Presentation on theme: "Mitigating Climate Change"— Presentation transcript:
1 Mitigating Climate Change Sources and sinks of atmospheric CO2Emissions tradingHistorical and projected CO2 emissionsClimate wedgesAlternative energy
2 The Global Carbon Cycle Atmosphere/yrAbout half the CO2 released by humans is absorbed by oceans and land“Missing” carbon is hard to find among large natural fluxes~120~90~120~908 GtC/yrOcean38,000LandHumans2000
3 Variable Sinks Half the CO2 “goes away!” Some years almost all the fossil carbon goes into the atmosphere, some years almost noneInterannual variability in sink activity is much greater than in fossil fuel emissionsSink strength is related to El Niño. Why? How?
4 European Climate Exchange Futures Trading: Permits to Emit CO2 European “cap-and-trade” market set up as described in Kyoto Protocol (http://www.europeanclimateexchange.com)7/18/2008 price €25.76/ton of CO2 emitted 12/ = $149.73/ton of CarbonSupply and demand!
5 Present Value of Carbon Sinks Terrestrial and marine exchanges currently remove more than 4 GtC per year from the atmosphereThis free service provided by the planet constitutes an effective 50% emissions reduction, worth about $600 Billion per year at today’s price on the ECX!Carbon cycle science is currently unable to quantitatively account forThe locations at which these sinks operateThe mechanisms involvedHow long the carbon will remain storedHow long the sinks will continue to operateWhether there is anything we can do to make them work better or for a longer time
6 Where Has All the Carbon Gone? Into the oceansSolubility pump (CO2 very soluble in cold water, but rates are limited by slow physical mixing)Biological pump (slow “rain” of organic debris)Into the landCO2 Fertilization (plants eat CO2 … is more better?)Nutrient fertilization (N-deposition and fertilizers)Land-use change (forest regrowth, fire suppression, woody encroachment … but what about Wal-Marts?)Response to changing climate (e.g., Boreal warming)
7 Coupled Carbon-Climate Modeling “Earth System” Climate ModelsAtmospheric GCMOcean GCM with biology and chemistryLand biophysics, biogeochemistry, biogeographyPrescribe fossil fuel emissions, rather than CO2 concentration as usually doneIntegrate model from , predicting both CO2 and climate as they evolveOceans, plants, and soils exchange CO2 with model atmosphereClimate affects ocean circulation and terrestrial biology, thus feeds back to carbon cycle
8 Carbon-Climate Futures Friedlingstein et al (2006) AtmosphereLandOcean300 ppm!Coupled simulations of climate and the carbon cycleGiven nearly identical human emissions, different models project dramatically different futures!
9 Emission Scenarios Each “storyline” used to generate A1: Globalized, with very rapid economic growth, low population growth, rapid introduction of more efficient technologies.A2: very heterogeneous world, with self-reliance and preservation of local identities. Fertility patterns across regions converge very slowly, resulting in high population growth. Economic development is regionally oriented and per capita economic growth & technology more fragmented, slower than other storylines.B1: convergent world with the same low population growth as in A1, but with rapid changes in economic structures toward a service and information economy, reductions in material intensity, introduction of clean and resource-efficient technologies. The emphasis is on global solutions to economic, social, and environmental sustainability, including improved equity, without additional climate initiatives.B2: local solutions to economic, social, and environmental sustainability. Moderate population growth, intermediate levels of economic development, and less rapid and more diverse technological change than in B1 and A1.Each “storyline” used to generate10 different scenarios of population, technological & economic development
