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Global Warming 6.2 Global Systems Carbon Cycle CO2 outputs Volcanoes Decaying plant matter Breathing creatures Surface of the sea CO2 inputs Used by plants Absorbed into ocean Stored in soil and sediment The greenhouse effect https://www.youtube.com/watch?v=VYMjSule0Bw Gases in the atmosphere Gases in the atmosphere How do greenhouses work? The Greenhouse Effect • The greenhouse effect is a natural process • Solar radiation passes through our atmosphere. Some is reflected by the Earth • Greenhouse gases such as CO2 traps the suns radiation in the earths atmosphere CO2 in air waiting to be reabsorbed traps a portion of the suns heat which would otherwise escape into space CO2 blanket of warmth keeps our earth from freezing http://www.climatechange.gov.au/greenhouse-effect The greenhouse effect Enhanced Greenhouse Effect The problem we now face is that human activities – particularly burning fossil fuels (coal, oil and natural gas), agriculture and land clearing – are increasing the concentrations of greenhouse gases. This is the enhanced greenhouse effect, which is contributing to warming of the Earth The excess amount of CO2 in the atmosphere accelerates the greenhouse effect trapping more heat near the surface Enhanced Greenhouse Effect This causes polar ice caps to melt thus less sunlight they are able to reflect Therefore making the oceans warm even faster which increases the rise of sea levels Greenhouse gases include water vapour, carbon dioxide, methane, nitrous oxide, ozone and some artificial chemicals such as chlorofluorocarbons (CFCs). Greenhouse gases http://rlch.org/content/climate-change-policy-and-greenhouse-gas-regulation Ozone is a naturally occurring molecule containing three atoms of oxygen. Ozone molecules form a gaseous layer mostly in the upper atmosphere (the stratosphere) 15-30 km above the surface of the earth, and protects life on earth by absorbing ultra-violet (UV) radiation from the sun. Ozone Layer The stratospheric ozone layer protects life on Earth by absorbing ultra-violet (UV) radiation from the sun. UV radiation is linked to skin cancer, genetic damage and immune system suppression in living organisms, and reduced productivity in agricultural crops and the food chain. http://www.environment.gov.au/protection/ozone/ozone-science/ozone-layer Depletion of Ozone Layer Scientific evidence has proven that the natural balance of stratospheric ozone has been upset by the production and release into the atmosphere of ozone depleting substances, including chlorofluorocarbons CFC, halons, CH3CCl3 (Methyl chloroform), carbon tetrachloride, hydrochlorofluorocarbons (HCFCs) and methyl bromide. These substances have applications in refrigerators, airconditioners, fire extinguishers, aerosols, agricultural fumigants, in foam and as solvents for cleaning electronic equipment. http://www.theozonehole.com/cfc.htm The ozone layer is depleted in two ways: Ozone layer depletion Firstly, the ozone layer in the mid-latitude (e.g. over Australia) is thinned, leading to more UV radiation reaching the earth. Data collected in the upper atmosphere have shown that there has been a general thinning of the ozone layer over most of the globe. This includes a five to nine per cent depletion over Australia since the 1960s, which has increased the risk that Australians already face from over-exposure to UV radiation resulting from our outdoor lifestyle. Secondly, the ozone layer over Antarctica is dramatically thinned in spring, leading to the `ozone hole’. These images show the progressive depletion of ozone over Antarctica from 1979 to 1999. This "ozone hole" has extended to cover an area as large as 10.5 million square miles in September 1998. The previous record of 10.0 million square miles was set in 1996. Hole in the Ozone Layer The Antarctic ozone hole develops each year between late August and early October. Regions with higher levels of ozone are shown in red. NASA and NOAA instruments have been measuring Antarctic ozone levels since the early 1970s. Large regions of depleted ozone began to develop over Antarctica in the early 1980s. Ozone holes of substantial size and depth are likely to continue to form during the next few years, scientists hope to see a reduction in ozone loss as levels of ozone-destroying CFCs (chlorofluorocarbons) are gradually reduced. Evidence of Climate Change Air Temperature Air temperatures have increased globally, by around 0.85 degrees Celsius since 1880, with most of the warming occurring since the 1970s. All three major global surface temperature records show that the Earth’s atmosphere has warmed since 1880 In Australia, annual average daily mean temperatures have increased by 0.9 degrees Celsius since 1910, and each decade has been warmer than the previous decade since the 1950s. Australia has observed a decrease in cold days, and an increase in warm days with more than double the number of record hot days observed since 1960 One of the best indicators of climate change is the