Guest Post by Willis Eschenbach
OK, this post has ended up having two parts, because as usual, I got side-tractored while looking at the first part. It’s the problem with science, too many interesting trails leading off the main highway …
Part The First
I wanted to point out an overlooked part of Dr. James Hansen’s 1988 oral testimony to the US Senate. At the time Dr. Hansen was the Director of GISS, the Goddard Institute of Space Studies. He told the Congresspersonages, or whatever the modern politically correct term is for that class of Politicritters, the following:
The observed warming during the past 30 years, which is the period when we have accurate measurements of atmospheric composition, is shown by the heavy black line in this graph. The warming is almost 0.4 degrees Centigrade by 1987 relative to climatology, which is defined as the 30 year mean, 1950 to 1980 and, in fact, the warming is more than 0.4 degrees Centigrade in 1988. The probability of a chance warming of that magnitude is about 1 percent. So, with 99 percent confidence we can state that the warming during this time period is a real warming trend.
Here is his accompanying graphic …
Now, I am either cursed or blessed with what I call a “nose for bad numbers”. It is a curious talent that I ascribe inter alia to using a slide rule when I was growing up. A slide rule has no decimal point. So if an answer from the slide rule is say 3141, you have to estimate the answer in order to decide if it means 314.1, or 3.141, or .003141, or 31,410. After doing this for years, I developed an innate sense about whether a result seems reasonable or not.
So when I saw Hansen’s claim above, I thought “Nope. Bad numbers”. And when I looked deeper … worse numbers.
First thing I did was to see if I could replicate Hansens’ results. Unfortunately, he was using the old GISS temperature record, made before they were as adjusted as they are today. His statement was that “The warming is almost 0.4 degrees Centigrade by 1987“. But in the modern GISS data, I found slightly more warming, 0.5°C.
OK, fair enough. So I went and digitized the dataset above so I could use Dr.Hansen’s data, and it turns out that his “almost 0.4 degrees Centigrade” increase by 1987″ is actually 0.32°C. You can see it in the graphic above. Hmmm … Dr. Hansen’s alarmism is unquenchable. Also, note that Dr. Hansen has spliced into the graphic and discussed the 1988 “annual” average even though at the time he only had a few months of 1988 data … bad scientist, no cookies. Comparisons gotta be apples to apples.
Next, his claim is that there is only one chance in a hundred that the 1987 warmth is a random result. That means his 1987 temperature should be 2.6 standard deviations warmer than the 1951-1980 mean. But once again, Dr. Hansen is exaggerating, although this time only slightly—it’s only 2.5 standard deviations away from the mean, not 2.6.
However, that’s not the real problem. In common with most climate-related temperature datasets, the GISS temperature dataset Hansen used has a high “Hurst Exponent”. This means that the GISS temperature dataset will be what has been called “naturally trendy”. In such datasets, large swings are more common than in purely random datasets.
How much more common? Well, we can actually test that. He’s comparing the 30-year “climatology” period 1951-1980 to the year 1987. So what I did was the exact same thing, but starting in different years, e.g. comparing the thirty-year period 1901-1930 to the year 1937, seeing how unusual that result is, and so on.
When we do that for all possible years of the GISS 1988 dataset, we find that being 2.5 standard deviations away from the climatological mean is not uncommon at all, occurring about one year out of fourteen.
And if we do the same analysis on the full GISS dataset up until today, we find it’s even more common. It has occurred in the historical record about one year out of seven. So Hansen’s “one percent chance” that the 1988 temperature was unusual was actually a fourteen percent chance … more alarmist misrepresentation, which is no surprise considering the source.
Conclusions the First
Regarding the warmth of 1987, which was 2.5 standard deviations warmer than the 30-year climatology average, Hansen claimed that “The probability of a chance warming of that magnitude is about 1 percent.”
In actuality, this kind of warming occurred in the record that he used about once every fourteen years or so … and it occurs in the modern GISS record about once every seven years. So the probability of a chance warming of that magnitude in the GISS temperature record is not one percent, it is between seven and fourteen percent … which means that it is not unusual in any way.
