Transcript Warming Deep Seas 0606 - Global Warming

Warming Neptune’s Kingdom
The Impacts of Global Climate
Change on Marine Ecosystems
By
Edward L. Miles
Bloedel Professor of Marine Studies and Public Affairs
Senior Fellow and Co-Director
Center for Science in the Earth System, JISAO
University of Washington
Seattle, WA. 98195
The Keeling Curve
Peter Brewer. 2004 ICES LECTURE
• “My message is simple; there are massive, and until very
recently unrecognized, changes of geologic scale taking
place in the ocean as we have entered the anthropocene
era, and these may very well have profound effects on
ocean ecosystems world wide…ocean chemistry is
being altered on a scale not seen for millions of years,
and there are very basic questions on the impact on
ecosystems and biogeochemical cycles to which we do
not yet have answers.
Framing the Problem: Climate in a World
of Multiple Stresses
• Increasing surface & sub-surface heat in the
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world ocean.
Large scale changes in ocean chemistry (Feely
et al., 2004; Sabine et al. 2004).
Global overfishing--”Fishing down the food
chain”, (Pauly, 2003).
Land-based pollution of the coastal ocean
(GESAMP, 2001).
Proliferation of invasive species
Trends in Surface and
Subsurface Heat in the World
Ocean
Major Sources of Dislocation for marine
Ecosystems: Changes in Surface and Sub-surface
Heat
• Levitus, Antonov, Boyer, and Stephens. 2000.
Warming of the World Ocean. SCIENCE. VOL. 287 (24 March).
Levitus, Antonov, and Boyer. 2005. Warming of the world ocean.
GEOPHYSICAL RESEARCH LETTERS. VOL. 32,
1029/2004GL021592.
Barnett, Tim P., David W. Pierce, Reinur Schnur. 2001. Detection of
Anthropogenic Climate Change in the World’s Oceans. SCIENCE,
VOL. 292 (13 April).
• [Barnett, Tim P. et al. 2005. Penetration of Human Induced Warming
into the World’s Oceans. SCIENCE,VOL. 309 (8 July)].
Levitus et al.
2000. Fig. 1.
Implications of Levitus et al. 2000 Results
• On basis of limited data set for years 1948 – 1996 based on standard depth
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measurements from surface through 3000 m, composites of deep ocean T.
data constructed for multiyear periods for each ocean basin and for world
ocean as whole.
In each basin prior to mid-1970’s, temperatures of all basins relatively cool;
warming increasing from mid-1970’s, particularly in N. Atlantic.
What looks like a significant PDO signal in both N & S Pacific in upper
ocean heat content. May be an NAO signal in significant increase in N.
Atlantic and Indian Ocean increases in mid-1990’s.
Global sea surface T. series from 1900 showing warming in 2 periods : 1920
– 1940 & from 1970’s. [This finding similar to changes in global mean T. for
last century (IPCC, 2001)]. But increase in world ocean heat content
preceding increase in SST’s.
The Implications of the Levitus et al 2005 Results
• Between 1955 – 1998, world ocean heat content
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between 0 – 3000 m increased 14.5 x 1022 J = mean T.
increase of 0.037° C at rate of 0.20 Wm- 2.
Large part of change occurring in upper 700 m of world
ocean. Substantial regional variability observed.
Note that increase of 0.037° C a very large increase,
since a 0.1° C increase roughly = mean T. change of
100° C of global atmosphere if all heat instantaneously
transferred.
Levitus et al. 2005.
Observed:
matches model
hindcasts very well
Global Averaged Upper-Ocean Temperature
in Models
Pierce
Global Averaged Upper-Ocean Temperature
in Models
in Models
Pierce
Global Averaged Upper-Ocean Temperature
in Models
in Models
Pierce
Climate Impacts on Marine
Ecosystems
How Does Climate Affect Ocean Ecosystems?
• Fish inhabit hydrographic structures consisting
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of temperature, salinity, and depth.
Ecosystems exist from the level of plankton on
up the food chain.
Climate is a very large driver in the stability and
productivity of marine ecosystems by sustaining
or changing habitat.
Multiple stresses now a significant threat;
between sub-surface heat increases and
increasingly acidic ocean major changes in
store. Prediction capability severely limited.
