Climate Change Reference Guide SOURCES OF CLIMATE CHANGE MEASURING CLIMATE CHANGE CONSEQUENCES OF GREENHOUSE GAS BUILDUP CLIMATE DIPLOMACY CLIMATE CHANGE GLOSSARY Climate Change Reference Guide by Alice McKeown and Gary Gardner At the heart of climate change is the greenhouse effect, in which molecules of var - ious gases trap heat in Earth’s atmosphere and keep it warm enough to support life. Carbon dioxide and other “greenhouse gases” (GHGs) are an important part of Earth’s natural cycles, but human activities are boosting their concentrations in the atmosphere to dangerous levels. The result is rising global temperatures and an unstable climate that threatens humans, economies, and ecosystems. This is an updated version of the reference guide that originally appeared in State of the World 2009: Into a Warming World , published by the Worldwatch Institute. For more information about the book, please visit www.worldwatch.org /stateoftheworld. © 2009 Worldwatch Institute ISBN 78 -1 -87807 1-88-0 (13) Global Emissions of Greenhouse Gases The primary human-generated greenhouse gases are carbon dioxide, methane, fluorinated gases (including CFCs), and nitrous oxide. Greenhouse gases are only one source of climate change; aerosols such as black carbon and land use changes such as deforestation also affect warming. E G Greenhouse Gas Generated by N A Share of Global Emissions, in Carbon H Carbon Dioxide (CO ) Fossil fuel combustion, land 2 Dioxide Equivalent, 200 4 C clearing for agriculture, E cement production T CO 2 from A cement Methane (CH 4) Livestock production, M CO2 from production I extraction of fossil fuels, L rice cultivation, landfills, deforestation, and gas C biomass flaring sewage F decay, etc. (2.8%) O (17.3%) Nitrous Oxide (N 2O) Industrial processes, S fertilizer use E CO 2 from fossil C Hydrofluoro- Leakage from refriger- fuel use (56.6%) CH 4 (14.3%) R carbons ators, aerosols, air U (HFCs) conditioners O S F gases Perfluoro- Aluminum production, carbons semiconductor industry Sulfur Hexa- Electrical insulation, N2O (7.9%) fluoride (S F6) magnesium smelting F-gases ( 1.1%) Source : IPCC Greenhouse Gas Sources, by Sector Greenhouse gases come from a broad range of human activities, including energy use, changes in land use (such as deforestation), and agriculture. E Source Sample Emission- G generating Activities Emissions by Sector, in Carbon N A Energy Supply Electricity and centralized heat Dioxide Equivalent, 2004 H C generation, resource extraction, Waste and E and grid base transmission/ T distribution wastewater A (2.8%) M Industry Production of metals, pulp and Industry I L (19.4%) paper, cement, and chemicals; Energy supply C petroleum refining (25.9%) F O Forestry Deforestation, decomposition S of biomass that remains after Forestry E logging (17.4%) C R Agriculture Crop and livestock production U O Transport Travel by car, freight truck, plane, Transport Agriculture S (13 .1%) (13.5%) train, or ship Buildings Residential and Heating, cooling, and electricity (direct emissions) Commercial Buildings (7.9%) Waste Landfills, incineration, wastewater Source : IPCC The Carbon Cycle Carbon flows among land, sea, and the atmosphere. But human activities since the mid-eighteenth century have changed carbon flows in ways that have lasting implications for the climate. This graphic depicts changes to global carbon flows in the 1990s relative to the preindustrial state. E G N Fossil fuel burning and Land use Net increase to the atmospher e=3.2 GtC A cement production H changes 6.4 GtC C 1.6 GtC N O I E T T N Land sinks P O A R I S S 2.6 GtC O T N M N S P I O O B R I I L A S S O C S S S I I B M M G A E E N I R U Ocean sinks S 2.2 GtC A E M Annual change in billions of tons of carbon (GtC) Source : IPCC Carbon, Carbon Dioxide, and Carbon Dioxide Equivalents Carbon, the basis of life on Earth, is at the center of the climate crisis. Carbon is found in solid, liquid, and gaseous form. CO 2 is the most prevalent of human-generated greenhouse gases. CO 2 is so dominant that all other greenhouse gases are evaluated in terms of their equivalency to CO 2. Indicator Carbon Carbon Dioxide Carbon Dioxide Equivalent Molecular One atom of carbon One atom of carbon and A measurement, not a chemical makeup two atoms of oxygen element, so no molecular formula Symbol C CO 2 CO 2eq or CO 2e Description Carbon cycles among A gaseous form of carbon, A unit of measurement that