Fuel Cells - Green Power - Martin's Marine Engineering Page

Climate Change,Greenhouse Gases, and FuelCells: What is the Link?There is a growing scientific consensus that increasinglevels of greenhouse gas emissions are changing theearth’s climate. The natural greenhouse gases includecarbon dioxide (CO 2), water vapor (H 2O), nitrous oxide(N 2O), methane (CH 4) and ozone (O 3), and are essentialif the Earth is to support life. With the exception ofwater vapor, carbon dioxide is the most plentiful. Sincethe beginning of the Industrial Revolution in 1765,burning fossil fuels and the increased energy needs of agrowing world population have added man-made, oranthropogenic, greenhouse gas emissions into theenvironment. Carbon dioxide constitutes a tiny fractionof the earth’s atmosphere — about one molecule in threethousand — but is the single largest waste product ofmodern industrial society. The concentration of carbondioxide in the atmosphere has risen from about 280 partsper million by volume to the current level of over 360parts per million by volume and anthropogenicallycaused atmospheric concentration of methane hasdoubled. In the past 100 years, levels of nitrous oxidehave risen about 15%. Increasing concentrations ofgreenhouse gases trap more terrestrial radiation in thelower atmosphere (troposphere), artificially enhancingthe natural greenhouse effect. The average temperatureof the Earth has warmed about 1°C since the mid-19thcentury when measurements began, and fragmentaryrecords suggest the Earth is warmer than it has been innearly 2,000 years.The CO 2 level has increased sharply since the beginning of theIndustrial Era and is already outside the bounds of natural variabilityseen in the climate record of the last 160,000 years. Continuation ofcurrent levels of emissions are predicted to raise concentrations toover 600 ppm by 2100. (Courtesy: Office of Science and TechnologyPolicy)“The balance of evidence suggests that thereis a discernible human influence on globalclimate.”United Nations Intergovernmental Panel on Climate Change, 1995Under the most optimistic scenarios proposed by theUnited Nations Intergovernmental Panel on ClimateChange, carbon dioxide is expected to rise to approximately600 parts per million by volume during the nextcentury — more than double the level held for 10,000years since the end of the last ice age.This document, and more, is available for download at Martin's Marine Engineering Page - www.dieselduck.net29