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CLIMATE CHANGE PROJECTIONS: SOURCES AND MAGNITUDES OF UNCERTAINTY Tom Wigley, National Center for Atmospheric Research, Boulder, CO 80307, USA ([email protected]) Presented at: NCAR Summer Colloquium on Climate and Health National Center for Atmospheric Research, Boulder, CO. July 22, 2004 OUTLINE OF TALK Goal: To provide information about future global-mean temperature and sea level change and rates of temperature change, and their uncertainties, for both no-climate-policy and policy (concentration stabilization) emissions scenarios. OUTLINE OF TALK Warming and sea level commitments No-climate-policy projections (probability density functions for temperature and rates of change of temperature) CO2 concentration stabilization: Concentration profiles and implied CO2 emissions Article 2 and choosing a CO2 stabilization target: Effects of adaptation and non-CO2 gases Effects of CO2 stabilization on future warming and sea level Multi-gas stabilization (CO2, CH4 and N2O) Effects of CH4 and N2O on CO2 emissions, warming and sea level Future climate change depends on: Perturbations already imposed on the climate system (because of oceanic thermal inertia, the effects of these perturbations have not yet been fully realized); and Perturbations we may impose in the future. The latter depends on what policies we introduce to limit future change. FUTURE CLIMATE CHANGE: THREE CASES (1) Changes already in the system – the ‘warming commitment’ (2) ‘No climate policy’ emissions scenarios (3) Policy (concentration stabilization) scenarios CASE 1: WARMING COMMITMENTS (changes already in the system) (a) If we were able to stabilize atmospheric composition at today’s (year 2000) level [constant-C commitment] (b) If we stabilized all emissions at today’s levels [constant-E commitment] COMMITMENT UNCERTAINTIES ….. are due to ….. (1) uncertainties in past natural and anthropogenic forcing (mainly aerosol forcing) (2) gas-cycle and climate model uncertainties ….. • carbon cycle feedbacks • • climate sensitivity ocean mixing FORCING BREAKDOWN IN 2000 3 HALOS 2.5 TROP. O3 N2O 2 CH4 FORCING (W/m**2) 1.5 1 CO2 0.5 0 -0.23 -0.5 AEROSOL -1 range used in analyses -1.5 -2 -1.91 UNCERTAINTY 2.68 CONSTANT-C WARMING COMMITMENT CONSTANT-Q WARMING COMMITMENT: DT2x AND QAER EFFECTS 1 0.9 GLOBAL-MEAN TEMPERATURE CHANGE (degC) 0.8 DT2x = 4.5 degC 0.7 0.6 0.5 L 0.4 M DT2x = 2.6 degC H 0.3 0.2 DT2x = 1.5 degC 0.1 0 2000 2050 2100 2150 2200 YEAR 2250 2300 2350 2400 CONSTANT-E WARMING COMMITMENT CONSTANT-E WARMING COMMITMENT: DT2x AND QAER EFFECTS 6 L 5.5 M H 5 GLOBAL-MEAN TEMPERATURE CHANGE (degC) DT2x = 4.5 degC 4.5 4 3.5 3 2.5 2 DT2x = 2.6 degC 1.5 DT2x = 1.5 degC 1 0.5 0 2000 2050 2100 2150 2200 YEAR 2250 2300 2350 2400 CONSTANT-C SEA LEVEL COMMITMENT CONST-Q SEA LEVEL RISE COMMITMENT: DT2x, QAER & MELT EFFECTS 110 DT2x = 4.5 degC; QAER = LOW; MELT = HIGH 100 KEY : DT2x = 1.5, 2.6, 4.5 degC GLOBAL-MEAN SEA LEVEL RISE (cm) 90 80 70 L 60 M 50 40 H 30 20 10 DT2x = 1.5 degC; QAER = HIGH; MELT = LOW 0 2000 2050 2100 2150 