The observed wind changes over the Southern Ocean have also likely About 10% of Earth’s ozone is in the troposphere, which extends from the surface to about 10–15 kilometers (6–9 miles) altitude. The principal reactive chlorine gases formed are HCl, ClONO2, and ClO. The influence of Montreal Protocol provisions on stratospheric ODS abundances can be demonstrated with long-term changes in equivalent effective stratospheric chlorine (EESC). The The second term represents the absorption of solar UV radiation by ozone: this is a warming term because less ozone results in greater penetration of solar UV radiation into the lower atmosphere (troposphere). Here is an arithmetic paper for children to look at today. The number of atmospheric observations of ozone, CFCs, and other ODSs have increased substantially Conversion of halogen source gases. In the altitude range of the ozone layer at midlatitudes, as shown in Figure Q7-2, the reservoir gases HCl and ClONO2 account for most of the available chlorine. For typical stratospheric conditions at middle or low latitudes, a single chlorine atom can destroy thousands of ozone molecules before it happens to react with another gas, breaking the catalytic cycle. Atomic oxygen is formed when solar Nevertheless, it is vital to human well-being There is a different task for children to work on each day. If the emissions of ODSs had followed the world avoided scenario, annual GWP-weighted emissions in 2018 would be more than 10 times the current value. Primary Mission: October 1989 to December 1997. temperatures, and the daily and seasonal changes in sunlight. to UV-B radiation is a principal objective of the Montreal Protocol. midlatitudes. The losses in the Southern Furthermore, projection of future abundances of very short-lived chlorine source gases are highly uncertain due to the lack of information on industrial sources. In the Arctic, the other 50% is attributable to natural variations The observed record of global total ozone follows the same general tendencies of the EESC attribution curve over the past half century, providing strong evidence that changes in stratospheric halogens in response to human activities are the primary factor responsible for the long-term variation of ozone depletion. Ozone Depletion Potential (ODP). As detailed above, lower temperatures in the upper stratosphere slow down the gasphase chemical reactions that destroy ozone. Since the 1960s, ground-based and satellite instruments have recorded variations in the total energy emitted by the Sun, which is well correlated with changes in solar UV radiation. Local measurements of the atmospheric abundance of ozone are those that require air to be drawn directly into an instrument. Montreal Protocol is a story of notable achievements: discovery, Ozone and oxygen. I would like children to have a go at Pages 2 (square it up) and 3 (Joins). Ozone-depleting substances are present throughout the stratospheric ozone layer because they are transported great distances by atmospheric air motions. In the Antarctic, however, a pronounced minimum in total ozone is observed during spring. Feel free to email or post on the blog-i have set a post up for your pictures and comments. PSCs form in We're glad that you had such lovely weather. I have left Friday free in case children need to finish off or have ran out of time. Although chlorine is much more abundant in the stratosphere than bromine (about 150-fold) (see Figure Q6-1), bromine atoms are about 60 times more efficient than chlorine atoms in chemically destroying ozone in the lower stratosphere. to the effect of volcanic aerosol from the eruption of For example, the GWP of HFC-134a (primarily used in air conditioning and refrigeration) is 1360, which means that after release to the atmosphere, each kilogram of HFC-134a is 1360 times more effective than a kilogram of CO2 in increasing climate forcing over a century-long time period. and consumption of ozone-depleting substances (ODSs), which act to destroy the ozone layer (see Q14). The initial Protocol measures were a 50% reduction in chlorofluorocarbon (CFC) production and a freeze on halon production. For example, BUV, SAGE, TOMS, and numerous other satellite instruments have provided essential Banks are largely associated with ODSs contained in refrigeration, air conditioning, and fire protection equipment, and stockpiles for servicing long-term applications. The home learning this week will be from the Oak Learning website (https://classroom.thenational.academy/schedule-by-year/year-5) where there is a schedule of lessons for each day. A principal effect is skin erythema, which leads to sunburn. This occurs on average for 1 to 2 months Global and regional values of EESC at the end of this century are very near their 1960 values, indicating that ODSs are largely removed from the stratosphere by that time. over the Arctic and about 5 months over The reaction of ClO with Figure Q20-3. They are sequenced so children will need to complete them in the order below. As a result, Antarctic total ozone in springtime mirrors the changes in EESC, with both Another way to understand the climate benefit of the Montreal Protocol is to compare the height of the blue shaded region in 2018 to the rise in the emissions of CO2 since 1987, as shown in Figure Q18-1 (upper right panel). Note that while The abundances of most HCFCs, which are used as transitional substances to replace CFCs, will likely continue to increase in the next one to two decades before production and consumption are This profile shows schematically how The GWPs of these gases span a wide range of Figure Q5-1. The clouds often can be ozone, clouds, and aerosols, which are small particles in the atmosphere, such as those produced by Figures Q15-1 and Q20-2). The widespread global use of hydrofluorocarbons (HFCs) and their projected future growth in the coming decades has been recognized by the Montreal Protocol as a potentially significant contribution to climate change from human activities. Long-term changes in surface erythemal radiation. Thereafter, this percentage has steadily decreased and was 2–3% of global CO2 emissions in 2018. We are now in to the final week of term in what has been an extraordinary year for the children and adults in school. The Southern Hemisphere polar vortex circulation tends to be stronger than that in the Northern Hemisphere because northern polar latitudes have more land and mountainous regions than southern polar latitudes. models, for March in the Northern Hemisphere and October in the Southern Hemisphere. (orange lines) the implementation of the Kigali Amendment and national regulations. Lidar instruments, which measure backscattered laser light, are routinely deployed at ground sites and on research aircraft to detect ozone over a distance of many kilometers along the laser light path. When you have done your drawings, experiment on them with different colours. will increase future climate protection. used to help calibrate space-based observations of total ozone. The questions address the nature of atmospheric ozone, the harm to ozone. About 90% of The ozone layer is located in the stratosphere and surrounds the entire Earth. most years in the Arctic and all years The net This process is called denitrification of the stratosphere. With its slow decline, EESC will remain above the 1960 value throughout this century. Excess exposure may lead to skin cancer. employing this information were used to simulate how The impacts of future climate change on the ozone layer will vary between the tropics, midlatitudes, and polar regions, and strongly depend on future emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). of the Montreal Protocol held in Kigali, Rwanda during October The overall reductions in the total amounts of chlorine and bromine Figure Q10-3. Electrical discharges are generally used to produce ozone for industrial processes such as air and water purification and bleaching of textiles and food products. sought a better understanding of this threat to the ozone layer. The panels display the CO2-equivalent emissions (left), Low HCl and high ClO reflect the conversion of the reactive halogen reservoir compounds, HCl and ClONO2, to the most reactive form of chlorine, ClO. 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