What happens when the ice melts?

You might have already seen video of the 10,000-year-old Wilkins Ice Shelf collapsing in Antarctica the other week. Brian at Larvatus Prodeo has also collected some maps and graphics to put it into context. This particular collapse isn’t much in the grand scheme of things, but it’s part of a larger pattern. There have been many ice shelves disappearing lately – Wordie, Larsen B, Larsen A, Mueller and Jones have all gone in recent years.

What effect does all this ice running into the ocean have? If you remember a bit of high-school science, you probably already know that glaciers in the sea don’t increase sea-levels when they melt. It’s just like an ice-cube in a glass of water. But these ice-shelves are partly in the sea already, and partly on land. As they melt, they do increase sea levels. And that’s not good news for us.

I haven’t got any Antarctic melting to show you, but for comparison you should check out this dramatic video showing scientists taking ice-melt measurements in Greenland by hanging over a giant crevasse filled with rushing water.

The problem isn’t just sea-levels – it’s that the bright white ice also reflects a lot of sunlight back into space. If there’s less ice, more sunlight is absorbed by the oceans, which heats them up even more. It creates a runaway effect that’s difficult to stop.

We’ve probably already heated up the planet enough that we’re going to lose summer ice in the Arctic in the next 10 years, and will be living with 1-2 metres of sea-level rise within a few decades. It doesn’t sound like much, does it? You might have dived that kind of depth into a pool as a kid.

But it will have a huge effect on our ports and coastal towns. Something like 80% of the Australian population lives on the coast. At the very least, we’ll need to shift people from low-lying coastal areas inland a bit. And what happens if we don’t stop climate change?

If we continue with business as usual, we’ll be locked into much higher sea-levels. As the temperature increases, we could end up with over 50 meters of increase after a century or two. We won’t be around to see it, so here’s a graphic from the Climate Code Red website (Science A pdf, page 6, via) to illustrate the effect it’d have on Australia.

The good news is that this is preventable. By becoming energy efficient, reducing our reliance on coal, and even scrubbing some CO2 out of the atmosphere, we can stop this from happening. We just need to get started…