Locations of Coral Reef Bleaching
BLEACHING OF
CORAL REEFS BY
OCEAN TEMPS >
85deg F (29 deg C)
Spring bud-burst dates for Aspen in Edmonton,
Beaubien and Freeland I.J.Biomet 44:53-59, 2000
The increase in growing season length over the last 50 years averaged for eight
stations in Alaska having the longest and most consistent temperature records.
Birch Decline 1930-1960 and thaw-refreeze zone
Area of thaw and refreeze
Area of thaw only
Border of dieback area
What’s Going On?
Climate Change and Other Environmental Stress
impacts on North American
Forests and Rangelands
Presented to the North American Forestry Commission
October, 2006
Steven McNulty, USDA FS
Roger Cox, NRC
Allen R. Riebau, USDA FS
Douglas G. Fox, CSU
Gonzalez Vicente, CONAFOR
400,000 Years of Antarctic CO2 and Temperature
Change
Source: Climate Change Impacts on the US, NAST, 2001
Northern Hemisphere Carbon Emissions
Source: Climate Change Impacts on the US, NAST, 2000
Atmospheric CO2 Concentrations
Source: Climate Change Impacts on the US, NAST, 2000
Northern Hemisphere Surface Temperature
Source: Climate Change Impacts on the US, NAST, 2000
What Will Happen Next?
Presented in Order from Most to Least Likely
Certain change
Atmospheric CO2 will continue to increase
Extremely Likely
Water and air temperature will continue to increase
“Simulations of the response to natural
forcings alone … do not explain the warming in
the second half of the century”
SPM
Stott et al,
Science 2000
“..model estimates that take into account both
greenhouse gases and sulphate aerosols are consistent
with observations over this period”
SPM
Stott et al,
Science 2000
Management Strategy for Coping with
Increased Sea Level Rise
Coastal forests will be inundated and coastal
beach erosion will increase. Forest managers
should work with land owners at a local scale
to plant mangroves and other soil retention
vegetation to delay terrestrial loss for a long as
reasonably possible.
Likely Impacts
Changing Patterns in Wildfire Occurrence
400
350
300
250
200
150
100
50
0
Fire (lower 48)
Fire (AK)
total
19
20
s
19
30
s
19
40
s
19
50
s
19
60
s
19
70
s
19
80
s
19
90
s
20
00
s
20
10
s
20
20
s
20
30
s
20
40
s
TgCO2
Average Annual CO2 Emitted to Atmosphere Due to Fire,
Projected to 2050
Decade
Average Yearly Gross CO2 Emitted to Atmosphere Due to Fire
Disturbance in Alaska by Decade
25
TgCO2
20
15
10
5
0
1920s
1930s
1940s
1950s
1960s
Decade
1970s
1980s
1990s
2000s
Large scale (> 400 ac) Wildfires and Air Temperature
From Westerling et al. 2005
Management Strategy for Coping with
Increased Wild Fire
Manage for and encourage more fire tolerant
grass and tree species
Increase public education and preparedness
regarding wild fire prevention and individual
preparation and control
Compared to climatic drivers, fuel reduction control
measures will be largely ineffectual
Likely Impacts
Inter-annual precipitation variability and soil erosion
Percent of the continental USA with a much above normal proportion of
total annual precipitation from 1-day extreme events
(more than 2 inches or 50.8mm)
BW 7
Karl et al. 1996
Uwharrie National Forest Current Soil Erosion Map
Areas of Soil Erosion By 2030 On UNF
Management Strategy for Coping with
Increased Soil Erosion
Continue to encourage standard soil erosion
control practices such as contour plowing,
winter cropping, shelter belts, and buffer strips
Relocate trails away from streams
Use bridge mats and culverts at stream crossings
Likely Impacts
Changes in Productivity and Economic Value
Timberland Acreage Shift 1993 – 2040:
No Climate Change Baseline
> 25%
DECLINE
5%-25% DECLINE
<5%
CHANGE
5%-25% INCREASE