10 Emission Scenarios vs Reality Raupach et al PNAS
11 Carbon intensity of the world economy fell steadily for 30 years Canadell et al. 2007
13 Dramatic contrast – history versus future DevelopingIndiaChinaFormer SovietOther developedJapanEuropeUSACO2 emissionsCumulativeRaupach et al. PNAS 2007
14 Dramatic contrast – history versus future DevelopingIndiaChinaFormer SovietOther developedJapanEuropeUSACO2 emissionsRaupach et al. PNAS 2007
15 Dramatic contrast – history versus future DevelopingIndiaChinaFormer SovietOther developedJapanEuropeUSACO2 emissionsRaupach et al. PNAS 2007
16 Dramatic contrast – history versus future Least DevelopedDevelopingIndiaChinaFormer SovietOther developedJapanEuropeUSACO2 emissionsRaupach et al. PNAS 2007
17 CO2 “Budget” of the Atmosphere AT606 Fall 20064/11/2017CO2 “Budget” of the Atmosphere2=4billion tons go outOceanLand Biosphere (net)Fossil FuelBurning+8800billion tons carbonbilliontons go inATMOSPHEREbillion tons added every yearCSU ATS Scott Denning
18 How Far Do We Choose to Go? AT606 Fall 20064/11/2017How Far Do We Choose to Go?Billions of tons of carbon“Doubled” CO2TodayPre-IndustrialGlacial8001200600400billions of tons carbonATMOSPHERE(ppm)(570)(380)(285)(190)Past, Present, and Potential FutureCarbon Levels in the AtmosphereCSU ATS Scott Denning
19 AT606 Fall 20064/11/2017Historical EmissionsBillions of Tons Carbon Emitted per Year16Historicalemissions81950200020502100CSU ATS Scott Denning19
20 The “Stabilization Triangle” Stabilization Triangle AT606 Fall 20064/11/2017The “Stabilization Triangle”Billions of Tons Carbon Emitted per Year16Current path = “ramp”Stabilization TriangleInterim GoalHistoricalemissions8Flat path1.61950200020502100CSU ATS Scott Denning20
21 Stabilization Triangle AT606 Fall 20064/11/2017The Stabilization TriangleBillions of Tons Carbon Emitted per YearEasier CO2 target16Current path = “ramp”~850 ppmStabilization TriangleInterim GoalHistoricalemissions8Flat pathTougher CO2 target~500 ppm1.61950200020502100CSU ATS Scott Denning21
22 “Satbilization Wedges” AT606 Fall 20064/11/2017“Satbilization Wedges”Billions of Tons Carbon Emitted per Year16Current path = “ramp”16 GtC/yEight “wedges”Goal: In 50 years, sameglobal emissions as todayHistoricalemissions8Flat path1.61950200020502100CSU ATS Scott Denning22
23 AT606 Fall 20064/11/2017What is a “Wedge”?A “wedge” is a strategy to reduce carbon emissions that grows in 50 years from zero to 1.0 GtC/yr. The strategy has already been commercialized at scale somewhere.1 GtC/yrTotal = 25 Gigatons carbon50 yearsCumulatively, a wedge redirects the flow of 25 GtC in its first 50 years. This is 2.5 trillion dollars at $100/tC.A “solution” to the CO2 problem should provide at least one wedge.CSU ATS Scott Denning
24 Fifteen Wedges in 4 Categories AT606 Fall 20064/11/2017Fifteen Wedges in 4 CategoriesEnergy Efficiency &Conservation (4)16 GtC/yFuel Switching(1)Renewable Fuels& Electricity (4)StabilizationStabilizationTriangleTriangleCO2 Capture& Storage (3)8 GtC/yForest and Soil Storage (2)20072057Nuclear Fission (1)CSU ATS Scott Denning24
25 AT606 Fall 20064/11/2017Photos courtesy of Ford Motor Co., DOE, EPAEfficiencyProduce today’s electric capacity with double today’s efficiencyDouble the fuel efficiency of the world’s cars or halve miles traveledAverage coal plant efficiency is 32% today“E,T, H” = can be applied to electric, transport, or heating sectors, $=rough indication of cost (on a scale of $ to $$$)There are about 600 million cars today, with 2 billion projected for 2055Use best efficiency practices in all residential and commercial buildingsE, T, H / $Replacing all the world’s incandescent bulbs with CFL’s would provide 1/4 of one wedgeSector s affected:E = Electricity, T =Transport, H = HeatCost based on scale of $ to $$$CSU ATS Scott Denning
