Jae Edmonds
DRAFT PRESENTATION—COMMENTS WELCOME
United Nations Framework Convention on Climate Change Article 2 (a) Holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 °C above pre-industrial levels,.... Article 4: In order to achieve the/ščiš-term temperatưŕe goal set out in Article 2, Parties aim to […], achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century, on the basis of ëquity, and in the context of sustainable development and efforts to eradicate poverty. Courtesy: Jan Sigurd Fuglestvedt United Nations Framework Convention on Climate Change UN Criwa ibly. • When the Paris Agree ment was negotiated no scenario pathways had been developed that showeld that 1.5 was possible. • That literature has grown rapidly since.
• Cumulative emissions of CO, will determine climate CO 2 climate forcing- and climate—for the next century. •  Non-CO, emissions will become more important as CO, emissions decline to zero • CO, has no atmospheric sink—it doesn't disāppear •  Carbon that was removed from the atmosphere over millions of years, can only be partitioned between atmosphere, ocean and land •  Atmosphere (~20% on average will remain permanently) •  Oceans (~80% on average will end up in oceans) 4 Representative Concentration Pathways and Extensions
• Energy efficiency—reduce demand for energy as much as economical •  Decarbonize power generation •  Fossil fuel with CCS • Renewable power • Nuclear power • Bioenergy •  Bioenergy with CCS •  Electrify Buildings and Industry as much as economical • Decarbonize transport • Electrify •  Biofuels • H2 • Halt deforestation/afforestation and continue improving crop yields DRAFT PRESENTATION—COMMENTS WELCOME
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● CO₂ is measured in both tons of CO, and tons of C • 3.667 ton CO₂ = 1 tons C • $1/tCO₂ = $3.67/tC CO, May 2019 414.7 PPM at NOAA’s Mauna Loa Atmospheric Baseline Observatory
* Assumes a climate sensitivity of 3ºC. Climate sensitivity is the number of degrees the planet would warm in the long term if the concentration of CO, doubled.
By the end of 2017, 2200 ± 320 GtCO, has been emitted by human activities ● Currently, emitting 42 ± 3 GtCO,/yr . Choice of the measure of global temperature affects the estimated remaining carbon budget Using global mean surface air temperature, as in IPCC AR5: 580 GtCO, left (50% chance of 1.5 °C) 420 GtCO, left (66% chance of 1.5 °C) Using global mean surface temperature (GMST) 770 GtCO, left (50% chance of 1.5 °C) 570 GtCO, left (66% chance of 1.5 °C)
Global total net CO₂ emissions Timing of net zero CO2 Line widths depict the 5-95th percentile and the 25-75th percentile of scenarios INTERGOVERNMENTAL PANEL ON CLIN
Non-CO2 emissions relative to 2010 Emissions of non-CO 2 forcers are also reduced or limited in pathways limiting global warming to 1.5°C with no or limited overshoot, but they do not reach zero globally. INTERGOVERNMENTAL PANEL ON CliMA
●  Current policies and measures are not adequate to meet Nationally Determined Contributions (NDC) to Paris Agreement. • NDCs are inadequate to meeting either 2º or 1.5º long-term stabilization goals.
• Limiting climate change to any level involves eventually transitioning to a zero CO₂ emissions world — All sectors of energy and land systems must also decline toward zero or lower – All regions of the world must also decline toward zero or lower •   Lower limits of global temperature require faster transitions • The challenge to achieving the 1.5° goal should not be underestimated. — Global emissions must begin to decline before 2030 — Global carbon emissions must reach zero around 2050 – And then go negative. • Technology, policy and institutions will shape the mix of sectors and fuels. • The world is currently NOT on track to achieve the 1.5° goal. DISCUSSION