Environmental Effects of Stratospheric Ozone Depletion, UV Radiation, And
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Photochemical & Photobiological Sciences https://doi.org/10.1007/s43630-020-00001-x PERSPECTIVES Environmental efects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Efects Assessment Panel, Update 2020 R. E. Neale1 · P. W. Barnes2 · T. M. Robson3 · P. J. Neale4 · C. E. Williamson5 · R. G. Zepp6 · S. R. Wilson7 · S. Madronich8 · A. L. Andrady9 · A. M. Heikkilä10 · G. H. Bernhard11 · A. F. Bais12 · P. J. Aucamp13 · A. T. Banaszak14 · J. F. Bornman15 · L. S. Bruckman16 · S. N. Byrne17 · B. Foereid18 · D.‑P. Häder19 · L. M. Hollestein20 · W.‑C. Hou21 · S. Hylander22 · M. A. K. Jansen23 · A. R. Klekociuk24 · J. B. Liley25 · J. Longstreth26 · R. M. Lucas27 · J. Martinez‑Abaigar28 · K. McNeill29 · C. M. Olsen30 · K. K. Pandey31 · L. E. Rhodes32 · S. A. Robinson33 · K. C. Rose34 · T. Schikowski35 · K. R. Solomon36 · B. Sulzberger37 · J. E. Ukpebor38 · Q.‑W. Wang39 · S.‑Å. Wängberg40 · C. C. White41 · S. Yazar42 · A. R. Young43 · P. J. Young44 · L. Zhu45 · M. Zhu46 Received: 5 November 2020 / Accepted: 10 November 2020 © The Author(s) 2021 Abstract This assessment by the Environmental Efects Assessment Panel (EEAP) of the United Nations Environment Programme (UNEP) provides the latest scientifc update since our most recent comprehensive assessment (Photochemical and Photobio- logical Sciences, 2019, 18, 595–828). The interactive efects between the stratospheric ozone layer, solar ultraviolet (UV) radiation, and climate change are presented within the framework of the Montreal Protocol and the United Nations Sustain- able Development Goals. We address how these global environmental changes afect the atmosphere and air quality; human health; terrestrial and aquatic ecosystems; biogeochemical cycles; and materials used in outdoor construction, solar energy technologies, and fabrics. In many cases, there is a growing infuence from changes in seasonality and extreme events due to climate change. Additionally, we assess the transmission and environmental efects of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is responsible for the COVID-19 pandemic, in the context of linkages with solar UV radiation and the Montreal Protocol. 1 Introduction and human health (Fig. 1). Due to the Montreal Protocol, large increases in UV-B (280–315 nm) radiation have been The contribution of the Montreal Protocol to several of the avoided and global warming reduced through regulation United Nations Sustainable Development Goals (SDGs) is of the ozone depleting substances, most of which are also addressed in this EEAP 2020 Update Assessment. The SDGs potent greenhouse gases. The resulting changes in strato- and their targets are provided for a number of sustainabil- spheric ozone, ultraviolet (UV) radiation and climate are ity themes, including climate change, air and water quality, evaluated regarding the efects on humans and the environ- biodiversity and ecosystems, contaminants and materials, ment. Some of the potential consequences are assessed of recent unexpected events, such as the COVID-19 pandemic (Sect. 9), and unprecedented increases in UV radiation over Electronic supplementary material The online version of this the Arctic in 2020 due to stratospheric ozone depletion article (https ://doi.org/10.1007/s4363 0-020-00001 -x) contains (Sect. 2). supplementary material, which is available to authorized users. * J. F. Bornman [email protected] * S. Hylander [email protected] Extended author information available on the last page of the article Vol.:(0123456789)1 3 Photochemical & Photobiological Sciences Fig. 1 The Sustainable Development Goals (SDG) relevant to this ment of chemicals and wastes; 12.5 reduce waste generation; 13.1 assessment are shown outside the circle with specifc targets (num- strengthen resilience to climate-related hazards and disasters; 13.2 bers in white) linked to EEAP Working Groups (1–7, numbers in integrate climate change measures into policy; strategy and planning; black) in concentric circles. These SDG targets include: 2.3 increase 13.3 improve education on climate-change mitigation; 14.1 reduce productivity of small-scale food producers; 2.4 ensure sustainable marine pollution; 14.3 minimise impacts of ocean acidifcation; 15.1 food production systems; 2.5 maintain genetic diversity of agricul- ensure the conservation of terrestrial ecosystems; 15.3 combat deser- tural plants and animals; 3.3 end epidemics of communicable dis- tifcation; and 17.14 enhance policy coherence for sustainable devel- eases; 3.9 reduce deaths caused by air; soil and water contamination; opment. Topics covered by the EEAP Working Groups 1–7 are: (1) 6.1 achieve access to safe drinking water; 6.3 reduce water pollution; Stratospheric ozone, UV radiation and climate interactions; (2) 6.6 protect water-related ecosystems; 7.A enhance international coop- human health; (3) terrestrial ecosystems and biodiversity; (4) aquatic eration around clean energy; 9.4 upgrade industries to be sustainable; ecosystems; (5) biogeochemistry