Figure 4.9. Summer minimum arctic sea ice extent from 1979 to 2005. Symbols indicate annual mean values while the smooth blue curve shows decadal variations (see Appendix 3.A ). The dashed line indicates the linear trend, which is –60 ± 20 × 10³ km² yr^–1, or approximately –7.4% per decade (updated from Comiso, 2002).