land, sea, air, and CO 2 is the breath people compares the global warming biological systems and exhale, the fizz in soda—and contribution of other green- is the building block part of the exhaust from house gases to that of carbon of many but not all burning fossil fuels. Most dioxide, for standardization greenhouse gases human carbon emissions are in the form of CO 2 E Calculation One ton of carbon = Not typically converted Quantity of a greenhouse G 3.67 tons of carbon to other units. Measured gas multiplied by its global N dioxide as emissions and as a warming potential A concentration in the H C atmosphere E T A M I L C G N Global Warming Potential of Selected Greenhouse Gases I R U Global warming potential (GWP) expresses a gas’s heat- Greenhouse Gas Global Warming S A trapping power relative to carbon dioxide over a particular Potential E time period (this table uses the common 100-year frame). M Carbon Dioxide 1 A methane molecule, for example, has 25 times the warm - ing potential of a carbon dioxide molecule over a 100-year Methane 25 period, and some gases are hundreds or thousands of Nitrous Oxide 298 times more powerful. However, carbon dioxide is a more Hydrofluorocarbons 124 – 14,800 stable molecule and lasts longer in the atmosphere than most of the other greenhouse gases, and is also emitted Perfluorocarbons 7,390 – 12,200 in far greater quantities. Sulfur Hexafluoride 22,800 Temperature Conversion Changes to global temperature caused by climate change are usually measured in degrees Celsius. One degree Celsius is equal to 1.8 degrees Fahrenheit—meaning that a 2-degree Celsius rise is 3.6 degrees Fahrenheit. Actual temperature readings in the different scales are easily compared when placed side by side. ˚F 100.4 96.8 93.2 89.6 86.0 82.4 78.8 75.2 71.6 68.0 64.4 60.8 57.2 53.6 50.0 46.4 42.8 39.2 35.6 32.0 ˚C 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Top 10 CO 2-Emitting Nations, Total and Per Person, 2007 National emissions levels vary greatly. Among the top 10 emitters, China generates nearly 15 times more CO 2 than Mexico does. The 10 leading emitters generate many more times the emissions of most developing coun - tries, although emissions in those countries are rising rapidly and could soon overtake the annual emissions in industrial countries. The top 10 emitting nations also exhibit a broad range of emissions per person. Wealthy countries tend to emit more carbon dioxide per person than poor countries do. 7000 20 Total Emi ssions (not including emissions from land use changes) Source : CDIAC 6000 Emissions Per Person T 15 o n 2 5000 s o O f C C f o 4000 O s 2 n 10 p o e t 3000 r n p o e i l r l i s o M 2000 5 n E 1000 G N 0 0 A a d s 7 ia ia n a th a n o H n e s a d e a c i e t 2 s d p a u r Ir xi h it ta - u In a n o o e C C n U R J a S K U S E C M E T A M I L C G N Top 10 CO -Emitting Nations’ Share of Global CO Emissions, 1950–2007 I 2 2 R U Over time, early industrializing S 30 nations typically have emitted A Source : CDIAC E more carbon dioxide to the M 25 Source : DLR atmosphere than nations that Note: shares are based on CO 2 emissions data that industrialized later. But some do not include emissions from land use changes. 20 developing countries emit large quantities of greenhouse t n gases through changes in land e c 15 r use, especially through forest e P clearing for crop production. 10 Contemporary data for emis - sions resulting from land use changes by country are not 5 available, but would push Indonesia and Brazil into the 0 top 10 emitters when all emis - d s 7 a ia n ia a o n th ea e te 2 in s a d ad ic ra u r sions sources are considered. it a - h us ap In n x I o o n t U C R J a e S K U S E C M Concentration of CO 2 in Earth’s Atmosphere, 1744–2008 Since the mid-eighteenth century fossil fuel use and cement production have released billions of tons of CO 2 to the atmosphere. Carbon dioxide levels in the atmosphere before the Industrial Revolution were some 280 parts per million (ppm). By 2007, levels had reached 384 pp m— a 3 7-percent increase. E G N 390 A Source : Neftal et al., Etheridge et al., NOAA H C 370 E T Atmospheric A measurements M n 350 I o i L l l i C m r e G 330 p N s I t r R a P U 310 S Ice core A measurements E 290 M 270 1740 177 01800 1830 1860 1890 1920 1950 1980 2010 Average Global Temperature at Earth’s Surface, 1880 –2008 P Average global temperature increased by 0.74 degrees Celsius between 1906 and 2005.