Primer on Polar Warming and Implications for Global Climate Change How fast action can slow the rate of global warming and protect the Arctic and Antarctic from devastating climate change impacts Institute for Governance & Sustainable Development IGSD Working Paper: 13 May 2019 Lead Authors Kristin Leigh Campbell & Durwood Zaelke Contributors Gabrielle B. Dreyfus, Stephen O. Andersen, Tad Ferris, Nancy J. Sherman, Korey Silverman- Roati, & Megan Matthews Acknowledgements We would like to thank our outside reviewers for their valuable contributions. About IGSD IGSD’s mission is to promote just and sustainable societies and to protect the environment by advancing the understanding, development, and implementation of effective and accountable systems of governance for sustainable development. Beginning in 2005, IGSD embarked on a “fast-action” climate mitigation campaign that will result in significant reductions of greenhouse gas emissions and will limit temperature increase and other climate impacts in the near term. The focus is primarily on strategies to reduce non- CO2 climate pollutants as a complement to cuts in CO2, which is responsible for more than half of all warming. It is essential to reduce both non-CO2 pollutants and CO2. Neither alone is sufficient to limit the increase in global temperature to a safe level. A three-level strategy of achieving carbon neutrality, slowing the rate of warming with the reduction of non-CO2 climate pollutants, and removing carbon from the atmosphere are key to climate stability. IGSD’s fast-action strategies include reducing emissions of short-lived climate pollutants—black carbon, methane, tropospheric ozone, and hydrofluorocarbons. They also include measures to promote energy efficiency of air conditioners and other appliances, and measures to capture, reuse, and store CO2 after it is emitted, including biosequestration and mineralization strategies that turn carbon dioxide into stable forms for long-term storage while enhancing sustainable food supply. Institute for Governance & Sustainable Development This Primer is available on IGSD’s website (http://www.igsd.org/primers/polar/) with active links to the references and periodic updates. IGSD’s Primer on HFCs and Primer on Short-Lived Climate Pollutants are also available on IGSD’s website. Unless otherwise indicated, all content in the Primer carries a Creative Commons license, which permits non-commercial re-use of the content with proper attribution. Copyright © 2019 Institute for Governance & Sustainable Development. 2 Preamble This Primer covers the present and future impacts of climate change on the Polar Regions and what solutions and resources are available to slow the progression of climate change. The Primer discusses observations of recent warming as well as tipping elements and impending tipping points particular to the Polar Regions before a thorough discussion of the present observations and future projections for Arctic sea ice, permafrost, and the ice sheets of Greenland and Antarctica. The Primer also relates potential solutions to combat climate change, especially in the crucial near-term given the proximity to some tipping points. Furthermore, the Primer includes discussion of existing laws and policies as well as organizations and collectives working to protect the vulnerable Polar Regions. 3 TABLE OF CONTENTS 1. Introduction 6 2. Recent Warming, Proximity to 1.5 ºC, and Arctic Amplification 9 Recent warming observations 9 Proximity to 1.5 ºC and timing of reaching 1.5 ºC and 2 ºC 10 Arctic amplification 10 Unmasked warming with reduction of aerosols 11 3. Self-Reinforcing Feedbacks and Tipping Elements 12 Understanding self-reinforcing feedbacks and critical thresholds of tipping elements 12 Timing and tipping points 14 4. Arctic Sea Ice 15 Reduced Arctic sea ice and self-reinforcing warming 15 Recent observations and climatology of the extent of Arctic sea ice 16 Thickness of sea ice 18 Projections for the future and the likelihood of ice-free Arctic 20 Cumulative emissions and aerosols contributing to Arctic warming and ice loss 21 Decreased Arctic sea ice and more cyclones and larger ocean waves 21 Teleconnections—what happens in the Arctic does not stay in the Arctic 21 Reversibility with cooler temperatures or geoengineering 22 5. Permafrost 24 Defining the permafrost-carbon feedback 24 Current state of permafrost 25 Palaeoclimate information on permafrost 27 Projections for permafrost 27 Costs and non-climate impacts from permafrost thaw 28 6. Greenland and Antarctic Ice Sheets 29 Melting ice sheets of Greenland and Antarctica lead to sea-level rise 29 Greenland 33 Recent observations 33 Feedbacks and accelerated melting in Greenland 34 Greenland’s palaeoclimate and associated sea-level rise 