EXECUTIVE SUMMARY
The Earth’s weather and climate are the result of the redistribution of heat. The major source of heat to the surface of the Earth is the sun, principally through incoming visible radiation most of which is absorbed by the Earth’s surface. This radiation is redistributed by the ocean and the atmosphere with the excess radiated back into space as longer wavelength, infrared radiation. Clouds and other gases, primarily water vapor and carbon dioxide, absorb the infrared radiation emitted by the Earth’s surface and remit their own heat at much lower temperatures. This "traps" the Earth’s radiation and makes the Earth much warmer than it would be otherwise.
Most of the incoming solar radiation is received in tropical regions while very little is received in polar regions especially during winter months. Over time, energy absorbed near the equator spreads to the colder regions of the globe, carried by winds in the atmosphere and by currents in the ocean. Compared to the atmosphere, the ocean is much denser and has a much greater ability to store heat. The ocean also moves much more slowly than the atmosphere. Thus, the ocean and the atmosphere interact on different time scales. The ocean moderates seasonal and longer variations by storing and transporting, via ocean currents, large amounts of heat around the globe, eventually resulting in changing weather patterns.
The ocean also plays an important role in climate change. Long-term impacts of climate change in coastal areas, such as sea level rise or storm surges, could result in the increased erosion of shores and associated habitat, increased salinity of estuaries and freshwater aquifers, altered tidal ranges in rivers and bays, changes in sediment and nutrient transport, and increased coastal flooding. Such changes have considerable implications for U.S. coastal areas where the majority of the country's population and significant economic activity is concentrated.
The purpose of this document is to consider how the ocean influences weather and climate and how climatic changes could impact valuable coastal areas. It also addresses the barriers to progress and the opportunities presented by the 1998 Year of the Ocean to better understand and predict weather and climate variability and to address the coastal impacts of global climate change. This topic spans such a broad array of considerations that it will be split into three parts: seasonal to interannual climate impacts, decadal to centennial climate impacts, and coastal global climate change impacts. Options for consideration to further advance efforts in each topical area are included.