Climate impacts on ecosystems
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DIRECT
Habitat suitability
changes
– thermal stress, or
thermal tolerances are
exceeded, too little
sunlight, too much
current …
• Timing shifts due to
temperature change
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INDIRECT
“Bottom-up”
– Habitat change causes
changes in food-web
production
• “Top-down”
– changes in the
predator field
• “match-mismatch” in
timing
How Do We Know What We Know Concerning
Climate Impacts on Marine Ecosystems?
• Via the fossil record over millennia--primarily through benthic
invertebrates ( Roy and Pandolphi, 2005).
• Inferences re T. changes & shifts in ocean chemistry possible, as
well as fluctuations in sea level.
• Focus on shifts in ocean circulation, surface & subsurface, and
implications for shifts in geographic ranges of spp., localized
extinction events, and changing phenology of plankton blooms with
consequent breaks in linkage between phytoplankton and the
zooplankton that feed on them--changes which ricochet up the food
chain with community-scale effects.
• But these effects do not occur equally across all spp.
Current Evidence from the North Pacific Ocean
• In 20th century, shifts in PDO from cool to warm phase
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result in ~1° C in SST  major shifts in composition of
coastal ocean foodwebs.
Cold water forage fish & plankton in reduced abundance;
warm water fish--mackerel, hake, sardines--significantly
increased in abundance. Salmonid distribution in NCCS
declining significantly (Field, 2004).
1960’s
1970’s
1980’s
Bottom trawl surveys
in Pavlov Bay, Alaska
(source: Bottsford et
al. 1997 Science)
the North-South see-saw in salmon production has
broken down in the past few years -- and so has the
regional coherence in coastal ocean temperatures
Alaska pink and sockeye
catch (millions)
spring chinook returns to the
Columbia River mouth
(1000s)
Pacific Decadal Oscillation (PDO)
Cool PDO
Warm PDO
Cool PDO
Warm PDO
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upwelling food webs in our coastal ocean:
the California Current
Cool water, weak stratification
high nutrients, a productive
“subarctic” food-chain with
abundant forage fish and few
warm water predators
Warm stratified ocean, few
nutrients, low productivity
“subtropical” food web, a
lack of forage fish and
abundant predators
And the top …
Source: NMFS acoustic surveys
PICES Conclusions re Effects of Regime Shifts in
North Pacific Over 20th Century
• Ecosystem responses to ocean climate most quickly detected in
lower trophic levels, i.e., phytoplankton, zooplankton, and
invertebrates--rapid reproduction rates reveals fluctuations in
abundance over short periods of time (PICES, 2004, Edwards and
Richardson, 2004).
• Now becoming clearer and clearer that climate variability and
change impact marine ecosystems most significantly via a bottomup process (changes in primary productivity) and secondarily via a
top-down process mediated through predator-prey interactions.
• It is the bottom-up process that cascades all the way up the food
chain(Field, 2004; Ware and Thomson, 2005). Must think about
planktonic ecosystems and community structure and interactions
across multiple trophic levels(Ruhl and Smith,Jr., 2004).
Findings re Planktonic Ecosystems and Cod
Recruitment in Northeast Atlantic
• Very similar to N.E. Pacific. Same bottom-up/top-down
pattern. Bottom-up process is primary driver (Richardson
and Schoeman, 2004; Beaugrand et al., 2003).
Recent Evidence of the Impacts of
Climate change on Marine
Ecosystems
A Focus on the Bering Sea and the
Northeast Atlantic
The Northeast Atlantic
• Study by Perry, Low, Ellis, and Reynolds(2005) with focus on
demersals,both exploited & unexploited spp.
• North Sea warming by 0.6 C 1962-2001 and 1.05 C 1977-2001. 15
of 36 spp. studied moving north--latitudinal changes combined with
depth.
• Evidence of differential rates of shifts suggest possibility of altering
spatial overlap among spp. Disrupting interactions and
compounding phenological shifts.
• Beaugrand et al (2003) with focus on cod in North Sea suggesting
that larval cod survival sensitive to variability in T. Rising T. since
mid-1980’s modifying planktonic ecosystem in way that reduces
survival of young cod--the bottom-up process at work.
