ABSTRACT
Scientists have been aware since the nineteenth century of the planetary impacts of carbon dioxide (CO2) and other greenhouse gases in the atmosphere. The changes in global climate, including temperature, precipitation, storm frequency and intensity, and changes in carbon and water cycles, that result from increased concentrations of greenhouse gases in the atmosphere. Global pollution creates a 'public bad' affecting everyone, a negative externality with a wide impact. The sun's rays travel through a greenhouse's glass to warm the air inside, but the glass acts as a barrier to the escape of heat. In addition to increased burning of fossil fuels such as coal, oil, and natural gas, manmade chemical substances such as chlorofluorocarbons (CFCs) as well as methane and nitrous oxide emissions from agriculture and industry contribute to the greenhouse effect. Warmer temperatures have produced noticeable effects on ecosystems. Wildfires were once primarily a seasonal threat, taking place mainly in hot, dry summers.
