Early Warning

Surveillance, identification, and assessment that enable the government and military leaders to respond effectively to threats in a timely manner. Having learned an important lesson from the Japanese attack on Pearl Harbor, the United States after World War II planned to develop an early warning system that could provide surveillance of the North American airspace. The system, however, was difficult to develop because of the size of the United States, the short range of existing radar, and the lack of radar systems in North America.

By 1950, however, the U.S. Air Force had developed the Lashup medium-range radar network at 43 sites located near major urban areas throughout the country. In 1951, the United States and Canada began the joint Pinetree Radar Line project, which consisted of 33 stations located along the United States-Canadian border. The project was completed in 1954. By 1957, the system known as the Distant Early Warning (DEW) Line project became operational.

The DEW Line consisted of a series of 58 radars along the Arctic Circle from Alaska to Greenland. After a series of upgrades to the system, the North Warning System became operational in 1985. The North Warning System currently consists of 10 long-range radars (AN/FPS-117), 36 short-range radars (AN/FPS-124), and a developmental site in northern Canada.

The backbone of the U.S. early warning system is the Joint Surveillance System (JSS), which is a jointly operated network of long-range surveillance radars in Canada, Mexico, and several South American countries. Primarily operated in the United States by the Federal Aviation Agency (FAA) and the U.S. Air Force, the JSS collects data from various points throughout North American and feeds it to command, fusion, and intelligence centers where it is collated and monitored.

The information provided by the JSS heightens the capability of the North American Aerospace Defense Command (NORAD) to effectively defend North American airspace in the event of a missile or air attack. Similar early warning systems to alert the United States and its allies of a possible attack have been put in place in other countries, including Iceland and Norway.

Early warning systems have also recently been implemented to assess domestic threats, such as the increased risk of famine, natural disaster, or civil war. For example, the United States Agency for International Development (USAID) has a Famine Early Warning Systems Network (FEWS) that measures changes in land vegetation. FEWS uses satellites to collect photosynthetic activity data and infrared data on rainfall. The system evaluates a country's or a region's vulnerability to environmental changes to better inform authorities so that they can manage famine risks through timely intervention.