Table 9.

30-Year Normal Periods, Anomalies, Trends, and Uncertainties.

Normal Period	Anomaly Mean (Δ°C) a	RMS 2σ Uncertainty (±°C)	100-Year Trend (Δ°C) a
1901–1930	−0.30	0.71	0.79
1911–1940	−0.20	0.73	1.23
1921–1950	−0.09	1.15	0.74
1931–1960	−0.03	1.41	0.26
1941–1970	−0.91	1.57	−0.31
1951–1980	0.0	1.48	0.40
1961–1990	0.09	1.49	1.50
1971–2000	0.24	1.44	1.82
1981–2010	0.43	1.26	0.0

^a Relative to a 1951–1980 normal.