Discussion Topics:
Connections Discussion:
Coral reefs are significant because they serve as habitats for many diverse species. The amount of biodiversity found in the coral reefs is astonishing! Coral reefs are often called "rainforests of the sea" because of their rich biodiversity. Due to higher sea temperatures from gobal warming, major bleaching events have occurred. These bleaching events were caused by the response of corals to the stress of warmer temperatures. The corals expel the colorful algae that live within them. Some coral are able to recover but the ones that aren't usually die. The entire ecosystem for which it forms the base, virtually disappears. Additionally, ocean acidification is a threat to coral. This occurs when oceans absorb carbon dioxide from the atmosphere. The corals are restrained from growing due to oceans becoming more acidic. People might not want to tour these reefs if the main attraction, the coral, are dying out. Water quality is being improved by reducing water pollution from sources and improving watershed management of nearby lands are conservation efforts being made to reduce the destruction.
The southern forests shelter many species and the diverse and beautiful ecosystem is critically endangered. Global warming and urban development have caused a loss in habitats of species and also droughts and wildfires have misplaced the homes of many of these species. The maintenance and restoration of the natural forest and wetland systems is required to keep the southern forests in tact. An alternative to this destruction would be to store ground water in aquifiers because global warming leads to more evaporation of lakes and reservoirs.
Ozone Discussion
Both the tropospheric and stratospheric ozone pose negative human health effects. For example, the tropospheric ozone irritates the respiratory system which causes throat irritation, coughing and decreased lung function. Additionally many diseases are associated with diseases of the respiratory system like asthma and bronchitis. This ozone can also irritate the eyes. The UVB from stratospheric ozone causes nonmelanoma skin cancer and plays a major role in malignant melanoma development.
The stratospheric ozone layer provides protection from ultraviolet solar radiation but can also pose negative human health effects due to anthropogenic contributions to ozone destruction. Chemical catalysts like chlorine enter the atmosphere in many ways. The major source of chlorine in the stratosphere is a class of anthropogenic compounds known as chlorofluorocarbons, a family of organic compounds whose properties make them ideal for use in refrigeration and air conditioning. The CFCs are extremely helpful because they are stable, inert, nontoxic, and nonflammable but these same features enable them to harm the stratosphere.
First, UV-C radiation breaks the bonds holding together the oxygen molecule (O2), leaving two free oxygen atoms. Oxygen is then converted to ozone in the presence of ultraviolet radiation. Ozone is broken down into O2 and free oxygen atoms when it absorbs both UV-C and UV-B ultraviolet light. The free oxygen atoms and molecular oxygen may again react to produce ozone molecules; thus, ozone is continuously formed and continuously broken down in the presence of sunlight, maintaining a steady state concentration of ozone.
During high-temperature combustion, combustion in automobile engines, combustion in fuel-burning power plants and burning of fossil fuels, nitrogen reacts with oxygen or nitric oxide reacts with oxygen and that is how photochemical smog is formed.
Positive and Negative Feedbacks
Positive Feedbacks: Global soils contain more than twice as much carbon as the amount currently in the atmosphere. Higher temperatures are expected to increase the biological activity of decomposers in these soils. This decompostion leads to the release of additional CO2 from the soil to the atmosphere. With more CO2 in the atmosphere, the temperature change will be amplified even more. This is expected in tundra biomes containing permafrost. As atmospheric concentrations of CO2 from anthropogenic source increase, the Arctic regions become substantially warmer and the frozen tundra begins to thaw.
Negative Feedbacks: Plants respond to increases in atmospheric carbon. Because carbon dioxide is required for photosynthesis, an increase in CO2 can stimulate plant growth. More plants will cause more CO2 to be removed from the atmosphere. This negative feedback causes carbon dioxide and temperature increases to be smaller than they otherwise would have been. This negative feedback appears to be one of the reasons why only about half of the CO2 emitted into the atmosphere by human activites has remained in the atmosphere.
Big Picture
Human Impact: People use coal and oil every day. In order to acquire coal and oil, many corrosive gases are released into the atmosphere. For example, Sulfur dioxide comes primarily from combustion of fuels such as coal and oil. This gas serves a respiratory irritant and can also exacerbate asthma. Additionally, people use motor vehicles as the main source for transportation. This and stationary fossil fuel combustion are the primary anthropogenic sources of nitrogen oxides. Nitrogen oxides also serve as respiratory irritant and increase susceptibility to respiratory infection. Furthermore, due to vehicle exhaust and most other combustion processes carbon monoxide gas is formed. This gas bonds to hemoglobin thereby interfering with oxygen transport in the bloodstream. Moreover, it causes headaches in humans at low concentrations and can cause death with prolonged exposure at high concentrations.
Environmental Impact: The release of excess Sulfur dioxide into the air can harm stomates and other plant tissue. The SO2 gas converts to sufluric acid in the atmosphere which is harmful to aquatic life and some vegetation. Similarly, the release of excess Nitrogen oxides convert to nitric acid in the atmosphere which is also harmful to aquatic life and some vegetation. Also, it contributes to overfertilizing of terrestrial and aquatic systems. In addition to these gases harming the environment, global warming has serious consequences for the environment and organisms. The melting of polar ice caps, glaciers, and permafrost and rising sea levels are effects that are already occurring which are damaging the environment. Other effects are predicted to occur in the future, including an increased frequency of heat waves, reduced cold spells, altered precipitation patters and storm intensity, and shifting ocean currents, but it is less clear whether they will actually occur.
Economic Impact: Due to the release of notorious gases in the atmosphere, the creation of new industrial chemicals have sparked up. Also, pollution control includes prevention, technology, and innovation. A lot of money is spent on these innovations in order to reduce the amount of pollutants being released into the air. For example, beginning in 1975, all new automobiles sold in the United States were required to include a catalytic converter. This converter reduced the nitrogen oxide and carbon monoxide emissions. In order to operate properly, the precious metals in the catalytic converter could not be exposed to lead. This, in turn, meant that gasoline could no longer contain lead. Although this was beneficial to human health, a lot of time and money was put into the improvements in the combustion of technology of power plants and factories to reduce air emissions of lead.
Government Legislation:
Clean Air Act: require that EPA establish standards to control pollutants that are harmful to human health and welfare.
National Ambient Air Quality Standards (NAAQS): the EPA periodically specifies concentration limits for each air pollutant. For each pollutant the NAAQS note a concentration that should not be exceeded over a specified time period
No comments:
Post a Comment