FIGURE 2.1 Global surface temperature change from 1880 to 2010, reported as a deviation from the 1951-1980 average. The black curve shows the globally and annually averaged near-surface temperature derived from a variety of instruments including thermometers, satellites, and various ocean sensors, all carefully calibrated and quality-controlled to remove errors. Green bars indicate the 95 percent confidence interval. The red curve shows a five year running average. The data show considerable year-to-year and decade-to-decade variability, but the long-term trend is clearly one of warming. SOURCE: NASA/ GISS (other research groups find similar results; see, for example, http://www.cru.uea.ac.uk/cru/data/ temperature/).
Global warming has been accompanied by a number of other global and regional environmental changes, which are broadly consistent with the changes expected in a warming world. However, establishing a direct, empirically-based causal link between