premise three basic forms of uncertainty - level of change - process impacts - time and space 1
TRANSCRIPT
Premise
• Three Basic Forms of Uncertainty
- Level of Change
- Process Impacts
- Time and Space
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Premise
• Three Basic Forms of Uncertainty
- Level of Change
- Process Impacts
- Time and Space
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Simulated Temperature over the US
Source: Climate Change Impacts on the US, NAST, 2000
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Premise
• Three Basic Forms of Uncertainty
- Level of Change
- Process Impacts
- Time and Space
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ha
Landscape
Region
1/10 ha
Week Month Year Decade Century
Landscape Dynamics ForestSelection
Tree
Disease
Forest Competition
Species Selection
Species Competition
BiomeSelection
BiomeCompetition
Insect
Scale Uncertainty 6
Global Change Certainty across Southeastern United States Ecosystems:
Impacts and Implications
Steven McNulty
Research Ecologist
USDA Forest Service
Raleigh, NC
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Global change impacts range from the certain to the unknown
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Certain change
Increased atmospheric CO2
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Very Likely Impacts In Southeastern Forests(independent of climate change)
Increased Population
Increased Fuel loads
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This will lead to…
Further forest fragmentation
Further restrictions in forest management options
Increase Fire Severity and Frequency
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Likely Impacts In Southeastern Forests(with and without climate change)
Inter-annual precipitation variability
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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)
Karl et al. 1996
BW 7
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= +119%
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= +232%
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Uwharrie National Forest Current Soil Erosion Map
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Areas of Soil Erosion By 2030 On UNF 23
American beech
Iverson et. al GTR NE265
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Sugar maple
Iverson et. al GTR NE265
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Likely Impacts In Southeastern Forests(with and without climate change)
Inter-annual precipitation variability
Extended growing season and warming
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> 25% DECLINE
5%-25% DECLINE
<5% CHANGE
5%-25% INCREASE
Timberland Acreage Shift 1993 – 2040: No Climate Change Baseline
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Timberland Acreage Shifts by 2040 Due to Hadley Climate Change
5%-25% DECLINE
<5% CHANGE
5%-25% INCREASE
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Unlikely Impacts In Southeastern Forests(dependent of climate change)
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Loblolly pine
Iverson et. al GTR NE265
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Sweetgum
Iverson et. al GTR NE265
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Unknown Impacts In Southeastern Forests(dependent of climate change)
Increasing CO2 on forest growth
Insect and disease impacts
Integrated stress impacts
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How a different critical nitrogen load could be determined within the same ecosystem
N dep = 10 kg/ha/yr
N leaching = 0Mortality = 0%
Critical N > 10 kgLoad
N dep = 10 kg/ha/yr
N leaching = 1Mortality = 10%
Critical = 10 kgLoad
+ 3 yr Drought Stress
N dep = 10 kg/ha/yr
N leaching = 15Mortality = 75%
Critical = 8 kgLoad
+ 3 yr Drought Stress
+ insects
N dep = 10 kg/ha/yr
N leaching = 25Mortality = 100%
Critical < 5 kgLoad
+ 3 yr Drought Stress
+ insects
S dep = 10 kg/ha/yr
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Conclusions
• There is sufficient certainty regarding several areas of global change for assessing probable ecosystem impacts across the southern US during the next 50 years
• Other less certain impacts need to be prioritized for future research study based on cost and potential impact
• Synergistic impacts will be very difficult, if not impossible to predict
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Conclusions (cont.)
• Thresholds and positive feedback impacts are poorly understood and could have the greatest potential for catastrophic change
• More emphasis should be placed on coping and mitigating those impact which have a high probability of occurrence while time and funding exist to address these issues
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