Concerning the Limits of What We Know and the
Significance of What We Don’t Know
• All the studies cited couple the physics to the biology; only 2
consider explicitly the impacts of fishing effort as well as climate
change; none considers the increasing acidification of the world
ocean; and none considers the increasing pollution of the coastal
ocean on a global basis.
• In a word, we don’t have reliable knowledge about the future of
marine ecosystems in a world of multiple stresses where climate
change and the large anthropogenic footprint (overfishing and
coastal pollution) are the principal drivers.
• Most urgent problem is almost total ignorance about the potential
large scale effects on marine ecosystems of an increasingly low pH
ocean.
So, What is To Be Done?
• Constraints: tax cuts & deficits; 9/11 & homeland
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security; Iraq; Mars; Katrina.
Unlikely that funds for large scale effort would come from
U.S. Gov’t. at present.
So shift strategy to private sector in U.S. as catalyst-NGO’s, corporations, & foundations & try to get
international participation beginning with UK Royal
Society as lead into ICES community.
Agent is Heinz Center & “four sector” mode. Why Heinz?
Miles on the Board. Feely & Langdon to participate in
Steering Com.
What Strategy?
• Four products:
• Seek funding for international meeting to define research agenda for
impacts of acidification on marine ecosystems. Use output to shop
around internationally and in U.S. for support. Choose large marine
regions and seek to begin with North Pacific & North Atlantic??
• Connect levels of ocean acidification to thresholds and targets issue
as defined in FCCC. Seek separate foundation support for that
group in Heinz Center.
• Create working group in HC for elaborating a methodology for a
bounded multiple stress analysis.
• Do the multiple stress analysis. Staggered products over 5-year
period initially.
References
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Agostini, Vera. 2005.Climate, Ecology, and Productivity of Pacific Salmon and Hake.
Unpublished Ph.D. Dissertation, School of Aquatic and Fishery Sciences, University of
Washington.
Barnett, Tim P., David W. Pierce, Reiner Schnur. 2001. Detection of Anthropogenic Climate
Change in the World’s Oceans, SCIENCE, vol. 292(13 April), 270-274.
Barnett, Tim P. et al. 2005. Penetration of Human-Induced Warming into the World Oceans,
SCIENCE, vol. 309(8 July), 284-287.
Beaugrand, Gregory et al. 2003. Plankton effect on cod recruitment in the North Sea.
NATURE, vol. 426(11 December), 661-664.
Botsford, Louis W., Juan Carlos Castilla, Charles H. Peterson. 1997. The Management of
Fisheries and Marine Ecosystems. SCIENCE, vol 277(25 July), 509-515.
Brewer, Peter G. 2004. Beyond Climate: The Emerging Science of a Low pH-High CO2
Ocean, ICES Annual Science Conference, Open Lecture, unpub. Doc.
Edwards, Martin and Anthony J. Richardson. 2004. Impact of climate change on marine
pelagic phenology and trophic mismatch. NATURE, vol. 430(19 August), 881-884.
References, cont’d.
• Feely, Richard A. et al. 2004. Impact of Anthropogenic CO2 on the CaCO3
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System in the Oceans. SCIENCE, vol. 305(16 July), 362-366.
Field, John C. 2004. Application of Ecosystem-Based Fishery Management
Approaches in the Northern California Current. Unpub. Ph.D. dissertation,
School of Aquatic and Fishery Sciences, University of Washington, 407pp.
Joint Group of Experts on the Scientific Aspects of Marine Environmental
Protection (GESAMP). 2001. A Sea of Troubles, (Geneva: UNEP), Report
No. 70.
GESAMP. 2001. Protecting the Oceans from Land-based Activities,
(Geneva: UNEP),Report No. 71.
Levitus, Sydney, John I. Antonov, Timothy Boyer, Cathy Stephens. 2000.
Warming of the World Ocean. SCIENCE, vol. 287(24 March), 2225-2229.
Levitus, S., J. Antonov, and T. Boyer. Warming of the World Ocean, 19552005. GEOPHYSICAL RESEARCH LETTERS, vol. 32,
1029/2004GLO21592, LO 2604.
References, cont’d.
• Pauly, Daniel, et al. 2003. The Future for Fisheries. SCIENCE, vol. 302(21
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November), 1359-1361.
