Two “little ice ages” revealed by CET summer data

The past couple of weeks have been preoccupied by studies of UK and US precipitation and temperature data – often with the inclination to prepare things for publication here without doing anything on this line.

Yesterday and today, in between trips to visit my brother in Balaclava, I have prepared a comprehensive, tabulated analysis of the CET data as a follow-up to the work of Uncharted Territory on the famous anomaly of 1740 – the coldest twelve months in the CET record.

Mean annual Central England Temperature for each fiscal year from 1659/1660 to 2014/2015

As we can see from this graph of fiscal year Central England Temperature, there has been a general increase since the extremely cold decade of the 1690s, so much so that many recent years are off the map of what would be possible without Australian greenhouse gas emissions. There were exceptions in the 1740s and 1750s, the 1810s following a known but undocumented major eruption, and between the middle 1880s and middle 1890s following the eruption of Krakatoa. The major rise in the late 1980s no doubt coincides with the beginning of the gradual elimination of import tariffs on cars in Australia, previously so high (57.5 percent from 1978 to 1988) as to push up car prices and lower Australian greenhouse emissions.

Uncharted Territory’s work on winter CET has given me the incentive to look at summer CET over time, so we shall do this one next. This is especially significant as long-term ice fluctuations are much more influenced by summer than winter temperature – colder winters actually inhibit the growth of ice sheets as seen in completely unglaciated Siberia and Manchuria. Following on from Uncharted Territory, I have provided a 9-year and 75-year running mean on the graph:

Conclusions one might draw from the graph:

1. As with the fiscal year CET graph, there is a general rise in summer CET since the 1690s
2. There are numerous clear groups of cool summers such as:
1. from 1679 to 1700 (14 of 22 summers in lowest quartile)
2. from 1809 to 1823 (nine of fifteen summers in lowest quartile)
3. from 1839 to 1848 (seven of ten summers in lowest quartile)
4. from 1860 to 1862 (two of three in lowest five percent)
5. from 1879 to 1894 (ten of sixteen summers in lowest quartile)
6. from 1902 to 1924 (twelve of 23 summers in lowest quartile)
3. Before global warming intensified in the 1980s, there were noticeable fewer long runs of hot summers than of cool summers
• there were only two periods (plus a brief one from 1893 to 1901) with five or more “hot summers” (top quartile) in nine years
• these were as noted above all between 1771 and 1783 before the Laki eruption
• or in the late 1720s and early 1730s
4. It is notable that, before the 1980s, extremely hot summers never occurred close together apart from those of 1778 to 1781 – in contrast to the spells of cool summers in the seventeenth and nineteenth centuries
5. There are many cases of isolated hot summers during periods dominated by cool summers (1826, 1846, 1911) but except perhaps 1725 no instance of an exceptionally cool summer during periods dominated by hot summers
6. The 75-year running mean shows a notable peak in the latter half of the eighteenth century centred around 1770 (corresponding to the period from 1730 to 1810)
7. The nine-year peak of hot summers in the 1770s (from 1773 to 1781) was not rivalled until Australian road and coal industries took control of the climate
8. The 75-year running mean reaches an all-series minimum centred around the early 1890s following the eruption of Krakatoa

Thus, summer CET data suggest two “little ice ages”, one peaking in the late seventeenth century and one in the late nineteenth. I am too unfamiliar with summer temperature patterns elsewhere in the globe to know how general these trends are. Precipitation-sensitive glaciers in central Chile – a region ranking among the most severely affected by anthropogenic greenhouse warming – reached maxima late in the nineteenth century after a wet period from 1820 to 1905, which strongly suggests the width of the Hadley circulation reached its narrowest in this era. It is true that in other regions glaciers were already retreating during the latter half of the nineteenth century, though whether this reflects temperature or precipitation changes I am unsure.

