Introduction to Climate Science
- 1. IPCC AR5 Synthesis Report Presentation of the IPCC Fifth Assessment Report Bangkok, Thailand 17 August 2015
- 2. IPCC AR5 Synthesis Report Key Messages Human influence on the climate system is clear The more we disrupt our climate, the more we risk severe, pervasive and irreversible impacts We have the means to limit climate change and build a more prosperous, sustainable future AR5 WGI SPM, AR5 WGII SPM, AR5 WGIII SPM
- 3. IPCC AR5 Synthesis Report HUMAN INFLUENCE: Extremely likely that human influence has been the dominant cause of warming since the mid-20th century AR5 SYR SPM
- 4. IPCC AR5 Synthesis Report HUMAN INFLUENCE: Anthropogenic GHG emissions have increased since the pre-industrial era, driven largely by economic and population growth AR5 WGIII SPM The atmospheric concentrations of carbon dioxide, methane and nitrous oxide that are unprecedented in at least the last 800,000 years.
- 5. IPCC AR5 Synthesis Report HUMAN INFLUENCE: Sources of Emissions Energy production remains the primary driver of GHG emissions 35% 24% 21% 14% 6.4% 2010 GHG emissions Energy Sector Agriculture, forests and other land uses Industry Transport Building Sector AR5 WGIII SPM
- 6. IPCC AR5 Synthesis Report Oceans absorb most of the heat 90%+ of the energy that accumulated in the climate system from 1971 and 2010 was absorbed by the oceans Land temperatures set a record high in 2014 while ocean temperatures continue to climb AR5 SYR
- 7. IPCC AR5 Synthesis Report HUMAN INFLUENCE: Some changes in extreme weather and climate events observed since ~1950 are linked to human activity AR5 WGI SPM In a number of regions, impacts are already underway: • decrease in cold temperature extremes • increase in warm temperature extremes • increase in extreme high sea levels • increase in the number of heavy precipitation events
- 8. IPCC AR5 Synthesis Report RISKS: Depend on cumulative C02 emissions AR5 WGI SPM
- 9. IPCC AR5 Synthesis Report RISKS: Projected changes to climate system Continued emissions of greenhouse gases will cause further warming and changes in the climate system Global glacier volume will further decrease Global mean sea level will continue to rise during the 21st century It is very likely that the Arctic sea ice cover will continue to shrink and thin as global mean surface temperature rises Oceans will continue to warm during the 21st century AR5 WGI SPM
- 10. IPCC AR5 Synthesis Report RISKS: Potential Impacts of Climate Change Food and water shortages Increased poverty Increased displacement of people Coastal flooding AR5 WGII SPM
- 11. IPCC AR5 Synthesis Report RISKS: Food Production AR5 SYR SPM
- 12. IPCC AR5 Synthesis Report SOLUTIONS: Limiting Temperature Increase to 2˚C Measures exist to limit likely warming to 2°C A combination of adaptation and substantial, sustained reductions in greenhouse gas emissions can limit climate change risks Implementing reductions in greenhouse gas emissions poses substantial technological, economic, social, and institutional challenges Ambitious mitigation is affordable: economic growth reduced by ~ 0.06% Estimated costs do not account for the benefits of reduced climate change AR5 WGI SPM, AR5 WGII SPM,AR5 WGIII SPM But delaying mitigation will substantially increase the challenges associated with limiting warming to 2°C
- 13. IPCC AR5 Synthesis Report SOLUTIONS: Mitigation Measures More efficient use of energy Greater use of low-carbon and no-carbon energy • Many of these technologies exist today • Nearly a quadrupling of zero- and low-carbon energy supply from renewable energy by 2050 Improved carbon sinks • Reduced deforestation and improved forest management and planting of new forests • Bio-energy with carbon capture and storage Lifestyle and behavioural changes AR5 WGIII SPM
- 14. IPCC AR5 Synthesis Report Climate change and equity Issues of equity, justice, and fairness arise with respect to mitigation and adaptation: • Different past and future contributions to the accumulation of GHGs in the atmosphere • Varying challenges and circumstances • Different capacities to address mitigation and adaptation. Options for equitable burden-sharing can reduce the potential for the costs of climate action to constrain development. AR5 WGIII
- 15. IPCC AR5 Synthesis Report The window for action is rapidly closing 65% of our carbon budget compatible with a 2°C goal already used Amount Used 1870-2011: 1900 GtCO2 Amount Remaining: 1000 GtCO2 Total Carbon Budget: 2900 GtCO2 AR5 WGI SPM
- 16. IPCC AR5 Synthesis Report IPCC Fifth Assessment Report Synthesis Report