Air pollution and greenhouse gases are the reason for the planet as it is today; the reason why we see campaigns flooding the media informing us to ‘switch off’, ‘save the planet’ and ‘turn down the heat’ and the reason why the government is trying to develop a successful scheme, such as the carbon tax scheme, to reduce air pollution caused by major industries. Air pollution and greenhouse gases are the two immediate causes of global warming and climate change.
Air pollution occurs when chemicals or particulate matter enter the atmosphere. They can cause damage to living organisms on the planet, as well as destruction to the natural and synthetic environment (Energy Environment. net 2008). Greenhouse gases are gases in the atmosphere that absorb infrared radiation emitted from the earth. They trap infrared radiation in the form of heat, and hence contribute to global warming. Anthropogenic greenhouse gases are a direct result of air pollution. They are the physical gases emitted that cause air pollution.
Naturally occurring greenhouse gases also have an influence on the earth’s atmosphere, though it is not as conspicuous as anthropogenic causes. Together, air pollution and greenhouse gases are intensifying climate change and global warming on a world-wide basis. Until 10 years ago, air pollution was thought to be just an urban or local problem until it was discovered that the pollutants could move across continents and oceans. Air pollution is the fundamental factor that causes greenhouse gases, hence climate change and global warming.
Air pollutants are the waste products generated from industrial and other processes. They usually come in gases, though aerosols (particles suspended in air, emitted as or formed by transformations of SO2, and ammonia into sulphates, nitrates and ammonium) are common as well, and just as significant. Aerosols absorb and reflect sunlight, which increases the atmospheric temperature, enhancing greenhouse warming. There are two main classifications of air pollutants; primary, those emitted directly into the atmosphere, and secondary pollutants, those hat form in the air when primary pollutants interact and react. Air pollution is most commonly caused by anthropogenic emission, the most predominant being the burning of fossil fuels. Other major causes of air pollution include chemical processing, agriculture, airborne particles and Volatile Organic Compounds (VOC’s) (Irina Ignatova 2008). Air pollution does occur naturally as well, from volcanic eruptions, water vapor, animal resuscitation and lightening fires. Air composition changes regularly, depending on the place, season and weather, as well as for many other reasons (NSW Gov. 2008).
The most prevalent air pollutants, as established by the Australian Government, are; carbon monoxide, lead, nitrogen dioxide, ozone, particles and sulfur dioxide (2. Aust. Gov. 2009. ). Carbon monoxide occurs in the atmosphere naturally at low levels, and is mainly sourced from volcanoes and bushfires. It is emitted from anthropogenic sources by exhaust emissions and some industrial activities(2. Aust. Gov. 2009). Since approximately 1950, anthropogenic sources of CO2 have escalated, as Figure 1 below demonstrates. Lead occurs naturally in the air in tiny amounts, but is added to from lead smelting and other processes. 2. Aust. Gov. 2009). Nitrogen dioxide occurs naturally by lightning and some organic sources, and is added to mainly by the burning of fossil fuels and exhaust emissions (2. Aust. Gov. 2009). Some of the major anthropogenic sources of three major air pollutants, CO, and SO2 are shown in Table 1: Some Important Air Polluting Sectors below. Table 1: Some Important Air Polluting Sectors (2) Sector Air pollutants emitted Biofuel Combustion Mostly CO; also SO2 and NOx . Industry &ump; Refineries Mostly SO2 and NOx; also CO . Power Generation Mostly SO2 and NOx; also CO .
Residential and Commercial Sector Mostly SO2 and CO; also NOx . Road, Rail, Air &ump; Other Transport Mostly NOx and CO; also SO2 . As can be seen from table 1, the three air pollutants CO, SO2 and NOx are emitted from a range of sources. The sectors listed in the table are some of the worst anthropogenic polluters present. These air pollutants, plus others are also known as greenhouse gases. Greenhouse gases (hereafter GHGs) are gases in the atmosphere that absorb infrared radiation emitted from the earth. GHGs can have both natural and anthropogenic causes. They ccur naturally in the atmosphere; however, increased anthropogenic GHGs has led to what is known as the enhanced greenhouse effect. The greenhouse effect is a naturally occurring process where greenhouse gases allow sunlight to pass into the atmosphere, but prevents some of the long wave radiation (heat) from escaping. This process maintains a livable temperature on earth, as without it the average temperature would be -18oC instead of the 15oC presently (Pidwirny, M. 2006). Naturally, the balance of GHGs is maintained in the atmosphere, ensuring the planet doesn’t become too hot or cold.
