Greenland ice sheet mass balance from Mankoff et al 2021.
Equivalent sea level rise is on the scale to the right; cumulative mass loss is on the scale to the left.
Greenland ice sheet mass balance from Mankoff et al 2021.
Equivalent sea level rise is on the scale to the right; cumulative mass loss is on the scale to the left.
my back of envelope makes that between 15 and 16 cubic kilometers. staggering.
ReplyDeleteThat must not be right. Wolfram Alpha suggests that 5 trillion tons of ice = 4948 km^3 = ~124 Km^3/year (over 40 years).
ReplyDelete- https://www.wolframalpha.com/input/?i=5+Trillion+Tons+of+Ice+in+cubic+kilometers
Wikipedia says "In 2006, estimated monthly changes in the mass of Greenland's ice sheet suggest that it is melting at a rate of about 239 cubic kilometers (57 cu mi) per year. A more recent study, based on reprocessed and improved data between 2003 and 2008, reports an average trend of 195 cubic kilometers (47 cu mi) per year.[13]"
Even at this rate though, Greenland ice would melt in 2,850,000/195= ~14,500 years or 2,850,000/195= ~12,000 years.
Of course there are impacts along the way, and the rate is clearly accelerating. Just want to add the denominator for perspective.
To put these figures into perspective, 360 cubic kilometres of Greenland ice melt produces 1mm of sea level rise.
ReplyDeleteThat 5 trillion tone of ice is 5000 cubic kilometres and raised sea level by
ReplyDelete5000/360= 14mm
So it's contributing something north of 1mm to SLR every other year based on the studies referenced in the Wikipedia article.
ReplyDeleteL: Yes. But until the last few years, Greenland ice loss was accelerating. Not sure why the acceleration has slowed down but I doubt it's likely to stick.
ReplyDeleteIIRC about 40% of sea level rise is due to thermal expansion, 25% each from Greenland and Antarctica The remaining 10% includes mountain glaciers, water from aquifers etc.
ReplyDeleteAt the current 4mm/year thermal expansion contributes 1.6mm, Greenland and Antarctica 1mm each, and the rest 0.4mm.
By volume that would be an increase of 1440 cubic kilometres/year. 576 from thermal expansion, 360 each from Greenland and Antarctica, 144 from the rest.
Each cubic kilometres weighs 1 billion tonnes. The 5 trillion tonnes mentioned above is 5000 cubic kilometres.
"until the last few years, Greenland ice loss was accelerating. Not sure why the acceleration has slowed down but I doubt it's likely to stick."
ReplyDeleteIt's been a quiet few years in the Arctic, with less melting than the "new normal". Less heat melting ice in the Arctic also probably means less heat melting in Greenland.