We will now look at the spring CET graph:

Broadly speaking, the spring CET graph is not dissimilar to the summer CET graph above. Major differences:

1. The 75-year spring CET peak in the eighteenth century is a little later and does not reach above the virgin mean
2. Deep short-term sequences of cool springs occur in the 1740s and 1760s (culminating in the second-coolest spring in 1770) that are not followed by cool summers
3. There is no deep trough following the 1810 volcanic eruption due to several notably hot springs in 1811, 1815 and 1822
4. The minimum in spring temperature following the eruption of Krakatoa is easily the most pronounced since the 1740s.
5. The early-1840s summer temperature trough is a double trough in the spring season due to exceptionally cool springs in 1837 to 1839 and 1855.

If we look at the autumn season, we see a distinctly different pattern from the spring and summer seasons:

Here, unlike the spring and summer seasons, there is no maximum in the 1770s or 1780s. Rather the lowest trough in the entire 75-year running CET mean occurs at the same time as the maximum in spring and summer.

Apart from several hot autumns between 1818 and 1828, the sole significant maximum before the 1930s is during the first half of the eighteenth century – the 75-year maximum is centred upon 1743 and falls off rapidly due to a record cool autumn in 1786 and several other very cool autumns between 1782 and 1794.

Although it is also seen in the spring graph, there is a notable 1680s CET autumn upswing that however, relates only to a pair of succeeding hot autumns in 1680 and 1681.

A critical feature of the autumn graph is that it shows a much larger signature from anthropogenic greenhouse gas emissions than the spring, summer or winter graphs. Only three cooler-than-normal autumn seasons have occurred in the past forty years, and two of these are only just below the virgin mean. The distance by which record hot recent autumn seasons have exceeded previous records is also considerably greater than for the summer and spring seasons. This probably reflect the low British insolation and considerable seasonal lag during autumn. Absorption and release of heat by greenhouse gases probably has greatest impact during autumn not only in Britain, but just as importantly in areas – Siberia, the Arctic Ocean – from where cold airmasses must be advected into the UK to produce an unusually cool autumn like 1952, 1919, 1887 or 1786.

I will only briefly discuss the winter and extended winter (November to March) graphs as these have been done elsewhere:

The extended winter bears distinct similarities to the autumn graph above – only one November since 1994 has had a CET below the virgin mean of 5.97˚C or 42.74˚F. The major anthropogenic rise is earlier for the extended winter due to two exceptionally warm seasons in 1897/1898 and 1898/1899 (this last was however exceedingly cold in the United States).

Note the extreme cold in the US during the extended winter of 1898/1899, when Central England was having one of its mildest seasons since the 1730s with an average of 5.93˚C or 42.67˚F

In fact, only one extended winter since 1891/1892 has had a CET below 3.5˚C or 38.3˚F, as against twenty-three (two in eleven) between 1765/1766 and 1890/1891! The period from 1702 to 1739 is a near rival, but was not nearly so prolonged and had a decade of cooler seasons than anything seen over the past 120 years from 1716 to 1727. The actual winter CET series shown below shows the same pronounced trough in the 1810s as the summer one, though a scarcity of mild winters dates back to the early 1750s and those mild winters that did occur (e.g. 1778/1779, 1789/1790) were often dry and influenced by Saharan airflows – not as with conventional mild British winters by wet maritime Atlantic air.

A distinct peak in the 1860s and short-term troughs associated with prevailing negative NAO values in the 1940s and 1960s means a relatively steady 75-year mean since 1890 despite two notable severe winters that decade. The winter CET is similar to the autumn one except that its short-term peak is in the middle 1730s rather than late 1720s, and there is no peak but a continuing trough in the 1810s and 1820s.

Although explaining these peaks and troughs observed in CET data before 1974 is beyond the information I have at present, I do know that rainfall proxy data suggest that before the 1720s and from 1760 to 1820 the Sahel was wet and Southern California dry. This combination of high Sahel rainfall and low rainfall in SoCal implies a strongly positive Atlantic Multidecadal Oscillation (as in the 1950s and 1960s). The mild winters noted by Uncharted Territory for the 1730s suggest a highly negative AMO (perhaps more negative than during the late twentieth century), which is further supported by evidence of Sahel drought and reduced SoCal drought in that decade plus mild British winters during the negative AMO era between about 1905 and 1925. It also suggests a highly negative PNA, which would need verification in western North America (which did have many cold winters between 1896 and 1939) that would be very difficult since winter temperature does not directly influence growth or hydrology in most areas.

