Environmental Impacts of industrialisation, the Greenhouse and Enhance Greenhouse Effect

many chemical compounds such as carbon dioxide methane water vapor and nitrous oxide occur naturally in the atmosphere and have an important role to play in the natural physical process called the greenhouse effect this process regulates earth’s temperature keeping it at optimum levels needed for life to exist without the greenhouse effect the world’s average temperature will be minus 18 degrees Celsius these greenhouse gases allow direct sunlight i.e. relative short wave energy to reach the Earth’s surface unimpeded. As the short wave energy (i.e. the visible and ultraviolet part of the spectra) is absorbed and heats the land and oceans, longer waves (infrared energy or heat) is reradiated to the atmosphere greenhouse gases absorb this energy allowing less heat to escape back to space and trapping it in the lower atmosphere. Over the last few centuries, due to the Industrial Revolution and as the global population has continued to grow atmospheric concentrations of both natural and man-made heat-trapping gases have been rising. People produce larger amounts of some greenhouse gases compared to others. Carbon Dioxide is the greenhouse gas most commonly cited because human activities produces more carbon dioxide compared to any other greenhouse gas and it’s responsible for most of the warming for example a) burning fossil fuels (coal, oil and natural gas) b) increased combustion from vehicles and machinery with internal combustion engines and c) small contributions from agriculture and land-use changes such as land clearing also have significant impact on the earth But how are emissions normally controlled? trees have a natural process to remove carbon dioxide from the air but increased cutting down at forests reduces its removal from the atmosphere, prevents its escaping from the planet and hinders the planet from cooling itself in this is increasing the planet’s temperature. Water vapor which is naturally present in the atmosphere has a strong effect on weather and climate but as the planet gets warmer more water evaporates from the earth’s surface to reside as water vapor in the atmosphere this creates what is called a positive feedback loop meaning that the more water vapor that is in the atmosphere, the more warming to the Earth’s surface that will occur. in summary, human activity has interfered with the carbon cycle and artificially moved carbon from solid storage to its gaseous state thereby increasing its concentration in the atmosphere. But the story does not end with changes we’ve made that affect natural greenhouse gases just as important is what has been happening due to man-made or Synthetic Greenhouse Gases. When and why dis SGGs begin to be made? Our modern lifestyle has fuelled the need to make and use these substances in the late eighteen hundreds and early nineteen hundreds, refrigerators used toxic gases as refrigerants by the 1920s their safety started being questioned this sparked the search for less toxic replacements In 1928 the first chlorofluorocarbons were synthesizers and considered a safe non-toxic non-flammable alternative to dangerous substances used then. After world war II they were used as propellants for bug spray paint hair conditioners and other healthcare products. This continued during the late 1950s and early 1960s because CFCs made air conditioning in automobiles homes and office buildings more affordable. What chlorofluorocarbons? CFCs are a family of chemical compounds where one element is chlorine they considered safe to use in most applications and are inert in the lower atmosphere there is usually very little chlorine in the stratosphere but with the increased use of CFC more is being released into the atmosphere eventually making it to the stratosphere where UV radiation breaks it down and releases the chlorine into the ozone layer What’s the effect of chlorine in the ozone layer? Ozone is located mostly in the stratosphere – the increasing loss of stratospheric ozone allows more harmful UVB radiation to reach the earth’s surface ozone absorbs much of the harmful UV radiation that causes biological damage in plants and animals therefore its depletion is a major concern globally. How does ozone depletion occur? UV radiation breaks down CFCs in the stratosphere by breaking off the chlorine atom from the CFC molecule, once free the chlorine atom steals an oxygen atom from the ozone molecule to make chloride monoxide. Other free oxygen atoms then steal the oxygen atom back off the chloride monoxide molecule and releases the chlorine which then is free to steal more oxygen atoms from other ozone molecules. This process creates more oxygen molecules and depletes the number of ozone molecules in the stratosphere – some of the released chlorine becomes active in destroying ozone in the stratosphere at a rate of one hundred thousand molecules of ozone destroyed per chlorine atom that exists. By 1985 ozone loss included the Antarctic ozone hole and ozone loss in the mid-latitudes there was also concern because CFCs have very long atmospheric lifetimes which limits our ability to reduce their accumulation in the atmosphere. By the 1980’s a group of synthetic greenhouse gases were recognized as depleting the ozone layer in the stratosphere and they were called ozone-depleting substances in 1987 the Montreal Protocol was signed to reduce the production and use of ozone-depleting substances by 50 cent before the year 2000 – by 2010 nearly ninety seven percent of ozone-depleting substances have been phased out – this was amended in 1990 to include phasing out various CFCs chlorinated solvents methyl chloroform and carbon tetrachloride but the chemical industry still needed substances to use in their equipment and thus began searching for more ozone friendly substances those that don’t deplete the ozone layer thus hydrofluorocarbons was substituted for ozone depleting substances. Today hydrofluorocarbons are used offensively in Australia largely in air conditioning and refrigeration initially as ozone friendly replacement for chlorofluorocarbons and hydrochloro fluorocarbons. Minor uses of hydrofluorocarbons in Australia are as aerosol propellants including metered dose inhalers as blowing agents and in fire extinguishers. Did these replacements work? Though hydro fluorocarbons are emitted in smaller quantities in do not harm the ozone layer like the CFCs did this is a good thing however some HFCs have high global warming potential values because they act strongly as greenhouse gases in the atmosphere the most common HFC in australia is hfc-134a which has a DWP of 