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Global Ecology Composite satellite image (“Blue Marble 2012”) from Wikimedia Commons Global Carbon Cycle Boxes = major pools or reservoirs; petagrams (1 Pg = 1015 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 Cain, Bowman & Hacker (2014), Fig. 25.3 Global Nitrogen Cycle Boxes = major pools or reservoirs; teragrams (1 Tg = 1012 g) Arrows = fluxes or rates of movement; Tg/yr Orange arrows = anthropogenic fluxes Main pool = atmosphere (N2) Biological fluxes predominate Human activity has altered the global N cycle even more than the global C cycle! Cain, Bowman & Hacker (2014), Fig. 25.7 Global Phosphorus Cycle Boxes = major pools or reservoirs; teragrams (1 Tg = 1012 g) Arrows = fluxes or rates of movement; Tg/yr Orange arrows = anthropogenic fluxes Main pools = terrestrial soils & marine sediments Geochemical fluxes predominate 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”) Cain, Bowman & Hacker (2014), Fig. 25.9 Global Sulfur Cycle Boxes = major pools or reservoirs; teragrams (1 Tg = 1012 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 Cain, Bowman & Hacker (2014), Fig. 25.10 Global Change Climate change – a shift of average weather across a region E.g., Eocene temperature was 4 – 6 °C warmer than today 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 Eocene on Ellesmere Island, far north Canada Images from www.thecanadianencyclopedia.com Modern day on Ellesmere Island, far north Canada Global Change Climate change – a shift of average weather across a region E.g., Eocene seas were 100 - 150 m higher than today Image from www.thecanadianencyclopedia.com Global Change Climate change – a shift of average weather across a region E.g., Milankovitch Cycles – Earth’s changing orbit influences temperature with ~41,000 & ~100,000 yr periodicities Image from Wikimedia Commons Global Change Climate change – a shift of average weather across a region E.g., Pleistocene glacial and inter-glacial periods Then relative stability during pre-Industrial Revolution Holocene Image from Wikimedia Commons Global Change Do you recognize this curve? Image from NOAA Global Change Do you recognize this curve? Keeling curve Image from NOAA Global Change International Panel on Climate Change (IPCC) est. 1988 by the United Nations 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 IPCC predictions are for [CO2] by 2100: 500 to 1000 ppm; with concomitant global temperatures 1.1 to 6.4 °C higher Image from www.epa.gov Global Change Earth’s avg. temp. = 14 °C (57 °F) Without the atmosphere’s greenhouse effect it would be about -18 °C (-0.4 °F) Image from: www.grida.no Global Change – Physical Consequences Feb. 17, 1993 Global reduction in ice Feb. 21, 2000 Photo of glacial retreat on Mount Kilimanjaro (Feb. 1993 to Feb. 2000) from Wikimedia Commons; Map of Africa from www.admin.uio.no Global Change – Physical Consequences Decreasing oceanic pH Tatoosh Island, Washington CO2 + H2O H2CO3 (carbonic acid) H+ + HCO3(bicarbonate) 2 H+ + CO32- (carbonate) Photo from Wikimedia Commons; figs. from Wootton et al. (2008) PNAS 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) Range map and image of polar bear (Ursus maritimus) from Wikimedia Commons Global Change – Public Opinion Do you think human activity is a significant contributing factor in changing mean global temperature? From Doran & Zimmerman (2009) Eos (formerly Transactions of the American Geophysical Union) Global Change Montreal Protocol (1987) 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” September 2006 Image from Wikimedia Commons – NASA image of largest Antarctic ozone hole ever recorded Has generally been effective! [Strong political will] Global Change Kyoto Protocol (1997) 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” Green = signed & ratified Red = signed, but not ratified Grey = non-signatory Image from Wikipedia (see “Kyoto Protocol”) Has NOT been effective! [Weak political will]