Perry, Allison L. et al. 2005. Climate Change and Distribution Shifts in
Marine Fishes, SCIENCE, vol. 308(24 June), 1912-1915.
North Pacific Marine Science Organization (PICES). 2004. Marine
Ecosystems of the North Pacific Ocean. PICES Special Publication Number
1.
PICES. 2005. PICES Advisory Report on Fisheries and Ecosystem
Responses to Recent Regime Shifts. North Pacific Marine Science
Organization, Sidney, Canada. 12p.
Richardson, Anthony J. and David S. Schoeman. 2004. Climate Impact on
Plankton Ecosystems in the Northeast Atlantic. SCIENCE, vol. 305(10
September), 1609-1612.
References, cont’d.
• Roy, Kaustuv and John M. Pandolphi. 2005 Responses of Marine Species
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and Ecosystems to Past Climate Change in Thomas E. Lovejoy and Lee
Hannah (eds.), (New Haven and London: Yale University Press),160-175.
Ruhl, Henry A. and Kenneth L. Smith Jr. 2004. Shifts in Deep-Sea
Community Structure Linked to Climate and Food Supply. SCIENCE, vol.
305(23 July), 513-515.
Sabine, Christopher L. et al. 2004. The Oceanic Sink for Anthropogenic CO2
. SCIENCE, vol.305(16 July), 367-371.
Ware, Daniel M. and Richard E. Thomson. 2005. Bottom-Up Ecosystem
Trophic Dynamics Determine Fish Production in the Northeast Pacific.
SCIENCE, vol. 308(27 May), 1280-1284.
IPCC Consensus on climate
change
• Carbon dioxide and other greenhouse gases warm the planet (*****)
• Greenhouse gases have been increasing (CO2 up 32%) and will
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increase for a long time, because of human activities (*****)
Pre-industrial ambient concentration of CO2 in atmos. = 282 ppmv;
2005 = 380 ppmv. This higher than at any time in last 420k yrs. &
maybe 20m.
The planet has warmed 0.4-0.8°C (0.7-1.4°F) since 1900 (****)
Natural causes an unlikely explanation (***)
Further warming of 1.4-5.8°C (2.5-10.4°F) by 2100, faster than any
time in at least 10,000 years (****)
[Most recent model inter-comparisons (Science,2004) provide est. of
climate sensitivity of 3.0-3.2C.]
Revelle : “Human beings are conducting an unplanned, uncontrolled
experiment on a planetary scale”.
Spatial patterns of
climate trends:
Model versus Observed
Boreal Summer Mean:
Warming strongest over land
in observations
Cooling in N. Hemisphere
oceans in observations
Weaker land-sea
temperature contrast in
models
Boreal Winter Mean:
Strongest warming in high
latitudes
Barnett et al., 1999
A 20th century climatology of North
America’s Pacific salmon
• Warm periods favored increased salmon production
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in Alaska but decreased salmon production in the
NW
PDO variability caused coherence in warm and cool
periods in the NE Pacific for much of the century, but the
PDO pattern was not prominent from the mid-1990s to
~2002
– There are other factors influencing Pacific climate … including
century-long warming trends
Stabeno & Overland. 2004. Fig. 1.
The Bering Sea/Shelf (Overland
& Stabeno, 2004)
• Depth-averaged T’s for 15 July-15 Sept. warmer by 2° C,
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mean of 2001-2003 as compared to 1995-1997.
Primary pattern is transition from predominantly cold
anomalies (blue) to warm (yellow/red). 1976 marks
beginning of trend to warmer summers.
Decrease in sea ice delaying spring phytoplankton
bloom to later in season, out of synch. with max.
zooplankton growth.
Consequence that spring phytoplankton bloom benefits
primarily the benthic community; later zooplankton bloom
benefits primarily the pelagic ecosystem.
Bering Sea/Shelf, cont’d.
• Observed dislocations- large-scale biogeographic shifts
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northwards in ecosystem of the Bering Sea involving
demersals (very large & profitable fishery), walrus,
salmonids, etc.
Other major shifts expected.
Demersals particularly sensitive to T changes in NCCS;
pelagics markedly less so at surface(Agostini, 2005).