Atmosphere The lowest layer is the troposphere, which extends from the surface to the bottom of the stratosphere. Three quarters of the atmosphere's mass resides within the troposphere, and is the layer within which the Earth's terrestrial weather develops. The depth of this layer varies between 17 km at the equator to 7 km at the poles. The stratosphere, extending from the top of the troposphere to the bottom of the mesosphere, contains the ozone layer. The ozone layer ranges in altitude between 15 and 35 km, and is where most of the ultraviolet radiation from the Sun is absorbed. The
Vienna Convention for the Protection of the Ozone Layer Groups that help facilitate functions under the convention. A Multilateral Fund exists to aid developing nations transition from ozone-depleting chemicals using guidelines under the convention, which is administered by a Multilateral Fund Secretariat. The Multilateral Fund has aided thousands of projects in nearly 150 countries, preventing the usage of roughly 250,000 tons of ozone-depleting chemicals. Vienna Convention for the Protection of the Ozone Layer The Vienna Convention for the Protection of the Ozone Layer is a multilateral environmental agreement signed in 1985 that provided frameworks for international reductions in the production of chlorofluorocarbons due to their contribution to the destruction