Ozone depletion involves two related events first noticed in the late 1970s: a general decrease in the total amount of ozone in Earth’s upper atmosphere and a much larger drop in ozone levels during springtime near Earth’s polar regions. This second event, called the ozone hole, happens in the stratosphere, the layer of the atmosphere that contains the ozone layer. There are also similar ozone decreases in the troposphere, the lower part of the atmosphere, near the poles during springtime.
Ozone depletion includes two related events first noticed in the late 1970s: a decrease in the total amount of ozone in Earth’s upper atmosphere and a much larger drop in ozone levels during spring near Earth’s polar regions. This second event, called the ozone hole, happens in the stratosphere, which is the layer of the atmosphere that contains the ozone layer. There are also similar decreases in ozone levels in the troposphere, the lower part of the atmosphere, during spring near the poles.
Ozone depletion refers to two related events first noticed in the late 1970s: a general decrease in the total amount of ozone in Earth’s upper atmosphere, and a much larger loss of ozone during springtime in Earth’s polar regions. The second event, called the ozone hole, happens when ozone in the stratosphere (the ozone layer) is greatly reduced during spring near the poles. In addition, there are similar ozone losses in the troposphere (lower atmosphere) during spring near the poles.
The ozone layer, also called the ozone shield, is a part of Earth’s stratosphere that absorbs most of the Sun’s ultraviolet radiation. This layer has a higher amount of ozone (O₃) compared to other parts of the atmosphere, but ozone still makes up only a small portion of the gases in the stratosphere. The ozone layer reaches concentrations of 8 to 15 parts per million, while the average ozone level in Earth’s entire atmosphere is about 0.3 parts per million.
The Montreal Protocol, officially called the Montreal Protocol on Substances That Deplete the Ozone Layer, is an international treaty created to protect the ozone layer by stopping the use of many substances that harm it. It was signed on September 16, 1987, and became active on January 1, 1989. Over time, the treaty has been updated several times, with changes agreed to in 1990 (London), 1992 (Copenhagen), 1995 (Vienna), 1997 (Montreal), 1999 (Beijing), 2007 (Montreal), 2016 (Kigali), and 2018 (Quito).
The Montreal Protocol, officially called the Montreal Protocol on Substances That Deplete the Ozone Layer, is an international agreement created to protect the ozone layer by reducing the use of many harmful substances. It was signed on September 16, 1987, and became active on January 1, 1989. Over time, the agreement has been updated several times through amendments approved in 1990 (London), 1992 (Copenhagen), 1995 (Vienna), 1997 (Montreal), 1999 (Beijing), 2007 (Montreal), 2016 (Kigali), and 2018 (Quito).
The United Nations Conference on the Human Environment took place in Stockholm, Sweden, from June 5 to June 16, 1972. When the United Nations General Assembly decided to hold the 1972 Stockholm Conference, it accepted Sweden’s offer to host the event. The UN secretary-general, U Thant, invited Maurice Strong to lead the conference as its Secretary-General.
The United Nations Conference on Environment and Development (UNCED), also called the Rio de Janeiro Conference or the Earth Summit (Portuguese: ECO92, Cúpula da Terra), was a major United Nations meeting held in Rio de Janeiro from June 3 to June 14, 1992. The Rio conference brought together 108 heads of state and government. It helped introduce the idea of sustainable development to the world.
The 2023 United Nations Climate Change Conference, also called COP28, was the 28th meeting of the United Nations Framework Convention on Climate Change (UNFCCC). It took place from November 30 to December 13, 2023, in Expo City Dubai. Since the first UN climate agreement in 1992, the COP conference has been held every year, except in 2020 because of the COVID-19 pandemic.
The 2021 United Nations Climate Change Conference, often called COP26, was the 26th meeting of the United Nations Climate Change conference. It took place at the SEC Centre in Glasgow, Scotland, United Kingdom, from October 31 to November 13, 2021. The president of the conference was Alok Sharma, a UK cabinet minister.