Issue 89: Tipping Points: Greenland
August 24, 2023
In this week’s issue:
- Greenland’s cold hard climate truth
- A curious ring surrounds a glacier
- Maybe space, maybe ice
This is an archived issue. Sign up here to receive the Planet Snapshots newsletter every Thursday morning.
Welcome to the first issue of Tipping Points, a series on the most urgent and concerning climate thresholds.
Feature Story: Tipping Points: Greenland
Greenland is the world’s largest island and very likely its least green one too. It’s less a landmass and more an icemass, with a 2 mile (3.2 km) thick ice sheet stretching over an area three times larger than Texas. The island is so blindingly white from the snow and ice that it can be difficult for satellites to image it. But unfortunately for us, its name might be more of a forewarning than a descriptor of its current state. Over the decades, Greenland’s melting has moved from a trickle to a torrent to a full-blown crisis.
Greenland is one of Earth’s most pressing climate tipping points — thresholds in the planet’s fine-tuned, self-regulating system that, once breached, cause dramatic and damaging changes. Its life support systems work like a game of Jenga: removing a few blocks may compromise the structure’s stability without ending the game. But there’s a critical block that will bring it crashing to the ground. Hiding within Jenga-Earth are critical blocks that, when pulled, will tip the whole structure.
Earth’s thermostat is inching up linearly, but the repercussions it precipitates will be exponential. Tipping climate systems into major, reinforcing, and accelerating new directions will catastrophically impact life as we know it. Earth’s atmosphere is at least 1.1°C warmer tha pre-industrial levels, and recent estimates show these tipping thresholds can begin anywhere from 1 to 2°C. Meaning we’re rushing to the finish line on a race we really don’t want to win.
Rewind about 400,000 years ago and Greenland was, in fact, green. Temperatures were warmer and global sea level was at least 5 feet (1.5 m) higher. The key difference is that back then there weren’t billions of people living by the coast. Global sea level would rise 23 feet (7 m) if Greenland’s ice sheet completely melted. The goal is to keep that “if” from turning into a “when.”
Scientists don’t know exactly how much atmospheric warming would trigger that level of melt, but some estimate a figure as low as 1.6°C. We’re well on track to surpass that target, especially considering that the loss of Greenland’s ice is creating a positive feedback loop. That same reflectivity that makes it difficult for satellites to image the ice sheet is also great at bouncing back sunlight. But more of the ice is melting and the surface is darkening, reducing its reflectivity, or albedo, and further accelerating ice loss.
While summer runoff is a normal part of Greenland’s yearly cycle, it’s losing more than usual, with 3.5 trillion tons of ice in the past decade. Satellites have been tracking this decline, from runoff trends to retreating glacier termini to calving icebergs. And new research based on satellite measurements are yielding higher and more concerning estimates for sea level rise than earlier studies made from models that didn’t incorporate up-to-date information.
Greenland’s ice sheet has lost mass every year since the satellite record began in 1992. But like the icebergs that calve from its glaciers, this is only the observable tip. The full weight of the issue is just below the surface but there nonetheless. We’re skating on literal thin ice. And unfortunately, without drastic action soon, there will be more ice-related metaphors than ice pack in Greenland.
Bonus: There is one golden-colored lining to this storm cloud: sand. Back in issue 73 we covered the growing global appetite for sand and its dwindling reserves. But Greenland’s rapidly melting ice is promoting a huge surge in sediment runoff and is providing the island with abundant sand. It’s not really a victory for anyone in the scheme of things, but it’s an interesting intersection between climate collapse and the global economy.
What in the World: Glacial Mystery
While perusing Greenland’s icy shores for images this week, we came across these glacial outflows with varying colors (lighter blue in the middle and green at the bottom). At first we thought that was the mystery here, but, upon closer inspection, it’s actually the top-most glacier in the image that’s most surprising.
Surrounding the glacier terminus is a near-perfect concentric ring of ice with a radius over 2 km (1.2 mi), suggesting some kind of propulsion down the channel. The catch is we’re just not quite sure what it is.
Like any good mystery, this too has plot development. Data from the day after shows that the ring expanded (despite trying to hide behind the cloud cover). Our best guess is a glacier calving, a massive iceberg turning, or the movement of some ancient eldritch creature beyond comprehension. Seriously though, we’re a bit stumped. We’ve provided the clues, you’ve got the ideas, and if you figure it out, reach out to us or drop us a comment on X-Twitter.
Remote Sensations: Greenland Galaxy
Do you ever look up at the stars and realize you’re actually looking down at icebergs? Yeah, us too. Anyway, in case you weren’t tired of Greenland pictures yet here’s one more. Ad glacia.
All imagery Ⓒ 2023 Planet Labs PBC
Editor: Ryder Kimball | Images: Ryder Kimball, Max Borrmann, Julian Peschel, and Maarten Lambrechts
