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