The role of the Montreal Protocol in protecting present and future climate: A scientific perspective

Transcription

1 ATOC4800/ATOC5000/ENVS5830: Policy Implications of Climate : Critical Issues in Climate and the Environment, Prof. Weiqing Han University of Colorado Boulder Boulder, CO 20 February 2019 The role of the in protecting present and future climate: A scientific perspective by Dr. David W. Fahey, Director Chemical Sciences Division Earth System Research Laboratory National Oceanic and Atmospheric Administration Outline Boulder, Colorado USA Ozone basics The and dual benefits HFCs and Kigali Amendment Climate Change Building Summary remarks Ø Protection from ultraviolet light from the ozone layer. The ozone layer resides in the stratosphere and surrounds the entire Earth. UV-B radiation (280- to 315nanometer (nm) wavelength) from the Sun is strongly absorbed in this layer. UV-A (315- to 400-nm wavelength), visible light, and other solar radiation are not strongly absorbed by the ozone layer. Human exposure to UV-B radiation increases the risks of skin cancer, cataracts, and a suppressed immune system. UV-B radiation exposure can also damage terrestrial plant life, single-cell organisms, and aquatic ecosystems. UNEP,

2 The Ozone Layer Good ozone Bad ozone Ø The stratospheric ozone is good ozone and excess ozone in the troposphere is bad ozone. UNEP, 2010 Ozone concepts: Total ozone & the Dobson Unit (DU) Total ozone = ozone vertical sum Thought experiment: Ar + others Stove pipe thought experiment: sort the atmosphere column into its different component gases O2 + N2 O3 3??? mm = 0.12 in = 300 DU Ø Total ozone at a point on the globe is the amount of ozone from the surface to the top of the atmosphere. Ø Ozone is a small fractional component of our atmosphere. UNEP,

3 The on Substances that Deplete the Ozone Layer 16 September 1987 The Parties to this, Being Parties to the Vienna Convention for the Protection of the Ozone Layer, Mindful of their obligation under that Convention to take appropriate measures to protect human health and the environment against adverse effects resulting or likely to result from human activities which modify or are likely to modify the ozone layer, Recognizing that world-wide emissions of certain substances can significantly deplete and otherwise modify the ozone layer in a manner that is likely to result in adverse effects on human health and the environment, 17 September 2009 Antarctic Ozone Hole Conscious of the potential climatic effects of emissions of these substances, Universal ratification in September 2009 by 197 members of the United Nations. à The world s most successful environmental treaty Technical aspects of the Ø The has imposed legally binding controls on the global consumption and production of ozone depleting substances (ODSs) and introduced short-term and long-term substitute gases. - chlorofluorocarbons (CFCs) - halons - hydrochloroflurocarbons (HCFCs) Ø The has imposed legally binding controls on the global consumption and production of hydrofluorocarbons (HFCs) Ø ODSs are used to meet application demand for refrigeration, air conditioning, insulating foams, fire suppression, and many other society needs. Ø The addresses the governance, technical, economic and social aspects of its regulations and distinguishes between the developed and developing world. 3

4 Ozone-depleting substances (ODSs) entering the stratosphere in 1993 and 2016: an inventory Ø Human uses of synthetic chemicals have significantly increased their abundance in the stratosphere. Ø Most synthetic gases have no significant loss processes in the troposphere, i.e., very unreactive. Ø Chlorine ~3290 ppt; Bromine ~19.6 ppt; Bromine ~60x more effective UNEP, 2018 Ø Chlorine and bromine from ozone depleting substances (ODSs) destroys ozone. Ø The has been very successful in reducing chlorine and bromine in the atmosphere. Ø Strategy: Start and strengthen. Atmospheric chlorine and bromine The & Amendments (World avoided) City names are locations of the meetings of the parties UNEP/WMO,

5 UNEP/WMO and scientific assessments UNEP (United Nations Environment Programme) WMO (World Meteorological Organization) Ø Scientific assessments of ozone depletion have been an important component of the. Ø Strategy: Start and strengthen. Ø Future vigilance is required UNEP, 2014 The 2018 ozone assessment was released to the 197 parties and the public in February 2018 (590 pgs) 5

6 Timelines of ozone-depleting substances (ODSs) Ø Peak halogens (chlorine + bromine) occurred in the late 1990s Ø Atmospheric abundances of most synthetic gases are in slow decline UNEP,

7 The dual benefit of the Metrics for ODSs and substitutes: ODP = ozone depletion potential à increased ozone depletion (CFC-11 = 1) GWP = global warming potential à increased climate warming (CO2 = 1) High ODP Low ODP Zero ODP CFCs & halons HCFCs HFCs High to low GWPs High GWP Ø By reducing the use and emissions of ozone depleting substances, the has provided to date the dual benefit of protecting ozone and climate. Demonstrating the dual benefit of the The Protection Ozone and Climate The Protection of of Ozone and Climate From global emissions of all ozone-depleting substances (ODSs) From global emissions of all ozone-depleting substances (ODSs) andand COCO in protecting ozone and climate 2 (Megatonnes CFC-11-equivalent per year) (Megatonnes CFC-11-equivalent per year) weighted weighted by by ozone-depletion potentials (ODPs) ozone-depletion potentials (ODPs) weighted weighted by by global-warming potentials (GWPs) global-warming potentials (GWPs) Kyoto Kyoto reduction target reduction target for for (Gigatonnes CO 2-equivalent per year) (Gigatonnes CO2-equivalent per year) Ozone layer Ozone layer Year Year Climate Climate Year Year Equivalent Effective Stratospheric Equivalent Effective Stratospheric Chlorine (EESC) Chlorine (EESC) Radiative forcing of climate Radiative forcing of climate Ozone layer Ozone layer Radiative forcing Velders et al., 2007; UNEP/WMO, 2014 (watts per square meter) Radiative forcing (watts per square meter) EESC (Relative amounts) EESC (Relative amounts) Ø By 2010, the has avoided substantial ozone depletion and achieved 5-6 times Kyoto target in Climate Climate 7

