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Terra Alpha Investments, LLC Greenhouse Gases – A Primer 1. What are Greenhouse Gases? Greenhouse gases (GHG) are specific molecules in the air that have the ability to trap heat in the Earth's atmosphere. Most of these molecules, such as carbon dioxide (CO2) and methane (CH4), occur naturally and have historically helped to keep our planet temperate. However, many human activities (e.g., the burning of fossil fuels, the landfilling of waste, and the removal of carbon sinks through deforestation) emit molecules of CO2 and other greenhouse gases, increasing overall GHG concentrations in the atmosphere and contributing to the warming of the planet. (https://www.wunderground.com/climate/co2.asp) Greenhouse gases each have different attributes that affect climate change: some last longer in the atmosphere, some are more abundant, and some are more efficient at trapping heat. For example, methane is far less abundant in the atmosphere than carbon dioxide and has a shorter atmospheric lifetime, but it is much more efficient at trapping heat, making it a more potent GHG. 2. How Do They Work? As sunlight passes through the atmosphere to the earth’s surface, some of this solar energy is reflected off of the surface back into the atmosphere. Greenhouse gases trap some of this reflected energy and prevent it from escaping the earth’s atmosphere. The more greenhouse gases there are in the atmosphere, the more of the sun’s heat they will trap; this results in a rise of the earth’s air and ocean temperatures. 3. Three Factors Affect the Degree to Which Any Greenhouse Gas Will Influence Global Warming: Abundance in the Atmosphere: The concentration of a particular gas in the air – measured in parts per million. Atmospheric Lifetime: The length of time a certain gas stays in the atmosphere. Each gas can remain in the atmosphere for different amounts of time – from a few years to several thousand years. Global Warming Potential: The potency of a gas. GWP is the measure of how strongly a gas absorbs energy, per pound of emissions, relative to CO2. A gas with a higher GWP means it absorbs more energy per pound and is therefore more effective at warming the earth. GHG Primer│ April 2016 │ 1 Terra Alpha Investments, LLC 4. The Composition of the Earth’s Atmosphere Earth’s atmosphere is comprised mainly of nitrogen, oxygen and water. Anthropogenic greenhouse gases, i.e., caused by human activity, are actually a very small percentage. a) Water Vapor concentrations in the atmosphere are not significantly impacted by any direct human action but instead by the natural water cycle. Changes in atmospheric H2O concentrations are considered to be a result of climate feedbacks related to the warming of the atmosphere, rather than a direct result of humans. b) Ozone emissions do not last very long and thus dissipate before reaching the stratosphere. As a result, tropospheric ozone emissions play no significant role in exacerbating the greenhouse effect. 5. Which Gases Should We Really Care About? Sourced from: http://science.kqed.org/quest/2014/12/12/what-are-greenhouse-gases-and-where-do-they-come-from/ GHG Primer│ April 2016 │ 2 Terra Alpha Investments, LLC While carbon dioxide is a main greenhouse gas, it isn’t the only one. Long-lived GHGs (carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O)), and the fluorinated gases listed under the Kyoto Protocol (sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs)) are the main drivers of climate change. (Blasing, T.J. ad K. Smith 2011. "Recent Greenhouse Gas Concentrations." In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, US Department of Energy, Oak Ridge, TN, USA. http://cdiac.ornl.gov/pns/current_ghg.html) 6. What Are the Biggest Emission Sources? AFOLU- Agriculture, Forest and Other Land Uses; http://www.ipcc.ch/report/ar5/wg3/ The energy, agricultural, and industrial sectors account for roughly 80% of all global GHG emissions. World Resources Institute; http://www.wri.org/blog/2014/11/6-graphs-explain-world’s-top-10-emitters Emissions by country are similarly unbalanced. From 1990 to 2011, the U.S., the E.U., China, and the Russian Federation accounted for slightly more than half of all global GHG emissions. GHG Primer│ April 2016 │ 3 Terra Alpha Investments, LLC 7. Breakdown of the Greenhouse Gases 1. Carbon