Climate Change and its impact on Forests in Europe and North America

Andrew J. R. Gillespie, Ph. D. United States Environmental Protection Agency

Office of Research and Development2

• Overview of climate science relevant to forests

• Implications for forests in Europe and North America

• What we are doing about it

Goal of Presentation

Office of Research and Development3

Climate – long term (~30 year) trends in atmospheric behaviors such as temperature, rainfall, humidity, wind patterns, and storms.

Weather – short term (days) atmospheric behavior

• Climates are always changing – dynamic systems, not constant

• Difference today is the rate at which climate is changing:

– Evidence that it is more rapid than usual for last 800,000 years

– Evidence that it is due to fossil fuels and deforestation

Office of Research and Development4

• Direct measurements since the mid 1800s– Daily temperature, precipitation/many

locations

– Glacier shrinkage

• Multiple other lines of research prior to 1800s

– Ice cores

– Tree rings

– Pollen analysis

– Geologic evidence of ice ages, warm periods

How do we know climate is changing?

Office of Research and Development5

Office of Research and Development6

Climate Change Impacts in the United States: The Third National Climate Assessment 

Office of Research and Development7

Office of Research and Development8

Office of Research and Development9

Office of Research and Development10

Increase in heat retained in ocean and atmosphere

• Slight increase (~2-4 degrees) in average global temperature by the end of the century

– More change at the poles

– Hotter summers, milder winters

– Warmer oceans

• More energy = more extreme weather– Hurricanes, blizzards, heat waves, wind storms

• Change in rain patterns– More precipitation but uneven distribution

– More droughts, floods

• Rising sea levels as ice melts

Likely Aspects of Climate Change

Office of Research and Development11

Ecological NicheSet of environmental conditions which enable a species to survive and thrive. Combination of multiple factors:

Climate: temperature, precipitation, storm events

Physical: soil characteristics, elevation, aspect

Analogous to concept of terroir for wine making…

Change in climate => change in niche Animals can migrate to follow niches

Trees move much more slowly…

Relationship between Climate and Forests

Office of Research and Development12

Change in climate => change in niche

Change in niche => existing forests come under stress

Increase in stress => vulnerability to other threats

disease, insects, fire, loss of biodiversity

Loss of forest => more CO2 in atmosphere

=> more climate change

Relationship between Climate and Forests

Office of Research and Development13

• Warmer average temperatures

• Longer growing season

• CO2 fertilization effect

• Increased precipitation, changes in rainfall patterns

• More extreme weather (ice storm, wind storm, drought, flood)

• Changes in soil moisture – wetter and drier seasons

• Increased insect/disease presence due to less winter die-off

Net result is general increase in ecosystem stress, resulting in increased forest vulnerability to other threats

Likely changes in forest ecosystems

Office of Research and Development14

• Northward migration of some tree species

• Changes in forest species composition, succession

• Increased tree mortality, fire risk

• Increased spread of invasive species

• Loss of biodiversity, genetic resources, ecosystem

services

Likely forest ecosystem response

Office of Research and Development15

Canada: ~397 million haUS: ~327 million haMexico: ~ 50 million ha

TOTAL: ~774 million ha

(~ 80 x area of Hungary)

North America forest extends from subtropical to boreal

Many different forest types, ecological conditions

Climate and Forests: North America

Office of Research and Development16

Office of Research and Development17

Successful forest fire prevention => overstocked forests

• Overstocking causes stress

• Climate-related drought adds to stress

• Insects able to infest stressed forests

Result is greatly increased tree mortality, higher fire risk

Illustrates need for systems thinking, sustainability perspective

Relationship between Climate and Forests

Office of Research and Development18

Office of Research and Development19

Impacts of Climate Change on European Forests and Options for Adaptation

European Forest Institute et al.

Office of Research and Development20

• Changes in rainfall distributionWetter winters = flooding, wind damage, ice storms

Dryer, longer summers = more drought stress

• Warmer temperatures => increased pest problemsBark beetles, gypsy moth, Phytophthora

Increase insect, disease populations due to less winter die-off

Increased northern ranges

Climate Change and Ecosystem Response: Temperate Continental

Region

Office of Research and Development21

Climate Change and Forest Response: Hungary

Office of Research and Development22

Example: European beech in Hungary (C. Mátyás et al.)

• Beech at southern limit of range in Hungary

• Xeric limit: genetically determined dryness tolerance

• Northward shift in xeric limit could lead to complete loss

of beech, replacement with oak

• Permanent loss of genetic diversity

Climate Change and Forest Response: Hungary

Office of Research and Development23

Climate Change and Forest Response: Hungary

Office of Research and Development24

• Mitigation – reduce C emissions, increase C sequestration by growing forests

• Adaptation – manage forests to maintain health, reduce vulnerability

• Transformation – change society expectations, behaviors regarding what people want, need from forests – and what we are willing to give back

Strategies for Managing Forests in a Changing Climate

Office of Research and Development25

Adaptive strategies are synergistic across large areas:

• More ecological niches to work with

• More resources (financial, intellectual) to work with

Argues for benefit to international cooperation

• Certainly at continental scale

• Also at global scale

Scale Matters

Office of Research and Development26

Need for Action

Continue research to provide good foundation

Need to move beyond research to action

Adaptive management, systems thinking:Plan – Act – Measure – Analyze … and repeat

Office of Research and Development27

Winter Summer

is coming…

Office of Research and Development28

Thank you for your Attention

Andrew Gillespie

Gillespie.andrew@epa.gov

Twitter: @ajrgillespie1