Changes in the Arctic EnvironmentStephen Macko, Professor Department of Environmental Sciences, University of Virginia

May 21, 2009; Seward, AlaskaPhoto 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” suspectsMethane 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 tourismPhoto: Stephen Macko

Greater Risks of Introduction of Environmental Contaminants

2006, Prudhoe Bay, 1 million litersGreater wind velocities

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

Potentially many times the reserves of fossil fuel carbon exists as methane hydrates.

The Arctic alone is estimated to have greater than 400 Gt .

Photo: Stephen Macko

The seabed of the East Siberian ArcticShelf serves as a source of methane tothe water columnDistribution of methane in the bottom layer (2003-2007)Shakhova and Semiletov, 2008

Methane levels are rising in the Arctic Ocean

Graphic courtesy Introduction to Oceanography, Sverdrup et al. Prentice Hall

Arctic Peats and PermafrostLena River delta , Siberia

Mallick Well in Canada Photo credit Department of Energy

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

A bloom of coccolithophore plankton recorded near Newfoundland in 1999 by NASA’s SeaWiFs satellite

dinoflagellate

coccolithophore

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

Upper ocean temperatures have increased by 1ºC in the last 50

years -WAP most rapidly warming region on planet

Southern Ocean is also Undergoing Major Environmental Changes

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30% decline in Antarctic krill in SouthAtlantic in last 30 years

Graphics Eileen Hoffman, Old Dominion University/GLOBEC

GLOBEC INTEGRATED ANTARCTIC STUDY

Graphics Eileen Hoffman, Old Dominion University/GLOBEC

The Southern Ocean Food Web?

Graphics Eileen Hoffman, Old Dominion University/GLOBEC

Multiple Food Webs

Ross Sea

Western AntarcticPeninsula

Classical Food Web

Graphics Eileen Hoffman, Old Dominion University/GLOBEC

Differences influence structure, just like the Arctic

HighAntarctic

SubAntarctic

LowProduction High Production

Seasonal length

Differences due toCirculation

Sea-iceBiogeochemistry

ProductionSeasonality

Graphics Eileen Hoffman, Old Dominion University/GLOBEC

Alternative pathways buffer the effect of the change – but possibly lead to long-term modification.

Need better quantification of alternative pathways

And Change leads to Alternative Food Web Pathways

High krill Low krill

Graphics Eileen Hoffman, Old Dominion University/GLOBEC

Energy flow inalternative food webpathways

Less energy reaching higher trophiclevels

Top predators nutrition affected, potential decline in abundances

Graphics Eileen Hoffman, Old Dominion University/GLOBEC

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 circulatescyclonically (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

From 1986-1996; anticyclonic

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

Higher trophic levels, like the mammals

Belugas

Photo Stephen MAcko

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

Red Knot Declines in migratory birdsPhoto courtesy Mike Erwin

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)

pH of the Ocean 8.24 8.13

(1.29x H+)7.87(2.35x H+

Continued CO2 Emissions and Ocean Acidification

Anthropogenic CO2predicted 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

While climate change has uncertainty, these geochemical changes are highly predictable. Only the time scale, and thusmixing scale length are really under debate.

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

PISCIVOROUS FISH

DISSOLVED ORGANIC MATTER

PLANKTIVOROUS FISH

ZOOPLANKTON CILIATES

NANOFLAGELLATES

BACTERIA

PHYTOPLANKTON

2x104

Size

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m)

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Change in any part of the foodweb may have consequences on the rest of the

foodweb, ocean biogeochemistry and the whole ecosystem

Whole Ecosystem Effects

Graphics Eileen Hoffman, Old Dominion University

An opportunity in a time of unprecedented change?

Photo Stephen Macko

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

SCIENCE AND GOVERNMENT:Governance and Environmental Change in the Arctic OceanPaul Arthur Berkman and Oran R. Young Science April 17, 2009

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

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

A team effort

Photo courtesy GIFT Workshop, Committee on Education, EGU