Climate Change Climate Change Climate Change ...
Climate Change
Climate Change
• Objectives – Past, present and future changes in global climate
• Is the global climate changing and, if so, is it the result of human activities? – Only need to believe 2 things • 1) Atmospheric constituents (i.e., greenhouse gases) trap outgoing longwave radiation, thereby warming the atmosphere • 2) Human activities are increasing the concentrations of greenhouse gases in the atmosphere
– There is no argument about #s 1 and 2 – The questions we should be asking are: – How much will the climate change? – What will the impacts of that change be for the goods and services that ecosystems provide humankind? 1
Climate Change
2
Climate Change
• Will climate change impact ecosystem structure and function?
• Impacts of climate change on biotic communities and ecosystems
Walther et al. 2005 3
4
1
Climate Change
Climate Change • Atmospheric gases and the greenhouse effect
• Mauna Loa Observatory
– Fourier (1827) • Greenhouse gas concept • ↑ greenhouse gases = ↑ temp • Makes Earth inhabitable (15°C vs. -18°C)
– Greenhouse gases absorb outgoing longwave radiation, warming the Earth’s surface • CO2, CH4, N2O, H2O, CFCs, HCFCs, etc.
– Many atmospheric constituents do not absorb longwave radiation and are, therefore, not greenhouse gases • e.g., O2 and N2 (~99.9% of atmosphere)
– Arrhenius (1896) • If CO2 doubles from fossil fuel burning, temperature will rise ~5°C Keeling 2008
5
Climate Change
Climate Change
• Climate has always been variable in the past, so why should we care if it is changing now?
• Climate has always been variable in the past, so why should we care if it is changing now? – Rate of change far exceeds that from anytime in the past
• Ice cores –Strong correlation between greenhouse gas conc. and temp. (D as a temp. proxy) –Higher conc. of CO2, CH4, and N2O than anytime in the past 600,000 years –Biosphere has taken up ~50% of anthropogenic CO2 emissions
6
• Prior to 1750, CO2 increased by 20 ppm over 8,000 years • Since 1750, CO2 has increased by >100 ppm
IPCC 2007
7
IPCC 2007
8
2
Climate Change
Climate Change
• Climate has always been variable in the past, so why should we care if it is changing now?
• Major greenhouse gases occur naturally, but have increased in past 250 yrs from human activities
– Warming is already occurring in Hawaii
– CO2 • fossil fuels burning (2/3); land use/land cover change (1/3)
– MAT increasing for ≥85 yrs – Accelerated rise in past 30 yrs – More pronounced at elevations >800m – More associated with increased nighttime temperatures
– CH4 • domestication of ruminants (37%); reservoirs (>20%); landfills & waste treatment (20%); biomass burning (12%); rice ag.; fossil fuels
– N2 O • animal waste products (~65%), industry and fossil fuels (~20%), fertilizers & agriculture
– Other greenhouse gases are entirely due to human activities • CFCs, HCFCs, etc. from industrial activities Giambelluca et al. 2008
9
10
Climate Change
Climate Change • Major greenhouse gases occur naturally, but have increased in past 250 yrs from human activities
• Concentration vs. Warming potential
– H2O is the major greenhouse gas •
Climate Change
• Objectives – Past, present and future changes in global climate
• Is the global climate changing and, if so, is it the result of human activities? – Only need to believe 2 things • 1) Atmospheric constituents (i.e., greenhouse gases) trap outgoing longwave radiation, thereby warming the atmosphere • 2) Human activities are increasing the concentrations of greenhouse gases in the atmosphere
– There is no argument about #s 1 and 2 – The questions we should be asking are: – How much will the climate change? – What will the impacts of that change be for the goods and services that ecosystems provide humankind? 1
Climate Change
2
Climate Change
• Will climate change impact ecosystem structure and function?
• Impacts of climate change on biotic communities and ecosystems
Walther et al. 2005 3
4
1
Climate Change
Climate Change • Atmospheric gases and the greenhouse effect
• Mauna Loa Observatory
– Fourier (1827) • Greenhouse gas concept • ↑ greenhouse gases = ↑ temp • Makes Earth inhabitable (15°C vs. -18°C)
– Greenhouse gases absorb outgoing longwave radiation, warming the Earth’s surface • CO2, CH4, N2O, H2O, CFCs, HCFCs, etc.
– Many atmospheric constituents do not absorb longwave radiation and are, therefore, not greenhouse gases • e.g., O2 and N2 (~99.9% of atmosphere)
– Arrhenius (1896) • If CO2 doubles from fossil fuel burning, temperature will rise ~5°C Keeling 2008
5
Climate Change
Climate Change
• Climate has always been variable in the past, so why should we care if it is changing now?
• Climate has always been variable in the past, so why should we care if it is changing now? – Rate of change far exceeds that from anytime in the past
• Ice cores –Strong correlation between greenhouse gas conc. and temp. (D as a temp. proxy) –Higher conc. of CO2, CH4, and N2O than anytime in the past 600,000 years –Biosphere has taken up ~50% of anthropogenic CO2 emissions
6
• Prior to 1750, CO2 increased by 20 ppm over 8,000 years • Since 1750, CO2 has increased by >100 ppm
IPCC 2007
7
IPCC 2007
8
2
Climate Change
Climate Change
• Climate has always been variable in the past, so why should we care if it is changing now?
• Major greenhouse gases occur naturally, but have increased in past 250 yrs from human activities
– Warming is already occurring in Hawaii
– CO2 • fossil fuels burning (2/3); land use/land cover change (1/3)
– MAT increasing for ≥85 yrs – Accelerated rise in past 30 yrs – More pronounced at elevations >800m – More associated with increased nighttime temperatures
– CH4 • domestication of ruminants (37%); reservoirs (>20%); landfills & waste treatment (20%); biomass burning (12%); rice ag.; fossil fuels
– N2 O • animal waste products (~65%), industry and fossil fuels (~20%), fertilizers & agriculture
– Other greenhouse gases are entirely due to human activities • CFCs, HCFCs, etc. from industrial activities Giambelluca et al. 2008
9
10
Climate Change
Climate Change • Major greenhouse gases occur naturally, but have increased in past 250 yrs from human activities
• Concentration vs. Warming potential
– H2O is the major greenhouse gas •