2200 YEAR 2250 2300 2350 2400 CONSTANT-E SEA LEVEL COMMITMENT CONST-E SEA LEVEL RISE COMMITMENT: DT2x, QAER & MELT EFFECTS 220 DT2x = 4.5 degC; QAER = LOW; MELT = HIGH 200 KEY : DT2x = 1.5, 2.6, 4.5 degC GLOBAL-MEAN SEA LEVEL RISE (cm) 180 160 L 140 M H 120 100 80 60 40 20 DT2x = 1.5 degC; QAER = HIGH; MELT = LOW 0 2000 2050 2100 2150 2200 YEAR 2250 2300 2350 2400 CASE 2: CLIMATE CHANGE IN THE ABSENCE OF CLIMATE MITIGATION POLICIES PREDICTING FUTURE CLIMATE CHANGE Predict future socioeconomic changes Use these to predict future emissions From these predict changes in atmospheric composition Use these results to drive a climate model Question: How do we do this probabilistically? [Results in this presentation use the MAGICC climate model. MAGICC can be downloaded from www.cgd.ucar.edu] THE SRES EMISSIONS SCENARIOS (The basic drivers for future climate change) The Intergovernmental Panel on Climate Change (IPCC) has sponsored production of a new set of ‘no-climate-policy’ emissions scenarios for GHGs, sulfur dioxide, and other gases These scenarios are based on a range of assumptions regarding future population, economic growth, energy technology growth, etc. The scenarios are published in a Special Report on Emissions Scenarios – hence the acronym SRES (Special Report on Emissions Scenarios, eds. N.Nakicenovic and R. Swart, Cambridge University Press, 2000) FUTURE EMISSIONS IPCC SPECIAL REPORT ON EMISSIONS SCENARIOS (SRES) GASES CONSIDERED: CO2 CH4 N2O SO2 Reactive gases (CO, NOx, VOCs) Halocarbons (CFCs, HCFCs, HFCs, PFCs, SF6) RELATIVE IMPORTANCE OF DIFFERENT GASES FORCING CONTRIBUTIONS : A1B EMISSIONS 4 CO2 3.5 RADIATIVE FORCING (W/m**2) 3 2.5 2 1.5 1 AEROSOLS 0.5 HALOS N2O TROP O3 CH4 0 -0.5 1990 2000 2010 2020 2030 2040 2050 YEAR 2060 2070 2080 2090 2100 SRES CARBON DIOXIDE (CO2) PROJECTIONS (emissions and concentrations) SRES DECADAL FOSSIL-FUEL CO2 EMISSIONS 40 35 A1 - RED B1 - BLACK A2 - GREEN B2 - BLUE FOSSIL CO2 EMISSIONS (GtC/yr) MEAN - MAGENTA 30 25 20 15 10 5 0 1990 2000 2010 2020 2030 2040 2050 YEAR 2060 2070 2080 2090 2100 SRES RANGE OF CO2 PROJECTIONS 1100 1050 1000 CO2 CONCENTRATION (ppm) 950 900 850 800 750 700 650 600 550 500 450 400 350 1990 2000 2010 2020 2030 2040 2050 YEAR 2060 2070 2080 2090 2100 IPCC TAR GLOBAL-MEAN TEMPERATURE PROJECTIONS MAGICC MAGICC projections projections in in the the IPCC IPCC TAR TAR PREDICTING FUTURE CLIMATE CHANGE Predict future socioeconomic changes Use these to predict future emissions From these predict changes in atmospheric composition Use these results to drive a climate model Question: How do we do this probabilistically? A PROBABILISTIC PROJECTION IS ONE THAT … quantifies uncertainties by … (1) giving confidence intervals, or (2) presenting results in the form of a probability density function (p.d.f) p.d.f. FOR GLOBAL-MEAN WARMING OVER 1990-2100 0.45 0.4 PROBABILITY DENSITY (degC**-1) 0.35 0.3 0.25 1.7 0.2 4.9 0.15 0.1 AREA = 0.05 AREA = 0.05 90% CONFIDENCE INTERVAL 0.05 0 0 1 2 3 4 5 1990-2100 TEMPERATURE CHANGE (degC) 6 7 8 SOURCES OF UNCERTAINTY IN GLOBAL-MEAN TEMPERATURE