He knows not what he’s doing

Really.

Truly, he doesn’t know. He hasn’t got a clue. As usual, he doesn’t even suspect that he doesn’t have a clue. When he finds out about it — which he probably will, because one of you will comment about it at WUWT and the comment will be deleted (they can’t allow pesky truth to appear at WUWT!) but he’ll still find out — he probably won’t believe it.

Bob Tisdale has another post at WUWT which is actually titled “Warming Rate in the US Slowed during the Recent Warming Period.” Apparently he believes this — because he knows not what he’s doing.

From Skeptical Science:

Deep Heat … Shallow Thinking

Back in mid-2011, Chip Knappenberger treated us to his brand of shallow thinking about temperature data for the U.S.A. We discussed it soon after. In spite of the fact that 2011 wasn’t even over yet, Knappenberger said this:

… 2011 will mark the continued return of U.S. national temperatures to conditions much closer to the 20th century mean, down from the unusually elevated temperatures that characterized the 1998–2010 period.

Tell it like it is

Fake skeptic draws fake picture of Global Temperature

Clearly, David Whitehouse has enough rope. To hang himself.

The WUWT blog has a post by David Whitehouse (of the “Global Warming Policy Foundation”) discussing global temperature data. It features this graph from the leaked copy of the not-yet-completed 5th assessment report (AR5) of the IPCC (Intergovernmental Panel on Climate Change):

Horseshit Power

Two fake skeptics of global warming, Willie Soon and Nils-Axel Morner, have written a commentary in the Washington Times about sea level rise in which they use the most shoddy “science” imaginable to claim that sea level rise data is based on shoddy science.

Global Temperature Update

November marks the end of the “climatological” year, which extends from Dec. through Nov. rather than Jan. through Dec. as the calendar year. Since NASA GISS has updated their global temperature estimate through November, we can compute the global average annual temperature for the climatological year.

And here it is (animated GIF, you may have to click the graph to see the animation):

Sea Level Rise: Faster than Projected

A new paper by Rahmstorf et al. compares observed climate changes, specifically global temperature and sea level rise, to projections from IPCC reports. The result: temperature is rising in outstanding agreement with IPCC projections, while sea level is rising faster than expected.

the Wild, Wild West … on Fire

A frightening report from Climate Central details the increase in wildfires in 11 western states of the U.S.

Response from Ian Eisenman

We recently looked at trends of sea ice extent (and even forecast next year’s value) using not just the extent itself, but the latitude of the sea ice edge. To compute that, I used a 5th-degree polyonomial approximation from the original paper by Ian Eisenman (who identified the importance of geometry on Arctic sea ice).

It was pointed out that the figures computed by a different method — by actually averaging the latitude of the ice-ocean boundary based on gridded sea ice concentration — differed from the values computed from the polynomial approximation. This is to be expected, since the approximation is the value for ice which is re-arranged to be as far north as possible, whereas for actual sea ice the detailed distribution can strongly impact the average ice-ocean boundary latitude. But the difference seemed larger than expected.

So, I emailed Ian Eisenman and asked whether he could shed light on the matter. He was kind enough to respond in detail, saying this:

In the GRL paper, I focused on a measure of the ice edge latitude that was based on the average location of the contour line representing the transition from sea ice to ice-free ocean. This was computed from the full gridded daily ice concentration fields. In the Auxiliary Material, I briefly described an alternative way to account for continents based on a slightly different (and more subtle) physical justification that involves “rearranging” the ice cover. The alternative measure is perhaps more crude physically, but its advantage is that it can be computed directly from the ice extent, and I gave an approximate polynomial expression to allow others to easily compute this measure of the ice edge latitude from a time series of ice extent. The two measures – the more onerous one used in the paper and the quick rough one described at the end of the Auxiliary Material – produce different quantitative values, but both appear to do a sufficient job of accounting for the influence of coastline geography that the trend in ice edge latitude for each month (trend for 30 Januaries, etc) doesn’t have substantial seasonal structure for either measure (in contrast to ice extent).

It makes sense to me. It also confirms what I had already found, that the main result — indeed the main purpose of investigating ice edge latitude — was unchanged, namely: that most of the seasonal differences in Arctic sea ice trends are a geometric effect. When viewed in terms of ice edge latitude (whether computed from detailed gridded ice fields of the approximation formula), the trends in sea ice loss from one month to another are much more similar.