Climate Change: Science and Society A PREAMBLE

Global mean temperatures are rising faster with time Warmest 12 years: 1998,2005,2003,2002,2004,2006, 2001,1997,1995,1999,1990,2000 50 0.1280.026 100 0.0740.018 Period Rate Years /decade

Carbon dioxide has risen by 36% since accurate measurements began in 1958 388 ppm (2008) The photo in the background shows the Mauna Loa Observatory at dusk (courtesy Forrest Mims). This is where, in 1958, Charles David Keeling began his now-famous atmospheric carbon dioxide data set – sometimes called “the Keeling Curve.” The data trend shows carbon dioxide has risen from about 318 parts per million in 1958 to about 388 ppm in 2008. The gray “saw-toothed” line shows actual measurements and the red line shows the running mean value. (Data courtesy NOAA Earth System Research Laboratory) 318 ppm (1958) Mauna Loa Observatory on Hawai’i

Svant Arrhenius, 1896 Dai et al. J. Hydromet (2004)

Arctic sea ice breaks lowest extent on record August 27, 2012

Variations of the Earth’s surface temperature; 1000 to 2100

Fossil Fuel CO2 Emissions: Top Emitters Time 1990 95 2001 05 2009 97 99 03 93 400 800 1200 1600 2000 Carbon Emissions per year (C tons x 1,000,000) China USA Japan Russian Fed. India 07 The biggest increase in fossil fuel emissions in recent years took place in developing countries (with close to 6 billion people) while emissions from developed countries (with less than 1 billion people), on average, show rather steady emissions for the last decade. However, emissions of a number of developed countries declined abruptly in 2009 (USA −6.9%, UK −8.6%, Germany −7%, Japan −11.8%, Russia −8.4%), while emerging economies continued to display rapid growth (China +8%, India +6.2%, South Korea +1.4%). The countries with highest absolute values of emissions are China, US, India, Russia, and Japan although the emissions per capita in China and India are still a fraction of the emissions in US, Russia and Japan. Prior to 2009, about one quarter of recent growth in emissions in developing countries resulted from the increase in international trade of goods and services produced in developing countries but consumed in developed countries. From a historical perspective, developing countries with 80% of the world’s population account for about one fifth of the cumulative emissions since 1751; the poorest countries in the world, with 800 million people, have contributed less than 1% of these cumulative emissions. Uncertainty of emissions from CO2 fossil fuel is large in some countries. Global Carbon Project 2010; Data: Gregg Marland, Tom Boden-CDIAC 2010

Image Credit: Robert A. Rohde, Global Warming Art This figure shows the relative fraction of man-made greenhouse gases coming from each of eight categories of sources, as estimated by the Emission Database for Global Atmospheric Research version 3.2, fast track 2000 project. These values are intended to provide a snapshot of global annual greenhouse gas emissions in the year 2000. The top panel shows the sum over all greenhouse gases, weighted by their global warming potential over the next 100 years. This consists of 72% carbon dioxide, 18% methane, 8% nitrous oxide and 1% other gases. Lower panels show the comparable information for each of these three primary greenhouse gases, with the same coloring of sectors as used in the top chart. Segments with less than 1% fraction are not labeled. The increase in greenhouse gas concentrations in the Earth's atmosphere is believed to be the primary cause of global warming. Image Credit: Robert A. Rohde, Global Warming Art

http://berkeleyearth.org/ The scientific finding that settles the climate-change debate – Washington Post Global warming study finds no grounds for climate sceptics' concerns – The Guardian UK

My generation caused this mess… your generation has to fix it!