Oct 31 Happy Halloween Antarctic ice core archives climate and atmospheric composition over past 740 000 years Global change Atmosphere climate biosphere Systems positive and negative feedbacks Alternate ecosystem states Pleistocene steppe tundra Hudson Bay marsh mudflat Sustainability Resilience This ice is about 491 0000 years old 1 2 The concentration of CO2 in air today is higher than it has been in the last 650 000 years and probably since it has been in the last 50 my CO2 ppm Before 1850 274 1958 Keeling 316 2005 370 2075 est 3 Evidence of global warming 540 1995 2004 vs 1940 1980 4 Melting permafrost drunken trees Glacier shrinkage on mountains around the globe Permafrost melting in Arctic Acceleration of Greenland deglaciation due to moulins Warming of upper layers of the ocean Melt of Arctic sea ice opening of the Northwest Passage 5 6 Thermokarst lakes Chapin Zimov 7 The area burned in western North America has doubled in the last 40 years 9 Water will be more heterogeneously distributed in Arctic landscape System group of entities united by interaction or interdependence to form or act as an entire unit Feedback Loops can enhance or buffer changes that occur in a system Positive feedback change increase or decrease in some variable results in the same type of change increase or decrease in a second variable Enhancing or amplify changes destabilizing a system by moving a it away from equilibrium Negative feedback change produces a change in the opposite direction which dampens or buffers changes holding a system near some equilibrium state making it more stable 8 10 Where is the system now and how will it change fire Drying of uplands Fewer trees Alternative stable states Positive Feedbacks Greenhouse warming More CO2 11 12 Scheffer et al 2000 LIDAR data from W E Dietrich Positive fdbks destabilizing Earth s response to global warming The clathrate surprise Methane clathrates on the ocean floor release more methane the clathrate gun hypothesis Oxidation of ancient carbon stored in arctic ecosystems with melt of permafrost terrestrial ecosystems leading to an increase of atmospheric CO2 levels Higher albedo of sea ice and seasonal snow cover Darker earth and sea surfaces absorb more sunlight leading to further warming Moulins deep holes in continental glaciers allow melt water to lubricate base accelerating slippage of ice shelfs off continents e g Greenland into the ocean Acidification of the ocean elevating CO2 concentration will lower ocean pH interfering with the ability of ocean biota to produce calcium carbonate E Colbert New Yorker Nov 20 2006 pp 67 76 13 Beyond Color Mapping Schmitz et al 2003 Wolves Moose Climate envelopes based on Fundamental Niches won t predict ecosystem consequences of interactions Spruce 14 Hudson Bay Blue water Green marsh vegetation Red had vegetation in 1973 mudflat in 1993 Snow geese numbers exploding due to drop in hunting and agricultural subsidies in goose wintering grounds in the U S 15 Canadian Arctic goose switch from grazing to grubbing converts marsh to mudflat evaporation causes mud to become hypersaline killing vegetation Goose exclosure 16 Zimov Chapin s Pleistocene Park Sergei Zimov and woolly rhinoceros bone in Siberia 17 12 ky bp vegetation changed across all of Beringia from steppe grass to mossy tundra Assumed this due to climate change but no record of this in ocean sediment or ice cores Zimov et al hypothesize overkill of megafauna by Pleistocene hunters 18 Siberian ponies pastured downslope from grass refuges on hills extend steppe grasses over tundra trampling and grazing kills moss Moss tundra is a good insulator so permafrost shallow soils waterlogged and hypoxic Grasses dry up soils support more productivity and floral diversity and might change decrease runoff to the Arctic Ocean Pleistocene overkill hypothesis extinctions of megafauna coincided with arrival of H sapiens 19 20 http ww2010 atmos uiuc edu Gh guides mtr hurr home rxml 21 Alternative stable States tipping point hunting Hurricanes instabilities driven in part by Coriolis effects Sea temperatures warmer than 26 5 C red orange yellow will sustain hurricanes warmer temperature sustain more intense storms 22 Bayou Mangroves Ecosystem Services 4 miles forested wetlands removes 80 feet of storm surge 23 Could species impacts change global climate change in continental scale burning or freshwater runoff from Beringia 24 Land cover change in Glacier National Park Trees and water Todd Dawson IB 25 Keck Hydrowatch Berkeley Inez Fung 26 Charles Cochrane Hydraulic Lift by deep rooted trees Todd Dawson Bill Dietrich Night 27 How muchdeep rooted forest dotrees we need to maintain stable How many will it take to get California stream flow to keep regions of California moist through the coming droughts Day Lee Oliveira Dawson and Fung 2005 Root functioning modifies seasonal climate Proc Natl Acad Sci USA 102 17576 17581 28 Ecosystem services NY City s water comes from Catskill Mt Reforested watershed cost 1 1 5B Now it saves NYC construction costs of 8B and operating yearly costs of 300M for water filtration and purification Wetlands restoration levee and channel reconstruction and barrier island protection for Gulf Coast estimated at 14B cost of rebuilding New Orleans estimated at 200B 29 30 Ball in a basin metaphor for system stability and resiliency Resiliency Alliance Walker and Salt 2006 Resiliency thinking is about understanding and engaging with a changing world By understanding how and why the system as a whole is changing we are better placed to build a capacity to work with change as opposed to being a victim of it Walker and Salt 2006 p 14 31 Everything changes Everything is connected Pay attention Jane Hirshfield 33 32
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