Anthropogenic and natural factor associated with high GHGs concentration in the atmosphere

Anthropogenic and natural factor associated with high GHGs concentration in the atmosphere In the Atmosphere, there are many chemical compounds that are described as greenhouse gases due to their characteristics. These gases allow solar radiation (shortwave radiation) to penetrate freely through the Earth’s atmosphere thereby heating the land surface and oceans. When the earth’s surface is heated and warms up, it releases the heat in the form of infrared light (longwave radiation), invisible to human eyes. Some of the infrared light released by the Earth passes through the atmosphere back into space. However, greenhouse gases will not let all the infrared light pass through the atmosphere. They absorb some and radiate it back down to the Earth. This phenomenon, called the greenhouse effect, is naturally occurring and helps to regulate and maintain the warmth of the earth’s surface. It is vital to our survival on Earth. Without the greenhouse effect, the Earth’s average surface temperature would be about 15Â ° Celsius cooler, and life would be u nbearable. Human activities, however, have contributed greatly to an increase in the number of greenhouse gases in the atmosphere. Emissions started to rise dramatically in the 1800s due to the Industrial Revolution and changes in land use. Although greenhouse-gas-emitting activities are essential to the world economy and a fundamental part of modern life, they have majorly contributed to climate change and the increase in the average global temperatures. Anthropogenic Factors Contributing to High GHGs Human activities result in emissions of four principal greenhouse gases: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and the halocarbons (a group of gases containing fluorine, chlorine, and bromine). These gases accumulate in the atmosphere, causing concentrations to increase with time. Significant increases in these gases have occurred in the industrial era and the increase is attributable to human activities; The following are some of the contributors of increased Greenhouse Gases in the atmosphere from anthropogenic activities; Agricultural Activities The increase in Methane concentration is attributable to human activities in agriculture, natural gas distribution, and landfills. In agriculture, it is estimated that Rice cultivation releases methane roughly one-fifth to one-quarter of global methane emissions from human activities. Accounting for over 90 percent of all rice production, wetland rice is grown in fields that are flooded or irrigated for much of the growing season. Bacteria and other micro-organisms in the soil of the flooded rice paddy decompose organic matter and produce methane. Domesticated animals especially cattle emit methane. Methane is produced by cattle, dairy cows, buffalo, goats, sheep, camels, pigs, and horses. Most livestock-related methane emissions are produced by enteric fermentation of food by bacteria and other microbes in the animals digestive tracts; another source is the decomposition of animal manure. Livestock account for about one-quarter of the methane emissions from human activities, which total to about 100 million tonnes annually. Carbon Emissions Carbon dioxide has increased from fossil fuel use in transportation, building heating and cooling and the manufacture of cement and other goods. Deforestation releases CO2 and reduces its uptake by plants. Carbon dioxide is also released in natural processes such as the decay of plant matter. Carbon dioxide from the burning of fossil fuels is the largest single source of greenhouse gas emissions from anthropogenic activities. Most emissions associated with energy use result from the combustion of fossil fuels. Oil, natural gas, and coal (which emits the most carbon per unit of energy supplied) furnish most of the energy used to produce electricity, factories, in-vehicle engines and houses heating. If fuel is burned completely, the only by-product containing carbon would be carbon dioxide. But combustion is often incomplete, so carbon monoxide and other hydrocarbons are also produced. The supply and use of fossil fuels account for about three-quarters of human carbon dioxide (CO2) emissions, one-fifth of the methane (CH4), and a significant quantity of nitrous oxide (N2O). It also produces nitrogen oxides (NOx), hydrocarbons (HC), and carbon monoxide (CO), which, though not greenhouse g ases themselves, influence chemical cycles in the atmosphere that create or destroy other greenhouse gases, such as tropospheric ozone. Nitrous Oxides emissions Nitrous oxide and other nitrogen oxides are produced because fuel combustion causes nitrogen in the fuel or air to combine with oxygen in the air. Nitrous oxide is also emitted by human activities such as the use of fertilizer which increases nitrous oxide emissions. The nitrogen contained in many fertilizers enhances the natural processes of nitrification and denitrification carried out by bacteria and other microbes in the soil. Human Induced Ozone Ozone is a greenhouse gas that is continually produced and destroyed in the atmosphere by chemical reactions. In the troposphere, human activities have increased ozone through the release of gases such as carbon monoxide, hydrocarbons, and nitrogen oxide, which chemically react to produce ozone. As mentioned above, halocarbons released by human activities destroy ozone in the stratosphere and have caused the ozone hole over Antarctica. Halocarbon gas concentrations have increased primarily due to human activities. Principal halocarbons include the chlorofluorocarbons (e.g., CFC-11 and CFC-12), used extensively as refrigerants and in other industrial processes.