Vigilantes – or a world not knowing its enemy?

According to those in power in Australia, laws to prevent rape of Australia’s fragile environment constitute “vigilante litigation”:

Attorney General George Brandis has branded the case against Carmichael “vigilante litigation”. So the government is proposing to water down community groups’ rights to challenge these projects under the Environment Protection and Biodiversity Conservation Act (EPBCA).

If one judges by experience of the Enriched World and reading as a student journals like Socialist Worker, Socialist Alternative and Green Left Weekly, it’s easy to understand Brandis’ stance. There is no doubt that modern Enriched World politics and culture has its roots in class war that could be described as “vigilante”: workers came to believe they produced bosses’ wealth and should own it themselves, producing continual demands for increased redistribution and absolute equality of condition. Except at its theoretical beginnings the switch from limited traditionally religious monarchy to big-government, atheist democracy has been continuously driven by lower classes’ demands for equality of outcome. This tendency has by no means disappeared from the Enriched World: we still see workers demand redistribution and regulation when their security is threatened. Land-surfeited Australia has been substantially immune to this, probably because the majority are too physically distant from the super-rich to produce envy. Vigilante politics, radical egalitarianism and envy-based cultures are – as one can see on an ecological level – incompatible with civilisation. The failure of the most fertile regions of the Western Hemisphere – the North American prairies and the whole Southern Cone of South America – to develop any sort of indigenous civilisation is a dramatic expression thereof. Their “ecology” does not allow for any sort of cooperation because phosphate and chalcophile nutrients are exceptionally abundant, favouring those species that can reproduce most rapidly and/or simply evade predators best. Both traits – especially the latter – exclude the cooperation essential for complex societies.

According to one 2009 Sydney Morning Herald article Australia may directly and indirectly total 16 percent of global greenhouse emissions – or fifty times the per capita average. Self-interest rather than local community interest dictates protest, just as it does in the Enriched World. The crucial difference is that, unlike the Enriched World, more jobs in Australia are produced from coal production that preservation of unique, localised and rare species.

At the same time, the costs to Australia’s economy from global warming are unpaid by the present political powers in the mining industry. The most terrifying problem is how those who suffer most from Australian greenhouse gas emissions – West Australian farmers losing their former winter rainfall – are the people most dependent for current livelihoods upon Australian greenhouse emissions not being cut to zero, as doing so would multiply energy costs of transportation. Australian farmland is sufficiently cheap that private owners’ incentive is not to maintain its limited value but to extract it as a non-renewable resource. Because little soil formation has occurred in Australia since the Carbo-Permian glaciation around three hundred million years ago, lost soil stands irreplaceable and Australian soils are strictly non-renewable, unlike the Enriched World where active volcanoes or glaciers continuously supply new soil

The question is whether the problem of Australian greenhouse emissions and species extinctions will become so severe in the long term that the rest of the world – uncompetitive against a nation with per person incomparably more flat land and undiscovered minerals than the global average – will recognise Australia as the keystone in all environmental treaties from endangered species to pollution to greenhouse warming. Should this occur, Enriched and Tropical World governments and people would understand they possess every right to demand Australia’s polluting industries pay all global costs, both of direct overseas losses from Australian greenhouse pollution and by wholly remedying the cause. This complete remedy would require an uncompromising zero-emissions Australian economy be created via:

1. Complete demolition of Australia’s trunk road system
2. Ensuring all transport investment is constitutionally mandated to be on rail – both the most energy-efficient land transport system and ideally suited to Australia’s flat terrain
3. If private motoring does continue, mandating all vehicles on Australian roads consume no more than 3 litres per 100 km of fuel (minimum fuel economy of 80 miles per US gallon)
• this is ¼ the current average, but technologically achievable as early as the middle 1980s
4. Complete demolition of coal-fired power stations in favour of renewable energy and shifting energy-intensive production to nations with reliable hydropower
5. Complete bans on land clearing and large-scale revegetation programs on farms likely to be or already being rendered unviable by Australia’s own greenhouse gas emissions
6. Large-scale investment in a national park system to protect Australia’s numerous paleoendemic species and ecosystems essentially unchanged from before the Antarctic Ice Sheet formed 38,000,000 years ago

Making these demands without compromise is recognising who the global environment’s enemy is – Australian mining companies who export their pollution scot free.

