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Global Ecology Composite satellite image (“Blue Marble 2012”) from Wikimedia Commons
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Global Carbon Cycle Cain, Bowman & Hacker (2014), Fig. 25.3 Boxes = major pools or reservoirs; petagrams (1 Pg = 10 15 g) Arrows = fluxes or rates of movement; Pg/yr Orange arrows = anthropogenic fluxes Main pools = atmosphere, oceans, land surface (soils & veg.), rocks & sediments Terrestrial pool exchanges C with atmosphere mostly via photosynthesis & respiration Post-Industrial Revolution anthropogenic inputs have dramatically increased
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Global Nitrogen Cycle Cain, Bowman & Hacker (2014), Fig. 25.7 Boxes = major pools or reservoirs; teragrams (1 Tg = 10 12 g) Arrows = fluxes or rates of movement; Tg/yr Orange arrows = anthropogenic fluxes Main pool = atmosphere (N 2 ) Biological fluxes predominate Human activity has altered the global N cycle even more than the global C cycle!
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Global Phosphorus Cycle Cain, Bowman & Hacker (2014), Fig. 25.9 Boxes = major pools or reservoirs; teragrams (1 Tg = 10 12 g) Arrows = fluxes or rates of movement; Tg/yr Orange arrows = anthropogenic fluxes Main pools = terrestrial soils & marine sediments Mining releases 4x more P than weathering of rock (apparently not shown) Eutrophication can result from anthropogenic oversupply of P or N (e.g., linked to Gulf “Dead Zone”) Geochemical fluxes predominate
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Global Sulfur Cycle Cain, Bowman & Hacker (2014), Fig. 25.10 Boxes = major pools or reservoirs; teragrams (1 Tg = 10 12 g) Arrows = fluxes or rates of movement; Tg/yr Orange arrows = anthropogenic fluxes Main pools = rocks, sediments, ocean Anthropogenic emissions have quadrupled since the Industrial Revolution Atmospheric deposition is a cause of acid rain
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Image from Wikimedia Commons Global Change Climate change – a shift of average weather across a region E.g., Eocene temperature was 4 – 6 °C warmer than today
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Images from www.thecanadianencyclopedia.com Eocene on Ellesmere Island, far north Canada Modern day on Ellesmere Island, far north Canada Global Change E.g., Eocene temperature was 4 – 6 °C warmer than today Climate change – a shift of average weather across a region
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Image from www.thecanadianencyclopedia.com E.g., Eocene seas were 100 - 150 m higher than today Global Change Climate change – a shift of average weather across a region
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E.g., Milankovitch Cycles – Earth’s changing orbit influences temperature with ~41,000 & ~100,000 yr periodicities Global Change Image from Wikimedia Commons Climate change – a shift of average weather across a region
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E.g., Pleistocene glacial and inter-glacial periods Global Change Then relative stability during pre-Industrial Revolution Holocene Image from Wikimedia Commons Climate change – a shift of average weather across a region
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Image from NOAA Global Change Do you recognize this curve?
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Image from NOAA Global Change Do you recognize this curve? Keeling curve
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Taking all the accumulated evidence into account, anthropogenic increases in greenhouse gases are the principal causes of modern global warming; i.e., we are experiencing an anthropogenically enhanced greenhouse effect Image from Wikimedia Commons Global Change International Panel on Climate Change (IPCC) est. 1988 by the United Nations
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Image from www.epa.gov IPCC predictions are for [CO 2 ] by 2100: 500 to 1000 ppm; with concomitant global temperatures 1.1 to 6.4 °C higher Global Change
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Image from: www.grida.no Earth’s avg. temp. = 14 °C (57 °F) Without the atmosphere’s greenhouse effect it would be about -18 °C (-0.4 °F) Global Change
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Photo of glacial retreat on Mount Kilimanjaro (Feb. 1993 to Feb. 2000) from Wikimedia Commons; Map of Africa from www.admin.uio.no Feb. 17, 1993 Feb. 21, 2000 Global Change – Physical Consequences Global reduction in ice
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Photo from Wikimedia Commons; figs. from Wootton et al. (2008) PNAS Decreasing oceanic pH Tatoosh Island, Washington CO 2 + H 2 O H 2 CO 3 (carbonic acid) H + + HCO 3 - (bicarbonate) 2 H + + CO 3 2- (carbonate) Global Change – Physical Consequences
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Range map and image of polar bear (Ursus maritimus) from Wikimedia Commons Global Change – Biotic Consequences Altered expression of traits (owing to phenotypic plasticity, e.g., phenology) Range shifts (especially upslope & to higher latitudes) Adaptation (to changing environment) Extinctions (when range shifts and adaptation fail to keep pace with changing environments)
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From Doran & Zimmerman (2009) Eos (formerly Transactions of the American Geophysical Union) Do you think human activity is a significant contributing factor in changing mean global temperature? Global Change – Public Opinion
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Treaty to enact resolutions from the United Nations’ Vienna Convention on the Protection of the Ozone Layer (1985) to “protect the ozone layer by taking precautionary measures to control equitably total global emissions of substances that deplete it [e.g., CFCs], with the ultimate objective of their elimination” Montreal Protocol (1987) Image from Wikimedia Commons – NASA image of largest Antarctic ozone hole ever recorded September 2006 Global Change Has generally been effective! [Strong political will]
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Legally binding treaty through 2012 (when ratified by states) intended to enact resolutions from the United Nations’ Framework Convention on Climate Change (1992) to achieve “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system” Image from Wikipedia (see “Kyoto Protocol”) Green = signed & ratified Red = signed, but not ratified Grey = non-signatory Kyoto Protocol (1997) Global Change Has NOT been effective! [Weak political will]
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