CHANGE KEY SOURCES OF UNCERTAINTY FOR GLOBAL-MEAN TEMPERATURE (1) (2) (3) (4) (5) (6) Future emissions The climate sensitivity* Heat flux into the ocean Radiative forcing due to aerosols Carbon cycle/climate feedbacks Changes in ocean circulation * The climate sensitivity determines how much the climate will change for a given change in atmospheric composition. It is usually expressed as the eventual global-mean warming for a doubling of the CO2 concentration, and lies in the range 1.5-4.5oC with approx. 90% confidence. INPUT REQUIREMENTS FOR PRODUCING GLOBAL-MEAN TEMPERATURE PDFs (from Wigley & Raper, Science 293, 451-454, 2001) Emissions pdf (based on SRES) Climate sensitivity (DT2x) pdf Ocean mixing (Kz) pdf Aerosol forcing pdf Carbon cycle parameter pdfs NOTE: Other climate model parameters are also altered (land-ocean sensitivity ratio, exchange coefficients, THC slowdown rate), but the values are tied to DT2x based on AOGCM results. 1.8 PROBABILISTIC PROJECTIONS OF GLOBAL WARMING 1990-2030 1.4 o -1 PROBABILITY DENSITY (( C) ) 1.6 1.2 1 0.8 1990-2070 0.6 0.4 1990-2100 0.2 0 TAR RANGE 0 1 2 3 4 5 6 o 7 GLOBAL-MEAN TEMPERATURE CHANGE FROM 1990 ( C) PROBABILISTIC PROJECTIONS FOR THE RATE OF FUTURE GLOBAL-MEAN WARMING MAGICC MAGICC projections projections in in the the IPCC IPCC TAR TAR PDFs FOR DECADAL WARMING TRENDS PROBABILITY DENSITY FUNCTIONS FOR DECADAL TRENDS 8 1991-2000 PROBABILITY DENSITY (decade/degC) 7 6 5 4 3 2051-2060 2 1 2.6% 2091-2100 0 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 GLOBAL-MEAN TEMPERATURE TREND (degC/decade) 1.1 1.2 CONFIDENCE LIMITS FOR DECADAL WARMING TRENDS TREND UNCERTAINTIES AS PERCENTILES : SRES EMISSIONS 0.8 GLOBAL-MEAN TEMPERATURE TREND (degC/decade) 99% 0.7 95% 0.6 0.5 0.4 50% (=median) 0.3 0.2 5% 0.1 Trend over 1900-1999 0 1% -0.1 1991 2001 2011 2021 2031 2041 2051 2061 DECADE (1991 = 1991-2000, etc.) 2071 2081 2091 CASE 3: CLIMATE MITIGATION POLICIES ARTICLE 2 OF THE UNFCCC Our objective should be … “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system ….. within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner”. POLICY CASES (CO2 CONCENTRATION STABILIZATION) CO2 CONCENTRATION STABILIZATION PATHWAYS 800 WRE750 750 CO2 CONCENTRATION (ppm) 700 P50 BASELINE WRE650 650 600 550 CONST EFOSS(2000) WRE550 500 450 WRE450 400 350 1990 2010 2030 2050 2070 2090 2110 2130 2150 2170 2190 2210 2230 2250 YEAR CO2 CONCENTRATION STABILIZATION PATHWAYS 800 WRE750 750 KEY POINTS CO2 CONCENTRATION (ppm) 700 P50 BASELINE WRE650 650 600 550 CONST EFOSS(2000) WRE550 500 450 WRE450 400 350 1990 2010 2030 2050 2070 2090 2110 2130 2150 2170 2190 2210 2230 2250 YEAR (1) Stabilizing emissions does not stabilize concentrations (magenta line in plot) (2) These concentration stabilization pathways depart from the ‘no-policy’ baseline (black P50 line in plot) in 2005 (450ppm stabilization), 2010 (550ppm), 2015 (650ppm) and 2020 (750ppm) (3) A future departure date does not mean ‘do nothing’ until then – it means setting in place now the mechanisms for future (substantial) emissions reductions below