dioxide (CO2) is the primary greenhouse gas emitted by humans, mainly through the combustion of fossil fuels (responsible for 87% of all CO2 emissions). The three types of fossil fuels that are used the most are coal, oil, and natural gas. 43% of the carbon dioxide emissions from fuel combustion are from coal, 37% are from oil, and 20% are from natural gas.1 The remainder is caused by the clearing of forests and other land-use changes, as well as by certain industrial processes such as cement production, steel production, and glass manufacturing.2 2. Methane levels have more than doubled over the last 150 years, primarily from human actions such as the production, transportation, and use of fossil fuels; landfilling of waste; and intensive livestock farming. U.S. methane emissions have spiked 30% since 2002 – precisely the era when fracking became mainstream.3 These activities account for 64% of total methane emissions.4 The main natural sources of methane include: wetlands, termites, and the oceans, all of which account for 36% of methane emissions worldwide. Methane lasts for only a couple of decades compared to centuries for CO2, but it is much more efficient at trapping heat (it has 86105 times the potency of carbon dioxide). 3. Nitrous Oxide (N2O) is more potent than both carbon dioxide and methane. 62% of N2O emissions come from natural sources, and 38% from anthropogenic sources - mainly agriculture, fossil fuel combustion, and industrial processes.5 Human activities have virtually doubled the amount of reactive nitrogen compounds existing in the environment since the beginning of the industrial age.6 The vast majority of manufactured nitrogen is used in agriculture as fertilizer, but there are huge inefficiencies of plant and animal nitrogen intake. Only about 1015% of reactive nitrogen enters a human mouth, the rest is lost to the environment, cascading through the Earth's soils, water ways, and into the atmosphere. Sources: see endnote 7 ; GHG Primer│ April 2016 │ 4 Terra Alpha Investments, LLC 4. Fluorinated Gases have virtually no natural sources. These chemicals were developed and introduced as a replacement for chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) in order to abate depletion of the stratospheric ozone layer. Fgases now have been discovered to be potent greenhouse gases with long atmospheric lifetimes and high GWPs. Due to F-gases’ high GWPs and long atmospheric lifetimes relative to other greenhouse gases, even small atmospheric concentrations can have large effects on global temperatures. They are released into the atmosphere through leaks in, servicing of, and disposal of equipment in which they are used. HUMAN SOURCES OF FLUORINATED GAS PFC-14 5% HFC-152a 20% HFC-125 9% PFC-116 1% SF6 3% HFC-134a 57% HFC-23 5% (http://ozone.unep.org/Assessment_Panels/SAP/Scientific_Assessment_2010/00SAP-2010-Assement-report.pdf) There are four main categories of fluorinated gases--hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3). HFCs – The major emissions source of these compounds is their use as refrigerants (e.g., air conditioning systems in vehicles and buildings). HFCs are both the largest source of fluorinated gas emissions and the fastest growing source of greenhouse gas emissions. Leakage of the gases results in emissions during manufacturing, maintenance, as well as through regular usage and even disposal. SF6 – Sulfur hexafluoride is used as an insulator and arc interrupter in electrical transmission equipment, including circuit breakers, as well magnesium processing and semiconductor manufacturing. The GWP of SF6 is 22,800, making it the most potent greenhouse gas that the Intergovernmental Panel on Climate Change has evaluated. Emissions occur through leakage and maintenance losses. PFCs – PFCs are a significant source of fluorinated gas emissions. These gases are created during the production of aluminum and semiconductors. PFC-14 (CF4) and PFC-116 (C2F6) account for the majority of PFC emissions. The aluminum industry produces 12,000 tons of CF4 and 900 tons of C2F6 annually, making it the largest source of PFC emissions.8 NF3 – Nitrogen trifluoride is primarily produced in the manufacture of semiconductors and LCD (Liquid Crystal Display) panels, as well as certain types of solar panels and chemical lasers. NF3 emission rates have increased 40-fold between 1992 