How is climate change affecting land-based ice and glaciers?

Greenland’s ice sheet is shrinking by more than 250 billion metric tons every year. Since 2006, the melting of this ice sheet has contributed more than 7 millimeters per decade to the rise in the average global sea level.¹ The rate of ice loss on Greenland has accelerated drastically in recent years. Between 1981 and 2010, some 15 percent of Greenland’s ice surface experienced melt during the months of June and July; in June and July 2020, that figure had already ballooned to around 25 percent.² Parts of the Antarctic ice sheet are also exhibiting heavy losses, with an annual ice-mass loss of around 150 billion metric tons since 2006 (contribution to sea-level rise: around 4 millimeters per decade).³

Most mountain glaciers are shrinking, too. Even though a few glaciers are growing due to specific regional features, the total global mass of mountain glaciers has declined significantly since 1980. On average, an ice sheet more than 20 meters thick has disappeared since then.⁴ According to glaciologists, there has never been a development like this on record.⁵ While part of the glacier shrinkage is likely still an aftereffect of the warming that followed the Little Ice Age in the northern hemisphere between the 15th and 19th centuries, climate change due to human activity has been the main driver for several decades.⁶ The duration of snow cover has also decreased significantly in many regions in recent decades.⁷