The general warming trend
Timo Niroma (timo.niroma@tilmari.pp.fi)
5 Jul 1996 16:26:07 GMT
The smoothed temperatures in Helsinki, Kaisaniemi, degrees of
Celsius.
Winter temperatures from 1830 to 1996.
Summer temperatures from 1829 to 1995.
Smoothed by 27 years (amount suggested by G. Plaut et al.:
Interannual and Interdecadal Variability in 335 Years of Central
England Temperatures (Science, vol. 268, 1995)).
Every 10th interval selected (to reduce the overwhelming amount of
numbers). Be aware of the partial overlapping.
The smoothed yearly sunspot numbers, socalled Wolf numbers (Zurich
until 1980, International numbers from 1980 (NGDC, Boulder,
Colorado)).
Calibrated to begin at the same year as the winter interval (the 4-5
years omitted from the end correspond to the best statistical
correlation, which is achieved by choosing the sunspot number 4-5
years earlier than the corresponding temperature).
Smoothed by 22 years (the socalled Hale cycle which equals 2 sunspot
cycles).
Every 10th interval selected.
Interval Janu Febr Interval June July Interval ss
1830-1856 -7.2 -7.1 1829-1855 13.7 16.2 1830-1851 63
1840-1866 -6.6 -7.5 1839-1865 13.5 16.4 1840-1861 53
1850-1876 -6.7 -7.3 1849-1875 13.6 16.8 1850-1871 53
1860-1886 -6.5 -6.8 1859-1885 13.7 16.5 1860-1881 50
1870-1896 -5.8 -7.0 1869-1895 13.8 16.5 1870-1891 42
1880-1906 -5.4 -6.5 1879-1905 14.1 16.5 1880-1901 38
1890-1916 -5.3 -5.9 1889-1915 14.1 16.9 1890-1911 38
1900-1926 -5.2 -5.7 1899-1925 13.6 17.3 1900-1921 37
1910-1936 -4.8 -5.9 1909-1935 13.5 17.7 1910-1931 40
1920-1946 -5.4 -5.9 1919-1945 14.0 17.9 1920-1941 48
1930-1956 -5.2 -6.1 1929-1955 14.4 17.8 1930-1951 63
1940-1966 -5.9 -6.5 1939-1965 14.5 17.3 1940-1961 82
1950-1976 -5.4 -5.7 1949-1975 14.8 17.1 1950-1971 77
1960-1986 -5.8 -6.4 1959-1985 14.9 16.9 1960-1981 69
1970-1996 -4.6 -5.3 1969-1995 14.8 17.2 1970-1991 79
Coldest periods (overlapping periods united):
January smoothed -7 or colder in 1829-1996:
1829-1872
February smoothed -7 or colder in 1829-1996:
1829-1896
June smoothed below 14 in 1829-1995:
1829-1944
July smoothed below 17 in 1829-1995:
1829-1915 and 1953-1988
Warmest periods (overlapping periods united):
January smoothed warmer than -5 in 1829-1996:
1908-1939 and 1969-1996
February smoothed warmer than -6 in 1829-1996:
1890-1996
June smoothed 15 or warmer in 1829-1995:
1960-1992
July smoothed 18 or warmer in 1829-1995:
1912-1951
Sunspot number (the socalled Wolf number) 1789-1995:
- smoothed value below 40:
-- 1789-1836 and 1871-1934
- smoothed value 70 or above:
-- 1936-1995
Non-overlapping periods of 27 years:
The last period for winter 1970-1996, for summer 1969-1995.
Six periods, the years from 1829 to 1834 or 1835 omitted.
Sunspots avg. 22 years from the beginning of the same period.
January avg med s.d corr ss temp. diff. comp. to the 1st per.
