Changes in the Arctic Environment
Stephen Macko, Professor
Department of Environmental Sciences, University of Virginia
May 21, 2009; Seward, Alaska
Photo courtesy John Snyder
This is a time of unprecedented
change in the Arctic. Conditions
are changing faster than at any
time in the past 10,000 years.
Photo: Stephen Macko
Graphics courtesy Robert A. Rohde / Global Warming Art
Potentially 100’s of millions will be
affected by rising sea level
Graphics courtesy Robert A. Rohde / Global Warming Art
The Arctic receives less recognition
Graphics courtesy Robert A. Rohde / Global Warming Art
Graphics courtesy Michael Mann/ IPCC
Graphics courtesy
Michael Mann/ IPCC
The “usual” suspects
Methane has 10-20 times
the effect of carbon dioxide,
but does not reside in the
atmosphere as long
Most of the emissions come
from the developed world,
and chiefly a few countries.
This will change with higher
and warmer seas.
Projected Future Warming
Graphics courtesy Michael Mann, IPCC
Graphic courtesy
Introduction to
Oceanography, Sverdrup et
al. Prentice Hall
Some of the changes influenced
by rising sea levels and warming
temperatures are obvious:
Increased exploration and
exploitation of Arctic mineral
resources (hydrocarbons)
Increased avenues for maritime
transport between the Atlantic and
Pacific (Northwest Passage)
Increased tourism
Photo: Stephen Macko
Greater Risks of Introduction of
Environmental Contaminants
Greater wind velocities
2006, Prudhoe Bay, 1 million liters
Propagation of those contaminants
within the Arctic food webs
Some of the effects or “collateral”
impacts are not so obvious and
desperately need further study
• Release of methane from either gas
hydrates on the seabed, or stored in the
coastal permafrost peats
• Loss of diversity and modification of
sustainable trophic structure (food webs)
• Changes to the Ocean chemistry itself (pH)
Gas Hydrates on the Seabed
Photo: Stephen Macko
Potentially many times the reserves of
fossil fuel carbon exists as methane
hydrates.
The Arctic alone is estimated to have
greater than 400 Gt .
Methane levels
are rising in the
Arctic Ocean
The seabed of the East
Siberian Arctic
Shelf serves as a source
of methane to
the water column
Distribution of methane
in the bottom layer
(2003-2007)
Shakhova and
Semiletov, 2008
Graphic
courtesy
Introduction to
Oceanography,
Sverdrup et al.
Prentice Hall
Arctic Peats and Permafrost
Lena River
delta , Siberia
Photo credit Department of Energy
Mallick Well
in Canada
With Rising Temperatures
Permafrost will Shrink
Graphic courtesy Introduction to Oceanography, Sverdrup et al. Prentice Hall
Graphic courtesy Introduction to
Oceanography, Sverdrup et al. Prentice Hall
Primary Production of the Water
Column: Phytoplankton
coccolithophore
A bloom of coccolithophore plankton
recorded near Newfoundland in 1999
by NASA’s SeaWiFs satellite
dinoflagellate
SEAWIFS Image courtesy NASA
Life at the edge: Melosira arctica
Massive production supports the
community of the benthic
environment. Diminished sea ice
suggests significant loss of this
production to coastal food webs
Photo Stephen Macko
Arctic coastal food web
Graphic courtesy Introduction to
Oceanography, Sverdrup et al.
Prentice Hall
Southern Ocean is also Undergoing
Major Environmental Changes
Parkinson (2002)
30% decline in Antarctic krill in South
Atlantic in last 30 years
2002
2000
1998
1996
1994
1992
1990
1988
1986
1984
1982
1
1980
10
1978
Upper ocean temperatures have
increased by 1ºC in the last 50
years -WAP most rapidly warming
region on planet
100
1976
Density (no. m-2)
1000
Year
Graphics Eileen Hoffman, Old Dominion University/GLOBEC
Graphics Eileen Hoffman, Old Dominion University/GLOBEC
GLOBEC INTEGRATED ANTARCTIC STUDY
Graphics Eileen Hoffman, Old Dominion University/GLOBEC
The Southern Ocean Food Web?
Multiple Food Webs
Graphics Eileen Hoffman, Old
Dominion University/GLOBEC
Classical
Food Web
Western
Antarctic
Peninsula
Ross Sea
Differences influence structure,
just like the Arctic
Seasonal length
Sub
Antarctic
Differences due to
Circulation
Sea-ice
Biogeochemistry
Production
Seasonality
High
Antarctic
Low
Production
High Production
Graphics Eileen Hoffman,
Old Dominion
University/GLOBEC
And Change leads to Alternative
Food Web Pathways
High krill
Low
krill
Alternative pathways buffer the effect of the change – but possibly
lead to long-term modification.
