COP21 Paris: Deliverance or Disappointment? John D. Sterman Jay W. Forrester Professor of Management Director, MIT System Dynamics Group MIT Sloan School of Management

2.6 to 5.9°C (4.8 to 10.6°F) 90% CI 2.0 to 4.6°C (3.6 to 8.2°F) 0.9 to 2.4°C (1.7 to 4.4°F)

Global Greenhouse Gas Emissions (GtonsCO 2 e / year) No Action Expected Temp Anomaly 2100 November 2015, 1.8°C 3.2°F 3.5°C 6.3°F 4.5°C 8.1°F 2.6 to 5.9°C (4.8 to 10.6°F) 90% CI 2.0 to 4.6°C (3.6 to 8.2°F) 0.9 to 2.4°C (1.7 to 4.4°F) Emissions (GtCO2e/year)

Regional Emissions (GtCO2e/year)

Delaying reductions needed to limit warming to ≤ 2°C requires much faster rate of decline (ave. of 4.8%/yr vs. 3.5%/yr)

Paris: Deliverance or Disappointment? 7 Historic global agreement involving almost all nations – Voluntary; already being undermined (SCOTUS; dissension in the EU over coal; low fossil prices; continued fossil subsidies) Stronger goals: limit warming to "well below 2°C... and pursuing efforts to limit [warming] to 1.5°C” – The Dieter’s Delusion: Goals without action are meaningless INDCs from >180 nations – Full implementation of all INDCs  3.5°C Ratchet review process to strengthen INDCs – No requirement for greater ambition or earlier action; continued debate over historical responsibility; inadequate funding for mitigation in developing nations: The agreement merely "strongly urges" the developed nations to "scale up their level of financial support." "an enhanced transparency framework..." to use "metrics assessed by the [IPCC]" to "ensure methodological consistency.” – No guarantee loopholes and cheating will be prevented – Positive surprises unlikely. Instead: Porter Ranch, Indonesian fires, etc. See Sterman, The Paris Climate Agreement: Deliverance or Disappointment?