35 Antarctica 36 West Antarctic Ice Sheet (WAIS) 36 East Antarctic Ice Sheet (EAIS) 37 Sea-level rise contribution from Antarctica 38 Antarctic sea ice 39 7. Long- and Short-term Priorities and Solutions 40 Priorities 40 Securing long-term climate stability through three-lever approach 40 Achieving near-term success through SLCP mitigation 41 Carbon neutrality must be achieved by mid-century 41 Avoiding catastrophic climate threat with carbon dioxide removal (CDR) 41 Solutions for reducing SLCPs 42 Mitigation measures to reduce SLCPs 42 Co-benefits from SLCP reductions 44 4 SLCPs directly impacting the Arctic 45 8. Opportunities for Strengthening SLCP Mitigation 47 UN Framework Convention on Climate Change (UNFCCC) and the Paris Agreement 47 International action on HFCs through the Kigali Amendment to the Montreal Protocol 49 SLCPs managed through the Convention on Long-Range Transboundary Air Pollution 50 Climate and Clean Air Coalition (CCAC) 50 International Maritime Organization (IMO) 51 International Civil Aviation Organization (ICAO) 52 Arctic Council 53 National and subnational laws regarding SLCP mitigation 54 U.S. Climate Alliance 54 Intersection of SLCP mitigation with Sustainable Development Goals (SDGs) 55 9. Conclusion 56 Appendix I: List of acronyms and abbreviations 57 Endnotes 58 Figures and Tables Fig. 1: Arctic Region 6 Fig. 2: Antarctic Region 7 Fig. 3: Tipping elements and temperature ranges of their tipping points 12 Fig. 4: Breakdown of tipping points within temperature ranges 13 Fig. 5: Change in temperature (red), sea ice (black), & albedo (green) 15 Fig. 6. Arctic sea ice extent for March and September from 1979 to 2018 16 Fig. 7: Arctic sea ice extent for March 2018 and September 2018 17 Fig. 8: Monthly anomalies of Arctic sea ice extent from November 1978 to July 2018 18 Fig. 9: Quantity and extent of old and young Arctic sea ice 19 Fig. 10: Schematic diagram of permafrost feedback mechanism of deepening active layer 24 Fig. 11: Soil carbon content in the Arctic Region 26 Fig. 12: Sources of sea-level contribution 30 Fig. 13: Sea-level rise for 1.5 and 2 ºC 31 Fig. 14: Sea-level rise contributions from Greenland and Antarctica 32 Fig. 15: Geography of Antarctica—glaciers, ice shelves, ice streams, and basins 36 st Fig. 16: Prediction reductions in 21 century sea-level rise due to SLCP and CO2 mitigation 45 Fig. 17: Probable tipping points in the range of the Paris Agreement goal 48 Table 1: Global average warming in 2018 and 2016 (warmest year on record) 9 5 INTRODUCTION This Primer will focus on the impact climate change is already having on the Polar Regions, the projections for what will happen in the future, and what can be done about it. The Arctic is warming at twice the global rate,1 but both poles are considered in this Primer because they are subject to a number of globally consequential climate tipping elements2—for which passing a critical threshold (tipping point) unleashes significant and often unstoppable change—and self- reinforcing climate feedbacks, the triggering of which can permanently alter the state of the global and regional climate through a domino-like effect.3 Self-reinforcing feedbacks and tipping elements of the Polar Regions include: declining Arctic sea ice; thawing permafrost; and melting ice sheets in Greenland and Antarctica.4 Another feedback—the poleward migration of mid- latitude clouds—plays a role in Arctic amplification, exacerbating warming and bringing the region closer to tipping points.5 Fig. 1: Arctic Region This map of the Arctic was created by State Department geographers as part of the U.S. Chairmanship of the Arctic Council. (U.S. Department of State, Map of the Arctic Region (last accessed 23 May 2018).) 6 The Antarctic region is comprised of Antarctica and the Southern Ocean that surrounds the continent. Antarctica is divided into two parts: West Antarctica and the much larger East Antarctica. West Antarctica is home to the Antarctic Peninsula and also many ice shelves. See Figure 2. Fig. 2: Antarctic Region This map shows the major geographical features on the Antarctic continent and the USA and UK research stations, to accompany the Landsat Image Mosaic of Antarctica (LIMA). For information about LIMA and to access the imagery, go to http://lima.usgs.gov. (U.S. Geological Survey, Antarctic Overview Map (last accessed 23 May 2018).) 7 Because the poles are routinely covered in snow and ice, they are part of the global cryosphere and are crucial to the climate system.6 These frozen areas of the planet are particularly vulnerable to the rising temperatures that induce melting. The Arctic Ocean is covered in sea ice, and the Arctic region also includes the Greenland ice sheet and large areas of permafrost.7 At the other pole, Antarctica