RAPID SHIFTS IN THE ARCTIC SYSTEM : Implications for vulnerability and resilience John E. Walsh ARCUS Arctic Forum 2003

“If you take the last 100,000 years from the Greenland ice core, the only few thousand years that have not had abrupt changes are the few thousand we are living in.” - Richard Alley/Earth and Sky

from Dansgaard et al. (1993) GRIP ice core temperature reconstruction

 Assess recent Arctic changes in context of abrupt changes of the past  Highlight issues of resilience and vulnerability to abrupt changes  Examine some projections of changes in the Arctic   Assess recent Arctic changes in context of abrupt changes of the past  Highlight issues of resilience and vulnerability to abrupt changes  Examine some projections of changes in the Arctic Objectives :

Abrupt climate change from CLIVAR/PAGES

 Smaller changes have had large impacts on people e.g., Viking settlements in Greenland  Although climate has been relatively quiescent during the past few thousand years, greenhouse gas emissions may alter the likelihood of abrupt climate changes   The Younger-Dryas changes of ~12K BP were abrupt.  Smaller changes have had large impacts on people e.g., Viking settlements in Greenland  Although climate has been relatively quiescent during the past few thousand years, greenhouse gas emissions may alter the likelihood of abrupt climate changes

Surface temperature trend - recent 1000 years from Michael Mann

Abrupt climate change from CLIVAR/PAGES

Surface air temperature : January ( ) – ( )

Arctic surface air temperature anomalies from Polyakov et al. (2002)

Spawning stock biomass of herring in the Nordic Seas from Torensen and Ostvedt (2000)

Vulnerability decreases as adaptive capacity increases -- increasing size and interconnectedness of system provide more possibilities for compensation within the system   Vulnerability = Impacts - Adaptive Capacity Vulnerability decreases as adaptive capacity increases -- increasing size and interconnectedness of system provide more possibilities for compensation within the system

Net economic value from National Academy of Sciences (2002)

Variability of total U.S. farm output :

from National Academy of Sciences (2002) Relative variability of U.S. farm output as share of total domestic product :

  Longer-term vulnerability decreases with 1) Longer warning time 2) Decreased lifetime (infrastructure, capital investment) (Both enhance adaptability)

Vulnerability of capital stocks from National Academy of Sciences (2002)

 How might 21 st -century climate change test the vulnerability and adaptability of the Arctic system? growing season length open water season length sea level coastal storms, erosion permafrost degradation fire frequency

CCC growing season - T min greater than 0 °C ( ) - ( )

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 composite March-July

  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