Detection and attribution of climate change dependexplicitly on proper characterization of naturalpatterns of climate over time. This book examinesmultiple types of climate data, from ocean heatcontent over a few years to ice core data going back60,000 years. Multi-scale analyses are employed totest for stationarity or acceleration of warming insatellite and ground instrumental data. Problemsthat arise when combining instrumental data into longrecords are evaluated. The CO2 rise pattern ischaracterized and the problem of extrapolation isaddressed. It is finally shown that periodicpatterns can be detected at multiple time scales,from decades to millenia. These patterns arecharacterized and used to address the attributionproblem. The human contribution to climate is shownto be separable from natural variability and ischaracterized. Human forcing of climate is shown tobe detectable beginning in 1942. This forcingpattern is used along with patterns of naturalvariability to make a 100 year forecast.