Vidar Helgesen, former Minister of Climate and Environment in Norway, made history when he warned the NATO Parliamentary Assembly in 2017 that “What happens in the Arctic does not stay in the Arctic.”. At the time, the Arctic was clearly showing signs of severe distress from a changing climate, and it was determined that the far north was warming two times faster than the rest of the planet.
Fast forward to today, and that rate has increased four times faster than in 2017. Our northern air conditioner is a broken refrigerator whose contents are thawing and spoiling as we watch in terror at what this means for life and the future of civilization.
A new study reviewed in AGU’S EOS magazine found that with all the scientific advancements in monitoring the health of the planet's ice, such as “satellite altimetry, flux gates, and gravimetry,” each assuming steady ice loss from calving ice streams. All three excel at capturing what happens on the surface but “could miss changes near the ice sheet’s edges, beneath its surface, or within its many narrow fjords.”
What we can add to Vidar Helgesen's words from those few short years ago is that tropical deforestation, industrial activity, far north wildfires, methane from landfills, and so on do not stay where the destruction unfolds. Combined with the Earth’s Energy Imbalance, where more heat is now being absorbed by the atmosphere and the oceans than in the last hundred thousand years, we have created a toxic stew in the Arctic that could unleash a domino effect of tipping points we can’t free ourselves from.
The Greenland Ice Sheet has lost more than 1,000 gigatons (Gt) of ice to calving since 1985—increasing previous estimates of mass loss by 20%. This revised number comes from a recent study of the territory’s glaciers over almost 4 decades. The research also revealed marine-terminating glaciers that responded more strongly to seasonal temperature changes also lost more mass over time.
“Glaciers that are highly sensitive…to the warming that happens over the summer are also probably going to be the ones that are sensitive to what happens over longer timescales as well,” said Chad Greene, a glaciologist and remote sensing specialist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., and lead scientist on the research.
“The fact that retreat is happening in every single sector, that’s a huge thing.”
Scientists previously calculated that Greenland had lost around 5,000 Gt of ice in the past several decades. This number came from three independent techniques: satellite altimetry, flux gates, and gravimetry. Each method assumes some steady amount of calving and can capture the bulk of changes occurring on an ice sheet but could miss changes near the ice sheet’s edges, beneath its surface, or within its many narrow fjords.
But for this ice sheet, those finer details matter. “Greenland is basically a big, giant bathtub of ice, and most of that ice ends up draining through narrow fjords on its way out to the ocean,” Greene said. The boundary between the edge of the ice and environment beyond is called the calving front or terminus.
For decades, glaciologists have recognized that calving front retreat is “a significant process through which Greenland contributes mass to contemporary sea level rise,” said Derrick Lampkin, a cryosphere scientist at George Mason University in Fairfax, Va., who was not involved with the study.
“The calving front is oftentimes what responds first to a changing environment,” Greene said, calling it “the frontlines of climate change.” But most remote sensing techniques can’t track a front’s solid ice discharge and meltwater runoff at the same time.
The study mentions the rise in sea level and the AMOC.
But it turns out that even though the Greenland Ice Sheet has lost more ice mass than previously thought, that loss hasn’t changed calculations of sea level rise. “The old numbers are still the correct ones,” Greene said. “We had already measured the response,” he said, referring to rising sea levels, “and now we’re zeroing in on one of the causes.”
Driven by weather in the atmosphere, salinity, and temperatures, the Atlantic Meridional Overturning Circulation (AMOC) is a critical surface and deep current system moderating the climate of the Northern Hemisphere. AMOC has been in the news recently as science reveals that circulation could collapse by the end of the century or next year.
I did some basic energy and water calculations on the scary AMOC study (1) that's making headlines, so you don't have to. It's quite simple, so please don't let the orders of magnitude scare you off. This is a Big F*cking Deal (BFD)! First, what are we talking about here? What is the Atlantic Meridional Overturning Circulation?
It's a shitload of water transporting a shit ton of heat energy North, through the Atlantic Ocean! The study starts with an AMOC strength of about 15 sverdrups, or 15,000,000 cubic meters of ocean water per second. This transports about 1 PW (1 petawatt = 1*10^15 watt) of heat North from the Southern Hemisphere and the tropics. That's about 32 ZJ (32 zettajoules = 32*10^21 joules) of heat per year.
When the AMOC tips, most of this ocean heat transport stops. The obvious question people are asking is "could this happen any time soon and how?"The study (as have others, for example @DrJamesEHansen et al. (2016) (2), which is not referenced for some reason) shows that a lot of fresh water input from rainfall and Greenland ice melt could shut this thing down this century. The more fresh water is added, the slower the AMOC becomes. The tipping in the model happens at about 0.5 sverdrups (0.5 Sv, 500,000 m³ per second) of fresh water input. There is a lot of fresh water waiting to add those 0.5 Sv, if only there was enough heat available to melt the ice sheet of Greenland.0.5 Sv is 1.6*10^13 m³ of water per year. Greenland holds 2.85*10^15 m³ of ice, which could provide about 170 years of 0.5 sverdrups of fresh water (after which global sea levels would be over 7 meters higher).
