- Changes in the concentration of gases can increase or decrease Earth s temperature.

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1 Greenhouse effect Human and natural causes The source of energy that drives the Earth s climate is the radiation of the sun. To balance the incoming energy, the Earth itself must radiate on average the same amount of energy back to space. - The greenhouse effect is a Natural process - The Earth s atmosphere naturally contains several gases which trap energy and moderate the earth s temperature. - Changes in the concentration of gases can increase or decrease Earth s temperature. Instead, thanks to greenhouse gases, the Earth s average temp is Greenhouse gases are often seen as bad, but if there were no greenhouse gasses, earth would be about 33 C cooler during the day and hundreds of degrees cooler at night (-180 C or colder) 1

2 A Climate Minute - Video - However, problems arise when the atmospheric concentration of greenhouse gases increases by human activities. When we have too many greenhouse gases the heat cannot escape. As a result too much heat is being trapped in the atmosphere and therefore contributing to global warming. Video - What is the Greenhouse Effect =BPJJM_hCFj0 -water vapour -carbon dioxide -methane -nitrous oxide 2

3 1) Chlorofluorocarbons (CFC s) - products of refrigeration and air conditioning. 2) Hydrofluorocarbons (HFC s) and perfluorocarbons (PFC s) generated by industrial processes. 1) Carbon dioxide- when waste, fossil fuels, wood, and wood products are burned. 2) Methane- decomposition in landfills, and raising of livestock. 3) Nitrous oxide- emitted during agricultural and industrial activities, as well as combustion of wastes and fossil fuels. - concentrations of greenhouse gases have increased since pre-industrial times. (1750A.D) - Carbon dioxide: 280 to 360 ppm - Methane: 700 to 1720 ppb - Nitrous oxide: ppb Let s see what human s recent CO 2 emissions look like. 1) Increased fossil fuel use 2) Land use change (deforestation); note agricultural ecosystems have a smaller capacity to accumulate carbon than forests. ( times less) 3) Agriculture- 9-15% increase due to methane emissions by cows. 3

4 Waste Coal mining Aviation Power Plants Residential Buildings Cement, Ceramics, & Glass Production Agricultural Soils Deforestation Road Transport Chemical Industries Oil & Gas Production Iron & Steel Manufacturing Commercial Buildings Livestock Argentine scientists say cows could be generating 30% of Argentina s emissions. Almost half of all global methane emissions come from belching livestock and their manure, making livestock farming a significant contributor to climate change see next slide. For Example Volcanoes: 4

5 - Volcanoes: the amount of carbon dioxide they release is extremely small compared to human emissions. - On average, volcanoes emit between 130 and 230 million tonnes of carbon dioxide per year. - By burning fossil fuels, people release in excess of 100 times more, about 26 billion tonnes of carbon dioxide, into the atmosphere every year (as of 2005). As a result, human activity overshadows any contribution volcanoes may have made to recent global warming. How can we prevent the increase of greenhouse gas emissions? An international treaty that commits countries to reduce greenhouse gas emissions. is the first and only binding international agreement that sets targets to reduce the greenhouse gas emissions that cause climate change. This treaty was negotiated in 1997 in Kyoto, Japan and came into force in The goals of Kyoto were to see participants collectively reducing emissions of greenhouse gases by 5.2% below the emission levels of 1990 by

6 If participating countries continue with emissions above the targets, then they are required to engage in emissions trading; i.e. buying "credits" from other participating countries who are able to exceed their reduction targets in order to offset The previous government of Canada developed a plan to meet our Kyoto targets, which included: -mandatory emissions cuts for large factories and power plants -a voluntary agreement with automakers to improve fuel efficiency in Canadian vehicles -a climate fund to purchase emission reduction credits from Canada and abroad -a partnership fund to assist provinces and municipalities in making investments in infrastructure projects that would decrease greenhouse gas emissions. - the government never got the chance to implement or improve the plan before it lost the election in January The current government has, unfortunately, moved Canada backwards on climate change. It announced that it would not even try to meet its Kyoto targets, and it reduced funding for Canada's climate change plan and cut most of Canada's climate change programs In December of 2011, the government of Canada became the first nation to withdraw from the Kyoto Protocol 1) How can we reduce human s impact on the greenhouse effect? 2) Why do you think Canada would withdraw from the Kyoto Protocol? 3) Is it realistic to create a law of some kind in order to reduce greenhouse gas emissions? What would that law look like? 6