Climate Change: Current State of Scientific Understanding Bob Watson

1. Climate Change:Current State of Scientific UnderstandingBob Watson

2. Slide 1: Climate Change • Climate change is both a development and global environmental issue, which undermines: • environmental sustainability • poverty alleviation and the livelihoods of the poor • human health • national and regional security • Climate change is an inter- and intra-generational equity issue: • developing countries and poor people in developing countries are the most vulnerable • the actions of today will affect future generations because of the long life-times of the greenhouse gases and the inertia within the climate system

3. Slide 2: Atmospheric composition Since the industrial era began, human activities have increased the atmospheric concentrations of greenhouse gases, which tend to warm the Earth, and sulfate aerosols, which tend to cool the Earth, primarily due to energy and land management practices

4. Slide 3: Climate Change • The Earths climate has changed, in part due to human activities, and is projected to continue to change, globally and regionally: • Warmer temperatures • Changing precipitation • Higher sea levels • Retreating glaciers • Reduced arctic sea ice • More frequent extreme weather events • heat waves, floods and droughts

5. Slide 4: Surface Temperature A mid-range projection of change from 1990 to 2100 – a global average of 3.1oC The full projected range for changes in global average temperature is 1.4oC to 5.8oC Projected changes from 1990 to 2100 Observed changes from 1976 to 1999

6. Slide 5: Precipitation Projected changes in precipitation from 1990 to 2100 Observed changes in precipitation from 1900 to 2000

7. Slide 6: Most (greater than 50%) of the Observed Warming of the Last 50 Years is Attributable to Human Activities (b) observed and modeled changes disagree between 1920 and 1970 with anthropogenic forcing alone (a) Observed and modeled changes disagree between 1950 and 2000 with natural forcing alone (c) Observed and modeled changes in are in good agreement with natural and anthropogenic forcing

8. Slide 7:Extreme Weather Events Model Prediction Confidence in Observed Change • Higher maximum temperatures and more hot days 66-90% • Higher minimum temperatures, fewer cold days and frost days over nearly all land areas90-99% • Reduced diurnal temperature range over most land areas 90-99% • Increased heat index over most land areas 90-99% • More intense precipitation events over many areas 90-99% • Increased summer continental drying and associated risk of drought – mid-latitude continental interiors 66-90%

9. Slide 8: Recent Findings • Compared to the IPCC TAR, there is greater clarity and reduced uncertainty about the impacts of climate change • A number of increased concerns have arisen: • Increased oceanic acidity likely to reduce the oceans capacity to absorb carbon dioxide and effect the entire marine food chain • A regional increase of 2.7oC above present (associated with a temperature rise of about 1.5oC above today or 2oC above pre-industrial level) could trigger a melting of the Greenland ice-cap • An increase in ocean surface temperature of 1oC is likely to lead to extensive coral bleaching • Reversal of the land carbon sink – possible by the end of the Century • Possible destabilization of the Antarctic ice sheets becomes more likely above 3oC – the Larson B ice shelve is showing signs of instability • The North Atlantic Thermohaline Circulation may slow down or even shut down: one study suggested that there is a 2 in 3 chance of a collapse within 200 years, while another study suggested a 30% chance of a shut down within 100 years

10. Slide 9: Climate Change Human-induced climate change is projected to: • Decrease water availability and water quality in many arid- and semi-arid regions – increased risk of floods and droughts in many regions • Decrease the reliability of hydropower and biomass production in some regions • Increase the incidence of vector- (e.g., malaria and dengue) and water-borne (e.g., cholera) diseases, as well as heat stress mortality, threats nutrition in developing countries, increase in extreme weather event deaths • Decrease agricultural productivity for almost any warming in the tropics and sub-tropics and adverse impacts on fisheries • Adversely effect ecological systems, especially coral reefs, and exacerbate the loss of biodiversity

11. Slide 10: Climate Change and Conflict • Tens of millions of people displaced • Low lying deltaic areas • Small Island States • Food shortages where there is hunger and famine today • Water shortages in areas already with water shortages • Natural resources depleted (e.g., coral reefs, forests), loss of ecological goods and services • Increased incidence of disease • Increased incidence of severe weather events Climate Change, coupled with other local and global environmental issues can lead to local and regional conflict

12. Slide 11:The Kyoto Protocol • All industrialized governments, except the US and Australia have ratified the Kyoto Protocol, which contains: • A commitment to reduce GHG emissions, on average, by about 5% between 2008-2012 relative to 1990 • The flexibility mechanisms – carbon trading • Land-use, land-use change and forestry activities • Funding mechanisms to assist developing countries • The US stated that the Kyoto Protocol was flawed policy because it was neither fair nor effective and not in the best interests of the US • scientific uncertainties – Article 3 (precautionary principle) • high compliance costs – inconsistent with IPCC • ineffective without the participation of the large developing countries

