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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. Long-wave radiation.

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Global Warming: the Science, the Impacts and the Politics

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  1. Global Warming: the Science, the Impacts and the Politics John Houghton University of California, Irvine 20 February 2003

  2. The Science of Global Warming

  3. Variations of the Earth’s surface temperature for the past 1,000 years SPM 1b

  4. The Greenhouse Effect Long-wave radiation Solar radiation

  5. 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.

  6. 700 CO2 in 2100 (with business as usual) The last 160,000 years (from ice cores) and the next 100 years 600 Double pre-industrial CO2 500 Time (thousands of years) Lowest possible CO2 stabilisation level by 2100 400 CO2 concentration (ppm) CO2 now 300 10 Temperature difference from now °C 200 0 –10 100 160 120 80 40 Now

  7. The Enhanced Greenhouse Effect S L 236 236 S L 236 232 S L 236 236 S L 236 236 Solar (S) and longwave (L) radiation in Wm-2 at the top of the atmosphere T = -18°C CO2 x 2 + Feedbacks H2O (+60%) Ice/Albedo (+20%) Cloud? Ocean? CO2 x 2 CO2 x 2 TS = 15°C TS = 15°C DTS ~ 1.2K DTS ~ 2.5K

  8. IPCC Synthesis Report

  9. Estimated solar irradiance variations 1750-2000

  10. Simulated annual global mean surface temperatures

  11. The climate system

  12. The effect of the Mt. Pinatubo eruption (June 1991) on global temperature

  13. The Impacts ofGlobal Warming

  14. Contributions to sea level rise (metres), 1990-2100 ESTIMATED FOR IS92a SCENARIO Thermal Expansion 0.28 Glaciers 0.16 Greenland 0.06 Antarctica –0.01 TOTAL 0.49

  15. Sea-level transgression scenarios for Bangladesh Adapted from Milliman et al. (1989).

  16. People at Risk from a 44 cm sea-level rise by the 2080s Assuming 1990s Level of Flood Protection

  17. Projected changes in annual temperatures for the 2050s 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 BW 11 The MetOffice. Hadley Center for Climate Prediction and Research.

  18. Global water use, 1900–2000 5500 Total use 5000 4500 4000 3500 Agricultural use km /year 3 3000 2500 2000 1500 Industrial use 1000 Domestic use 500 0 1900 1920 1940 1960 1980 2000 (from Shiklomanor (1988))

  19. 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

  20. Changes in rainfall with doubled CO2 (CSIRO model) 160 Australian 40°N 40°S land 140 points 120 100 Change in 80 frequency 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

  21. 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

  22. El Niño years La Niña years The 1997/98 El Niño - strongest on record BW 14 *As shown by changes in sea-surface temperature (relative to the 1961-1990 average) for the eastern tropical Pacific off Peru

  23. Estimate (after Myers) of environmental refugees in a greenhouse-affected world (by ~2050) Country or region Refugees Country or region Refugees (millions) (millions) Bangladesh 15 Bangladesh 15 Egypt 14 Egypt 14 China 30 China 30 India India 30 Other Delta Areas and Coastal Zones 10 Other Delta Areas and Coastal Zones 10 Island States 1 Island States 1 Agriculturally-Dislocated Areas 50 Agriculturally-Dislocated Areas 50 Total 150 Total 150

  24. IPCC Synthesis Report

  25. What can we do aboutGlobal Warming?

  26. Intergovernmental Panel on Climate ChangeThird Assessment Report 2001 Scientific assessment includes: Summary for Policymakers (SPM) 20 pages Technical Summary (TS) 60 pages 14 chapters 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.

  27. IPCC Website • http://www.ipcc.ch

  28. UNITED NATIONS FRAMEWORK CONVENTION ON CLIMATE CHANGE Rio de Janeiro : June 1992ARTICLE 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.

  29. 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.

  30. Four Principles governing International Agreements • Precautionary Principle • Principle of Sustainable Development • Polluter Pays Principle • Principle of Equity

  31. Carbon Emissions per capita per annum in 2000(tonnes C) USA 5.5 UK 2.5 China 0.7 India 0.3 World Average 1.0

  32. Carbon dioxide contraction for 450 ppm & convergence by 2030 to globally equal per capita emissions rights

  33. 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

  34. Important Energy Technologies • Renewable Technologies • Wind – onshore & offshoreMarine – wave and tidalEnergy CropsEnergy from WastePV Solar • Other Technologies • Combined Heat and Power • Carbon Sequestration • Fuel Cells • Hydrogen fuel infrastructure • Decentralised or Local Generation

  35. Biomass

  36. Local solar energy supply Solar cell array Light ~1m2 ~100 W peak power T.V. + - Refrigerator Car battery

  37. Energy Supply: Shell ScenarioSustained Growth Scenario Source: Shell International Limited.

  38. COST OF EMISSIONS REDUCTIONSEstimated 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 rateequivalent to loss of 6 months’ GDP growth over 50 yrs UK govt Policy Innovation Unit Energy Review 2002 para 7.115

  39. GLOBAL WARMING Cost of impacts ~1% GNP (DCs) ~1% GNP (DCs) ~2-5% GNP (LDCs) ~2-5% GNP (LDCs) Plus other less quantifiable but important impacts 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 <1% GNP

  40. Global Warming Presents a Challenge to: • scientists • industry and technologists • governments • everybody

  41. 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

  42. Reasons for optimism - Commitment of scientific community - Necessary technology available - God’s commitment to his creation

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