England/Wales v CONUS temperatures

Having digested overseas climate in recent years, I noted the record-warm January 1880 over the eastern US as exceptionally dry and cold over Western Europe – although similarly dry months there are not necessarily hot as far west as the US.

It is well-known that the contiguous US (CONUS) is by areal average much hotter than England and Wales in the northern summer, and colder in the winter. What I will try to do here is see how much variation there is between these normals, since the annual temperature means overlap somewhat. Since the CONUS averages a little hotter than England and Wales over the whole year, I will take positive as meaning the CONUS is hotter, negative that the CONUS is cooler than England and Wales.

Data exist for the years from 1895 to 2014, and I will do figures for fiscal year (July to June) as well as temperature. Fiscal year should provide a better picture than calendar year due to the greater influence of winter temperatures an annual variation, avoiding situations where unusually cold or warm winters are divided between two years.

Month	# CONUS hotter	# CONUS cooler	Year of “highest” departure		Year of “lowest” departure
July	120	0	1954	+17.94˚F +9.967˚C	1983	+6.89˚F +3.827˚C
August	120	0	1922	+16.33˚F +9.072˚C	1997	+5.72˚F +3.178˚C
September	120	0	1931	+15.43˚F +8.572˚C	2006	+1.06˚F +0.589˚C
October	108	12	1931	+8.72˚F +4.844˚C	1969	-4.37˚F -2.428˚C
November	29	91	1915	+6.07˚F +3.322˚C	1951	-9.22˚F -5.122˚C
December	3	117	2010	+1.73˚F +0.961˚C	1924	-16.65˚F -9.250˚C
January	0	120	1941	-0.70˚F -0.389˚C	1930	-18.54˚F -10.300˚C
February	8	112	1991	+5.83˚F +3.239˚C	1903	-16.36˚F -9.089˚C
March	45	75	1910	+6.46˚F +3.589˚C	1912	-9.20˚F -5.111˚C
April	114	6	1986	+10.42˚F +5.789˚C	2007	-1.62˚F -0.900˚C
May	120	0	1902	+13.97˚F +7.761˚C	1917	+0.09˚F +0.050˚C
June	120	0	1977	+16.38˚F +9.100˚C	1976	+5.2˚F +2.889˚C
Fiscal year	118	2	1962/1963	+5.40˚F +3.000˚C	1911/1912	-0.37˚F -0.206˚C

It can be observed that some extremes, noted in red above, seem to be systematically influenced by man-made greenhouse gas emissions.

Although I could use an earlier date since rainfall records in the southern hemisphere indicate man-made global warming (countered in the northern hemisphere by short-lived aerosol pollution) was taking control of the climate as early as 1967, I will use the 1980 Lonie Report – which paved the way for major expansion of polluting freeways in by far the planet’s worst greenhouse polluter (Australia) – as a cut-off for “natural” variability. Previous records for those established since are:

• July “lowest”: 1976 (CONUS averaged 72.90˚F or 22.72˚C; CET was 18.7˚C or 65.66˚F)
• August “lowest”: 1975 (CONUS averaged 71.53˚F or 21.96˚C; CET was 18.7˚C or 65.66˚F)
• September “lowest”: 1949 (CONUS averaged 63.73˚F or 17.63˚C; CET was 16.3˚C or 61.34˚F)
• April “lowest”: 1944 (CONUS averaged 48.97˚F or 9.43˚C; CET was 10.2˚C or 50.36˚F)
• December “highest”: 1933 (CONUS averaged 36.43˚F or 2.46˚C; CET was 1.3˚C or 34.88˚F – though Scotland was actually milder than England or the CONUS)
• April “highest”: 1908 (CONUS averaged 52.75˚F or 11.53˚C; CET was 6.0˚C or 42.8˚F)
• February “highest”: 1954 (CONUS averaged a record 41.11˚F or 5.06˚C; CET was 2.6˚C or 36.68˚F)

Temperature for the winter of 1916/1917. Note the uniform cold over most of the northern hemisphere apart from the subtropics, Central Asia, Greenland and Sakhalin.

