A metric unit of energy, representing the energy delivered at a rate of one watt for a period of one year. The watt year, equal to about 31.5569 megajoules (MJ), is used in discussions of the rate of global warming
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}