The Need for Fast Near-Term Climate Mitigation to Slow Feedbacks and Tipping Points Critical Role of Short-lived Super Climate Pollutants in the Climate Emergency Background Note DRAFT: 27 September 2021 Institute for Governance Center for Human Rights and & Sustainable Development (IGSD) Environment (CHRE/CEDHA) Lead authors Durwood Zaelke, Romina Picolotti, Kristin Campbell, & Gabrielle Dreyfus Contributing authors Trina Thorbjornsen, Laura Bloomer, Blake Hite, Kiran Ghosh, & Daniel Taillant Acknowledgements We thank readers for comments that have allowed us to continue to update and improve this note. About the Institute for Governance & About the Center for Human Rights and Sustainable Development (IGSD) Environment (CHRE/CEDHA) IGSD’s mission is to promote just and Originally founded in 1999 in Argentina, the sustainable societies and to protect the Center for Human Rights and Environment environment by advancing the understanding, (CHRE or CEDHA by its Spanish acronym) development, and implementation of effective aims to build a more harmonious relationship and accountable systems of governance for between the environment and people. Its work sustainable development. centers on promoting greater access to justice and to guarantee human rights for victims of As part of its work, IGSD is pursuing “fast- environmental degradation, or due to the non- action” climate mitigation strategies that will sustainable management of natural resources, result in significant reductions of climate and to prevent future violations. To this end, emissions to limit temperature increase and other CHRE fosters the creation of public policy that climate impacts in the near-term. The focus is on promotes inclusive socially and environmentally strategies to reduce non-CO2 climate pollutants, sustainable development, through community protect sinks, and enhance urban albedo with participation, public interest litigation, smart surfaces, as a complement to cuts in CO2. strengthening democratic institutions, and the It is essential to reduce both non-CO2 pollutants capacity building of key actors. and CO2, as neither alone is sufficient to provide a safe climate. CHRE addresses environmental policy and human rights impacts in the context of climate IGSD’s fast-action strategies include reducing change through numerous advocacy programs emissions of the short-lived climate pollutants— including initiatives to promote fast action black carbon, methane, tropospheric ozone, and climate mitigation policies to contain and hydrofluorocarbons (HFCs). Reducing HFCs reverse climate change, to reduce the emission starting with the Kigali Amendment to the of short-lived climate pollutants such as black Montreal Protocol has the potential to avoid up to carbon, HFCs and methane, to protect glaciers 0.5 °C of warming by end of century. Parallel and permafrost environments for their value as efforts to enhance energy efficiency of air natural water storage and basin regulators, due conditioners and other cooling appliances during to their melt impacts on sea level and its the phase down of HFCs can double the climate influence on ocean currents and air streams, as benefits at 2050, and by 2060 avoid the equivalent well as for their global albedo value and for the of up to 460 billion tonnes of CO2. many other roles glaciers play in sustaining planetary ecological equilibrium. CHRE also fosters corporate accountability and human rights compliance to address the social and environmental impacts of key climate polluting industries such as oil and gas (including hydraulic fracturing), mining, paper pulp mills and artisanal brick production. Institute for Governance Center for Human Rights & Sustainable Development and Environment (CHRE/CEDHA) Unless otherwise indicated, all content in the Background Note carries a Creative Commons license, which permits non-commercial re-use of the content with proper attribution. Copyright © 2021 Institute for Governance & Sustainable Development and Center for Human Rights and Environment. The Need for Fast Near-Term Climate Mitigation to Slow Feedbacks and Tipping Points Critical Role of Short-lived Super Climate Pollutants in the Climate Emergency Updated: 27 September 2021 Table of Contents 1. Introduction and summary .............................................................................................. 1 2. Feedbacks and tipping points are key to understanding planetary emergency .......... 3 3. Shrinking Arctic shield ..................................................................................................... 4 4. Permafrost emissions of CO2, CH4, and N2O.................................................................. 7 5. Methane from Arctic Shelf ............................................................................................... 9 6. Increasing melt rate of Greenland Ice Sheet and destabilization of West Antarctic Ice Sheet ............................................................................................................................. 9 7. Persistence of ocean warming ........................................................................................ 10 8. Limited role of CO2 mitigation for near-term cooling ................................................ 10 9. Maximum role for mitigating short-lived super climate pollutants ........................... 11 Methane (CH4) .................................................................................................................. 12 Black carbon and tropospheric ozone (O3) ....................................................................... 15 Hydrofluorocarbons (HFCs) ............................................................................................. 16 Nitrous oxide (N2O) .......................................................................................................... 17 10. Strategies for protecting the Arctic and for removing non-CO2 climate pollutants. 17 11. Importance of protecting forests and other sinks ........................................................ 18 12. Conclusion ....................................................................................................................... 18 References .............................................................................................................................. 19 List of Figures Figure 1. Projected warming ................................................................................................................... 2 Figure 2. Abrupt climate changes as global temperatures increase ........................................................ 3 Figure 3. Climate tipping points ............................................................................................................. 4 Figure 4. Monthly sea ice extent anomalies ........................................................................................... 6 Figure 5. Late winter sea ice in the Arctic .............................................................................................. 7 Figure 6. Changes in permafrost ............................................................................................................. 8 Figure 7. Climate temperature response to reductions in emissions of CO2, SLCPs, or both .............. 11 Figure 8. Methane reductions compared to global mean surface temperature responses to changes in fossil-fuel-related emissions ................................................................................................................. 13 1. Introduction and summary This Background Note summarizes the science supporting the need for fast climate mitigation to slow warming in the near-term (2021–2041). It also describes the importance of cutting short-lived climate pollutants and protecting sinks in order to slow self-reinforcing feedbacks and avoid tipping points,i and explains why winning a fast mitigation sprint to 2030 is critical for addressing the climate emergency and complements decarbonization and net-zero efforts. • Climate change presents two challenges that we must simultaneously address: longer-term climate stabilization and near-term risk reduction from climate extremes that scale with the rate of warming and threaten to accelerate feedbacks and cross irreversible tipping ponts. • Achieving 2050 Net Zero CO2 targets is essential to stabilizing the climate at 1.5 °C by the end of this century due to the long lifetime of CO2 in the atmosphere. • Reducing near-term risks requires pairing these decarbonization efforts with strategies that reduce the short-lived climate pollutants (SLCPs)—black carbon (BC), methane (CH4), tropospheric ozone (O3), and hydrofluorocarbons (HFC)—as fast as possible, along with other fast mitigation strategies, including protection of sinks; this is essential for achieving near-term and long-term climate targets, including the 2050 Net Zero target. (SLCPs are often referred to as “super pollutants” because of their potency and ability to quickly reduce warming.) • These strategies are complementary and not exchangeable. • Addressing the near-term climate emergency requires selecting fast mitigation climate solutions1 in order to provide the most avoided warming in the shortest period of time over the next decade or two, to slow the self-reinforcing feedbacks and avoid tipping points,2 and to protect the most vulnerable people and ecosystems3 from the heat, drought, flooding and other extremes that will dramatically increase in severity and frequency with every increment