8 Future HFC use CFCs & halons HCFCs HFCs High ODP Low ODP Zero ODP Ø Large expected growth of HFC use in the developing world Residential Air conditioning Refrigeration Ø Ultimately, the climate impact of future HFC use depends on choosing HFC substitutes that have low-gwps. Insulating foams Mobile air conditioning The future: Avoiding the large projected growth in HFC use Global HFC consumption Ø HFCs will be the primary choice for future applications of refrigeration, air conditioning, and foams. Ø Scenarios based on GDP and population growth projections. Ø Scenario assumes HCFC phaseout schedule and businessas-usual replacement schedule from developed nations. Velders et al., PNAS, 2009 Velders et al., Atmos. Environ

9 Initiatives for global phase down of HFCs in 2013 Ø Meeting of Chinese President Xi Jinping and US President Barack Obama at Rancho Mirage, California on 8 June Ø Will work together and with other countries to use the expertise and institutions of the to phasedown the production and consumption of HFCs. Ø 6 September 2013: G-20 leaders expanded the support for using the expertise and institutions of the to phase down the production and consumption of HFCs, while retaining HFCs within the scope of the UNFCCC and its Kyoto for accounting and reporting of emissions. Ø This was agreed by the following countries: Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Korea, Mexico, Russia, Saudi Arabia, South Africa, Turkey, the United Kingdom, the United States, and the European Union, as well as Ethiopia, Spain, Senegal, Brunei, Kazakhstan, and Singapore. G20 Summit, St. Petersburg September Kigali Amendment to control HFC production and consumption Kigali, Rwanda, 15 October 2016 Agreed upon baselines and phasedown schedules 9

10 HFC amendment Kigali, Rwanda, 15 October 2016) Dr. Tina Birmpili, Executive Secretary of the Annual Meeting, 2016, Kigali, Rwanda 20 10

11 Impact of the HFC amendment Global temperature increase Business-as-usual (BAU) range from o C in 2100 Kigali amendment: reduced to about 0.06 o C Policy implications First multilateral, fully funded, legally binding action to avoid climate change Unreported emissions of CFC-11 Global CFC-11 emissions, derived from measurements by two independent networks, increased after 2012 contrary to projections from previous Assessments, which showed decreasing emissions (Figure ES-2). Global CFC-11 emissions for 2014 to 2016 were approximately 10 Gg yr -1 (about 15%) higher than the fairly constant emissions derived for 2002 to 2012; the excess emissions relative to projected emissions for recent years is even larger. The CFC-11 emission increase suggests new production not reported to UN Environment. of CFC-11 from eastern Asia have increased since 2012; the contribution of this region to the global emission rise is not well known. The unreported emissions are unprecedented in the history of the. UNEP/WMO 2018 Ozone Assessment 11

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13 Summary Remarks Ø The is the most successful environmental treaty in history. It has the dual benefit: protecting ozone and climate. Strategy: Start and strengthen. Ø Chlorine and bromine compounds (ODSs) are largely phased out and most are in decline in the atmosphere. Ø By 2010, the avoided substantial ozone depletion and achieved reductions in climate gases 5-6 times Kyoto target. Ø Projected HFC use in the developing world as a result of regulations would lead to substantial climate forcing contributions by Ø The Kigali HFC amendment avoids HFC growth and limits temperature increases to <0.06 oc in 2100 representing the first multilateral, fully funded, legally binding action to avoid climate change. Ø Grand challenge: The and Kyoto parties working together to minimize the climate impact in meeting the global application demand for synthetic gases in the developing world. Ø Ongoing challenge: Identifying scientific contributions that provide the needed foundation for the climate change building. Science has the first word on everything, but the last word on nothing." Victor Hugo Thank you for your attention. 13

14 Backup slides Global radiative forcing components in 2005 IPCC AR4 (2006) Halocarbons = 0.34 Wm -2 = 20% of total RF of 1.66 Wm

15 Ozone-depletion potentials and global warming potentials for equal mass emissions Ozone-depleting substances (1) (0.05) CFC-11 = 1 Chlorine-containing gases Bromine-containing gases CFC-11 CFC-113 CFC-12 Carbon tetrachloride HCFC-22 Halon-1301 Halon-1211 Methyl bromide (5) CO2 = 1 Substitute gases (0) (0) (0) (0) (0) Hydrofluorocarbons (HFCs) HFC-23 HFC-143a HFC-125 HFC-152a Ozone depletion potential (ODP) Global warming potential (GWP, 100-yr) Increasing ozone depletion HFC-134a (0) HFC-1234yf (4) UNEP/WMO, 2010 (133) Increasing surface warming Ø ODSs contribute to both ozone depletion & climate change. HFCs contribute to climate change. What is happening in industry (car makers)? Ø Since the 1990s all mobile air-conditioners use HFC-134a (GWP = 1370) Ø In EU: mobile air-conditioning directive: - Refrigerant should have GWP < From 2011 for new type of vehicles (derogation until 12/2012) Ø Alternatives available for HFC-134a: - HFC-1234yf (Drop-in replacement with GWP = 5) 15