SBSTA-IPCC special event: Unpacking the new scientific knowledge and key findings in the Special Report on the Ocean and Cryosphere in a Changing Climate #SROCC The Ocean and Cryosphere in a Changing Climate COP25, Madrid 5 December 2019 SROCC Report by the numbers 36 countries 104 authors 824 expert reviewers 31,176 6981 studies comments COP25 / 5 December 2019 1 SBSTA-IPCC special event: Unpacking the new scientific knowledge and key findings in the Special Report on the Ocean and Cryosphere in a Changing Climate Photo: Jess Melbourne Thomas Polar Regions Ressource Local and indigenous Freshwater extraction people systems Arctic Snow Ocean Commercial International Marine Terrestrial Ice sheets Atmospheric Sea ice & frozen circulation activity cooperation ecosystems ecosystems & glaciers feedbacks ground Antarctic COP25 / 5 December 2019 12 SBSTA-IPCC special event: Unpacking the new scientific knowledge and key findings in the Special Report on the Ocean and Cryosphere in a Changing Climate Arctic sea ice is shrinking and its loss is projected to continue depending on global warming 100 Arctic sea ice extent (September) • September Arctic sea ice extent has Changes relative to 1986–2005 decreased between 1979 and 2018 50 • Summertime Arctic ship-based (%) Percentage 0 transportation has increased over the past two decades –50 –12.8% ± 2.3% per decade • At global warming of 1.5°C, the Arctic –100 Ocean will rarely be free of sea ice in 1950 2000 2050 2100 September. • At 2°C warming, this would occur on Historical (observed) Projected (RCP2.6) average in one to three times in ten Historical (modelled) Projected (RCP8.5) years Arctic permafrost is warming, and widespread thaw is projected this century 100 • Permafrost temperatures have Near−surface permafrost area Changes relative to 1986–2005 increased to record high levels 50 • Widespread permafrost thaw is Percentage (%) Percentage 0 projected for this century –24% ± 16% • Arctic and boreal permafrost contain –50 almost twice the carbon in the –69% ± 20% –100 atmosphere 1950 2000 2050 2100 • It is uncertain whether northern permafrost regions are currently Historical (observed) Projected (RCP2.6) releasing additional net methane Historical (modelled) Projected (RCP8.5) and CO2 COP25 / 5 December 2019 13 SBSTA-IPCC special event: Unpacking the new scientific knowledge and key findings in the Special Report on the Ocean and Cryosphere in a Changing Climate Arctic spring snow cover extent has decreased and is projected to decrease further 100 Arctic snow cover extent (June) • Arctic June snow cover has Changes relative to 1986–2005 50 declined since 1967 • Feedbacks from the loss of spring (%) Percentage 0 snow cover and summer sea ice –50 have contributed to amplified 13.4 ± 5.4% per decade Arctic warming –100 • Strong reductions in greenhouse 1950 2000 2050 2100 gas emissions in the coming decades are projected to reduce Historical (observed) Projected (RCP2.6) further changes after 2050 Historical (modelled) Projected (RCP8.5) Shrinking Arctic cryosphere affects water, wildfire, ecosystems, human activities and infrastructure • Food and water security have been negatively impacted by changes in cryosphere in many Arctic regions Seasonal snow • About 20% of Arctic land permafrost is Lake ice Shrubs Tundra vulnerable to abrupt permafrost thaw Abrupt thaw Boreal forest and ground subsidence Fire Permafrost Surface waters • The majority of Arctic infrastructure is Ground located in regions at risk from permafrost ice thaw by 2050 River discharge COP25 / 5 December 2019 14 SBSTA-IPCC special event: Unpacking the new scientific knowledge and key findings in the Special Report on the Ocean and Cryosphere in a Changing Climate The Greenland and Antarctic ice sheets are losing mass 0.3 0.15 m Greenland ice sheet mass loss (0.08– 0.2 Changes relative to 1986–2005 0.27 m) • Mass loss from the Antarctic ice Values as sea level equivalent Metres 0.1 –1 0.07 m sheet over the period 2007–2016 2006–2015 : 0.77 ± 0.03 mm yr (0.04– 0.12 m) tripled relative to 1997–2006 0 • For Greenland, mass loss doubled 0.3 Antarctic ice sheet mass loss 0.12 m (0.03– over the same period 0.2 Changes relative to 1986–2005 Values as sea level equivalent 0.28 m) • Acceleration of ice flow is observed 0.1 Metres 2006–2015: 0.43 ± 0.05 mm yr–1 0.04 m in the Amundsen Sea Embayment of (0.01– West Antarctica and in Wilkes Land, 0 0.11 m) 2100 East Antarctica 1950 2000 2050 • Ice sheets are projected to lose