Presentation on theme: "Thomas C. Midgely Jr. and the Environmental Impacts of Technological Procgress: Leaded Gasoline and CFCs Born 18th May 1889 at Beaver Falls, Pennsylvania,"— Presentation transcript:
Thomas C. Midgely Jr. and the Environmental Impacts of Technological Procgress: Leaded Gasoline and CFCs Born 18th May 1889 at Beaver Falls, Pennsylvania, U.S.A. Died Worthington, Ohio 2nd November 1944 Holder of 117 patents
Midgley and Leaded Gasoline As a mechanical engineer and self taught chemist at the General Motors Research Laboratory developed tetraethyl lead. (C2H5)4Pb in 1921, an anti-pinking (knocking) agent in petrol motors. This is the leaded gasoline which was eliminated in the 1970s.
Freon: A New Miracle Compound? Midgely asked by GMs Fridigaire division for an alternative to ammonia and sulfur dioxide, standard chemicals in the coils refrigerant units-but were dangerous and toxic. Midgely added some chlorine and fluorine atoms to a carbon chain: the result was an inert, nontoxic class of compounds called chlorofluorcarbons-(Freon)
CFCs one of the great triumphs of the chemical age-a purely synthetic substance that lasted for centuries and had no known adverse effects. Made refrigeration and air-conditioning possible (see Harper pp 85-86) also used in sprays, like underarm sprays, solvents, foam. It was great stuff and we used a lot of it.
estimated 16 million tons dumped into atmosphere in the last sixty years. When we were finished with it, or spilled it, we put it into the sink of the atmosphere.
Ozone is created by the action of sunlight on ordinary oxygen molecules. When its down low ozone is an air pollutant.
Planetary Sunblock: Ozone in the Stratosphere But up high its important. The ozone layer in the stratosphere at about 15 miles up Ozone is earths natural sunscreen. screens out the ultraviolet wavelengths (UV-B). UV-B tears apart organic molecules, in humans excessive UV-Bs can produce eye cornea damage, skin cancer. Why do you think there are so many sunblocks on the market now?
British scientists monitoring ozone layer over Antarctica since 1957. Data indicated that total amounts of ozone each October had been gradually falling, precipitous declines beginning in the 1970s.
By the mid-1980s, areas where the ozone disappeared entirely, thus a hole in the ozone. Evidence that between 1977-1984 the concentration of ozone above Antarctica plunged 40%. The ozone hole is not technically a hole where no ozone is present, but is actually a region of exceptionally depleted ozone in the stratosphere over the Antarctic that happens at the beginning of Southern Hemisphere spring (August–October). The average concentration of ozone in the atmosphere is about 300 Dobson Units; any area where the concentration drops below 220 Dobson Units is considered part of the ozone hole.
It was not clear for years if this was a natural phenomenon or due to a chemical reaction involving air pollutants. In 1986 an American emergency ozone research expedition was launched and using moonlight as a light source, team established that the hole occurred because of chlorine pollution, major source of which was chlorofluorocarbons. Chlorine attacks the ozone and converts it into oxygen, becoming the pac-man of the upper atmosphere.
Mario Molina and CFCs One of the scientists who first established that chlorine in CFCs could be destroying the ozone layer wass Mario Molina a Mexican, the first Latin American to win the Nobel Prize for Science (in Chemistry, in 1995) recipient of an honorary degree from FIU in 2004.
What did the nations of the world do with this information? The Montreal Protocol The Montreal Protocol on Substances That Deplete the Ozone Layer- international treaty designed to protect the ozone layer by phasing out the production of a number of substances believed to be responsible for ozone depletion. Treaty went into effect on September 16, 1987 Due to its widespread adoption and implementation it has been hailed as an example of exceptional international cooperation with Kofi Annan quoted as saying it is "Perhaps the single most successful international agreement to date...".
The treaty is structured around several groups of halogenated hydrocarbons that have been shown to play a role in ozone depletion. All of these ozone depleting substances contain either chlorine or bromine For each group, the treaty provides a timetable on which the production of those substances must be phased out and eventually eliminated.
Has since undergone 7 revisions. The Natural Resources Defense Council filed a lawsuit in 1984 that prompted the Environmental Protection Agency to seek broader bans. An international scientific assessment of CFCs and ozone created a near-worldwide consensus that the risks of allowing the long-lived chemicals to keep building in the atmosphere were unacceptable. DuPont, while gaining less than 2 percent of its revenues from such compounds, saw a need to find substitutes and the prospect of new markets, and began a $500 million research effort that spawned a suite of alternatives.
On Sunday, September 16, diplomats, scientists and environmentalists gathered in Montreal to celebrate the 20th anniversary of the treaty and to spend a week discussing possible new steps to speed an end to remaining ozone threats
Not Out of the Woods yet Unfortunately, the hydrochlorofluorocarbons, or HCFCs, and hydrofluorocarbons, or HFCs, are now thought to contribute to anthropogenic global warming. On a molecule-for-molecule basis, these compounds are up to 10,000 times more potent greenhouse gases than carbon dioxide. The Montreal Protocol currently calls for a complete phase-out of HCFCs by 2030, but does not place any restriction on HFCs. Since the CFCs themselves are equally powerful as greenhouse gases, the mere substitution of HFCs for CFCs does not significantly increase the rate of anthropogenic global warming, but over time a steady increase in their use could increase the danger that human activity will change the climate.
The Montreal Protocol currently allows developing countries to keep increasing their production of HCFC-22 until 2016, and then freezes production at that level until 2040, when it is supposed to be halted. But that schedule was devised in the early 1990s, when HCFC-22 was used mainly in industrial nations; developing countries were seen as too poor ever to afford much of the chemical.
Recent studies have shown that steeply rising production of HCFC-22 by China, India and other developing countries has slowed the healing of the ozone layer, which protects humans, animals and vegetation from the sun's dangerous ultraviolet rays. HCFC's and other ozone-depleting gases are extremely powerful warming gases. Gram for gram, the ones used as refrigerants have thousands of times the global-warming effect of carbon dioxide.
From Sept. 21 to Sept. 30, 2006, the average size of the Antarctic ozone hole was a record 10.6 million square miles. On Sept. 24 the hole equaled the one-day record of 11.4 million square miles, set six years ago. An unusual coalition of industrial and developing countries began pushing Wednesday for stringent limits on the world's most popular refrigerant for air-conditioners, as evidence mounts that the refrigerant harms the earth's ozone layer and contributes to global warming.
The coalition is pitted against China, which has become the world's leading manufacturer of air-conditioners that use the refrigerant, HCFC-22. Most window air- conditioners and air- conditioning systems in the United States use this refrigerant, as well.
Thus, this is an ongoing process….. Harper on p. 86 is not updated on this question, so pay attention to these slides.
Lessons for Global Warming? Much more difficult challenge, fossil fuels are more than 2% of Exxon-Mobils business. Changes require greater alternations in social behavior and lifestyles. Costs and benefits of change unevenly distributed across the globe