the no-policy case EMISSIONS REQUIREMENTS FOR CO2 CONCENTRATION STABILIZATION (Note: stabilization of emissions does not stabilize concentrations, but leads to steadily increasing concentrations – at around 100 ppm/century.) CO2 EMISSIONS TO ACHIEVE STABILIZATION 18 P50 BASELINE 17 16 15 TOTAL CO2 EMISSIONS (GtC/yr) 14 WRE750 WRE650 13 12 11 WRE550 10 9 8 7 6 WRE450 5 4 3 2 1 0 1990 2010 2030 2050 2070 2090 2110 2130 2150 2170 2190 2210 2230 2250 YEAR CO2 EMISSIONS TO ACHIEVE STABILIZATION KEY POINTS P50 BASELINE 17 16 15 14 TOTAL CO2 EMISSIONS (GtC/yr) Except for the 450ppm case, emissions can rise substantially above present levels and still allow concentration stabilization to be achieved 18 WRE750 WRE650 13 12 11 WRE550 10 9 8 7 6 WRE450 5 4 3 2 1 0 1990 2010 2030 2050 2070 2090 2110 2130 2150 2170 2190 2210 2230 2250 YEAR After peak emissions, rapid reductions in emissions are required to achieve stabilization, implying a rapid transition to non-fossil energy sources and/or a rapid reduction in carbon ‘intensity’ (CO2 emissions per unit of energy) Eventually, emissions must fall substantially below current levels Note that these results are for CO2 alone – in practice the effects of other greenhouse gases must also be accounted for WHAT SHOULD THE CO2 STABILIZATION TARGET BE? (What does ‘dangerous interference’ mean?) [From Wigley, ‘Choosing a stabilization target for CO2’, Climatic Change, in press] INPUT PDF FOR GLOBAL WARMING LIMIT (from 2000) PROBABILITY DENSITY (degC**-1) INPUT PDFs : CO2 STABILIZATION CONCENTRATION IS CONTROLLED BY WARMING LIMIT, CLIMATE SENSITIVITY AND NON-CO2 FORCING 0.6 0.5 0.4 0.3 0.2 0.1 0 0 INPUT PDF FOR CLIMATE SENSITIVITY 1 2 3 4 GLOBAL WARMING LIMIT (degC) 5 6 INPUT PDF FOR NON-CO2 FORCING 0.7 0.5 PROBABILITY DENSITY (m**2/W) PROBABILITY DENSITY (degC**-1) 0.6 0.4 0.3 0.2 0.1 0.5 0.4 0.3 0.2 0.1 0 0 0 1 2 3 4 CLIMATE SENSITIVITY, DT2x (degC) 5 6 -1 0 1 2 NON-CO2 FORCING (W/m**2) 3 4 CO2 CONCENTRATION STABILIZATION TARGET 0.0022 Median (536 ppm) 0.002 PROBABILITY DENSITY (ppm**-1) HIGH SENSITIVITY 0.0018 HIGH NON-CO2 FORCING 0.0016 LOW WARMING LIMIT 0.0014 0.0012 0.001 LOW SENSITIVITY 0.0008 LOW NON-CO2 FORCING 0.0006 HIGH WARMING LIMIT 0.0004 0.0002 17% 0 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 CO2 CONCENTRATION (ppm) WHAT CAN BE DONE TO RELAX THE CO2 TARGET? (….. AND SO REDUCE THE CO2 MITIGATION LEVEL AND COSTS) EFFECTS OF ADAPTATION AND NON-CO2 GASES EFFECT OF ADAPTATION PDFs FOR DANGEROUS INTERFERENCE WARMING 0.45 WITH ADAPTATION PROBABILITY DENSITY (degC**-1) 0.4 0.35 0.3 BASE CASE 0.25 0.2 0.15 0.1 0.05 0 0 1 2 3 4 GLOBAL-MEAN WARMING FROM 2000 (degC) 5 6 EFFECT OF NON-CO2 EMISSIONS REDUCTIONS PDFs FOR NON-CO2 FORCING 1.4 REDUCED EMISSIONS PROBABILITY DENSITY (m**2/W) 1.2 1 0.8 0.6 0.4 BASE CASE 0.2 0 -0.5 0 0.5 1 1.5 2 RADIATIVE FORCING (W/m**2) 2.5 3 3.5 REVISED PDF FOR TARGET CO2 LEVEL STAB TARGET PDFs : EFFECTS OF ADAPTATION AND NON-CO2 REDUCTIONS 0.0022 BASE CASE 0.002 NON-CO2 REDUCTIONS PROBABILITY DENSITY (ppm**-1) 0.0018 0.0016 ADAPTATION 0.0014 BOTH 0.0012 0.001 0.0008 