Harbinger?

Several people have mentioned (I think the first I heard of it was from the Rabett) that at the moment, Arctic sea ice is exceptionally fragmented. It has even been suggested that we should expect a precipitous decline over the next week or so, by some accounts because of a possible imminent storm. I don’t know whether or not such prognostications are true, but I am motivated to look at the relationship between the two most common measures of sea ice, its area and its extent.

The Small Picture

Over at WUWT there’s a new installment of Sea Ice News. The comments section includes this:

Arctic Sea Ice

Click on the graphs!

Much Ado about Nothing

A couple of recent events have caused some stir in the climate denial blogosphere.

I’m underwhelmed.

Temperature Variability part 2

I had some further thoughts about the subject of the last post. Here they are.

Increased Variability?

In the last post I mentioned that a change in either the mean value or the variance of a probability distribution will greatly affect the probability of extreme events. I also mentioned that a change in variance has a more profound impact on the likelihood of extremes than a change in mean value.

Craps

One of the analogies sometimes used to explain the impact of global warming on the weather is that we’re “loading the dice.” Perhaps a better desrciption is that we’re changing the dice.

USA Divisions

We’ve occasionally looked at temperature time series from NCDC (National Climate Data Center) for USA48 (the 48 states of the continental USA excluding Alaska). But in addition to data for individual states, NCDC also offers data for each individual climate division within each state. The temperature data, for example, can be found here.

Segmenting USA48 by division rather than state will give us a much more detailed geographical picture of climate change in the mainland U.S. Let’s take a look at some of the things the data have to say.

Where’s the Skepticism?

It’s getting tiresome.

There’s a new post on WUWT about how

“Authors Steirou and Koutsoyiannis, after taking homogenization errors into account find global warming over the past century was only about one-half [0.42°C] of that claimed by the IPCC [0.7-0.8°C].”

Anthony Watts was so excited he felt the need to alert Richard Muller to this result. The blog post leads to the usual frenzy of accusations that the global temperature estimates are a fraud. There’s much talk of how the entire global warming during the last 100 years is only 0.4C, and half of that must be natural, leaving a mere 0.2C (at most) attributable to humankind, so they’ve been right all along that we’re not changing the climate in any dangerous way. There are even some bizarre statements like one reader concluding “that is fully consistent with what we’ve said all along, that incresed water vapor is a negative, not positive feedback…” How water vapor got into the discussion, I don’t know.

What’s lacking is the faintest glimmer of actual skepticism about this claim.

Fifteen

The subject came up — yet again — whether or not there is a “pause” in global warming recently. Specifically:

Re looking at global warming over the last 15 years. I know it breaks all the “statistical” rules, but just simply eyeballing the graph of (annual average) temperatures shows a distinct change in the trend of global temperatures after 1998. In order to avoid a charge of “cherry picking” I could have said 10 years since 2002 – but to me the break in the trend is pretty clear.

We’ve often dealt with this subject, but since it’s so common, and seems to come from real skeptics as well as fake ones, we’ll address it once again. In depth.