mass Historical (observed) Projected (RCP2.6) Historical (modelled) at an increasing rate Projected (RCP8.5) • The polar regions will be profoundly different in future compared with today, and the degree and nature of that difference will depend strongly on the rate and level of global warming. This will challenge adaptation responses regionally and worldwide. COP25 / 5 December 2019 15 SBSTA-IPCC special event: Unpacking the new scientific knowledge and key findings in the Special Report on the Ocean and Cryosphere in a Changing Climate Photo: Glenn R. Specht Sea Level Rise Global mean sea level is rising • It has accelerated in recent decades due to mass loss from the Greenland and Antarctic ice sheets, as Rates of global mean sea level rise well as continued glacier mass loss and ocean 2006–2015 thermal expansion 3.6mm/yr (range 3.1–4.1) • Regional differences, within ±30% of the global mean sea-level rise, result from land ice loss and Of which : variations in ocean warming and circulation Glaciers and ice sheets • Extreme wave heights, which contribute to extreme 1.8mm/yr (range 1.7–1.9) sea level events, have increased in the Southern and North Atlantic Oceans Ocean • Anthropogenic climate change has increased 1.4mm/yr (range 1.1–1.7) precipitation, winds, and extreme sea level events, associated with some tropical cyclones COP25 / 5 December 2019 16 SBSTA-IPCC special event: Unpacking the new scientific knowledge and key findings in the Special Report on the Ocean and Cryosphere in a Changing Climate Sea level is projected to continue to rise at an increasing rate 0.3 Primary drivers of Greenland 0.3 Ocean heat content (0−2000 m depth) 2400 global mean sea level 0.2 21 ice sheet mass loss as 10 Joules (right axis) Values as sea level equivalent Metres 0.2 1600 Changes relative to 1986–2005 0.1 0.1 800 0 0 Projected (RCP8.5) 0 0.3 Antarctic Projected (RCP2.6) 0.2 ice sheet mass loss Metres 0.1 Global mean sea level 0 1 0.3 Glacier Metres 0.2 mass loss 0 Metres 0.1 1950 2000 2050 2100 0 1950 2000 2050 2100 Sea level rise is projected to continue over centuries Processes controlling the timing of future ice-shelf loss and the extent of Projected (RCP8.5) ice sheet instabilities could increase Antarctica’s contribution to sea Projected (RCP2.6) level rise to values substantially higher than the likely range on century and longer time-scales (low confidence) Metres 5 Rates 4 15 (10–20 mm yr-1) 4 (2–6 mm yr-1) Projected mean sea level rise 3 2 1 0 1950 2000 2050 2100 2150 2200 2250 2300 COP25 / 5 December 2019 17 SBSTA-IPCC special event: Unpacking the new scientific knowledge and key findings in the Special Report on the Ocean and Cryosphere in a Changing Climate Global mean sea level rise will cause the frequency of extreme sea level events at most locations to increase Many low-lying coastal cities and small islands will be exposed to risks of flooding and land loss annually by 2050 Depending on location the height of a HCE varies widely but can cause severe impacts, depending on frequency and the level of exposure and adaptation Black dots: Locations where HCEs already recur annually White dots: Locations where HCEs recur annually after 2100 HCEs = Historical Centennial extreme sea level Events COP25 / 5 December 2019 18 SBSTA-IPCC special event: Unpacking the new scientific knowledge and key findings in the Special Report on the Ocean and Cryosphere in a Changing Climate Photo: PauloMr. JK Krug Ocean The ocean is projected to transition to unprecedented conditions Changes relative to 1986–2005 Historical (observed) Projected (RCP2.6) Historical (modelled) Projected (RCP8.5) 0.3 Ocean heat content (0−2000 m depth) 2400 21 0.2 as 10 Joules (right axis) 1600 Metres 2 0.1 800 0 0 0 Ocean oxygen –2 5 Global mean sea surface temperature 4 –4 (%) Percentage °C 3 2 –6 1 0 –1 8.1 20 pH Marine heatwave days Surface pH 8.0 15 7.9 factor 10 Multiplication 5 7.8 1 1950 2000 2050 2100 1950 2000 2050 2100 COP25 / 5 December 2019 19 SBSTA-IPCC special event: Unpacking the new scientific knowledge and key findings in the Special Report on the Ocean and Cryosphere in a Changing Climate Our ocean and cryosphere – They sustain us. They are under pressure. Their changes affect all our lives. The time for action is now. More Information: Website: http://ipcc.ch IPCC Secretariat: [email protected] IPCC Press Office: [email protected] Find us on: @IPCC_CH @IPCC @IPCC www.vimeo.com/ipcc www.youtube.com/c/ipccgeneva COP25 / 5 December 2019 40.