Graphics Eileen Hoffman,
Need better quantification of alternative pathways Old Dominion
University/GLOBEC
Energy flow in
alternative food web
pathways
Less energy reaching
higher trophic
levels
Top predators nutrition
affected, potential
decline in abundances
Graphics Eileen Hoffman, Old Dominion University/GLOBEC
From 1986-1996; anticyclonic
Idealized patterns of the dominant
circulation regimes of the Arctic Ocean.
Two circulation regimes of surface
waters (anticyclonic—top; cyclonic—
bottom) are shown in wide blue arrows.
In the cyclonic regime the clockwise
circulation pattern in the Beaufort Sea
region (the Beaufort Gyre) weakens, and
the flow across the basin, from the
Siberian and Russian coasts to Fram
Strait (the Transpolar Drift), shifts
poleward. The cyclonic pattern
dominated during 1989–1996; the
anticyclonic pattern has prevailed since
1997. The Atlantic water circulates
cyclonically (red arrows) at approximately
200–800 m deep, independent of the
circulation regime of the surface layer.
(Adapted from Proshutinsky et al., 2005.)
Since 1997; cyclonic
Spawning and Higher Temperatures
Critical temperatures exist
for all fish
Need for ice cover is
unknown for all of the
species
Stock size for present
populations under ice
unknown- easy to
overfish
Photo Stephen MAcko
Higher trophic levels, like the mammals
Belugas
Seals, walruses, sea
lions, polar bears
Photo Stephen Macko
will have their survival threatened as the
habitat and tropic structure changes
Photo GIFT Workshop, EGU
Photo courtesy Mike Erwin
Red Knot
Declines in migratory birds
One of hundreds of species ….
and millions of shorebirds… that
use the coastal zone for breeding
One of hundreds of species …. and
millions of shorebirds… using the
Arctic coastal zone for breeding….
and are or will be in decline
The ocean is now > 0.1 pH units lower than
pre-industrial times and contains about 400
billion tons of fossil fuel CO2.
Photo courtesy GIFT Workshop, Committee on Education, EGU
Foraminifera: composed of
calcium carbonate
Declining pH of the Ocean
Year
1751
2000
2100?
CO2 ppmv
275
375 (1.36x)
750 (2.73x)
8.24
8.13
(1.29x H+)
7.87
(2.35x H+
pH of the
Ocean
Continued CO2 Emissions and Ocean Acidification
While climate change has uncertainty, these geochemical
changes are highly predictable. Only the time scale, and thus
mixing scale length are really under debate.
Anthropogenic CO2
predicted to decrease
surface ocean pH by 0.7
pH has probably already
changed by 0.1 in surface
waters due to absorption of
anthropogenic CO2
Caldeira & Wickett 2003, Nature: A simulation of changes in ocean pH assuming continued
usage of known fossil fuel reserves.
Coccolithophores and Ocean
Acidification
A bloom of coccolithophore plankton recorded near
Newfoundland in 1999 by NASA’s SeaWiFs satellite
Acidification of the
ocean waters
Whole Ecosystem Effects
PISCIVOROUS
FISH
2x10
4
PLANKTIVOROUS
FISH
Change in any part of the foodweb may
have consequences on the rest of the
foodweb, ocean biogeochemistry and the
whole ecosystem
2x10
3
ZOOPLANKTON
CILIATES
Size
(µm)
200
PHYTOPLANKTON
20
NANOFLAGELLATE
S
2
BACTERIA
0.2
DISSOLVED
ORGANIC
MATTER
Graphics Eileen Hoffman, Old Dominion University
= microbial loop
= classical
food chain
An opportunity in a time of
unprecedented change?
Photo Stephen Macko
SCIENCE AND GOVERNMENT:
Governance and Environmental Change in the Arctic Ocean
Paul Arthur Berkman and Oran R. Young
Science April 17, 2009
Jurisdictional representations of the Arctic Ocean with boundaries based on (left) sea floor as a
source of conflict among nations (different colors) and (right) overlying water column as a source of
cooperation, with the high seas (dark blue) as an international space in the central Arctic Ocean
surrounded by EEZs (light blue)
CREDITS: (TOP) INTERNATIONAL BOUNDARIES RESEARCH UNIT, UNIVERSITY OF DURHAM; (BOTTOM)
ADAPTED FROM CANADIAN POLAR COMMISSION
An unprecedented opportunity for
international environmental cooperation
Photo Stephen Macko
The future for consequential
change in the Arctic is
already here
Photo courtesy GIFT Workshop, Committee on Education, EGU
A team effort
Acknowledgements
Michael Mann, Michael Erwin,
Carleton Ray, Howie Epstein,
Eileen Hofman, Scott Doney,
Sarah Cooley, Carol Turley, the
IPCC, ACIA, GIFT and the
Community of Polar Researchers
and their graphics support
Photo courtesy GIFT Workshop, Committee on Education, EGU