To melt 0.5 sverdrups worth of ice for a year takes 5.3 ZJ of heat.Since 1970, our greenhouse gases have caused about 450 ZJ of additional heat to accumulate in the Earth system. ~90% of that warmed the oceans. Aerosols, notably from coal plants and ships burning sulfur rich fuels, have reduced that heat accumulation. Now that we are reducing aerosols, more heat is accumulating. The larger North Atlantic Ocean region shows a spike in how much sunlight is being absorbed over recent years, while higher temperatures cause more heat radiation to space. The net effect is a spike of over 2.4 W/m² above the 2000-2009 average. This spike added 4 ZJ of heat over 12-months:
The record high global energy imbalance is now (2023) about 1.8 W/m², which adds 29 ZJ of heat to the Earth system over a year. To make a long story short, the heat is there to melt enough Greenland ice to shut the AMOC down. And we don't need all that heat to be directed to the melting of ice, as more precipitation also contributes. And of course, we are only making the climate forcing and Earth's Energy Imbalance worse by rapidly increasing greenhouse gas concentrations while decreasing aerosols .Sorry I couldn't make this more hopeful. But numbers don't lie. (1): Physics-based early warning signal shows that AMOC is on tipping course René M. van Westen et al. (2024)https://science.org/doi/10.1126/sciadv.adk1189…(2): Ice melt, sea level rise and superstorms: Evidence from paleoclimate data, climate modeling, and modern observations that 2°C global warming is dangerous
The flow of glaciers off the edges of Greenland is causing the landmass to rise like a decompressing mattress.
The uplift of Greenland is a long-term and well-known process. Since the end of the last ice age about 11,700 years ago, the retreat of the ice sheet has taken a weight off of Greenland, allowing its bedrock to rise — a process known as glacial isostatic rebound.
On top of this long-running process, Greenland is now losing ice due to modern-day climate change. The Greenland Ice Sheet is shedding approximately 262 gigatons of ice each year. Its peripheral glaciers, the ice rivers found at the coastline flowing into the sea, are losing about 42 gigatons of ice alone, according to 2022 research.
Now, a new study published Jan. 13 in the journal Geophysical Research Letters finds that this glacial ice loss contributes a significant amount to the springing up of Greenland's bedrock. In some areas, the glacial ice loss is responsible for nearly a third of the total vertical land motion.
This story is sad; I have been following the shrubification (greening) of the Arctic tundra for many years. I did not expect it in Greenland, at least not this soon. Plants growing on land recently under thick ice damage the permafrost with roots, creating hairline fractures that only widen and lengthen as the plant takes root. Plants need water, and meltwater pools on permafrost mean methane is released into the atmosphere as the thaw heats up.
The Russell Glacier near Kangerlussuaq in west Greenland. Wetlands and shrub areas are growing In places where there was once ice and snow.
Significant areas of Greenland’s melted ice sheet are now producing vegetation, risking increased greenhouse gas emissions, rising sea levels and instability of the landscape.
A study has documented the change since the 1980s and shows that large areas of ice have been replaced with barren rock, wetlands and shrub growth, creating a change in environment.
Analysis of satellite records has shown that over the past three decades an estimated 11,000 sq miles of Greenland’s ice sheet and glaciers have melted, an area equivalent to the size of Albania and amounting to 1.6% of its total ice cover.
As ice has retreated, the amount of land with vegetation growing on it has increased by 33,774 sq miles, more than twice the area covered when the study began.
The findings show a near-quadrupling of wetlands across Greenland, which are a source of methane emissions.
“We were amazed by the video footage,” Anthony Pagano, a wildlife biologist at the US Geological Survey (USGS) in Alaska who led the study, said in an email to Vox. “The video footage really highlighted how intelligent these animals are by using different behavior strategies to survive their time on land while without access to their primary prey.”
Before capturing these videos, scientists suspected that polar bears might cope with life on land by either resting to save energy (i.e., burning fewer calories) or filling up on other prey, like seabirds and plants. These bears ultimately used both approaches, according to the footage and other data the scientists collected, including measurements of movement, body mass, and energy burned. Some individuals laid down to conserve energy whereas others were actively foraging for food.
Neither approach, however, was especially successful. All but one of the 20 bears lost weight, suggesting they would eventually go hungry. One individual lost nearly 80 pounds.
The study revealed that some bears took long swims, which is “new and unexpected for this time of year,” Andrew Derocher, a polar bear expert at the University of Alberta, who was not involved in the study, said in an email. “These are possibly acts of desperation,” he said. “Hungry and skinny bears take more risks than fat bears.”
Feasting on berries and other foods also does little to stave off hunger, the research reveals. “This study really brings home the message that there’s no salvation from terrestrial feeding to help polar bears through the ice-free period,” Derocher said.
