Montreal Protocol Benefits simulated with CCM SOCOL

Abstract

Ozone depletion is caused by the anthropogenic increase of halogen-containing species in the atmosphere, which results in the enhancement of the concentration of reactive chlorine and bromine in the stratosphere. To reduce the influence of anthropogenic ozone-depleting substances (ODS), the Montreal Protocol was agreed by Governments in 1987, with several Amendments and Adjustments adopted later. In order to assess the benefits of the Montreal Protocol and its Amendments and Adjustments (MPA) on ozone and UV radiation, two different runs of the chemistry-climate model (CCM) SOCOL have been carried out. The first run was driven by the emission of ozone depleting substances (ODS) prescribed according to the restrictions of the MPA. For the second run we allow the ODS to grow by 3% annually. We find that the MPA would have saved up to 80% of the global annual total ozone by the end of the 21st century. Our calculations also show substantial changes of the stratospheric circulation pattern as well as in surface temperature and precipitations that could occur in the world without MPA implementations. To illustrate the changes in UV radiation at the surface and to emphasise certain features, which can only be seen for some particular regions if the influence of the cloud cover changes is accounted for, we calculate geographical distribution of the erythemally weighted irradiance (<i>E</i>_ery). For the no Montreal Protocol simulation <i>E</i>_ery increases by factor of 4 to 16 between the 1970s and 2100. For the scenario including the Montreal Protocol it is found that UV radiation starts to decrease in 2000, with continuous decline of 5% to 10% at middle latitudes in the both Northern and Southern Hemispheres

A mid-latitude stratosphere dynamical index for attribution of stratospheric variability and improved ozone and temperature trend analysis

“…The stratospheric ozone layer has been damaged by the use of ODSs and following a ban through the 1987 Montreal Protocol (Solomon, 1999), levels of ODSs have declined since their peak in 1998 (Egorova et al, 2013;Chipperfield et al, 2015), although the peak may be earlier or later depending on the location of interest. However, the rate of ozone recovery is latitude dependent, with southern mid-to-high latitudes expected to recover from elevated ODSs (WMO, 2011).…”

The Importance of the Montreal Protocol in Protecting Earth’s Hydroclimate

“…By 2065,67% of the ozone is depleted globally, and ozone hole-type conditions become global and year-round, rather than being only predominant over Antarctica and confined to austral spring. Other recent studies have also performed WA simulations and documented some surface impacts, but with other chemistry-climate models (e.g., Morgenstern et al 2008;Egorova et al 2012;Garcia et al 2012); to date, none has focused on the hydroclimate impacts.…”

Short- and long-term variability of spectral solar UV irradiance at Thessaloniki, Greece: effects of changes in aerosols, total ozone and clouds

“…The successful implementation of the Montreal protocol decelerated the weakening of the ozone layer (Egorova et al, 2013;Mäder et al, 2010;Newman and McKenzie, 2011) and many recent studies indicate the first signs of recovery over the Northern Hemisphere (Kuttippurath et al, 2013;McLinden and Fioletov, 2011;Newchurch et al, 2003;Smedley et al, 2012). Signs from the onset of ozone recovery since the late 1990s on surface UV-B irradiance have been mainly detected over the northern high latitudes; recent studies indicate that UV-B has been declining during the last 2 decades (Bernhard, 2011;Eleftheratos et al, 2014).…”