How GISS Corrupt US Temperatures

By Paul Homewood

It is no great secret that GISS and their colleagues at GHCN have been tampering with US temperatures in recent years. Many examples have been unearthed of how they have cooled the past, to give the impression that US temperatures in the last decade have been “unprecedented”. Nevertheless there are some bits in the GISS archives, that shed a bit more light on things and are worth a look at.

The above maps were originally in Hansen’s 1999 paper, and show that most of the US had cooled between 1950 and 1998 by half a degree or so. The full paper is here.

A look at the global map shows just why this was such a problem for Hansen and his cronies. Much of the rest of the world was showing a warming trend, but in many countries historic temperature records were sparse and unreliable. Yet in the US, where high quality records had been maintained for decades, temperatures were falling. Surely this paradox would cast doubt on the whole question of global warming?

Hansen acknowledges this when he says in the paper:-

Temperature change in the United States (Figure 6) and in the global mean (Figure 4) have some similarity, but they are not congruent. In particular, evidence for long-term warming this century is less convincing for the United States than it is for the globe. Of course, year-to-year variability is much larger for the United States, which represents only about 2% of the area of the world.

The U.S. temperature increased by about 0.8°C between the 1880s and the 1930s, but it then fell by about 0.7°C between 1930 and the 1970s and regained only about 0.3°C of this between the 1970s and the 1990s. The year 1998 was the warmest year of recent decades in the United States, but in general, U.S. temperatures have not recovered even to the level that existed in the 1930s. This contrasts with global temperatures, which have climbed far above the levels of the first half of this century. …..

There is no requirement that regional temperatures should correspond in magnitude to global temperature change, or even that they be qualitatively similar. Yet, other things being equal, the expectation has been that a middle-latitude land area would warm more than the global average in response to a global forcing such as greenhouse gases [Manabe and Wetherald, 1975; Hansen et al., 1988]. The United States over the past 2-3 decades has reverted to a warming trend (Figure 6), but prediction of whether the United States temperature will climb to levels consistent with global warming requires an understanding of the mechanisms behind the cooling that began in the 1930s (Figure 6).

This is the Figure 6 he refers to .

As can be seen, the peak temperature was in 1934, reaching about 1.5C, and at least 0.5C higher than 1998.

Now let’s fast forward to today. The official GISS record for the US is below.

Miraculously, the 1998 temperature has overtaken that of 1934. The actual numbers given are :-

1934 – 1.196C

1998 – 1.342C

So instead of being about 0.50C colder, 1998 is now 0.15C warmer, a turnaround of 0.65C or more. Remember this, when they try to tell you that this year is the warmest on record in the US.

In any other field of work, Hansen would have quickly got the boot after getting his original numbers so wrong.

Is he a liar or simply incompetent? Or both?