Environmental Issues Test - 12

Global warming due to green house effect melts the glaciers and ice caps that increase the water level of oceans. The countries like Maldives and Bangladesh are in danger of submersion due to increasing ocean water level.

Global warming is caused by green house effect in which temperature of inner atmosphere increases that result into melting of ice caps and glaciers. The melting results into rise in levels of oceans.

Methane is being added to atmosphere by paddy fields, marshes and cows. Anaerobic decomposition of organic wastes in presence of methanogen bacteria release methane gas.

Ozone layer in upper atmosphere is being destroyed by chlorofluorocarbon. CFC’s breaks the molecular O₃ into O₂ and O. Thus layer of ozone get thinner and not able to prevent UV radiations.

The two main reasons for increase in CO₂ gas are destruction of forest and excessive combustion of fossil fuels. Forests help in decreasing CO₂ gas by photosynthesis process.

Greenhouse gases in the atmosphere (such as water vapor and carbon dioxide) absorb most of the Earth's emitted longwave infrared radiation, which heats the lower atmosphere. In turn, the warmed atmosphere emits longwave radiation, some of which radiates toward the Earth's surface, keeping our planet warm and generally comfortable. Increasing concentrations of greenhouse gases such as carbon dioxide and methane increase the temperature of the lower atmosphere by restricting the outward passage of emitted radiation, resulting in "global warming," or, more broadly, global climate change.

Snow blindness is a painful, temporary loss of vision due to overexposure to the sun's UV rays. The medical term for snow blindness is photokeratitis ("photo" = light; "keratitis" = inflammation of the cornea).

Essentially, snow blindness is caused by a sunburned eye — or more specifically, a sunburned cornea. And like sunburned skin, by the time you notice symptoms of snow blindness, you've already been in the sun too long.

Ozone present in stratosphere comes from photochemical interactions of oxygen molecules in which O₂ breaks into two O atoms in presence of UV rays. O₂ and O combine together to form O₃ (ozone).

Biochemical oxygen demand (BOD, also called biological oxygen demand) is the amount of dissolved oxygen needed (i.e., demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period. The BOD value is most commonly expressed in milligrams of oxygen consumed per litre of sample during 5 days of incubation at 20 °C and is often used as a surrogate of the degree of organic pollution of water.

Concentration of green house is increasing due to deforestation, increased use of refrigerators and increased combustions of coal and petroleum. Deforestation causes increased level of CO₂ gas, refrigerators releases CFC’s gas and burning of fossil fuels also increases carbon dioxide level in atmosphere.