Human activities may contribute to climate change by causing changes in Earth's atmosphere in the amounts of greenhouse gases (CO2, CH4, N2O and the halocarbons, a group of gases containing fluorine, chlorine and bromine linked to carbon), aerosols (small particles), and cloudiness. The largest known contribution comes from the burning of fossil fuels, which releases carbon dioxide, water vapour and other gases to the atmosphere. Significant increases in all of these gases have occurred in the industrial era because most of these gases accumulate in the atmosphere, causing concentrations to increase with time. This book presents and discusses the latest research in the climate change field and its relation to pollution.