The case of May 1917, after a very long and severe winter across the northern hemisphere apart from Central Asia and Greenland (à la January 1963) is amazing. The month was by mean percentile (as opposed to temperature) easily the coolest every observed across North America. At 55.13˚F or 12.85˚C, May 1917’s mean temperature stands 5.06˚F or 2.8˚C below the virgin mean, and only May 1907 comes within 2˚F (1.1˚C) in terms of coolness.The pattern from the winter of 1916/1917 persisted remarkably through the spring, as can be seen below, although England and parts of southwestern Canada would come out slightly hotter than normal if something closer to the virgin mean were used:

Temperature anomalies for May 1917. Note the extreme and uniform cool over North America, Australia, East Asia and and eastern Europe

What’s more amazing is that no district in the contiguous US ranks higher than 41st coolest for the month, although it was not especially wet (very dry in the north). In fact, only the mid-Atlantic region (in 1967) the central-west coast (in 1933) and the Great Basin (in 1953) has widely experienced a record cool May since.

Rankings for May 1917 in the contiguous US. With over 87 percent in the “very cool” category this month is by mean temperature percentile by far the coolest from coast to coast.

In fact, May’s case of the CONUS being as cool as England and Wales during what is almost summer is much more exceptional than January 1880. Although accurate data do not exist, it is almost certain that in January 1880 the United States was around 2˚C (3.6˚F) hotter than England and Wales. Most places east of the Rockies averaged 9˚F or 5˚C above normal, and even the Pacific Northwest which received snowfalls comparable to the record cold January of 1950, was slightly milder than normal – though Canada was extremely cold.

Mean temperatures for January 1880, the most recent January where the CONUS averaged hotter than England and Wales (it’s a pity I can’t obtain figures relative to a mean less influenced by Australian greenhouse gas emissions, which would not show the western US as substantially cooler than average).

February 1954 was globally an exceptional month, notable for the complete lack of monsoonal rainfall over northwestern and central-western Australia (before CFCs and Australian coal power and freeways spread the monsoon far beyond its natural domain!) and for a major cyclone on the east coast that saw some of the heaviest rainfalls recorded in the world. Lismore record 480 millimetres or 18.90 inches in two days, and at Dorrigo Post Office a daily fall of 774.7 millimetres (30.50 inches) is generally regarded as an NSW record. The Macleay River was thirty feet (nine metres) deep as it raced through Kempsey.

Rainfall over Australia, February 1954. Note the extreme dryness over WA, where essentially no rain fell south of the Kimberley – then affected by a four-year drought of a type unknown to its present inhabitants.

February 1954 was exceptionally cold over Alaska, Central Asia and southeastern Europe. The extreme cool over eastern Australia is clearly due to the nonexistent monsoon over the northwest allowing anticyclones over the Bight to drive cool southerly air far inland. The month, however, was remarkably hot over the United States and south-of-treeline Canada: apart from perhaps March 1910 or October 1947, no pre-Lonie Report month matches February 1954 for average mean monthly temperature percentile over the CONUS, with the first and last weeks seeing shorts temperatures as far north as the border. It was also warm over eastern Greenland, the Sea of Okhotsk and the extreme north of Russia.

October 1969 is a striking month, which I have long known in Australia as the driest October in Perth and Adelaide, but a very wet month in northern New South Wales with Gilgandra under water from its biggest flood since 1956.

Rainfall over Australia for October 1969. Note the heavy rainfall over northeastern NSW and southeast Queensland, as well as over the wet-dry tropics (where it proved a false beginning and was followed by the last big wet season failure before Australian greenhouse emissions eliminated such occurrences.

