1Welcome to Global Change!GEOS/ECOL/GEOG/RNR/HWR478/578Scott SaleskaEE BiologyJulia ColeGeosciences and ATMOTA: AmandaReynoldsGeosciencesGEOS 478/578• Handouts: Syllabus, initial schedule, questionnaire• Prerequisite: one year of upper-level science (notNATS!) - see us if you do not have this.Comfortable with simple quantitative calculations.• Both instructors travel for research; both will be inclass when they are in town– (get to know us both)– Amanda is away until 9/25• Class is full… but people do drop; see us if you areinterested but not yet enrolledClass elements• Format: lecture and studentpresentations; breakout sessions• Grading:– Exams: 20% each– Homeworks: 35%– Participation: 5%– For undergraduates: Presentation (20%)– For graduates: Proposal (20%)• Resources:– Website; linked thru Geoscience home page– Password is amazon (for readings)Schedule• Website links to notes and readings forlectures and presentations• Links to study guides and old exams willbe posted later• Dates may change by a day or two,except final which is fixed2Finally….• We welcome your comments abouthow the class is going! Please don’thesitate to see us if you have anyconcerns.What is global change?Climate changeHydrologic changeTectonic/geologic changeEcosystem changeLand use changePeople - population, consumption, energyExtinctionOcean circulation (Thermohaline circulation)Marine ecosystems, coral bleachingSea level changeExtreme events/disturbance changesDrivers of global change• Energy• Population and consumption• Land use changehttp://rsd.gsfc.nasa.gov/rsd/bluemarble/bluemarble2000.html3Stories we’ll be following… Hurricane seasonStories we’ll be following… Stratospheric ozone holehttp://ozonewatch.gsfc.nasa.gov/• Sea ice minimumusually falls inSeptember• Observations lastweek lower thanany previousobservations• Still a month to go!Record sea ice minimum(breaking news, August 17, 2007)Sea ice in retreathttp://nsidc.org/news/press/2007_seaiceminimum/20070810_index.html199319881983 1998 2003September sea ice, 1979-2006YEAR4Sea ice in retreathttp://nsidc.org/news/press/2007_seaiceminimum/20070810_index.htmlArctic se ice extent - August 2007 lowestsince observations began (record minimumexpected in September)Announcement - presentation• Aug. 23, 2:30-3:30, PAS 224• Prof. Roger A. Pielke, Sr.• University of Colorado (CIRES and ATOC)• "Human Impacts on Climate: A BroaderView than Reported in the 2007 IPCCReport"Global Change - introduction• Read this: IPCC AR4, Summary forPolicymakers (Feb 2007)• International efforts: IPCC, UNFCCC• Observations (IPCC and more current)– Global– Arctic– Western USWhat is the IPCC?• Intergovernmental Panel on Climate Change:UN and World Meteorological Office– 4th assessment report issued 2007 (AR4)– Earlier ones in 1990, 1995, 2001• Multipart assessment of climate change:– Working Group 1 (WG1): Physical Science basis– Working Group 2: Impacts (incl. regional/ecological),Adaptation, Vulnerability– Working Group 3: Mitigation• Draws on peer-reviewed scientific literature(what is this?)5What is the IPCC?• Peer-review science: not opinion; consensus• Heavily reviewed at scientific and politicallevels (>30,000 comments in WG1)• Careful treatment of uncertainties, likelihoods,types of uncertainty etc.– E.g. “very likely” means >90% sure– Likelihood vs confidence• IPCC is a conservative document!• Website: http://www.ipcc.ch/– WG1 - http://ipcc-wg1.ucar.edu/wg1/wg1-report.htmlLessons of IPCC-AR4 (so far!)• It’s happening, and we are doing it• Consequences are becoming apparent• Predictions are converging in many cases• Countries have unequal burdens, unequalvulnerabilities• Adaptation is imperative• Mitigation is still possible, and may not beas costly as we had thoughtUN Framework Convention onClimate Change (UNFCCC)- global perspective• 1992 Earth Summit (Rio de Janeiro)• 189 countries have signed on• Objective:– “Stabilization of greenhouse gasconcentrations at a level that would preventdangerous anthropogenic interferencewith the climate system”What is dangerous?(global perspective)• Demise of W. Antarctic Ice Sheet (6msea level rise!)• Ice-free Arctic• Large-scale decline of coral reefecosystems• Shutdown of ocean’s thermohalinecirculation• Release of methane from frozendeposits in marine sedimentsFrom O’Neill and Oppenheimer 2002 (Science) and Pittock (2005)6What is dangerous?(regional/local perspective)• Insufficient water supply• Inability to grow enough food• Loss of natural ecosystems and their goodsand services• Spread of disease• Sea level rise• Climate/hydrologic extremes (droughts,floods, tropical storms)• Others… (geopolitical, social…)http://www.esrl.noaa.gov/gmd/ccgg/trends/co2_data_mlo.htmlCarbon dioxide measurements fromice cores and instrumental dataWe know this much istrue!• CO2 is rising beyondrecent natural levels• Due to human activity(mainly fossil fuelburning)• CO2 is a greenhousegas that preventsenergy from escapingto space• Temperature is rising,coincident with CO2increase7Global mean surfacetemperature anomaly2006 temperature anomalies(deviation from 1951-1980 mean)(why is the Arctic warming faster?)http://www.giss.nasa.gov/research/news/20070208/°CSea ice is a powerful positive feedback• Ice is more reflective than water• Ice melts ==> more radiation absorbed, less reflected• More absorption means more warming• Positive feedback on warming:– Initial warming ==> melting ==> more warming• There are negative feedbacks on climate change too (andother positive ones)Meehl et al. (2004)Natural OnlyObservedModel simulations of climate require bothhuman and natural causes to get it right8How much more CO2?Doubling ofpreindustrialModernProjected change in globaltemperatureRegional patterns of change9Closer to home…Global drought projection720 ppm CO2, 2101-2200DJF PrecipJJA PrecipDJF SoilJJA SoilWang 2005, Climate Dynamics,