Related Research Articles
The Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion. It was agreed on 16 September 1987, and entered into force on 1 January 1989. Since then, it has undergone nine revisions, in 1990 (London), 1991 (Nairobi), 1992 (Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal), 1998 (Australia), 1999 (Beijing) and 2016 (Kigali) As a result of the international agreement, the ozone hole in Antarctica is slowly recovering. Climate projections indicate that the ozone layer will return to 1980 levels between 2040 and 2066. Due to its widespread adoption and implementation, it has been hailed as an example of successful international co-operation. Former UN Secretary-General Kofi Annan stated that "perhaps the single most successful international agreement to date has been the Montreal Protocol". In comparison, effective burden-sharing and solution proposals mitigating regional conflicts of interest have been among the success factors for the ozone depletion challenge, where global regulation based on the Kyoto Protocol has failed to do so. In this case of the ozone depletion challenge, there was global regulation already being installed before a scientific consensus was established. Also, overall public opinion was convinced of possible imminent risks.
The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 0.3 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere, from approximately 15 to 35 kilometers (9 to 22 mi) above Earth, although its thickness varies seasonally and geographically.
Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere, and a much larger springtime decrease in stratospheric ozone around Earth's polar regions. The latter phenomenon is referred to as the ozone hole. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events.
Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F), produced as volatile derivatives of methane, ethane, and propane.
Ground-level ozone (O3), also known as surface-level ozone and tropospheric ozone, is a trace gas in the troposphere (the lowest level of the Earth's atmosphere), with an average concentration of 20–30 parts per billion by volume (ppbv), with close to 100 ppbv in polluted areas. Ozone is also an important constituent of the stratosphere, where the ozone layer (2 to 8 parts per million ozone) exists which is located between 10 and 50 kilometers above the Earth's surface. The troposphere extends from the ground up to a variable height of approximately 14 kilometers above sea level. Ozone is least concentrated in the ground layer (or planetary boundary layer) of the troposphere. Ground-level or tropospheric ozone is created by chemical reactions between NOx gases (oxides of nitrogen produced by combustion) and volatile organic compounds (VOCs). The combination of these chemicals in the presence of sunlight form ozone. Its concentration increases as height above sea level increases, with a maximum concentration at the tropopause. About 90% of total ozone in the atmosphere is in the stratosphere, and 10% is in the troposphere. Although tropospheric ozone is less concentrated than stratospheric ozone, it is of concern because of its health effects. Ozone in the troposphere is considered a greenhouse gas, and may contribute to global warming.
Mario José Molina Henríquez was a Mexican physical chemist. He played a pivotal role in the discovery of the Antarctic ozone hole, and was a co-recipient of the 1995 Nobel Prize in Chemistry for his role in discovering the threat to the Earth's ozone layer from chlorofluorocarbon (CFC) gases. He was the first Mexican-born scientist to receive a Nobel Prize in Chemistry and the third Mexican-born person to receive a Nobel prize.
Frank Sherwood "Sherry" Rowland was an American Nobel laureate and a professor of chemistry at the University of California, Irvine. His research was on atmospheric chemistry and chemical kinetics. His best-known work was the discovery that chlorofluorocarbons contribute to ozone depletion.
Paul Jozef Crutzen was a Dutch meteorologist and atmospheric chemist. He and Mario Molina and Frank Sherwood Rowland were awarded the Nobel Prize in Chemistry in 1995 for their work on atmospheric chemistry and specifically for his efforts in studying the formation and decomposition of atmospheric ozone. In addition to studying the ozone layer and climate change, he popularized the term Anthropocene to describe a proposed new epoch in the Quaternary period when human actions have a drastic effect on the Earth. He was also amongst the first few scientists to introduce the idea of a nuclear winter to describe the potential climatic effects stemming from large-scale atmospheric pollution including smoke from forest fires, industrial exhausts, and other sources like oil fires.
Chlorotrifluoromethane, R-13, CFC-13, or Freon 13, is a non-flammable, non-corrosive, nontoxic chlorofluorocarbon (CFC) and also a mixed halomethane. It is a man-made substance used primarily as a refrigerant. When released into the environment, CFC-13 has a high ozone depletion potential, and long atmospheric lifetime. Only a few other greenhouse gases surpass CFC-13 in global warming potential (GWP). The IPCC AR5 reported that CFC-13's atmospheric lifetime was 640 years.
Jerry Mahlman was an American meteorologist and climatologist.
Susan Solomon is an American atmospheric chemist, working for most of her career at the National Oceanic and Atmospheric Administration. In 2011, Solomon joined the faculty at the Massachusetts Institute of Technology, where she serves as the Ellen Swallow Richards Professor of Atmospheric Chemistry & Climate Science. Solomon, with her colleagues, was the first to propose the chlorofluorocarbon free radical reaction mechanism that is the cause of the Antarctic ozone hole.