amount of heat stored in the world’s oceans. The heat content has increased during recent decades and accounts for more than 90 per cent of the total heat accumulated by the land, air and ocean since the 1970s. Ocean warming is continuing, especially in the top several hundred metres of the ocean. Sea surface temperatures in the Australian region have increased every decade since 1900. Oceans and Sea Levels Global sea levels have risen at an average rate of 1.8 millimetres per year over 1961 to 2003. This rate risen to around 3.2 millimetres per year from 1993 to 2012. Rates of sea level rise are not uniform around the globe and vary from year to year. Since 1993, the rates of sea level rise to Australia’s north and northwest have been 7 to 11 millimetres per year, with rates of sea level rise on the central east and southern coasts between 2 to 5 millimetres per year. Current scientific understanding indicates that natural climate variability (on decadal timescales) is the driver of this temporary higher rate of regional rate. Ocean currents are also changing, particularly in the Southern Ocean. Scientists have found a large reduction in the coldest deep ocean water, called Antarctic Bottom Water, over the past few decades. In addition, studies have shown that Antarctic Bottom Water has been warming and freshening over recent decades.The world’s deep ocean currents play a critical role in transporting heat and carbon around the planet, thus regulating the climate. Extreme Weather Events Extreme weather events include heat waves, bushfires, tropical cyclones, cold snaps, extreme rainfall and droughts. There is increasing evidence that the frequency and intensity of many extreme weather events are changing. Extreme hot days in Australia are getting hotter, with the rate of very hot (greater than 40°C) daytime temperatures increasing since the 1990s.In addition weather associated with high fire danger has shown a rapid increase in the late 1990s to early 2000s at many locations in south-eastern Australia. Early January 2013 saw unprecedented temperatures across Australia with a record breaking seven days where the national average maximum daily temperature exceeded 39 degrees Celsius. On 7 January 2013 a record daily maximum temperature across Australia was reached. The heatwave contributed to extreme bushfire conditions with extensive bushfires across New South Wales, Victoria and Tasmania.[iv] Research shows that human influences likely played a role in the extreme heat experienced during the 2012/13 Australian summer.[v] Rainfall patterns are changing around the world. Research shows the global water cycle is intensifying with a warming climate, which means wet areas are likely to get wetter and dry regions are likely to be drier in response to climate change. In Australia there has been a trend over recent decades towards: increased spring and summer monsoonal rainfall across the north Rainfall Patterns higher than normal rainfall across the centre decreased late autumn and winter rainfall across the south. South-west Western Australia has experienced long-term reductions in rainfall during the winter half of the year. Rainfall in this region has already reduced by around 15 per cent since the mid-1970s.South-eastern Australia experienced the most persistent rainfall deficit between 1997 and 2009 since records began at the start of the 20th century. Evidence The Montreal Protocol - is widely considered as the most successful environment protection agreement. The Protocol sets out a mandatory timetable for the phase out of ozone depleting substances. This timetable has been reviewed regularly, with phase out dates accelerated in accordance with scientific understanding and technological advances. What’s being done? The Kyoto Protocol - The Kyoto Protocol is an international agreement created under the United Nations Framework Convention on Climate Change (UNFCCC) in Kyoto, Japan in 1997. It aims to reduce the collective greenhouse gas emissions of developed country Parties by at least five per cent below 1990 levels during 2008 to 2012 Carbon Tax - The idea is that polluters will pay per tonne of carbon they release into the atmosphere. This cost will initially be set at $23, and increase gradually until 2015, when we will shift to a trading scheme that will let the market set the cost. This is widely thought of as the most effective and least costly mechanism to reduce carbon output and reduce the level of climate change that is occurring http://ed.ted.com/lessons/climate-change-earth-s-giant-game-of-tetris-joss-fong#watch Greenhouse Questions and Answers – CSIRO http://www.cmar.csiro.au/e-print/open/gh_faq.htm#gh7 Climate Change – Australian Government http://www.climatechange.gov.au/climate-change More Information Chicago – Field Museum http://climatechicago.fieldmuseum.org/faqs Environmental Protection Agency (EPA) http://www.epa.gov/ozone/science/sc_fact.html Ozone Layer – Australian Government http://www.environment.gov.au/protection/ozone/ozonescience/ozone-layer