These selected time series represent four indicator types (physical data, biology and fisheries, large scale climate indices, and composites). Red colors indicate the large changes in recent years (largest 1/3 of values in the record). The middle third are shown in grey and the lowest third are shown in green.
The combined indicators are the result of a mathematical analysis (principal component analysis) which resolves the trends in all the time series into two major components. To demonstrate covariabililty over time, the values in some series have been inverted, as noted by a star.