Sea Ice

On Monday I went to an interesting lecture in the Princeton Geosciences department by someone studying sea ice. Sea ice is really important for the global climate change. Look how it waxes and wanes each year with the seasons in the picture below. Sea ice also plays a major role in reflecting incoming sunlight that would otherwise warm the oceans.

(Source: National Snow and Ice Data Center)

One important climate warming feedback scenario is created by the melting of sea ice. More melting of sea ice leads to less sunlight reflected leads to more heat absorbed by arctic oceans leads to more ice melting.

I learned a lot during the talk. It turns out that sea ice actually doesn't melt per se, but it is dissolved by the influx of salty water. And there are lots of really interesting and complex interactions between the temperature of the ocean and the ice, especially when the ice gets thin. In short, we could be in for some major unpleasant surprises from future anthropogenic warming since the ice doesn't simply "melt" and "refreeze" as one might expect. There's a distinct possibility that we could reach a point of no return where extensive sea ice simply can't be regenerated.

The most astounding aspect of the speaker's talk was the fact that we still are so clueless about the basic properties of something as simple and ubiquitous as ice. Science still has so much to learn about our own planet!

Just couldn't resist this one: (Thanks iTunes search function!)