How has Arctic sea ice changed since the late 20th century?

Since the late 20th century, Arctic sea ice has experienced a persistent decline in both extent and thickness, a trend largely attributed to the effects of global warming.12

Key changes include:

• Reduced Extent: Satellite data indicates that Arctic sea ice coverage has decreased by approximately 3 percent per decade since 1978, with particularly rapid losses occurring from the late 1980s onward. Recent records show that the 14 lowest minimum sea ice extent measurements in the satellite era occurred between 2006 and 2020.123
• Decreased Thickness and Volume: Submarine sonar data revealed that the average ice draft in the 1990s was over 1 metre (about 3 feet) lower than in previous decades, with total ice volume estimated to be 40 percent lower than during the 1958–1976 period.2
• Environmental Drivers: The Arctic has warmed nearly four times as rapidly as the rest of the world since 1979. This warming lifts near-surface air temperatures above freezing for longer periods, triggering an ice-albedo positive feedback where melting ice exposes darker water that absorbs more solar radiation, further accelerating the melt.14