Milankovitch Cycles

James Hansen has a new paper (a draft for review), “Paleoclimate Implications for Human-Made Climate Change.” We’ll discuss it in a future post. There’s a so-called “review” by Martin Hertzberg at WUWT in which he claims that Hansen fails to understand the Milankovitch cycles. But it’s Hertzberg whose understanding is a failure.

Loaded Questions

When I chose the title for the last post, I didn’t really intend to stimulate discussion of the Phil Jones interview. I just thought it was a catchy title for a post about the fact that if you account for exogenous factors, you can establish a trend with less data than you’d need without accounting for exogenous factors.

Nonetheless, a lot of commentary mentioned the Phil Jones BBC interview. And that caused me to ponder such questions as “What should Jones have said?” and “What would I have said?” In fact, since I hadn’t done my recent analysis at that time, I might have responded very similarly to the way Jones did.

Phil Jones was Wrong

There. I said it.

Wrong about what, you wonder? During an interview for the BBC he was asked, “Do you agree that from 1995 to the present there has been no statistically-significant global warming?” Jones replied, “Yes, but only just.”

How Fast is Earth Warming?

We’ve already studied the rate of global warming in the GISS surface-temperature data and the two best-known satellite lower-troposphere data sets. We even removed approximations of the impact of exogenous factors (namely, the el Nino southern oscillation and volcanic eruptions) on the data, for a clearer comparison. Now that GISS, NCDC, and HadCRU have reported their year-end figures, let’s repeat the exercise using all five major global temperature records: GISS, NCDC, HadCRUT3v, RSS, and UAH. Also, let’s include another exogenous factor in our analysis: variations in solar output.

How to Hide the Decline (from yourself)

After exposing Christopher Monckton’s mendacity regarding global sea ice, a certain blogger called “Albertosaurus” decided to disagree. He’s entitled to his own opinion. But he’s not entitled to his own facts.

Monckton Skewers Truth

Christopher Monckton took such exception to an article in The Australian by Michael Steketee, that he has produced a response for the ultraconservative “think tank” SPPI. Monckton reports at WUWT, with his typical level of humility, that he has “skewered” Steketee.

Monckton only skewers two things: himself, and the truth.

Sharper Focus

The two major satellite-based estimates of lower-troposphere temperature, from RSS and UAH, have published their December values to complete the year 2010. In both cases the annual average for 2010 ended up a close 2nd to 1998. Some eagerly anticipate the imminent GISS value for surface temperature for December, to complete 2010, as many expect the GISS annual average for 2010 to set a new record high. But we don’t need December’s value from GISS to continue our comparison between different temperature data sets.

Hottest Year

It’s near certain that in the GISS global temperature data set, 2010 will end up the hottest year on record. In fact some of those who deny the reality of global warming have already begun to “spin” the event, downplaying its significance by suggesting that observing the “hottest year” is no big deal. This, from the same people who believe in the mythical “levelling off” or “cooling” of temperatures over the last decade or so.

History of Arctic Sea Ice, part 2

Since satellite observations began, the extent of sea ice in the arctic has declined dramatically; this year the summer minimum extent was the 3rd-lowest on record. There is also considerable observational evidence that arctic sea ice extent over the last few decades is much lower than it has been for at least a century prior to modern times.

Yet to put such dramatic change in context, one hopes to stretch even further back in time. A team of researchers led by Leonid Polyak of Ohio State University’s Byrd Polar Research Center has culled the available evidence from hundreds of studies of proxy data for sea ice extent. As reported at Science Daily, in a recent paper in Quaternary Science reviews they report their findings: that the present extent of arctic sea ice is at its lowest for at least several thousand years.

It’s the Trend, Stupid

Anthony Watts posts that Southern Hemisphere Sea Ice Extent Anomaly for November was a record high for the NSIDC data set. He also mentions that this year saw record highs in Southern Hemisphere ice extent for June, July, and August as well.

Watts also complains that “Oddly, they have a plot for extent, and a data file for area, but no plot for area or data for extent. Seems backwards, doesn’t it? Maybe I’ve missed something and they are in some other FTP folder?” This makes me suspect that he hasn’t looked at the actual data files, because those files with “area” in the name contain data for both area and extent.