and 2007 alone. This is particularly serious as NF3 is 17,200 times more effective than carbon dioxide in trapping atmospheric heat over a 100-year time span. GHG Primer│ April 2016 │ 5 Terra Alpha Investments, LLC 8. GHG Emissions Are Still Increasing Globally, emissions of the Kyoto greenhouse gases increased by 75% between 1970 and 2004 (CO2 by 90%, CH4 by 40%, N20 by 50%) to about 45,000 megaton CO2equivalents.9 The large amounts of GHG emissions have affected the planet’s atmospheric composition. Between 1750 and 2010, atmospheric concentrations of CO2 increased 40%, CH4 150%, and N2O 20%.10 These levels are unprecedented in at least 800,000 years. This increase was not a gradual change – over half of the cumulative anthropogenic CO2 emissions between 1750 and 2011 have occurred in the last 40 years, while emissions were the highest in history from 2000 to 2010. 11 Fluorinated gas emissions have greatly increased in recent years – by 73% in the U.S. and 60% in the E.U. since 1990.12 This growth largely has been driven by a 250% increase in emissions of hydrofluorocarbons (HFCs). HFC emissions are projected to grow by nearly 140% from 2005 to 2020 as demands for refrigeration continue to grow and as more ozone-depleting substances are replaced.13 (http://www.ipcc.ch/pdf/assessment-report/ar4/wg3/ar4-wg3-ts.pdf) GHG Primer│ April 2016 │ 6 Terra Alpha Investments, LLC 9. What Impact Will Emissions Increases Have? (http://i.telegraph.co.uk/multimedia/archive/01508/Climate-ChangeNEW_1508747a.jpg) Rising atmospheric concentrations of GHGs will continue to heat the planet’s lower atmosphere. Some of the detrimental effects of rising temperatures are highlighted below – for example, rising sea levels, greater water insecurity, and damage of ecosystems. The global increase of GHG emissions will continue to have serious impacts on the entire planet. GHG Primer│ April 2016 │ 7 Terra Alpha Investments, LLC Endnotes 1 CO2 Emissions from Fuel Combustions, International Energy Agency. CO2 Emissions from Fuel Combustion 2014, https://www.iea.org/publications/freepublications/publication/CO2EmissionsFromFuelCombustionHighlights2014. pdf 2 The Environmental Protection Agency, Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2014, February 2016, https://www3.epa.gov/climatechange/Downloads/ghgemissions/US-GHG-Inventory-2016-Chapter4-Industrial-Processes-and-Product-Use.pdf; The Global Carbon Budget 1959-2011, Le Quéré, C. et al., 2013, http://www.earth-syst-sci-data.net/5/165/2013/essd-5-165-2013.pdf 3 McKibben, Bill, Global Warming’s Terrifying New Chemistry, The Nation, 2016, http://www.thenation.com/article/global-warming-terrifying-new-chemistry/ 4 Contribution of anthropogenic and natural sources to atmospheric methane variability, Nature, 2006, http://www.nature.com/nature/journal/v443/n7110/abs/nature05132.html 5 Couplings Between Changes in the Climate System and Biogeochemistry, Intergovernmental Panel on Climate Change, 2007, https://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch7.html 6 Smith, Kevin A., Nitrous Oxide and Climate Change, 2010, http://www.researchgate.net/publication/267337982_nitrous_oxide_emissions_from_the_nitrogen_cycle 7 http://www.earth-syst-sci-data.net/5/165/2013/essd-5-165-2013.pdf; https://www.iea.org/publications/freepublications/publication/CO2EmissionsFromFuelCombustionHighlights2014. pdf; http://www.nature.com/nature/journal/v443/n7110/full/nature05132.html; https://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_FINAL_full.pdf 8 Worton. David R., Atmospheric Trends and Radiative Forcings of CF4 and C2F6 Inferred From Firn Air, 2007, http://www.researchgate.net/publication/6389386_Atmospheric_trends_and_radiative_forcings_of_CF4_and_C2 F6_inferred_from_firn_air 9 Global greenhouse gas emissions increased 75% since 1970, November 13, 2006, http://www.pbl.nl/en/dossiers/Climatechange/TrendGHGemissions1990-2004 10 Climate Change Synthesis Report 2014, International Panel on Climate Change, 2015, http://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_FINAL_full.pdf 11 Ibid. 12 European Commissions, Climate Action, Fluorinated Greenhouse Gases, http://ec.europa.eu/clima/policies/fgas/index_en.htm 13 The Environmental Protection Agency, Overview of Greenhouse Gases, https://www3.epa.gov/climatechange/ghgemissions/gases/fgases.html GHG Primer│ April 2016 │ 8