1835-1861 -6.6 -7 3.7 0.0 61
1862-1888 -5.8 -6 4.0 0.1 47 +0.8
1889-1915 -4.9 -5 2.9 0.1 38 +1.7
1916-1942 -5.1 -4 3.8 -0.2 47 +1.5
1943-1969 -5.0 -5 3.2 -0.3 79 +1.6
1970-1996 -4.2 -3 4.0 0.1 79 +2.4
The warming from period 1 to 2, 2 to 3 and 5 to 6 is very stabile,
0.8 or 0.9 degrees per 27 years, but there is a stall from period 3
to 5. This is also seen in the median of period 5, which is not in
line with the general warming tendency. In fact the correlation
shows a colding tendency during the periods 4 and 5. During low
activity of the Sun, in 1862-1942, the mean temperature of January
was -5.3 degrees, during high activity, since 1943, -4.6 degrees.
February avg med s.d corr ss temp. diff. comp. to the 1st per.
1835-1861 -6.7 -7 3.7 0.0 61
1862-1888 -6.4 -6 3.8 0.2 47 +0.3
1889-1915 -5.6 -6 3.5 0.3 38 +1.1
1916-1942 -6.0 -6 3.7 -0.1 47 +0.7
1943-1969 -5.5 -6 3.6 -0.2 79 +1.2
1970-1996 -5.0 -4 3.9 0.1 79 +1.7
The warming from period 4 to 5 and 5 to 6 is stabile, 0.5 degrees
per 27 years, but there is a colding spell from period 3 to 4. The
median does not much change except from period 5 to 6, when there is
a considerable warming. The correlation shows a colding tendency
during the periods 4 and 5. During low activity of the Sun, in 1862-
1942, the mean temperature of February was -6.0 degrees, during high
activity, since 1943, -5.2 degrees.
June avg med s.d. corr ss temp. diff. comp. to the 1st per.
1834-1860 13.3 13 1.18 0.2 61
1861-1887 13.3 13 1.60 0.2 48 0.0
1888-1914 13.7 14 1.54 0.0 37 +0.4
1915-1941 13.5 13 1.85 0.4 44 +0.2
1942-1968 14.1 14 1.40 0.3 80 +0.8
1969-1995 14.4 14 1.78 -0.1 78 +1.1
The warming from period 1 to 4 is very small (0.2 degrees in 81
years), but is clearly seen from period 4 to 5 and in a lesser
amount from 5 to 6. Medians make stronger the case for that there
was a small warming from period 2 to period 3, which almost was lost
from period 3 to period 4. The correlations show that there really
was a warming tendency during the periods 4 and 5, but it went
slightly negative during the period 6. During low activity of the
Sun, in 1861-1941, the mean temperature of June was 13.5 degrees,
during high activity, since 1942, 14.3 degrees.
July avg med s.d. corr ss temp. diff. comp. to the 1st per.
1834-1860 15.8 16 1.61 0.5 61
1861-1887 16.2 16 1.39 0.0 48 +0.4
1888-1914 16.4 16 1.85 0.2 37 +0.6
1915-1941 17.4 18 1.72 0.2 44 +1.6
1942-1968 16.6 17 1.29 -0.2 80 +0.8
1969-1995 16.7 16 1.60 0.0 78 +0.9
The warming from period 1 to 3 is slow (0.6 degrees in 81 years),
but then there is a really anomalous rise by 1 whole degree to the
period 4, and an equally dramatic drop of 0.8 degrees while moving
to the period 5, which in its turn is practically as cold or warm as
the period 6. Medians show a similar pattern. The correlations show
that the warming was first very rapid from the supposed cold 1810s
and that the period 5 was clearly negative. During low activity of
the Sun, in 1861-1941, the mean temperature of July was 16.7
degrees, during high activity, since 1942, 16.6 degrees. However,
the arbitrarily chosen breakpoints make here a trick because both
the July temperature and the sunspot number experience an anomalous
change in the 1930s.
