Table 1. The percentage change ± s.e.m. (%) in the average frequencies of extreme events (HW: heat waves; TI: temperature inversions; AS: atmospheric stagnation episodes) for the global non-polar continental regions between the two 30-yr periods: 1981–2010 vs. 1951–1980.
| Event | Season | Global | Northern Hemisphere |
|---|---|---|---|
| HW | Annual | 25.8 ± 3.3 | 24.5 ± 3.1 |
| March-May | 45.4 ± 4.3 | 44.9 ± 4.1 | |
| June-August | 40.3 ± 5.0 | 40.9 ± 5.3 | |
| September-November | 9.9 ± 3.6 | 6.5 ± 3.7* | |
| December-January | 17.9 ± 3.5 | 16.2 ± 3.3 | |
| TI | Annual | 6.2 ± 3.2 | 6.7 ± 3.4* |
| March-May | 9.1 ± 3.9 | 9.0 ± 4.3 | |
| June-August | 10.3 ± 5.3* | 17.4 ± 7.0 | |
| September-November | 8.8 ± 3.6 | 10.6 ± 3.9 | |
| December-January | 1.8 ± 3.4* | 1.6 ± 3.0* | |
| AS | Annual | 4.5 ± 0.8 | 6.8 ± 0.9 |
| March-May | 7.2 ± 0.9 | 9.8 ± 1.1 | |
| June-August | 6.7 ± 1.1 | 11.8 ± 1.3 | |
| September-November | 3.6 ± 0.9 | 5.5 ± 1.0 | |
| December-January | 0.5 ± 0.9* | 1.0 ± 1.1* |
‘*’ indicates statistically non-significant results at the 95% confidence interval.