1,300 meaning it is 1300 time’s more potent in the atmosphere as carbon dioxide since they tend to have a long lifetimes than CFCs and since their use is growing rapidly experts are becoming concerned that the increasing use means there will be more of these heat-trapping substances collecting in the atmosphere, that will be difficult to remove. After all some HFCs are up to 10,000 times more effective at trapping heat compared to CO2 Others are just so commonly used that is their repeated use that aggravates the problem other synthetic greenhouse gases also have high GWP level though they are present in the atmosphere in smaller concentrations and include perfluorocarbons sulfur hexafluoride nitrogen trifluoride sulfuryl flouride and trifluryl methyl sulfur pentaflouride which are collectively described as synthetic greenhouse gases SGGs account for one to two percent of all greenhouse gas emissions in Australia. How strongly they affect things is seen by their high global warming potential value sulfur hexafluoride is used extensively in the electricity distribution industry in Australia and overseas for dielectric installation and current interruption circuit breaker switch gear and other electrical equipment and as a cover gas in metal production such as magnesium. Sulfate hexafluoride has a GWP of twenty-three thousand nine hundred other SGGs are also powerful global warmers including PFC which has a GWP between 6500 and 9200 PFs are a byproduct of the production of aluminium in Australia and overseas and in addition are used overseas in the electronics industry during the manufacture of integrated circuits and plasma screens refrigeration represent a minor use of PFs in australia and overseas. There does not appear to be any significant use of nitrogen trifluoride in Australia which is used internationally in the semiconductor production industry initially as a replacement for perfluorocarbon. Sulfurylfluoride use in Australia is growing rapidly as a replacement for phosphine possibly methyl bromide in grain fumigation. It is unlikely that trifluoromethyl sulfur pentafluoride is used in Australia its occurrence in the atmosphere is largely as a byproduct of the production of perfluoroctane sulfonic acid which has never been manufactured in australia though is a key ingredient in fabric stain repellent such a 3M Scotch Guard and firefighting foam. Rapidly growing hydrofluorocarbon emissions are seen as a significant driver of climate change over the next 50 years and projections suggest that are mitigated hydrofluorocarbons growth could result in increased global warming potential weighted emissions but even if a substitute is found HFC concentrations are still expected to rise by a hundred and forty percent because developing countries are expected to install around 700 million air conditioners over the next decade over the past decade governments and scientists have become increasingly concerned that as we continue to burn large amounts of fossil fuels and deplete our forests from doing their job that an exaggerated greenhouse effect will occur. Most scientists agree that two degrees Celsius of warming above the temperature during pre-industrial time has the potential to harm all sectors of civilization. There are a few things being considered. Scientists are working hard to determine ways in which technology can be used to try to slow down or avert climate change scientists are searching for ways to remove carbon dioxide from the atmosphere though they are not certain whether this will work on a big scale and if it will have any notable effect. Scientists are also considering whether injecting particles into the Earth’s atmosphere can effectively reflect the sun’s radiation back into space and thus cool the earth. Then there is the focus on designing power plants that emit less carbon dioxide into the atmosphere – this final option requires less reliance on coal power plants and more reliance on the use of nuclear power plants or wind turbines What suite of things has the government done? In June 2015 the government passed legislation to implement the enhanced renewable energy target scheme so that 23.5 percent of Australia’s electricity generation by 2020 will be from renewable sources. In December 2015 at the conference of the parties a global agreement for climate action post-2020 with made. It was as part of this that Australia committed to reduce greenhouse gases by 26 to 28 percent below 2005 levels by 2030 – this is good news because according to the organization for economic cooperation and development Australians are the highest GHG polluters per person in the OECD. The ozone Protection and Synthetic Greenhouse Gas Management Acts of 1989 and related Acts aimed to protect the environment by reducing emissions of ozone-depleting substances and synthetic greenhouse gases. The Acts control the manufacture-import-export and end-use of ozone-depleting substances and synthetic greenhouse gases and products containing these gases to further reduce emissions of ozone-depleting substances. On 5th of May 2016 the government decided on a range of measures to improve the efficiency and effectiveness of the Ozone Protection and Synthetic Greenhouse Gas Program. What are other countries doing about this? The US Environmental Protection Agency has proposed de-listing and putting controls on a number of high GWP hydrofluorocarbons. On the other hand the European Union also has a hydro- fluorocarbon phasedown in place. There are no mandated global or Australian targets to phasedown Kyoto protocol SGG emissions at present – except as contributors under Post-Kyoto agreements. There are no global or Australian targets two phasedown sulfuryl chloride or trifluoromethyl sulfur pentafluoride emissions. These are important strategies because the enhanced greenhouse effect is thought by many to have caused changes in the planets weather patterns i.e. Climate Change. Climate Change has changed where disasters occur and has caused more frequent and more severe weather events such as hurricanes droughts and heat waves which result in the devastating property damage, injury and death. This has caused increased migration away from these regions climate change is believed to also be responsible for melting of the polar ice caps which has raised sea levels – though are rising very slowly and only by a very small amount – over time it is expected to flood low-lying coastal areas and will also contribute to increased migration away from these regions Special thanks for probono work done by minbatkitty. Created and produced by Ivonne Buckley-Mendez

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