IPCC Synthesis Report Part III - David Griggs

1. IPCC Synthesis ReportPart III - David Griggs • Inertia in climate, ecological and socio-economic systems • Impact of stabilization scenarios on climate and corresponding impacts • Abrupt, high impact threshold/ non-linear events

2. Inertia is a widespread characteristic of climate, ecological and socio-economic systems • Time scale is the time taken for a perturbation in a process to show at least half of its final effect • Inertia means a delay, slowness, or resistance in the response of climate, biological, or human systems to factors that alter their rate of change, including continuation of change in the system after the cause of that change has been removed

3. There is a wide range of time scales associated with the climate, ecological and socio-economic systems

4. There are fast and slow processes in the carbon cycle

5. Climate-induced increases in sea level are caused by thermal expansion of the oceans and melting of land ice and ice sheets

6. CO2 concentrations, temperature and sea level continue to rise long after emissions are reduced

7. Stabilization of atmospheric concentrations of CO2 will require emissions reductions globally These dates are associated with CO2 stabilization alone – stabilization of CO2 equivalent concentrations need to occur even earlier because of the contribution of the non- CO2 greenhouse gases

8. Constant emissions ofCO2 do not lead to stabilization of atmospheric concentrations

9. Global terrestrial net uptake of carbon peaks during the 21st century then levels off or declines

10. The 1:1 relationship between GDP and CO2 emissions can be de-linked

11. Historical rates of changes in energy intensity are consistent with those needed for stabilization of CO2 concentrations from 450-1000 ppm Historical rates of changes in carbon intensity are far slower than those needed for stabilization of CO2 concentrations from 450-1000 ppm.

12. Stabilization of the atmospheric concentration of carbon dioxide will require significant emissions reductions

13. Temperature change relative to 1990 (C) There is a wide band of uncertainty in the amount of warming that would result from any stabilised concentration of greenhouse gases 10 10 Temperature change relative to 1990 (C ) Temperature change in the year 2100 9 9 Temperature change at equilibrium 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 0 0 450 550 650 750 850 950 1000 450 550 650 750 850 950 1000 Eventual CO2 stabilisation level (ppm) Eventual CO2 stabilisation level (ppm)

14. The risks of climate change damages increase with the magnitude of climate change

15. Some climate, ecological and socio-economic system changes are effectively irreversible over many human lifetimes, and others are intrinsically irreversible • The thermohaline circulation • Ice sheets • Migration of plant species

16. The themohaline circulation could be disrupted by climate change

17. Adaptation is a necessary strategy to complement climate change mitigation efforts • Adaptation and mitigation can contribute to sustainable development objectives • Mitigation actions to reduce greenhouse gas emissions would lessen the pressure on natural and human systems • The lower the level of stabilization of greenhouse gas concentrations the greater the benefits in terms of avoided damage • Comprehensive, quantitative estimates of the benefits of stabilization at various levels do not yet exist • The lower the magnitude and rate of change, the less chance there is of crossing thresholds