The enhanced greenhouse effect is an increase in the natural greenhouse effect, stimulated by human activity. GHGs are released into the atmosphere at a much faster rate than they would naturally, increasing their concentrations. This leads to an increase in long wave radiation absorption, raising the atmospheric temperature of the planet. This is known as global warming, and has been slowly occurring over a number of decades. The impact of GHGs has been rising since the industrial revolution, due to the enormous increase in toxic emissions.
The major GHGs are Carbon dioxide (CO2), Methane (NH4), Nitrogen oxide (NO) and Fluorocarbons. Figure 2 shows the proportions of the main U. S Anthropogenic GHG emissions. This graph clearly shows that CO2 is the most prevalent GHG emitted. Figure 2: U. S. Anthropogenic Greenhouse Gas Emissions by Gas, 2001. (Million Metric Tons of Carbon Equivalent) . What this graph fails to show, however, is the prevalence of another, very common GHG; water vapor. Approximately 60% of all greenhouse gas is water vapor.
Much of the water vapor is retained from natural sources, so it is often unspoken of when detailing climate change. This is generally justified by climate change commonly being referred to in an anthropogenic sense. The four major GHGs, CO2, NH4, NO and Fluorocarbons have increased considerably in amount from the pre-industrial (pre 1750) levels to today, as table 2, below, shows. Gas Preindustrial Level 2008 Level . Carbon Dioxide 280 parts per million 385 ppm . Methane 700 parts per billion 1782 ppb . Nitrous Oxide 270 parts per billion 321 ppb . Fluorocarbons 0 parts per trillion 533 pp.
Table 2: Comparative levels of Greenhouse Gases preindustrial (1750) and 2008 . Adapted from http://www. eea. europa. eu/data-and-maps/indicators/atmospheric-greenhouse-gas-concentrations/atmospheric-greenhouse-gas-concentrations-assessment-2 The various levels can be seen to have increased considerably since 1750, the most markedly being Fluorocarbons, which were not present in pre-industrial times , and now are at a level of 533 parts per trillion. The GHG that has had the most devastating increase since 1750 is carbon dioxide, increasing from 280 parts per million to 385 ppm.
This increase has led to many of the climate issues prevalent in today’s environment. It is these increasing GHG levels that cause the problems of climate change and global warming. Greenhouse gases caused by air pollutants have many adverse effects to the environment and to the health of living organisms living on the planet. The most significant effect is global warming. The average temperature rise worldwide in the last century was 0. 6oC (National Geographic 2004). Global warming is having many current, dramatic effects on the planet. The biggest danger is from sea level rise.
Because of the increasing temperatures, the oceans are expanding, causing the sea level to rise, which poses a massive danger to low lying continents and islands. The oceans have risen 15-20cm already. Figure 3 shows the changes in sea level due to global warming from 1880 to 1980. Greenhouse gases also cause climate change, which is long-term changes in the climate, including average rainfall and temperature. The climate worldwide at the moment is leading to increasingly extreme climate conditions, such as extended droughts, torrential rain leading to extensive flooding and short, intense storms.
Many of these severities of nature have already been witnessed, with droughts in Western Australia, floods in the Eastern States, Tornadoes in America and extreme monsoons in Asian countries. So it can be concluded that, as long as air pollution keeps increasing the prevalence of greenhouse gases, climate change and global warming will also increase. The evidence clearly provided in this essay strongly supports the argument that greenhouse gases caused by air pollution are the main cause of anthropogenic climate change. The tables and graphs demonstrate just how greenhouse gases contribute to climate change.
As is evident, climate change is an ever growing problem globally. Due to the increase in anthropogenic air pollution, greenhouse gases have amplified also, as shown by table 2. Figure one shows how carbon dioxide in the atmosphere has increased exponentially, mirrored by anthropogenic emissions of carbon dioxide. The various examples described clearly support the argument that greenhouse gases caused by air pollution are the major anthropogenic causes of climate change.