Dr Andy Reisinger on climate change


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Dr Andy Reisinger, Senior Research Fellow, New Zealand Climate Change Research Institute, presents evidence that global warming, caused by human activity, is an irrefutable scientific fact; this is having huge ecological and social impacts which will ramify into future generations; were facing a global train wreck and have to act now.

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Dr Andy Reisinger on climate change

  1. 1. Climate change: overview and update Andy Reisinger Climate Change Research Institute New Zealand Climate Change Research Institute
  2. 2. Warming is unequivocal and widespread • Global average atmospheric temperatures increasing • Extreme temperatures increasing • Ocean heat content increasing … • … now directly linked to sea level rise • Greenland and Antarctic Ice Sheets losing mass • Unequivocal Glaciers and snow cover declining • Arctic sea ice extent decreasing • Area of seasonally frozen ground decreasing • Atmospheric water vapour content increasing • More intense and longer droughts • More frequent heavy precipitation events over land • Tropical cyclone intensity increasing (in North Atlantic) 2
  3. 3. Recent warming is due to greenhouse gases Models reproduce observed changes only if we include the warming effect of greenhouse gases Combination of volcanic eruptions and solar change would have resulted in small cooling over the last 50 years Figure source: IPCC WGI Figure SPM.4 3
  4. 4. Future warming depends on emissions Figure source: based on IPCC WGI Figure SPM.5 and Third Assessment Report 4
  5. 5. Projected warming – does it matter? Even at the lower end of future scenarios, the global rate of change over the 21st century will almost certainly be greater than experienced by human civilisation over the past 10,000 years Changes greater over land and more variable We can no longer stop global warming, but reducing emissions would reduce its rate and magnitude Figure source: based IPCC WGI Figures 6.10 and Figure SPM.5 5
  6. 6. Global impacts of climate change Source: IPCC WGII Table TS.5 6
  7. 7. Settingemissions targets reductions: policy Stringent 450ppm CO2-eq 2° relative to pre- C industrial temperatures Adaptation is necessary: Mitigation is necessary: manage unavoidable change avoid unmanageable change Source: IPCC WGII Table TS.5 7
  8. 8. Global greenhouse gas emissions Figure source: IPCC WGII Figure 1.1 8
  9. 9. Emissions reductions • Each sector has options to reduce emissions • The more we want to reduce emissions, the more we have to include all sectors and all opportunities • Achieving emissions reductions requires: • a price on emissions that makes the use of alternative technologies attractive • policies that support change in behaviour and the development and deployment of new technologies 9
  10. 10. Example electricity sector Emissions of CO2 eventually have to reduce to zero to stabilise greenhouse gas concentrations. This requires research to develop new technologies, reduce costs and increase feasibility/scale. Figure: based on data from IPCC WGIII Figures 4.29, 4.30 and Tables 4.6, 6.7, 7.5 10
  11. 11. How does NZ compare? – income growth 35.00% World 30.00% United States of America European Union (27) 25.00% New Zealand 20.00% 15.00% 10.00% 5.00% 0.00% 1990 1992 1994 1996 1998 2000 2002 2004 2006 -5.00% Income in purchasing power parity relative to 1990. Source: cait.wri.org 11
  12. 12. How does NZ compare? – CO2 emissions 70.00% 60.00% World United States of America European Union (27) 50.00% New Zealand 40.00% 30.00% 20.00% 10.00% 0.00% 1990 1992 1994 1996 1998 2000 2002 2004 2006 -10.00% Domestic CO2 emissions relative to 1990. Source: cait.wri.org 12
  13. 13. Scale of emissions reductions • Stabilising concentrations at 450ppm CO2-eq: • Developed countries reduce their emissions by 25-40% by 2020, and 80-95% by 2050, relative to 1990 emissions • Developing countries reduce their emissions by 10-30% below business-as-usual by 2020 and much more substantial reductions by 2050. The most advanced developing countries would need to do more. • Stabilising concentrations at 450ppm CO2-eq gives us only a 50/50 chance of not exceeding 2° ! C • Delays or less stringent targets increase greenhouse gas concentrations further and increase the risk of serious and irreversible climate damages 13
  14. 14. Latest updates • Failure to make international progress would mean that we are about to loose the chance to limit warming to 2°C. • If everybody on the planet were allowed the same per capita emissions, and we wish to limit global warming to 2° then C, New Zealanders will exhaust their emissions allowance (even counting CO2 only !) by about 2020 • Polar ice sheets are loosing ice faster than predicted by ice sheet models. Glaciers that drain the ice sheets are accelerating with warming, leading to faster sea level rise. • Recent studies suggest that sea level could rise by more than 1m by 2100, and even 2m cannot be ruled out entirely for scenarios without stringent emissions reductions 14