13. Slide 12: Beyond Kyoto • Without the US taking real action to limit their GHG emissions it is doubtful that there will be a second commitment period – some OECD countries will withdraw and large developing countries, i.e., China and India will not be willing consider any commitments • Without a commitment of governments to limit GHG emissions beyond 2012 (the end of the first commitment period) the carbon market will remain soft and the private sector is unlikely to enter in a meaningful manner • The real question for governments is whether to: • set an emissions target for a second commitment period (2013-2017) or whether to set a long-term stabilization target for climate change (e.g., 2oC above the pre-industrial level) • a 2oC target would require stabilizing the atmospheric equivalent concentration of carbon dioxide at about 450ppm or less and stabilization or decreases in the atmospheric concentrations of other GHGs (see next slide) • this would require a global emissions target – the challenge would be to agree on intermediate emissions targets and an equitable allocation of emissions rights

14. Slide 13: Warming resulting from different stabilized concentrations of greenhouse gasespre-industrialized level - 280 ppm, current level - 370 ppm Temperature change relative to 1990 (C ) Even if the atmospheric concentration of carbon dioxide was stabilized at today’s level, the Earth’s temperature would still increase by over 0.5oC The atmospheric concentration of carbon dioxide equivalent (i.e., taking into account other GHGs) is close to 450ppm. The figure demonstrates that even if the atmospheric concentration of carbon dioxide was stabilized at 450-550 ppm, a significant increase in temperature is projected, thus adaptation is an important part of a climate strategy 10 Temperature change at equilibrium 9 8 76 5 4 3 2 1 0 450 550 650 750 850 950 1000 Eventual CO2 stabilisation level (ppm)

15. Slide 14: Conclusions from Exeter Meeting • Probability analysis suggests that to limit warming to 2oC above pre-industrial levels with a relatively high certainty requires the equivalent concentration of carbon dioxide to stay below 400ppm • Stabilization of the equivalent concentration of carbon dioxide at 450ppm would imply a medium likelihood of staying below 2oC above pre-industrial levels • If the equivalent concentration of carbon dioxide were to rise to 550ppm it is unlikely that warming would stay below 2oC above pre-industrial levels • The World Energy Outlook (2004) predicts that carbon dioxide emissions will increase by 63% over 2002 levels by 2030. This means that in the absence and urgent and strenuous actions to reduce GHG emissions in the next 20 years, the world will almost certainly be committed to a warming of between 0.5oC and 2oC relative to today by 2050, i.e., about 1.1oC and 2.6oC above pre-industrial

16. Slide 15: Potential Actions Energy Efficiency and Conservation:Efficient vehicles, Reduced use of vehicles, Efficient buildings, and Efficient coal plant Fuel shift:Gas power for coal power CO2 Capture and Storage:Capture CO2 at power plant; Capture CO2 at H2 plant; Capture CO2 at coal-to- synfuels plant; --- geological storage Nuclear fission:Nuclear power for coal power Renewable Electricity and Fuels:Wind power for coal power; PV power for coal power; Wind H2 in fuel-cell car for gasoline in hybrid car; Biomass fuel for fossil fuel Forests and Agricultural Soils:Reduced deforestation, plus reforestation, afforestation and new plantations; and Conservation tillage

17. Slide 16: Policy Instruments • Policies, which may need regional or international agreement, include: • Energy pricing strategies and taxes • Removing subsidies that increase GHG emissions • Internalizing the social costs of environmental degradation • Tradable emissions permits--domestic and global • Voluntary programs • Regulatory programs including energy-efficiency standards • Incentives for use of new technologies during market build-up • Education and training such as product advisories and labels • Accelerated development of technologies requires intensified R&D by governments and the private sector

18. Slide 17: Key Scientific Issues/Controversies • There is growing consensus regarding the state of knowledge regarding the science of climate change, but there remaining uncertainties: • What surprises could be in store – melting of the West Antarctic or Greenland Ice Sheets, shut-down of the oceanic conveyor belt, a non-linear response to greenhouse gas emissions? • What is the probability distribution around the climate projections and what is the probability of limiting a change in temperature to 2 degrees Celsius above pre-industrial for different GHG stabilization levels? • The economic costs of action and inaction are highly debated, hence there is a need to deepen our understanding of the economic issues, i.e., the costs of action to mitigate climate change and the costs of inaction on socio-economic sectors, ecological systems and human health? • Are today’s energy production and use technologies adequate to start to reduce GHG emissions cost-effectively - do we need a revolution or an evolution in energy technologies to provide affordable energy in a climate-friendly manner

19. Slide 18: Conclusions • Increased access to energy is critical for poverty alleviation and economic growth • Climate change undermines development and environmental sustainability • Access to affordable energy while also addressing climate change will require a collaborative effort involving governments, private sector, financial institutions, NGOs, and the research community • Increased public and private sector funding for energy S&T • Innovative public-private partnerships and technology transfer are needed • The Bank can play a critical role in assisting client countries reduce GHG emissions and adapt to climate variability and change • Developing a robust carbon market can reduce emission reduction costs in OECD and improve access to new technologies in developing countries - carbon financing is a source of new financing (non-ODA) • There are cost-effective and equitable solutions, but political will and moral leadership is needed