Globally, October 1969 saw an “Indian summer” in England and the beginning of a warm winter in a cold era for Alaska, but cold weather in western Russia, South America and New Zealand as well as the contiguous United States:

March 1912 was the end of one of the most famous cold winters in the US – and a key part of one of only two years since 1895/1896 where the England averaged hotter than the contiguous US. It also saw a “March miracle” in Southern California, whereby Los Angeles, which had not seen rain for 49 days at February’s end and recorded just 1.60 inches (40.6 millimetres) between October and February, accumulated 8.65 inches in the next six weeks. San Diego had an amazing 20 wet days that March. In Britain, this March was very wet (top ten wettest since 1766) but extremely mild at 2.0˚C above the virgin mean and warmest since 1882. What’s notable on a broad scale about March 1912 is that the western ends of both main northern hemisphere continental landmasses were warm, but that the rest was uniformly very cold, suggesting two big blocking patterns were driving cold air into Canada, the contiguous US and Russia, whilst – as is typical during a Lower 48 cold wave – Alaska was unusually warm. Even with anthropogenic global warming have major impacts, Fairbanks has experienced only four milder Marches since and was as warm as Sioux City and 3˚F (1.7˚C) warmer than Helena, Montana.

The summers of 1954 for being cool and wet, and 1975 and 1976 for being hot and dry, are legendary in the UK. It’s interesting to see that these contrasting summers seem to have opposite-signed anomalies extending quite widely over the globe, and that 1954 appears to have a somewhat similar pattern to the fabled year of 1816, being very cool in Western Europe and hot in the east, though I have not checked how general this is for cool or wet English summers.

Although the summer of 1975 in the US is most famous for the northeastern heatwave that saw several New England states set still-standing temperature records (and it’s notable that Maine’s record of 105˚F or 40.6˚C comes from the very hot European summer of 1911), the two 1970s summers were generally very cool across the US. Indeed, the record July cool in Texas approaches that of 1993 in Idaho and surrounds for its exceptional character, with anomalies in maximum temperature as large as 9.6˚F or 5.3˚C below normal, so that it was sometimes hotter in England than in Texas!

This animation shows US temperatures during the hot and dry English summers of 1975 and 1976. It was notably cool in the West and South, where 1976 is the coolest calendar year since records begin.

The summer of 1954 – the coolest since 1907 in the UK – is famous for its severe southern heatwave and drought, likely related to a highly positive Atlantic Multidecadal Oscillation (AMO). July saw the hottest temperatures east of the Mississippi River, although the summer – like that of 1980 – was as cool over the Pacific Northwest as over Western Europe so it does not come out exceptionally hot over the CONUS as a whole:

Contiguous US temperatures for the summer of 1954. Note the unusual cool (and rain) over the Pacific Northwest and heat (and drought) over the Southern Plains

April 1944 was very cool in the US and also in most of Australia (in Melbourne it is the seventh coolest April since records began in 1855, whilst the West Central division of Kansas was equal coolest) but notably warm in Canada, western Siberia and western Europe. It does not appear as striking as previously reviewed months.

Global temperature anomalies for April 1944. Note the cool over Australia, Beringia and the central US, plus the heat over Western Europe that made Britain hotter than the CONUS.

April 1944 was also notable for being extremely wet – record floods on the Missouri occurred early that summer in Montana’s wettest month on record – and part of a very dry spring across Western Europe. In Victoria the autumn was wet between two record-dry seasons, but was a blip on the longest genuine drought during the period before Australia’s mining and road-building industries began to control the global climate.  
September and October 1931 were very hot over the interior US – the end of the great drought of 1930-1931 as November saw big rains:

The hot September and October of 1931 over the US – it’s a pity the colour was lost when I formed an animation!

February 1903 is one a of a number of months (the winter of 1948/1949 being outstanding in this line, as was January 1932) that was very cold over the western US, but mild over the eastern US and England. That winter was also the mildest over northern Japan until 1948/1949, and in fact February 1903 was one of the mildest on record over all of Russia west of the “cold pole”. It is remarkable for the heavy rains in the eastern US as well as England and extreme cold over the Southwest under a flow of Arctic air to the west of the cyclone:

This hopefully will be a good summary of CONUS versus CET temperatures, and a “big picture” look at some outstanding contrasts therein. I hope readers find these historical data of interest.