in a changing environment; (6) air 11.5 reduce deaths caused by disasters; 11.6 reduce the environmen- quality; and (7) material damage (fgure created by Emma Leslie, tal impact of cities; 12.4 achieve environmentally sound manage- Global Challenges Program, Univ. of Wollongong, Australia) 1 3 Photochemical & Photobiological Sciences 2 Stratospheric ozone, UV radiation, has been avoided due to the Montreal Protocol. This new and climate interactions study is based on a coupled atmosphere–ocean–land–sea–ice model and took into account the efect of the Montreal This section provides an update since our last assessments Protocol on emissions of ODSs that have contributed the [1, 2] on recent fndings of the interactions between strato- most to stratospheric chlorine concentrations, namely the spheric ozone, solar ultraviolet (UV) radiation and cli- chlorofuorocarbons (CFCs) CFC-11 and CFC-12, as well mate, and discusses the impact of the Montreal Protocol as the CFC substitutes HCFC-22, HFC-125 and HFC-134a. on these processes. In addition to protecting life on Earth Increases in GHG concentrations (including the concentra- from harmful UV radiation, the Montreal Protocol is also tions of these ODSs) were described in this model by the 1 highly efective in mitigating global warming because most Representative Concentration Pathway (RCP) [11] that of the ozone-depleting substances (ODSs) regulated by the leads to the strongest warming at Earth’s surface (RCP 8.5). Montreal Protocol are also potent greenhouse gases (GHGs). The study concluded that, as of 2019, implementation of the According to new quantitative estimates, the implementation Montreal Protocol has prevented warming ranging between of the Montreal Protocol has prevented between a quarter 0.5 °C and 1.0 °C over large mid-latitude regions of land, and a third of the global mean increases in air temperature, particularly parts of Africa, North America and Eurasia. depending on the time period considered. The stratospheric As much as 1.1 °C warming has been avoided over parts ozone hole over Antarctica continues to recover, with 2019 of the Arctic. In addition to quantifying benefts from the being one of the years with the lowest spring-time UV index Montreal Protocol that have already been realised, Goyal measured at the South Pole since the start of measurements et al. [10] also assessed the Montreal Protocol’s efect on in 1991. In the Arctic, springtime episodes of stratospheric the future climate for the RCP 8.5 scenario. Projected tem- ozone depletion, identifed frst in the early 2010s, continue perature increases that are likely to be averted by 2050 are to occur. The last episode in the spring of 2020 led to the on the order of 1.5 °C to 2 °C over most extrapolar land largest ozone loss measured to date and resulted in UV areas, and between 3 °C and 4 °C over the Arctic. Averaged indices that were twice as high as typical at several Arc- over the globe (including the oceans), about 1 °C warming tic locations. Additional topics discussed include: trends would be avoided by 2050, which corresponds to about 25% in measured surface UV radiation from ground-based and mitigation of global warming expected from all GHGs. The satellite data that are driven by changes in total ozone, aero- Montreal Protocol is contributing to SDG 13.2 by reducing sols and clouds; efects of Antarctic ozone depletion on the global warming. climate in the Southern Hemisphere and linkages to Aus- These benefts of the Montreal Protocol were corrobo- tralian wildfres; and projections of surface UV-B radiation rated by Polvani et al. [3] using calculations with a diferent for the second half of the twenty-frst century. This section climate model. When all known forcings (GHGs, ODSs) contributes to SDG 11.5, 12.4, 13.2, and 17.14 by providing were taken into account, the simulated global-mean air further evidence that the Montreal Protocol has protected the temperature at the surface increased by 0.59 °C between climate and the stratospheric ozone layer. 1955 and 2005. When the concentrations of ODSs and atmospheric ozone were fxed at 1955 levels, the resulting 2.1 Additional evidence has accumulated temperature change was only 0.39 °C. Hence, ODSs were that the Montreal Protocol is reducing global responsible for about one-third of global warming over warming this period. Similar calculations for the Arctic (60–90° N) resulted in temperature changes of 1.59 °C and 0.82 °C for Most ODSs controlled by the Montreal Protocol and its the two scenarios, respectively, suggesting that ODSs con- amendments are also potent GHGs with global warming tributed about one-half to the warming at the Arctic surface. potentials (GWPs) that are substantially larger than those of Changes in Arctic temperatures have a direct efect on sea . carbon dioxide (CO 2) and methane (CH4). Over the second ice loss. Polvani et al [3] concluded that ODSs contributed half of the twentieth century, all ODSs taken together were the second-most important GHG with approximately one third of the radiative forcing of CO2 [3].