26 AT606 Fall 20064/11/2017Fuel SwitchingSubstitute 1400 natural gas electric plants for an equal number of coal-fired facilities“E,H” = can be applied to electric or heating sectors, $=rough indication of cost (on a scale of $ to $$$)Effort needed for 1 wedge:Build 1400 GW of capacity powered by natural gas instead of coal (60% of current fossil fuel electric capacity)Requires an amount of natural gas equal to that used for all purposes todaySo a slice is 50 LNG tanker discharges/day by m3/tanker, orone new “Alaska” 4 Bscfd.Detailed Description: NATURAL GAS TURBINES ARE BEING DEVELOPED TO PRODUCE ELECTRICITY IN A SIMPLE, LOW COST ENVIRONMENTALLY FRIENDLY WAY. DOE'S NATIONAL ENERGY TECHNOLOGY LABORATORY (NETL) INITIATED THE ADVANCED TURBINE SYSTEMS (ATS) PROGRAM AND HAS PARTNERED WITH INDUSTRY TO PRODUCE A NEW GENERATION OF HIGH EFFICIENCY GAS TURBINES FOR CENTRAL STATION ELECTRICITY PRODUCTION, USING CLEAN BURNING NATURAL GAS.700 1-GW baseload coal plants (5400 TWh/y) emit 1 GtC/y.Natural gas: 1 GtC/y = 190 BscfdYr 2000 electricity:Coal : TWh/y; Natural gas: 2700 TWh/y.Photo by J.C. Willett (U.S. Geological Survey).A wedge requires an amount of natural gas equal to that used for all purposes todayE, H / $CSU ATS Scott Denning
27 Carbon Capture & Storage AT606 Fall 20064/11/2017Carbon Capture & StorageImplement CCS at800 GW coal electric plants or1600 GW natural gas electric plants or180 coal synfuels plants or10 times today’s capacity of hydrogen plants“E,T, H” = can be applied to electric, transport, or heating sectors, $=rough indication of cost (on a scale of $ to $$$)Graphic courtesy of Alberta Geological SurveyThere are currently three storage projects that each inject 1 million tons of CO2 per year – by 2055 need 3500.E, T, H / $$CSU ATS Scott Denning
28 Nuclear Electricity E/ $$ AT606 Fall 20064/11/2017Nuclear ElectricityTriple the world’s nuclear electricity capacity by 2055“E” = can be applied to electric sector, $$=rough indication of cost (on a scale of $ to $$$)Plutonium (Pu) production by 2054, if fuel cycles are unchanged: 4000 t Pu (and another 4000 t Pu if current capacity is continued).Compare with ~ 1000 t Pu in all current spent fuel, ~ 100 t Pu in all U.S. weapons.5 kg ~ Pu critical mass.Graphic courtesy of NRCThe rate of installation required for a wedge from electricity is equal to the global rate of nuclear expansion fromE/ $$CSU ATS Scott Denning
29 Wind Electricity E, T, H / $-$$ AT606 Fall 20064/11/2017Wind ElectricityInstall 1 million 2 MW windmills to replace coal-based electricity,ORUse 2 million windmills to produce hydrogen fuel“E,T, H” = can be applied to electric, transport, or heating sectors, $-$$=rough indication of cost (on a scale of $ to $$$)Photo courtesy of DOEA wedge worth of wind electricity will require increasing current capacity by a factor of 30E, T, H / $-$$CSU ATS Scott Denning
30 Photos courtesy of DOE Photovoltaics Program AT606 Fall 20064/11/2017Solar ElectricityInstall 20,000 square kilometers for dedicated use by 2054“E” = can be applied to electric sector, $$$=rough indication of cost (on a scale of $ to $$$)Photos courtesy of DOE Photovoltaics ProgramA wedge of solar electricity would mean increasing current capacity 700 timesE / $$$CSU ATS Scott Denning
31 RememberHalf (4 GtC/yr) of the current emissions (8 GtC/yr) remain in the atmosphere and contribute to greenhouse forcing of downward longwave raditaionEconomic growth is on track to at least doubleCO2 emissions to 16 GtC/yr by 2050Reducing CO2 emissions requires choosing a combination of efficiency, fuel switching, and alternative energy generation (“wedges”)Each “wedge” is feasible given today’s technology, but also expensive
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