The Dam Continues to Crumble: Rate of Sea Level Rise Doubled or Tripled.

A study published in the Proceedings of the National Academy of Sciences has concluded that the rate of sea level rise between 1993 and 2012 was two or three times greater than before 1990. This appears to be partly due to a slight over-estimate in the rate of sea level rise prior to 1990, and partly due to the fact that higher temperatures mean more ice melt and faster thermal expansion.

As I’ve said before, it is inevitable that the waters will rise faster and faster as the planet gets hotter, and while the yearly increase in sea level is still a matter of a couple millimeters, it’s going to be a lot more pretty soon. You can read more on this from Chris Mooney at the Independent.

Rolling Dice on a Crumbling Dam: Running Out of Time to Prepare

As we look at what preparations need to be made for rising sea levels, it’s worth taking a moment to think about the pattern of sea level rise. Over the 20th century, it progressed at a fairly steady rate, and most of the rise was due to thermal expansion of water. The oceans absorbed a huge amount of the heat trapped by the greenhouse gas increase, and that’s what led to the few inches sea level we saw by the year 2000.

The 21st century is different. We’re now facing sea level rise due to melting ice on Greenland and Antarctica, and so the pattern of rise is likely to change. Of particular concern are the glaciers and ice shelves that are currently resting on the sea floor, held in place by the topography of the land underneath them.

As the warming waters get up under the ice sheets, there’s no clear prediction for when they’ll eat away enough ice to let the ice float free. When that happens, we could see a dramatic increase sea level – a foot or more per decade. [Read more…]

Choosing a way forward

The great tragedy of man-made global warming is that we knew it was coming, and we could have avoided it. Our changing climate is bringing with it a whole suite of other predictable problems that we should probably be preparing for, if we don’t want to screw them up as badly as we screwed up the climate. In particular, we need to be thinking about the second-layer problems – the ones caused by the immediate and obvious changes like sea level rise. [Read more…]

Climate teach-in videos from has released a couple good videos on climate science, and climate solutions. If you haven’t seen them yet, you should take a few minutes to watch them. I’ve requested transcripts for people who prefer not to watch videos, or who are unable to see or hear them, and I’ll update with those when I get them.