Transcript Week Eight
“America is on the verge of technological breakthroughs that will enable us to live our lives less dependent on oil. And these technologies will help us be better stewards of the environment, and they will help us to confront the serious challenge of global climate change.” John Tyndall (1820-1893), natural philosopher born in Ireland His major research was in the transmission and absorption of gases, liquids and vapors, thus laying the basis for infrared spectroscopy. Investigated radiant heat in1859. He built the first ratio spectrophotometer to measure the absorptive powers of gases such as water vapor, carbon dioxide, ozone and hydrocarbons (many of the greenhouse gases). Demonstrated that water vapor, carbon dioxide and ozone are some of the best absorbers of heat radiation His calculations demonstrated that if the atmosphere had no carbon dioxide, the surface temperature of the Earth would fall about 21 degrees Celsius, and that this cooler atmosphere would contain less water vapor, resulting in an additional temperature decrease of approximately 10 degrees Celsius He eventually made the suggestion that an increase in atmospheric carbon dioxide due to the burning of fossil fuels could be beneficial, making the Earth's climates “more equable,” stimulating plant growth, and providing more food for a larger population. . Using the best data available to him (and making many assumptions and estimates that were necessary), he performed a series of calculations on the temperature effects of increasing and decreasing amounts of carbon dioxide in the Earth's atmosphere. His calculations showed that the “temperature of the Arctic regions would rise about 8 degrees or 9 degrees Celsius, if the carbonic acid increased 2.5 to 3 times its present value. Water Vapor Carbon Dioxide Methane Nitrous Oxide Halocarbons Fig. 1. Column inventory of anthropogenic CO2 in the ocean (mol m-2) C. L. Sabine et al., Science 305, 367 -371 (2004) Published by AAAS Arctic sea ice extent during the 2008 melt season dropped to the second-lowest level since satellite measurements began in 1979, reaching the lowest point in its annual cycle of melt and growth on September 14, 2008. Average sea ice extent over the month of September, a standard measure in the scientific study of Arctic sea ice, was 4.67 million square kilometers (1.80 million square miles) (Figure 1). The record monthly low, set in 2007, was 4.28 million square kilometers (1.65 million square miles); the now-thirdlowest monthly value, set in 2005, was 5.57 million square kilometers (2.15 million square miles). http://nsidc.org/data/virtual_globes/i mages/seaice_2008_climatology_lr. mov On August 17, Arctic sea ice extent was 6.26 million square kilometers (2.42 million square miles). This is 960,000 square kilometers (370,000 square miles) more ice than for the same day in 2007, and 1.37 million square kilometers (530,000 square miles) below the 1979 to 2000 average. On August 8, the 2009 extent decreased below the 1979 to 2000 average minimum annual extent, with a month of melt still remaining. So far this year, neither the Northwest Passage nor the Northern Sea Route has opened. The Northern Sea Route appears likely to open soon, but ice still clogs many of the channels in the Northwest Passage. • We lack rigorously tested data or reliable modeling to determine with any sense of certainty the ultimate path and pace of temperature increase or sea level rise associated with climate change in the decades ahead. Our group found that, generally speaking, most scientific predictions in the overall arena of climate change over the last two decades, when compared with ultimate outcomes, have been consistently below what has actually transpired. There are perhaps many reasons for this tendency—an innate scientific caution, an incomplete data set, a tendency for scientists to steer away from controversy, persistent efforts by some to discredit climate “alarmists,” to name but a few—but the result has been a relatively consistent underestimation of the increase in global climate and ice melting. This tendency should provide some context when examining current predictions of future climate parameters. In the global approach to climate change, 2007 has been a landmark year. It began in January with President Bush’s State of the Union address, for the first time acknowledging “the serious challenge of global climate change,” and will conclude in December in Bali, Indonesia, where global negotiators will seek to finalize an agenda for a framework to replace the Kyoto Accord, due to expire in 2012. While this is the ambitious officially declared agenda, Yvo de Boer, the executive secretary of the UN Framework on Global Climate Change (UNFGCC), revealingly stated in an October 2007 interview that “I think the challenge in the next two years will be to design a climate policy that is good for the United Sates, good for China, and good for the EU.”291 According to the World Resource Institute’s Climate Analysis Indicator Tool (CAIT)292 these three global powerhouses alone are responsible for roughly half of global greenhouse gas emissions (GHG), emitting 20.4, 14.1, and 14.7 percent of global GHG emissions, respectively, in the most recent year for which all GHG emissions figures are available (2000). No other country is responsible for more than 5.7 percent. If these three players can agree, then the core of a global framework exists. The question is: can they?