These masses of ice are now contributing more new meltwater to the world’s seas than all other melting ice combined.

The Greenland and Antarctic ice sheets are losing mass at an accelerating pace, according to a new NASA-funded satellite study. The findings of the study — the longest to date of changes in polar ice sheet mass — suggest these ice sheets are overtaking ice loss from Earth’s mountain glaciers and ice caps to become the dominant contributor to global sea level rise, much sooner than model forecasts have predicted.

The nearly 20-year study reveals that in 2006, a year in which comparable results for mass loss in mountain glaciers and ice caps are available from a separate study conducted using other methods, the Greenland and Antarctic ice sheets lost a combined mass of 475 gigatonnes a year on average. That’s enough to raise global sea level by an average of 1.3 millimeters (.05 inches) a year. (A gigatonne is one billion metric tons, or more than 2.2 trillion pounds.)

The pace at which the polar ice sheets are losing mass was found to be accelerating rapidly. Each year over the course of the study, the two ice sheets lost a combined average of 36.3 gigatonnes more than they did the year before. In comparison, the 2006 study of mountain glaciers and ice caps estimated their loss at 402 gigatonnes a year on average, with a year-over-year acceleration rate three times smaller than that of the ice sheets.

This will result in a greater increase in sea level of the medium to long term than previously estimated. Unless you live in Kiribati, in which case you’ll be fine.

Lots more details here.

You’ve heard that the Arctic ice cap has shrunk, and that there are sea lanes open in the northern summer that had not been open previously, and on and so forth.

Since the start of the satellite record in 1979, scientists have observed the continued disappearance of older “multiyear” sea ice that survives more than one summer melt season. Some scientists suspected that this loss was due entirely to wind pushing the ice out of the Arctic Basin — a process that scientists refer to as “export.” In this study, Ron Kwok and Glenn Cunningham at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., used a suite of satellite data to clarify the relative role of export versus melt within the Arctic Ocean.*

Continue reading The melting of the Arctic ice cap is a complex process →

This is astonishing.

…Scientists and conservationists are expressing alarm at the appearance of thousands of walrus on Alaska’s northwest coast, a dramatic demonstration of the effects of diminished Arctic sea ice brought on by global warming….

source

I’ve noticed that a lot of smart people who nonetheless “did not accept” AGW, or at least, denied the “A” part of it, have stoped talking about it lately. I’m speaking here of people I know personally. You know who you are, and you know you were wrong, and I just wanted to say that I forgive you. Mostly.

In the mean time, have a look at this:

Continue reading Anthropogenic Climate Change: It’s for real. →

This Rob Dunbar is NOT Robin Dunbar the Archaeologist.

Rob Dunbar hunts for data on our climate from 12,000 years ago, finding clues inside ancient seabeds and corals and inside ice sheets. His work is vital in setting baselines for fixing our current climate — and in tracking the rise of deadly ocean acidification.

Continue reading Rob Dunbar: Discovering ancient climates in oceans and ice →

In the 1960s, the whole idea of a “greenhouse effect” was well understood, and assumed to be an important potential factor in climate change. So was glaciation, and the short and medium term future of the Earth’s climate was less clear than compared to now. But the basics were there … C02 was being released into the atmosphere, this could cause a greenhouse effect, and that would warm the earth. Certainly by the early 1980s, it was possible to make some thumb-suck estimates of how much the earth would warm given various assumptions about CO2, and it was not that difficult to see that a lot of fossil carbon was being put into the atmosphere.
Continue reading Science as a Contact Sport by Stephen Schneider →

See the missing bit? That is a 1.5 kilometer retreat of the so-called “calving front” of the glacier.

In truth, this particular sort of even is not that unusual, but what is interesting is that new satellite monitoring capabilities allow researchers to notice these events more or less when they happen, as opposed to during less frequent inspections of satellite imagery.

And, there are some climate-change related features of this event.

Continue reading What was that splash? Oh. Greenland melting. →