Global Warming the Science the Impacts and the Politics

Global Warming: the Science, the Impacts and the Politics John Houghton University of California, Irvine 20 February 2003 The Science of Global Warming Variations of the Earth‟s surface temperature for the past 1,000 years SPM 1b The Greenhouse Effect Solar radiation Long-wave radiation Concentration of Carbon Dioxide and Methane Have Risen Greatly Since Pre-Industrial Times Carbon dioxide: 33% rise Methane: 100% rise BW 5 The MetOffice. Hadley Center for Climate Prediction and Research. 700 Lowest possible CO2 stabilisation level by 2100 CO2 now 400 10 300 Temperature difference from now °C –10 160 120 80 40 0 200 Time (thousands of years) Now 100 CO2 concentration (ppm) The last 160,000 years (from ice cores) and the next 100 years CO2 in 2100 (with business as usual) 600 Double pre-industrial CO2 500 The Enhanced Greenhouse Effect Solar (S) and longwave (L) radiation in Wm-2 at the top of the atmosphere S 236 L 236 S 236 L 232 S 236 L 236 S 236 L 236 T = -18°C CO2 x 2 CO2 x 2 TS = 15°C TS = 15°C DTS ~ 1.2K CO2 x 2 + Feedbacks H2O (+60%) Ice/Albedo (+20%) Cloud? Ocean? DTS ~ 2.5K IPCC Synthesis Report Estimated solar irradiance variations 1750-2000 Simulated annual global mean surface temperatures The climate system The effect of the Mt. Pinatubo eruption (June 1991) on global temperature The Impacts of Global Warming Contributions to sea level rise (metres), 1990-2100 ESTIMATED FOR IS92a SCENARIO Thermal Expansion Glaciers Greenland Antarctica TOTAL 0.28 0.16 0.06 –0.01 0.49 Sea-level transgression scenarios for Bangladesh Adapted from Milliman et al. (1989). People at Risk from a 44 cm sea-level rise by the 2080s Assuming 1990s Level of Flood Protection Projected changes in annual temperatures for the 2050s BW 11 The projected change in annual temperatures for the 2050s compared with the present day, when the climate model is driven with an increase in greenhouse gas concentrations equivalent to about 1% increase per year in CO2 The MetOffice. Hadley Center for Climate Prediction and Research. Global water use, 1900–2000 5500 5000 4500 4000 3500 3 km /year 3000 2500 2000 1500 1000 500 0 1900 Total use Agricultural use Industrial use Domestic use 1920 1940 1960 1980 2000 (from Shiklomanor (1988)) Irrigated cropland appears red in this satellite photograph, made over the Nile where it flows through the Sudan. In the past 70 years, a variety of irrigation projects have increased the agricultural productivity of this dry region. More than half of the increase in the world‟s agricultural productivity during the past few decades has come from irrigation. From PR Crosson and NJ Rosenberg, 1989 Changes in rainfall with doubled CO2 (CSIRO model) 160 140 120 100 40°N 40°S Australian land points Change in frequency (%) 80 60 40 20 0 –20 0.2-0.4 0.4-0.8 0.8-1.6 1.6-3.2 3.2-6.4 6.4-12.8 12.8-25.6 >25.6 Daily rainfall class (mm day–1) Percent of the continental USA with a much above normal proportion of total annual precipitation from 1-day extreme events (more than 2 inches or 50.8mm) BW 7 Karl et al. 1996 The 1997/98 El Niño - strongest on record El Niño years La Niña years BW 14 *As shown by changes in sea-surface temperature (relative to the 1961-1990 average) for the eastern tropical Pacific off Peru Estimate (after Myers) of environmental refugees in a greenhouse-affected world (by ~2050) Country or region Bangladesh Egypt China India Refugees (millions) 15 14 30 30 Other Delta Areas and Coastal Zones Island States Agriculturally-Dislocated Areas Total 10 1 50 150 IPCC Synthesis Report What can we do about Global Warming? Intergovernmental Panel on Climate Change Third Assessment Report 2001 Scientific assessment includes: Summary for Policymakers (SPM) Technical Summary (TS) 14 chapters 20 pages 60 pages 780 pages prepared by 123 Co-ordinating Lead Authors & Lead Authors, 516 Contributing Authors, 21 Review Editors & 420 Expert Reviewers.. SPM agreed „line by line‟ at Plenary Intergovernmental Meeting at Shanghai, January 2001, with delegates from 99 countries and 50 scientists representing the Lead Authors. IPCC Website • http://www.ipcc.ch UNITED NATIONS FRAMEWORK CONVENTION ON CLIMATE CHANGE Rio de Janeiro : June 1992 ARTICLE 2: OBJECTIVE The ultimate objective of this Convention .... is to achieve, .… stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. •Such a level should be achieved 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. Global carbon emissions from fossil fuel Global carbon emissions from fossil fuel use, 1850 to 1990, and for scenarios to 2100, in GtC. For each scenario, the range shows the difference between gross and net emissions. From IIASA/WEC Global Energy Perspectives 1998. Four Principles governing International Agreements • • • • Precautionary Principle Principle of Sustainable Development Polluter Pays Principle Principle of Equity Carbon Emissions per capita per annum in 2000 (tonnes C) USA UK China India World Average 5.5 2.5 0.7 0.3 1.0 Carbon dioxide contraction for 450 ppm & convergence by 2030 to globally equal per capita emissions rights Saving Energy in Buildings • Use of white surfaces to reduce air conditioning • Low-energy lighting • Better insulation and control of space heating • More efficient appliances Important Energy Technologies • Renewable Technologies – Wind – onshore & offshore Marine – wave and tidal Energy Crops Energy from Waste PV Solar • Other Technologies – Combined Heat and Power – Carbon Sequestration – Fuel Cells – Hydrogen fuel infrastructure – Decentralised or Local Generation Biomass Local solar energy supply Solar cell array Light ~1m2 ~100 W peak power T.V. + - Car battery Refrigerator Energy Supply: Shell Scenario Sustained Growth Scenario exajoules 1500 Surprise Geoth. Solar Biomass 1000 Wind Nuclear Hydro 500 Gas Oil & NGL Coal 0 1860 1880 1900 1920 1940 1960 1980 2000 2020 2040 2060 Trad Bio. Source: Shell International Limited. COST OF EMISSIONS REDUCTIONS Estimated Cost of 60% reduction by 2050 On assumption of average economic growth at historic annual rate of 2.25%, estimated loss of 0.02% from the growth rate equivalent to loss of 6 months‟ GDP growth over 50 yrs UK govt Policy Innovation Unit Energy Review 2002 para 7.115 GLOBAL WARMING Cost of impacts ~1% GNP (DCs) ~2-5% GNP (LDCs) Plus other less quantifiable but important impacts Action required Energy efficiency and conservation Change to non-fossil-fuel energy sources Aforestation & Limit deforestation Move to Sustainable Consumption Cost of action <1% GNP Global Warming Presents a Challenge to: • • • • scientists industry and technologists governments everybody Message from Industry “No single company or country can solve the problem of climate change. It would be foolish and arrogant to pretend otherwise. But I hope we can make a difference not least to the tone of the debate - by showing what is possible through constructive action.” John Browne, BP, Berlin, 30 September 1997 Reasons for optimism - Commitment of scientific community - Necessary technology available - God‟s commitment to his creation „Nobody made a greater mistake than he who did nothing because he could only do a little‟ Edmund Burke