The Greenhouse Effect, Aerosols, and Climate Change

The earth's climate is constrained by its energy balance. Visible solar radiation absorbed by the atmosphere, ocean, and land surface warms the earth. Infrared radiation emitted by the atmosphere, ocean, and land surface cools the earth. The composition of the atmosphere can influence the climate by changing the transmission of infrared radiation from the land and ocean to space, or by changing the amount of solar radiation absorbed or reflected back to space. Greenhouse gases absorb and emit infrared radiation. Their ability to do this varies depending on their molecular structure, and their lifetime in the atmosphere varies depending on their chemical properties. Thus human emissions of different greenhouse gases can have very different impacts on the earth's climate. Climate change due to increasing concentration of greenhouse gases has significant implications for human welfare and for the natural world.