RAPID SHIFTS IN THE ARCTIC SYSTEM : Implications for vulnerability and resilience John E. Walsh
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Transcript of RAPID SHIFTS IN THE ARCTIC SYSTEM : Implications for vulnerability and resilience John E. Walsh
RAPID SHIFTS IN THE RAPID SHIFTS IN THE
ARCTIC SYSTEM :ARCTIC SYSTEM :
Implications for vulnerability and resilience
John E. Walsh
ARCUS Arctic Forum 2003
““If you take the last 100,000 years If you take the last 100,000 years from the Greenland ice core, the from the Greenland ice core, the
only few thousand years that have only few thousand years that have not had abrupt changes are the few not had abrupt changes are the few
thousand we are living in.”thousand we are living in.”
- Richard Alley/Earth and Sky- Richard Alley/Earth and Sky
from Dansgaard et al. (1993)from Dansgaard et al. (1993)
GRIP ice core temperature reconstruction
Assess recent Arctic changes in context of abrupt Assess recent Arctic changes in context of abrupt
changes changes of the pastof the past
Highlight issues of resilience and vulnerability to abrupt Highlight issues of resilience and vulnerability to abrupt changeschanges
Examine some projections of changes in the ArcticExamine some projections of changes in the Arctic
Objectives Objectives ::
Abrupt climate changeAbrupt climate change
from CLIVAR/PAGESfrom CLIVAR/PAGES
The Younger-Dryas changes of ~12K BP were abrupt.
Smaller changes have had large impacts on peopleSmaller changes have had large impacts on people
e.g., Viking settlements in Greenlande.g., Viking settlements in Greenland
Although climate has been relatively quiescent during the Although climate has been relatively quiescent during the past few thousand years, greenhouse gas emissions past few thousand years, greenhouse gas emissions may alter the likelihood of abrupt climate changesmay alter the likelihood of abrupt climate changes
Surface temperature trend - recent 1000 yearsSurface temperature trend - recent 1000 years
from Michael Mann
Abrupt climate changeAbrupt climate change
from CLIVAR/PAGESfrom CLIVAR/PAGES
Surface air temperature : January(1977-1986) – (1966-1975)
Arctic surface air temperature anomaliesArctic surface air temperature anomalies
from Polyakov et al. (2002)from Polyakov et al. (2002)
Spawning stock biomass of herring Spawning stock biomass of herring in the Nordic Seasin the Nordic Seas
from Torensen and Ostvedt (2000)from Torensen and Ostvedt (2000)
Vulnerability = Impacts - Adaptive Capacity
Vulnerability decreases as adaptive capacity increasesVulnerability decreases as adaptive capacity increases
-- increasing size and interconnectedness of system-- increasing size and interconnectedness of system provide more possibilities for compensation within provide more possibilities for compensation within the system the system
Net economic valueNet economic value
from National Academy of Sciences (2002)
from National Academy of Sciences (2002)
Variability of total U.S. farm Variability of total U.S. farm output : 1929-2000output : 1929-2000
from National Academy of Sciences (2002)
Relative variability of U.S. farm output Relative variability of U.S. farm output as share of total domestic product : as share of total domestic product :
1929-20001929-2000
Longer-term vulnerability decreases with
1) Longer warning time
2) Decreased lifetime (infrastructure, capital investment)
(Both enhance adaptability)
Vulnerability of capital stocksVulnerability of capital stocks
from National Academy of Sciences (2002)
How might 21st-century climate changetest the vulnerability and adaptability of the Arctic system?
growing season lengthopen water season lengthsea levelcoastal storms, erosionpermafrost degradationfire frequency
CCC growing season - Tmin greater than 0 °C(2071-2090) - (1976-1995)
from IPCC (2001)
Projected sea level rise
Projected continuous permafrost area : 5 GCMs
Projected total permafrost area : 5 GCMs
Sfc. air temperature : (high-low) fire severity compositeMarch-July 1951-2002
Key uncertainties in vulnerability ( = impacts-adaptability)
Uncertainties in impacts:
• climate change scenarios from coarse models are highly uncertain
-- large scatter among models-- common errors
• local effects are not captured by climate model projections
• changes in variability will likely be at least as important as changes in the mean
Uncertainties in adaptive capacity:
• Non-climatic factors (societal, cultural, economic,
technological) are at least as difficult to anticipate
as climate change