWS). Their work proposed that emperor penguins be
listed as threatened under the Endangered Species Act and this week,
USFWS submitted that listing proposal.


========================================================================== "Scientists have a responsibility to make people aware of the need for
change through objective evidence," explained Jenouvrier. "With the help
of a dedicated team, we put together this paper for the USFWS to provide additional analyses of future projections and help inform policy and
protection for the species." The study presents the projected dynamics
of all known emperor penguin colonies under different greenhouse gas
emission scenarios using a climate?dependent meta-population model that includes for the first time, the effects of extreme climate events based
on the observational satellite record of colonies.

According to co-author Shaye Wolf, Climate Science Director at the
Center for Biological Diversity, "Protection of species through legal frameworks should facilitate conservation actions that in turn should
help mitigate climate change impacts." Co-author Judy Che-Castaldo of the Lincoln Park Zoo added, "The study is framed in the context of the U.S Endangered Species Act, one of the most progressive pieces of legislation
in relation to species protection." The study demonstrates that extreme
events impact the resiliency, redundancy, and representation (3Rs)
of emperor penguins. Resiliency is the ability to withstand stochastic
(or random) disturbance, which may be measured through population size,
growth rate, and connectivity among populations. Redundancy is the ability
to withstand catastrophic events, and considers the number, distribution, resiliency, and connectivity of populations. Representation is the
ability to adapt to changing environmental conditions, and is related
to capturing the geographic, genetic, and life history variation that
exists across the species' ecological setting. Together, the 3Rs encompass aspects that contribute to species persistence (e.g., demography, spatial distribution, diversity) and are important for assessing climate threats
in the foreseeable future. The study shows that if sea ice declines
at the rate projected by climate models under current energy-system
trends and policies, the 3Rs would be dramatically reduced and almost
all colonies would become quasi-extinct by 2100.

The novel results described in the paper also have important implications
for assessing climate change risks to other species. According to
the authors, rapid climate change is increasing stress on species and ecosystems, and the risk of extinction will accelerate with continued
global warming. Emperor penguins live in the icy coastal regions of
Antarctica, but current climate models project significant declines in Antarctic Sea ice to which the emperor penguins' life cycle is closely
tied. The study reinforces the need for legal recognition and enhanced precautionary management, particularly given continued increases in
greenhouse gas emissions.



========================================================================== "Emperor penguins live in a delicate balance with their environment,
there is a sea ice 'Goldilocks' zone," said Jenouvrier. "If there is too
little sea ice, chicks can drown when sea ice breaks up early; if there
is too much sea ice, foraging trips become too long and more arduous,
and the chicks may starve." "Given the species' reliance upon sea ice
for breeding, molting, and feeding, the most important threat for emperor penguins is climate change, which would lead to Antarctic Sea ice losses
over this century," explained Marika Holland a climate scientist with
the National Center for Atmospheric Research. "Trends in warming and consequential sea ice losses through the end of the century are clear
and unidirectional under all projections from all climate models."
Christophe Barbraud, from the Centre d'Etudes Biologiques de Chize',
has been studying emperor penguins for decades, and added, "The long-term monitoring of emperor penguins at Pointe Ge'ologie, Antarctica, over the
past 70 years was critical to decipher how sea ice affects the bird's
life cycle. This knowledge, together with recent satellite imagery,
provided necessary information to build and validate population models."
"The high-resolution satellite images provided critical remote access to
places we'd never be able to see otherwise. As it turns out, sometimes
colonies "blink," seemingly because of drastic changes in the environment
that we are still working to solve," added Michelle LaRue of the
Department of Earth and Environmental Sciences, University of Minnesota.

Extreme events, as observed through the satellite records, amplify the projected declines by previous studies. If greenhouse gas emissions
continue to rise at levels similar to today -- causing temperatures to
rise and Antarctic Sea ice to shrink -- penguin population numbers will diminish slowly until about 2040, after which they would decline at a much steeper rate as sea ice coverage drops below a usable threshold, with
the species being quasi -extinct as 98% colonies will have disappeared
by 2100.

Phil Trathan, the head of conservation biology with the British Antarctic Survey (BAS), has studied Antarctic penguins for over 30 years. "Near-term global policy decisions under Paris Agreement objectives are intended
to limit temperature increases to well below 2DEGC. This would ensure
safe places for the emperor penguin, halting dramatic global population declines. As such, the future of emperor penguins ultimately depends upon decisions made today. The most important action is to reduce greenhouse
gas emissions to limit further warming." "We hope that global society
will listen to science and meet the moment.

Protecting these systems requires legal frameworks that must be
appropriately founded and based on the best available scientific
evidence. Building an international framework will be key, but in
the meantime immediate efforts should focus on those tools already in
place, such as the ESA." The international team that carried out the
study highlights how this work cuts across the boundaries of science disciplines and how interdisciplinary science is key in protecting the
future of this iconic species.

"This study provides the best available science for projecting emperor
penguin populations in the context of future climate change and informs
policy makers about whether the emperor penguin warrants listing under the ESA," concluded Jenouvrier. "The future of this iconic species depends
on immediate actions to decarbonize society and increased protections
for species endangered by climate change.

========================================================================== Story Source: Materials provided by
Woods_Hole_Oceanographic_Institution. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Stephanie Jenouvrier, Che‐Castaldo Judy, Shaye Wolf, Marika
Holland, Sara Labrousse, Michelle LaRue, Barbara Wienecke, Peter
Fretwell, Christophe Barbraud, Noah Greenwald, Julienne Stroeve,
Philip N. Trathan. The call of the emperor penguin: Legal responses
to species threatened by climate change. Global Change Biology,
2021; DOI: 10.1111/ gcb.15806 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210803121348.htm

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