0.0006 0.0004 0.0002 370 0 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 CO2 CONCENTRATION TARGET (ppm) HOW WILL CO2 STABILIZATION AFFECT FUTURE GLOBAL-MEAN WARMING? EFFECTS OF CO2 STABILIZATION ON TEMPERATURE PDFs NO-POLICY, WRE450 AND WRE550 PDFs 0.8 450ppm CO2 STABILIZATION PROBABILITY DENSITY (degC**-1) 0.7 0.6 550ppm CO2 STABILIZATION 0.5 0.4 0.3 0.2 NO POLICY (SRES) 0.1 0 0 1 2 3 4 5 6 1990 to 2100 GLOBAL-MEAN TEMPERATURE CHANGE (degC) 7 EFFECT OF CO2 STABILIZATION ON SEA LEVEL [WRE profiles; other gases follow median emissions to 2100, then constant emissions] SEA LEVEL PROJECTIONS FOR STABILIZATION PROFILES 90 650 80 550 GLOBAL-MEAN SEA LEVEL RISE (cm) 70 450 60 50 350 40 30 20 10 0 2000 2050 2100 2150 2200 YEAR 2250 2300 2350 2400 THE IMPORTANCE OF NON-CO2 GASES In the following, CO2, CH4 and N2O concentrations are stabilized. The emissions reductions required to do this are balanced between the gases in order to minimize the total cost (‘cost optimization’). This is done using the energy-economics model MERGE developed by economists Alan Manne and Richard Richels CO2 stabilization pathways CO2 CONCENTRATION STABILIZATION PROFILES 750 BASELINE (P50) 700 CO2 CONCENTRATION (ppm) 650 600 WRE550 550 500 550 to 450 450 WRE450 400 350 2000 2050 2100 2150 YEAR 2200 2250 2300 CH4 stabilization pathways CONCENTRATIONS FOR COST-EFFECTIVE METHANE EMISSIONS REDUCTIONS 2750 No-policy baseline (P50) 2500 If CO2 target is 550ppm METHANE CONCENTRATION (ppb) 2250 2000 1750 1500 1250 1000 750 If CO2 target is 450ppm (including overshoot case) 500 2000 2050 2100 2150 2200 YEAR 2250 2300 2350 2400 N2O stabilization pathways NITROUS OXIDE CONCENTRATIONS 410 No-policy baseline (P50) 400 N2O CONCENTRATION (ppb) 390 380 If CO2 target is 550ppm 370 If CO2 target is 450ppm 360 (including overshoot case) 350 340 330 320 310 2000 2050 2100 2150 2200 YEAR 2250 2300 2350 2400 Reducing CH4 and (to a lesser extent) N2O concentrations reduces future warming and so reduces the magnitude of climate feedbacks on the carbon cycle. As a consequence, the CO2 emissions required to follow a given concentration pathway can be higher than otherwise. CO2 emissions: with CH4 and N2O reductions (full lines) compared with the no CH4/N2O reduction case (dashed lines) CO2 EMISSIONS WITH (BOLD) AND WITHOUT (DASHED) CH4/N2O REDUCTIONS 11 10 FOSSIL CO2 EMISSIONS (GtC/yr) 9 8 7 6 5 4 WRE550 3 2 WRE450 1 550 to 450 0 -1 2000 2050 2100 2150 2200 YEAR 2250 2300 2350 2400 TEMPERATURE AND SEA LEVEL RESULTS Global warming: with CH4 and N2O reductions (full lines) compared with the no CH4/N2O reduction case (dashed lines) TEMPERATURES WITH (BOLD) AND WITHOUT (DASHED) CH4/N2O REDUCTIONS 3 2.8 GLOBAL-MEAN TEMPERATURE (degC) 2.6 2.4 2.2 2 WRE550 1.8 1.6 1.4 1.2 WRE450 1 550 to 450 0.8 0.6 0.4 0.2 0 2000 2050 2100 2150 2200 YEAR 2250 2300 2350 2400 Sea level change: with CH4 and N2O reductions (full lines) compared with the no CH4/N2O reduction case (dashed lines) SEA LEVEL WITH (BOLD) AND WITHOUT (DASHED) CH4/N2O REDUCTIONS 80 WRE550 75 70 GLOBAL-MEAN SEA LEVEL RISE (cm) 65 