Part The Second
In the process of researching the first part of this post, I realized why there is so much debate about whether Hansen’s predictions were right or wrong. The problem is that we’re living in what the most imaginative and talented cartoonist yclept “Josh” calls “The Adjustocene” …
The problem is that Dr. James Hansen is not only the guy who made the 1988 alarmist predictions. He’s also the guy who has been in charge of the GISS temperature record that he has long been hoping would make his prediction come true.
So … here are the changes between the version of the GISS temperature record that Hansen used in 1988, and the 2018 version of the GISS temperature record.
(GISS 2018 data available here. )
Gotta say, those are some significant changes. In the old GISS record (red), 1920 to 1950 were much warmer than in the new record. As a result, in the old record temperatures cooled pretty radically from about 1940 to 1970 … but in the new record that’s all gone.
And things don’t get any better when we add another modern record to the mix. Here’s the Hadley Center’s HadCRUT global average temperature, shown in blue …
Note that HadCRUT (blue) shows the same drop in temperature 1940-1970 that we see in the 1988 version of the GISS temperature record (red). More to the current point, the post-1988 divergence between the HadCRUT and the GISS record is enough to rule out any possibility of determining whether Hansen was right or wrong. The overall trend in the GISS 2018 data is about 40% larger than the trend in the HadCRUT data, so you can get the answer you wish by simply picking the right dataset.
Conclusions the Second
Depending on the dataset chosen, someone can show that Dr. Hansen’s predictions either did or did not come true … it’s the perfect Schrodinger’s Cat of predictions.
Finally, as an aside, just what is an “Institute of Space Studies” doing studying the climate? I’ve heard of “mission creep” before, but that’s more than mission creep, that is extra-terrestrial movement. Don’t know if the Goddard folks have noticed, but there is no climate in space … how about if they go back to, you know, studying the myriad of fascinating things that happen in space, and leave studying the climate to less alarmist folk?
Best regards to all,
w.
Short Version Of My Usual Request:
QUOTE THE EXACT WORDS YOU ARE DISCUSSING.
Digitized Hansen Data from Figure 1:
Year, Anom 1880, -0.403 1881, -0.366 1882, -0.427 1883, -0.464 1884, -0.729 1885, -0.541 1886, -0.461 1887, -0.547 1888, -0.388 1889, -0.184 1890, -0.38 1891, -0.438 1892, -0.44 1893, -0.481 1894, -0.382 1895, -0.408 1896, -0.274 1897, -0.177 1898, -0.38 1899, -0.223 1900, -0.025 1901, -0.086 1902, -0.282 1903, -0.357 1904, -0.493 1905, -0.254 1906, -0.175 1907, -0.45 1908, -0.317 1909, -0.334 1910, -0.313 1911, -0.289 1912, -0.316 1913, -0.254 1914, -0.053 1915, -0.009 1916, -0.258 1917, -0.474 1918, -0.363 1919, -0.197 1920, -0.154 1921, -0.079 1922, -0.143 1923, -0.128 1924, -0.119 1925, -0.097 1926, 0.133 1927, -0.006 1928, 0.066 1929, -0.165 1930, -0.002 1931, 0.085 1932, 0.049 1933, -0.158 1934, 0.047 1935, -0.016 1936, 0.055 1937, 0.17 1938, 0.188 1939, 0.052 1940, 0.111 1941, 0.126 1942, 0.094 1943, 0.034 1944, 0.108 1945, -0.027 1946, 0.035 1947, 0.152 1948, 0.034 1949, -0.018 1950, -0.136 1951, 0.02 1952, 0.071 1953, 0.2 1954, -0.028 1955, -0.069 1956, -0.184 1957, 0.094 1958, 0.113 1959, 0.061 1960, 0.006 1961, 0.077 1962, 0.027 1963, 0.022 1964, -0.264 1965, -0.174 1966, -0.09 1967, -0.024 1968, -0.128 1969, 0.028 1970, 0.034 1971, -0.117 1972, -0.077 1973, 0.168 1974, -0.09 1975, -0.039 1976, -0.235 1977, 0.164 1978, 0.1 1979, 0.131 1980, 0.267 1981, 0.359 1982, 0.058 1983, 0.305 1984, 0.096 1985, 0.053 1986, 0.173 1987, 0.325 1988, 0.562 (five months only)
Climate Collections 