The 22 years smoothed sunspot number is beginning from
1934 64
1935 70
1936 77
1937 81
The warm Julys occur just around this change:
1930 19
1931 17
1932 20
1933 18
1934 19
1935 17
1936 19
1937 18
1938 19
1939 18
1940 19
1941 21
Lastly to make the arbitrariness of the borders smaller, I have
joined the above groups pairwise thus reducing the amount of them
from 6 to 3. In addition of the reduced amount of chance, we get
more clearer comparison to the sunspot numbers, because the general
tendency during the period 1 was down, during the period 2 up, and
during the period 3 constantly high.
January avg s.d max min corr suns temp. diff. / 1st & 2nd per.
1835-1888 -6.2 3.9 -15 0 0.1 down
1889-1942 -5.0 3.4 -15 1 -0.1 up +1.2
1943-1996 -4.6 3.7 -16 0 0.1 high +1.6 +0.4
Maxima and minima have no significant change. The increase in mean
in 108 years is 1.6 degrees, from which 75% occurs from the late
1800s to early 1900s and only 25% from the first part of this
century to the last part. Notice the colding tendency during the
early 1900s.
February avg s.d max min corr suns temp. diff. / 1st & 2nd per.
1835-1888 -6.6 3.8 -18 -1 0.1 down
1889-1942 -5.8 3.6 -14 0 0.0 up +0.8
1943-1996 -5.2 3.7 -13 1 0.0 high +1.4 +0.6
Maxima and minima have a low upward trend. The increase in mean in
108 years is 1.4 degrees, almost the same as in January, but the
change is more even between the periods. The warming tendency during
this century is between the periods, not inside them.
June avg s.d. max min corr suns temp. diff. / 1st & 2nd per.
1834-1887 13.3 1.41 10 17 0.1 down
1888-1941 13.6 1.70 10 18 0.0 up +0.3
1942-1995 14.3 1.60 12 17 0.1 high +1.0 +0.7
As maxima show there has not been any real cold Junes during the
latter part of this century. The increase in mean in 108 years is
1.0 degrees, from which 30% occurs from the late 1800s to early
1900s and 70% from the first part of this century to the last part.
Note the lack of inherent trend during the early 1900s.
July avg s.d. max min corr suns temp. diff. / 1st & 2nd per.
1834-1887 16.0 1.52 13 20 0.2 down
1888-1941 16.9 1.85 13 21 0.3 up +0.9
1942-1995 16.6 1.46 14 20 0.0 high +0.6 -0.3
Maxima and minima have no significant change. There is however the
anomalous 1930s, where a great part of the highest temperatures in
the whole data occurs. Is it by chance (?) the same decade when the
smoothed sunspot numbers had their highest speed while rising from
the lowest spell during the first decade of this century to the high
since about 1945-50. The increase in mean in 108 years is 0.6
degrees, but here we have the anomaly of a decrease from the 1930s,
which has had its level stabile since the middle of the 1940s.
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What am I aiming at with these calculations?
1. The sunspot activity is as good or partly a better explanation
for the general warming trend in climate than the amount of
greenhouse gases. In particular the colder climate from 1895 to 1930
get an explanation in this way. And the warming during the recent
decades has here at least a rival explanation.
2. The fact that there are two rival theories does not exclude the
other. The amount in CO2 during the ice age was 160-180 ppm, but
rose to its pre-industrial value of 240 ppm almost immediately after
the ice age ended. Or immediately, we don't exactly know.
3. We should not be arguing how much the greenhouse gases really
affect the temperature, or why didn't that process function during
the early parts of this century, or why is the effect smaller than
expected or use any similar arguments, because it causes a great
damage to the greenhouse models and via that to the whole effort to
reduce their amount, if the models don't work. What we should
investigate are the other possible causative agents.
Remember Tambora, volcano that exploded in 1815? It has generally
been accused as being the cause of the "summerless year of 1816". It
need not be. The alltime low since 1710 with Hale-smoothed sunspots
is during 1815-1816 (17.7). But we still can't argue that Tambora
wouldn't have had its share.
Finally we have the Maunder minimum, the almost spotless decade of
1690s, that we based on many sources can consider as the coldest
decade (at least in Europe) during the last 500 years. And there was
no sunspots, but neither was there modern industry.
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