Climate Forcing

Readers have recently discussed the correlation through time between global temperature on the one hand, and CO₂ concentration on the other. Close examination shows that the correlation is stronger during some time intervals, weaker during others, and although it’s strong overall, there seems to be a lot happening to temperature other than mimicry of the CO₂ changes.

One suggestion was to study the relationship, not with CO₂ concentration, but with its logarithm. This is because climate forcing — a measure of the ultimate climate-changing impact — is proportional to the logarithm of the CO₂ concentration, not to the concentration itself. The idea is to look for correlation between temperature and climate forcing — and it makes sense.

The fascinating thing is: there are many different climate forcings. A lot more than just CO₂.

Jiggle Room for Bigger Bull

Some are trying to defend Judith Curry’s claim that early 20th century global warming (i.e. between 1900 and 1950) was “almost as large as the warming since 1950.” An ardent attempt from Jaime Jessup reveals a mind hard at work, trying to make the evidence fit belief.

Let me explain.

Global Temperature 2018

Some organizations which estimate global temperature change have been behind schedule because of the U.S. government shutdown. But the folks at the Berkeley Earth Surface Temperature project have released their figures for December’s temperature, bringing the year 2018 to a close. It was a hot one.

Hot and Cold Curry

A post by Judith Curry discusses the “Early 20th Century Warming,” i.e. the rise in global mean temperature during the early 20th century. True to form, Curry can’t get past the first sentence without telling the kind of whopper which shows how little she understands about the topic she has chosen:

A careful look at the early 20th century global warming, which is almost as large as the warming since 1950.

Bullshit. I’ve heard this bullshit before.

Maine and Global Warming

Mainers are so lucky to live in a place free from the trials and tribulations of global warming.

Climate: Good Graphs, Bad Explanations

Regular readers know, I love graphs. I use them a lot. I tend to make them “scientifically,” i.e. the kind of graph you’d see in a scientific journal article. Just the fact, ma’am.

The Oz Heat Distribution

We’ve spoken before (as have many before us) of the fact that climate isn’t just about the average, it’s about the whole distribution (the probability distribution if you want to get technical).

We also emphasized that the tails of the distribution — the probabilities for extreme values (very very cold or very very hot, if we’re talking about temperature) can change profoundly when we shift the distribution left or right, without otherwise changing its shape; we illustrated this with July temperature in Moscow:

It set me to wondering, how do things look down under?

Hot as Hell in Oz

With winter snow in the northern hemisphere, we tend to forget the heat that summer brings to the southern half of the world. It can get pretty hot down there. The Guardian reports that Australia is entering the third day of another terrible heat wave, remarkable not just for how hot it is, but how much of the country it covers: basically, all of it.

Masculinity

A recent advertisement by Gillette argues for men to be better, the best we can be, in part by shedding the ugliness of toxic masculinity. It has sparked some controversy. The main objection I’ve heard is from men who reject the premise. Masculinity isn’t toxic, so fuck you!

How strong should the biceps be to cradle a man’s ego? Because nothing is more fragile when dropped back down to earth. The mass alone accounts for 80% of the weight of the world on her shoulders.

Global Temperature: Why So Many Straight Lines?

Probably the most commonly used way to estimate a trend in something is a mathematical process called linear regression. Basically, it means to fit a straight line [for those who must be pedantic, a flat hyperplane if we have multiple predictor variables]. In the case of time series, use time as the predictor variable and look for a linear relationship. If we find it, we declare “Trend!” and might even posit how big it is.

Why linear? Does anybody really believe that global average temperature since, say, 1970 has followed a straight line? Couldn’t it have wiggled around a little, just a little maybe — not noise, mind you, but genuine signal, real climate change rather than random fluctuation? Might it actually have accelerated, or even decelerated, or — heavens forbid! — taken a “hiatus”? Hell, mightn’t there have been brief episodes of all three, just not strong enough to be detected statistically (for a stickler like me)?

Of course. To my mind, the idea that as far as global temperature goes the climate — the signal, not the noise — followed a perfect straight line, is ludicrous.