60 550 to 450 55 50 45 40 WRE450 35 30 25 20 15 10 5 0 2000 2050 2100 2150 2200 YEAR 2250 2300 2350 2400 Warming rate: with CH4 and N2O reductions (full lines) compared with the no CH4/N2O reduction case (dashed lines) dT/dt WITH (BOLD) AND WITHOUT (DASHED) CH4/N2O REDUCTIONS 0.28 0.26 0.24 WARMING RATE (degC/decade) 0.22 0.2 0.18 WRE450 0.16 0.14 0.12 0.1 0.08 WRE550 0.06 0.04 0.02 0 550 to 450 -0.02 -0.04 2000 2050 2100 2150 2200 YEAR 2250 2300 2350 2400 CONCLUSIONS 1: Commitments Concentrations stabilized 0.11 to 0.48oC warming by 2050 sea level rises at 2–27cm/century Emissions stabilized warming at 0.8 to 2.0oC/century sea level rises at 8–54cm/century CONCLUSIONS 2: NO-POLICY (1) 90% C.I. for 2000-2100 warming 1.5–4.7oC (2) 90% C.I.s for warming rates ….. 2050s: 0.16–0.65oC/decade 2090s: 0.02–0.58oC/decade [cf. 20th century warming at 0.07oC/decade] (3) 3% probability of cooling in the 2090s CONCLUSIONS 3: STABILIZATION (1) CO2 emissions must eventually drop well below present levels (2) Based on ‘dangerous interference’, there is a 17% chance that the CO2 stabilization target should be less than the present level (absent adaptation and non-CO2 emissions reductions) (3) Multi-gas concentration stabilization: • CO2 emissions targets less stringent [for a given conc. profile] • Asymptotic warming is reduced by almost 1oC • Sea level rise is reduced by up to 15cm • Maximum warming rate is reduced by 2% to16% POST SCRIPT Lead in to Nychka/Tebaldi presentation. RESULTS FOR PATTERNS OF CLIMATE CHANGE o (per 1 C global-mean warming) Normalized annual-mean temperature and precipitation changes in CMIP2 1%/year CO2 increase experiments 90 70 Normalized temperature change L a t it u d e _ t a s 50 30 10 -1 0 -3 0 -5 0 -7 0 -9 0 -1 8 0 -1 2 0 0 -6 0 0.5 0.25 0 Long itude_ta s 1.5 2 1 0.75 1.25 60 120 2.5 1.75 2.25 3 2.75 3.25 90 70 Normalized precipitation change L a t it u d e _ p r 50 30 10 -1 0 -3 0 -5 0 -7 0 -9 0 -1 8 0 -1 2 0 -1 2 . 5 -6 0 -7 . 5 -1 0 -2 . 5 -5 0 Long itude_pr 2.5 0 60 120 7.5 5 12.5 10 15 MODELS GIVE A WIDE RANGE OF RESULTS FOR PROJECTED PRECIPITATION CHANGES SPANNING THE RANGE OF POSSIBLE FUTURES (blue = better models) DJF PRECIP CHANGES vs DJF TEMP CHANGES (Control drift removed) 30 BMRC CCC1 NORMALIZED PRECIPITATION CHANGE (%/degC) 25 20 HadCM2 15 10 MRI 5 PCM CERF CSM 0 IAP ECHAM4 GISS Model mean -5 GFDL LMD -10 CSIRO2 W&M -15 ECHAM3 -20 HadCM3 -25 Sth. CA: 30 to 35N, 115 to 120W CCSR -30 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 NORMALIZED TEMPERATURE CHANGE (degC/degC) 1.6 1.7 FURTHER INFORMATION IPCC Third Assessment Reports published by Cambridge University Press (see www.ipcc.ch). These reports are quite technical. Summaries are downloadable from the web site. Pew Center on Global Climate Change (www.pewclimate.org). The Pew Center has published many plain language reports on various facets of the global warming issue; downloadable. The MAGICC (Global-mean temperature and sea level)/SCENGEN (Regional details for temperature and precipitation) software can be downloaded from ….. www.cgd.ucar.edu