Timberland Acreage Shifts by 2040
Due to Hadley Climate Change
5%-25% DECLINE
<5%
CHANGE
5%-25% INCREASE
Management Strategy for Coping with
Changing Rangeland and Forest Productivity
Work with local land owners to examine alternative
crops (e.g., shift from red pine to loblolly pine
plantations or from corn to wheat) as climate shifts
occur
Examine options for changing management
strategy for exists crops (e.g., wider tree planting,
fewer head per acre)
Less Likely Impacts
Gradual Ecosystem Shifts
American beech
Iverson et. al GTR NE265
Sugar maple
Iverson et. al GTR NE265
Loblolly pine
Iverson et. al GTR NE265
Sweetgum
Iverson et. al GTR NE265
Less Likely Impacts
Increasing western North American water crisis
Eastern Water Withdrawal
commercial
domestic
industrial
irrigation
livestock
mining
thermoelectric
Eastern Relative Water Withdrawal
commercial
domestic
industrial
irrigation
livestock
mining
thermoelectric
Western Water Withdrawal
commercial
domestic
industrial
irrigation
livestock
mining
thermoelectric
Western Relative Water Withdrawal
commercial
domestic
industrial
irrigation
livestock
mining
thermoelectric
Change in Water Supply Stress Index
Across the Conterminous US
2013=wet year | 2015=dry year
30
25
wet-no gw
wet-20%forest
wet-20%irrig
dry-no gw
dry-20% forest
dry-20%irrig
Percent Change
20
15
10
5
0
-5
Jan
May
Aug
-10
Time Period
Oct
annual
Management Strategy for Coping with
Water Stress
Largely a agricultural issue. Irrigation is the largest
single user of water. Shifting to a drip irrigation
system will greatly reduce water stress
.
Large scale, sustained reductions in grasses or trees
at a level sufficient to significantly increase water
availability is neither economically or technically
practical
Unknown Impacts of Climate Change
Integrated stress impacts
Example of Critical Load Calculated for N Across Canada
2004 Canadian Acid Deposition Science Assessment
Stress interactions on ecosystems
Elevated nitrogen deposition
Causing altered tree
physiology
Critical
Load
Climate Change
Reduces N demand,
changes forest composition
Fire
Reduces N demand,
changes forest composition
How a different critical nitrogen load could be
determined within the same ecosystem
N dep = 10 kg/ha/yr N dep = 10 kg/ha/yr
N leaching = 0
Mortality = 0%
+ 3 yr Drought
Stress
N dep = 10 kg/ha/yr
S dep = 10 kg/ha/yr
+ 3 yr Drought
Stress
N dep = 10 kg/ha/yr
S dep = 10 kg/ha/yr
+ 3 yr Drought
Stress
+ fire
Critical N > 10 kg
Load
N leaching = 1
Mortality = 10%
N leaching = 15
Mortality = 75%
Critical = 10 kg
Load
Critical = 8 kg
Load
N leaching = 25
Mortality = 100%
Critical < 5 kg
Load
Management Strategy for Coping with
Water Stress
None. More research is needed before effective
management strategies could be developed
Potential Extreme Consequences
(a.k.a. Armageddon Scenarios)
Gradual or Abrupt Loss of the Thermohaline to Fresh
Water Inputs
Thermohaline ocean Circulation Belt
Jayne Doucette, WHOI
Jayne Doucette, WHOI
Carbon Dioxide Loss from tundra thaw
triggering a “run-away” positive
feedback between air temperature
and tundra peat decomposition.
Conclusions
There is much we understand about climate change
and the impacts it is having and will continue to have on
North American rangelands and forests.
There are also management strategies that can be used
to minimize some of the negative impacts of climate
change
However, while we have great confidence in the direction
of climate change, there remains uncertainly regarding the
rate and ultimate level of climate change. Much of this
uncertainty is due to the uncertainty of society to address
future green house gas emissions.