Open Mind

Anthony Watts has had a number of posts suggesting that solar activity is the primary driver of climate change. It appears that most of the real work has been done by others, including Jim Goodridge, who contributed this one. It provides an almost unbelievable example of how not to analyze data.

Keep reading →

There’s been some hoopla in the blogosphere lately about comparing projections of temperature from the IPCC TAR (third assessment report), published in 2001, to observed temperature. The comparisons have been made to temperature data since 2001, on the basis of the claim that that’s when the projections start so that’s when the comparison should start. It appears such claims are in error.

Keep reading →

Global temperature shows a lot of variations; it goes up and down in a manner which is partly predictable and partly unpredictable. One of the important issues of global warming is how temperature will change over the long run. For this issue, we’re less interested in the short-term, year-to-year or month-to-month, day-to-day or moment-to-moment fluctuations which go up and down but average out to zero, and more interested in the persistent changes that behave more steadily and consistently over many years, decades, or longer. We’re interested in the trend.

Keep reading →

It seems some people want to discuss things in threads to which they don’t belong. So, here’s another open thread about climate science. If you want to discuss political candidates, talk about their climate-science policies but not other things; that’s just too big a can of worms. And if you want to discuss other climate-related topics, feel free.

Listen to this speech by Barack Obama. The whole thing.

I used to think we’d have to go back to JFK to find Obama’s equal in politics. Now I know better. We’d have to go back a lot further than that.

Time for more equations. Yay!!! (or Boo!, depending on your perspective)

Keep reading →

That’s the title of a film about a world in which the one thing humanity can’t seem to find is: dry land. I saw it on TV recently, and it lived up to its reputation as one of the worst movies ever. Thank goodness that’s not the topic of this post!

This post is about sea level rise. Climate change has a profound impact on sea level, primarily in two ways. First, water expands when it heats up, so a warmer climate and warmer seas will make the oceans expand and sea level rise. Second, during colder times there’s more water locked up as ice on land, both in glaciers and ice sheets.

Keep reading →

In parts 1, 2, and 3 we’ve looked into the basics of PCA. The essence is that we can view multiple data sets as a vector data set, or as points occupying a (sometimes very) high-dimensional space. The original basis for this space is simply the variables with which we express the raw data; we could call this the canonical basis. In this sense, a “basis” is like a coordinate system for the space, and the canonical basis is the set of variables which define the raw data.

Keep reading →

A reader mentioned, in a comment on another thread, that the discussion had gone off topic. So, here’s another “open thread” for readers to discuss — whatever, as long as it’s related to climate. No pokemon, no American Idol, no college basketball.

The next installment of the PCA series is pretty close to completion, I fully expect to have it up this week (probably by Friday). But please don’t discuss that here! General PCA discussion can go on the existing PCA threads, and discussion of the hockey-stick PCA issues should wait for the upcoming post.

Please use this thread for discussion of things not directly related to the topic of other threads.

Anthony Watts has a post comparing global average temperature anomaly from 4 major sources. Two of them are surface temperature estimates: GISS (NASA’s Goddard Institute for Space Studies) and HadCRU (the Hadley Centre/Climate Research Unit in the U.K.). The other two are satellite estimates of lower-troposphere temperature, from UAH (University of Alabama at Huntsville) and RSS (Remote Sensing Systems). It’s an interesting thing to compare these data sets, but it’s well to bear in mind that they don’t measure the same thing. The surface data are estimates of actual surface temperature, while the satellite data are for the lower troposphere, i.e., a rather large segment of the lower part of earth’s atmosphere. Nonetheless, we expect these data sets to show strong correlation.

Keep reading →