Wednesday, July 12, 2017

Giant Iceberg Nearly The Size Of Delaware Breaks Off Antartica

The White Whale:

Here's the report from the MIDAS Project.

They say it will be named "A68" -- I saw on Twitter that some were suggesting it be named the #ExxonKnew -- and weighs over a trillion tonnes. That's about how much ice the planet has been losing per year for a few years now.

In the picture to the right, I'm guessing that's sea ice to the outer edge of the breakoff, which this iceberg will begin pushing through.

The Larsen C ice shelf is, suddenly, 12% smaller, and, "potentially less stable," says MIDAS. "This is the furthest back that the ice front has been in recorded history," says a MIDAS scientist. Another said, interestingly:
“We have been anticipating this event for months, and have been surprised how long it took for the rift to break through the final few kilometres of ice."
Mind, it did break off in the depth of the dark, Antarctic winter, but I'm sure he took that into account.

Friday, July 07, 2017

Larsen C, Almost Free

When last we looked, the Larsen C ice shelf was hanging on by an 8-mile sliver.

That's now down to 3 miles.

In the spirit of Layjez's calculation in the comments, that's 5 miles in about 36 days, or 1/7th of a mile per day. That's an average of only 0.2 meters per minute, compared to his (earlier) value of about 3 m/min.

So clearly this isn't linear, or easy to predict. The Antarctic is just coming out of its winter depth, which you'd think might have helped the crack to heal. But nature has other ideas.

At least this won't kill any penguins. That'd be a hell of a way to die.

Thursday, July 06, 2017

Good Lord, Here We Go Again

Geostorm, 2017:

More About RSS's Large Changes to Their Temperatures.

RSS has posted a FAQ about their version 4.0 changes for the lower troposphere temperature anomaly, here.

Roy Spencer says, yabutt, their new numbers (+0.18°C/decade, up from +0.12°C/decade) are still nowhere close to the model calculation of 0.27°C/dec. I don't know where that number comes from, so I asked him. Will let you know.

Frankly, I'm starting to wonder if either of these satellite datasets can be useful. Roy writes:
In general, it is difficult for us to follow the chain of diurnal corrections in the new RSS paper. Using a climate model to make the diurnal drift adjustments, but then adjusting those adjustments with empirical satellite data feels somewhat convoluted to us.
This doesn't sound good. If the one set of supposed experts can't follow what the other set of supposed experts are doing, then who are we to possibly judge?

Maybe it's time to just forget about the satellite measurements of the atmosphere and focus on surface, where measurements are much easier. That's where we all live, anyway.

Anyway, here are the data for RSS v4.0's 12-month moving average:

Pretty obvious warming.

Also, whereas RSS LT v3.3 shows 2016 to be the warmest year by, like UAH, 0.02 C, the new version v4.0 shows it to be the warmest year by 0.16 C. Huge and indisputable.

These differences will probably remain for some time -- I doubt UAH will do another entirely new version before Christy and/or Spencer retires, after which the UAH dataset will probably, unfortunately, fade into insignificance. It's now clearly the outlier when compared to RSS and the several surface datasets.

The (Comparative) Size of the Moon