Andrew Emory Dessler is a climate scientist. He is Professor of Atmospheric Sciences and holder of the Reta A. Haynes Chair in Geoscience at Texas A&M University. He is also the Director of the Texas Center for Climate Studies. His research subject areas include climate impacts, global climate physics, atmospheric chemistry, climate change and climate change policy.
Greenhouse gases are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. What distinguishes them from other gases is that they absorb the wavelengths of radiation that a planet emits, resulting in the greenhouse effect. The Earth is warmed by sunlight, causing its surface to radiate heat, which is then mostly absorbed by greenhouse gases. The most abundant greenhouse gases in Earth's atmosphere, listed in decreasing order of average global mole fraction, are: Water vapor, Carbon dioxide, Methane, Nitrous oxide, Ozone, Chlorofluorocarbons, Hydrofluorocarbons (HFCs), Perfluorocarbons, SF
6, and NF
3. Without greenhouse gases in the atmosphere, the average temperature of Earth's surface would be about −18 °C (0 °F), rather than the present average of 15 °C (59 °F). Water vapor is a potent greenhouse gas but not one that humans are directly adding to. It is therefore not one of the drivers of climate change that the IPCC is concerned with, and therefore not included in the IPCC list of greenhouse gases.
Veronica Vaida is a Romanian-American chemist and professor at the University of Colorado Boulder. She is an expert in environmental chemistry and aerosols.
Stephen Oliver Andersen is the Director of Research at the Institute for Governance & Sustainable Development (IGSD) and former co-chair (1989–2012) of the Montreal Protocol Technology and Economic Assessment Panel (TEAP) where he also chaired and co-chaired Technical Options Committees, Task Forces and Special Reports. He is one of the founders and leading figures in the success of the Montreal Protocol on Substances that Deplete the Ozone Layer that has phased out the chemicals that deplete the stratospheric ozone that protects the Earth against the harmful effects of ultraviolet radiation that causes skin cancer, cataracts, and suppression of the human immune system, destroys agricultural crops and natural ecosystems and deteriorates the built environment. Because ozone-depleting chemicals are also powerful greenhouse gases the Montreal Protocol also protected climate. Dr. Andersen was instrumental in the 2016 Kigali Amendment that will phase down hydrofluorocarbons once necessary to phase out chlorofluorocarbons (CFCs) fast enough to avoid ozone tipping points, but no longer necessary now that environmentally superior replacements are available or soon to be available. For his ambitious campaign saving the ozone layer, Dr. Andersen earned the 2021 Future of Life Award along with Joe Farman and Susan Solomon.
Harold S. "Hal" Johnston was an American scientist who studied chemical kinetics and atmospheric chemistry. After beginning his teaching career at Stanford University, he was a faculty member and administrator at the University of California, Berkeley for nearly 35 years. In 1971, Johnston authored a paper suggesting that environmental pollutants could erode the ozone layer.
Azadeh Tabazadeh is an Iranian geophysicist and author known for her work in atmospheric science, work which has improved our understanding of the reactions that affect ozone depletion and highlighted the impact human activity has on the atmosphere.
John W. Birks is an American atmospheric chemist and entrepreneur who is best known for co-discovery with Paul Crutzen of the potential atmospheric effects of nuclear war known as nuclear winter. His most recent awards include the 2019 Haagen-Smit Clean Air Award for his contributions to atmospheric chemistry and the 2022 Future of Life Award for discovery of the nuclear winter effect.
John Maurice Campbell Plane,, , is a British atmospheric chemist, currently Professor of Atmospheric Chemistry at the University of Leeds. His research investigates planetary atmospheres using a range of theoretical and experimental techniques.
Margaret A. Tolbert is an American atmospheric chemist, specializing in polar stratospheric clouds.
References
- 1 2 Akkihebbal Ravishankara publications indexed by Google Scholar
- 1 2 Anon (2019). "Professor Akkihebbal Ravishankara". royalsociety.org. London: Royal Society. Archived from the original on 2019-04-23. One or more of the preceding sentences incorporates text from the royalsociety.org website where:
“All text published under the heading 'Biography' on Fellow profile pages is available under Creative Commons Attribution 4.0 International License.” --Royal Society Terms, conditions and policies at the Wayback Machine (archived 2016-11-11)
- ↑ "Biography on CSU Website" . Retrieved 2019-04-20.
- ↑ "Chemical Sciences Division, Earth System Research Laboratory, NOAA" . Retrieved 2019-04-20.
- 1 2 3 "Center for Oral History, Science History Institute" . Retrieved 2019-04-20.
- ↑ Advancing the Science of Climate Change. National Research Council (United States). 2010. doi:10.17226/12782. ISBN 978-0-309-14588-6 . Retrieved 2019-04-21.
- ↑ "Joining forces to understand ozone" . Retrieved 2019-04-20.
- ↑ "Nitrous oxide fingered as monster ozone slayer" . Retrieved 2019-04-20.
| International | |
|---|---|
| National | |
| Academics | |