Climate Change in Canada's Ecosystems: The Good, the Bad, and the Ugly Jay R' Malcolm, Faculty of Fo

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Climate Change in Canada's Ecosystems The Good,
the Bad, and the UglyJay R. Malcolm, Faculty of
Forestry
2004
1875
The Pasterze, Austria's longest glacier
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• PART 1
• Brief background on global warming the
  phenomenon and the evidence
• PART 2
• Case studies how bad might it be?
  1) projected extinctions in global
  hotspots 2) projected changes in
  Ontario's forests
• PART 3
• Optimistic or pessimistic?

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IPCC 4th Assessment
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Current
(kyr)
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Goddard Space Flight Center
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• "High certainty" that global warming is affecting
  living systems
• (increases in boreal growing seasons shifts of
  geographic ranges upward and pole-ward earlier
  breeding seasons true of 100s of species)

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Climate change caught in the act
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In 2003 captured 80 km NW of North Bay
350 individuals captured in 2002-2003 (APP)
Approximate historic range
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2004 not a single individual north of the
historic range
ZERO!
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cold winter proceeding peak
cold winter proceeding crash
crash preceded by bad mast year though (energetic
bottleneck)
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-69 alleles from the 5 microsatellite loci
-mtDNA suggests ? G. volans mating with ? G.
sabrinus
Garroway et al. in press, GCB
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so what?
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IPCC in 1995 the balance of evidence suggests
that there is a discernible human influence on
the climate General Circulation Models
(GCMs) -equations of momentum, mass, moisture,
and energy for a grid of the earth In order to
get the best match between observations and model
predictions, you need to incorporate greenhouse
gases
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GHG only
GHG sulphate aerosols
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Agreement between climate model incorporating
global aerosol cooling and the observed
temperature record
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The future.
Source IPCC
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2095
relative to 1990, A1B scenario
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PART 2 How bad might it be?

• enormous warming from an ecological viewpoint
• climate plays a fundamental role in determining
  the composition and functioning of ecosystems

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Spruce pollen record (from the National Pollen
Database)
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Ecosystem change, but also net area reductions
for certain habitat types
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1) Examine endemic-rich ecosystems worldwide
24 Hotspots 44 of plant species and 35 of
vertebrate species in lt2 of the land area
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Habitat loss and resulting species extinctions
Current area (ab) vs. future area (bc)
"Law" in ecology
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• Use of General Circulation Models (GCMs) and
  Global Vegetation Models (GVMs) to model the
  distribution of future vegetation types (and by
  SAR, species richness)
• Allow GCM to stabilize under pre-industrial CO2
  concentrations
• Allow GCM to stabilize under two times CO2
  concentrations
• Calculate climate deltas (differences between the
  two)
• Add the deltas to the current climate to generate
  the future climate
• Compare modeled vegetation distributions between
  the current and future climates

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Based on just climate, one can do a pretty good
job of predicting major habitat types
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Coupled GCMs and GVMs as a tool
Current Climate (GVM MAPSS)
Doubled-CO2 Climate (Hadley Centre, with
sulphate aerosol cooling) (GVM MAPSS)
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• Sensitivity Analyses
• Range of projections 14 combinations of GCMs and
  GVMs under 1CO2 and 2CO2 climates
• Habitat breadth 10 biome types vs. the original
  biome classification of the GVM (18 types for
  BIOME3, 45 types for MAPSS)
• Perfect vs. zero migration

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Zero migration scenario
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Percent loss of endemics from 24 hotspots
Perfect migration
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Percent loss of endemics from 24 hotspots Zero
migration
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Sensitivity factors approximately equal in
influencing variation in number of extinctions in
hotspots GVM (gtgtGCM) 32-43 Tolerances
27-31 Migration 30-35 Bootstrap
comparisons suggest that as a group, hotspots are
not unusually sensitive
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How does warming-induced habitat loss compare
with that due to deforestation?
A threat on par with tropical deforestation,
which is generally recognized as the greatest
threat to biodiversity on the planet
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2) Ontario's future tree communities
Black spruce
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2095
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Forest types
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2090
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Part 3 Pessimistic or optimistic?
Analysis Overly Optimistic
Analysis Overly Pessimistic
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Part 3 Pessimistic or optimistic?
Analysis Overly Optimistic
Analysis Overly Pessimistic
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How fast is warming induced migration anyway?
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cpDNA
Pollen
-ancestors of northerly populations much closer
to the ice front that previously thought -pollen
data does not pick up these sparse populations
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Calculating future rates
Migration rate distance time period
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Percent of 14 models showing high rates
(gt1,000 m/yr)
Finland (1st place)59.9 Canada (8th) 33.1
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Barriers to migration
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Increase in required migration rates due to human
development
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Required migration of Ontario's trees
Average rate gt3,000 m/yr CSIROMk2-A2 average
5,800 m/yr (!) -poorly understood, but only the
weediest plants capable of such rates!
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No migration limitation
Migration limitation
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No migration limitation
Migrationlimitation
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Analysis Overly Optimistic
Analysis Overly Pessimistic
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-appears to be a widespread effect across the
northern hemisphere -moisture deficit implicated
in Alaska, increased snow depth due to warmer
winters in Siberia
(Barber et al., 2000 Juday et al., 2003)
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Sw, Fairbanks, Alaska -among the most
commercially valuable in boreal Alaska
Northern Labrador -more northerly part of range
where water less likely to be limiting
(Barber et al., 2004, DArrigo et al., 1996)
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-less data for Sb both BOREAS and central Alaska
work in agreement though, suggesting widespread
decline -conspicuous aspen dieback in parts
western Canada
(Juday and Barber, 2005)
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Seasonal photosynthetic activity 1982 through 2003
Goetz, Scott J. et al. (2005) Proc. Natl. Acad.
Sci. USA 102, 13521-13525
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Analysis Overly Optimistic
Analysis Overly Pessimistic
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CO2 emissions (fossil-fuel burning and industrial
processes) increasing at 1.1 yr -1 1990-1999
gt3 yr -1 2000-2004
Raupach et al. 2007 PNAS, Roulet in litt.
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