Exploding The 'Global Warming Causes Unprecedented Extreme Weather' Myth - The European Summer Of 1540

When Europe sweltered through a remarkable summer heatwave in 2003 and thousands of people, especially in France, died from the heat, the global warming nutters were quick on the case and it was then in fact that the pseudo science of ‘extreme weather attribution was’ born. Peter Stott (of the Met Office), Myles Allen and D.A. Stone published this seminal study which kicked off the whole extreme weather attribution lark:

https://www.nature.com/articles/nature03089

The Abstract reads:

The summer of 2003 was probably the hottest in Europe since at latest AD 1500^1,2,3,4, and unusually large numbers of heat-related deaths were reported in France, Germany and Italy⁵. It is an ill-posed question whether the 2003 heatwave was caused, in a simple deterministic sense, by a modification of the external influences on climate—for example, increasing concentrations of greenhouse gases in the atmosphere—because almost any such weather event might have occurred by chance in an unmodified climate. However, it is possible to estimate by how much human activities may have increased the risk of the occurrence of such a heatwave^6,7,8. Here we use this conceptual framework to estimate the contribution of human-induced increases in atmospheric concentrations of greenhouse gases and other pollutants to the risk of the occurrence of unusually high mean summer temperatures throughout a large region of continental Europe. Using a threshold for mean summer temperature that was exceeded in 2003, but in no other year since the start of the instrumental record in 1851, we estimate it is very likely (confidence level >90%)⁹ that human influence has at least doubled the risk of a heatwave exceeding this threshold magnitude.

These authors pioneered the dubious method of calculating so called fraction of attributable risk to determine the influence of anthropogenic climate change on a given weather event, by simulating the event using climate models in a world with and without anthropogenic GHG forcings. Their conclusions were as follows:

Our analysis shows that European summers are warming owing to anthropogenic climate change. Under un-mitigated emissions scenarios, summers like 2003 are likely to be experienced more frequently in future; HadCM3 projections (Fig. 1) indicate that the probability of European mean summer temperatures exceeding those of 2003 increases rapidly under the SRES A2 scenario, with more than half of years warmer than 2003 by the 2040s. By the end of this century, Fig. 1 shows that 2003 would be classed as an anomalously cold summer relative to the new climate, for the scenario and model under consideration.

So 2003, according to Stott of the Met et al, was the hottest European summer since at least 1500 and by 2100, 2003 will look like a cool summer relative to the scorchers expected to be occurring regularly by then.

Well I can tell you now, 2003 was hot but summer 1947 was probably very nearly as hot and, in terms of duration, probably even more severe than 2003. I can also tell you that the summer of 1540 in Europe blew both away in terms of temperature, duration and drought. Here’s what I wrote about summer 1947 in Europe:

The heat period of 1947 can be compared with the year 2003 in terms of maximum temperatures and duration of the heatwaves. For instance, the maximum temperature anomaly, computed as departures from the 1961-1990 average, of the year 1947 amounted to 5 °C. This is only 1 °C less than for the year 2003. Another aspect is that in Basel, the threshold of 30 °C was exceeded 49 times in 1947, more often than in 2003 (41 times). 

The period of consecutive days during which the maximum temperature exceeded the 90% quantile of the summer temperature was also longer in 1947 than in 2003. During the year 1947 the longest heatwave lasted 14 days from 22 July to 4 August, whereas in 2003 only twelve consecutive heat days were recorded at the beginning of August (Z’Graggen, 2006; Beniston, 2004).

The meteorological situation during the heatwave event in 1947 analysed with the 20CR dataset shows typical features of a heatwave. The stationary high pressure system over the study region – the Central-European High – during the episode from the 22 July to 4 August 1947 is conductive for a heatwave according to Kysely and Huth (2008).

The analysis of the heatwaves in 1947 indicates that the event is comparable to 21stcentury heat periods such as the summer 2003 and that 1947 was extraordinary.

Even if the heatwave 2003 exceeded the maximum temperatures measured in 1947, in terms of the length of a heatwave and the exceedance of the 30 °C temperature threshold, the heat period 1947 was more intense.

So it’s fairly clear that:

• 1947 was comparable to 2003 and both heatwaves were caused by very similar meteorological patterns.

• 1947 maximum average temperatures were just 1C less than 2003

• In terms of duration and number of days above 30C, 1947 was more intense

Given that summers in Europe have warmed significantly since 1950, it is perhaps not surprising that the daily average maximum temperature in 2003 exceeded that in 1947, but that’s the only real difference and by all other metrics, 1947 was more intense. Not forgetting also that urbanisation has increased since 1947 and land use has changed considerably, either of which may have contributed to generally higher temperatures. So, if you’re looking for the climate change signal in the heatwave of 2003, the increase in mean maximum temperature anomaly of 1C is it. Scary (not). Climate crisis (not). But Peter Stott et al say different:

Many people remember 1947 ironically for the very bad winter that year, which was almost as severe in the UK as 1963, both winters occurring during a period of global cooling. So what we have is an extremely hot summer and a very cold winter happening back to back in the same year when the planet was actually cooling. That doesn’t quite fit the extreme weather/global warming narrative does it, therefore you won’t hear much about these past events from global warming cultists intent upon blaming your lifestyle choices for current bad weather. But when we look at the summer of 1540 in Europe, during the Little Ice Age (1350-1850), when Europe was probably the coldest it has ever been throughout the entire Holocene interglacial, the hottest, driest summer in at least the past 1000 years occurred. It surpassed 2003 by a long chalk which gives the lie to Stott’s statement that 2003 was the hottest summer in Europe ‘since at least 1500’.

This study demonstrates quite convincingly that 1540 was uniquely severe in terms of drought and heat:

The heat waves of 2003 in Western Europe and 2010 in Russia, commonly labelled as rare climatic anomalies outside of previous experience, are often taken as harbingers of more frequent extremes in the global warming-influenced future. However, a recent reconstruction of spring–summer temperatures for WE resulted in the likelihood of significantly higher temperatures in 1540. In order to check the plausibility of this result we investigated the severity of the 1540 drought by putting forward the argument of the known soil desiccation-temperature feedback. Based on more than 300 first-hand documentary weather report sources originating from an area of 2 to 3 million km², we show that Europe was affected by an unprecedented 11-month-long Megadrought. The estimated number of precipitation days and precipitation amount for Central and Western Europe in 1540 is significantly lower than the 100-year minima of the instrumental measurement period for spring, summer and autumn. This result is supported by independent documentary evidence about extremely low river flows and Europe-wide wild-, forest- and settlement fires. We found that an event of this severity cannot be simulated by state-of-the-art climate models.

The paper points out that the meteorological drought leading up to the precipitation deficit in 1540 was similar to that which happened in the 1990s:

From a documentary data-based temperature reconstruction for Central Europe (Dobrovolný et al. 2010) it is concluded that the 1540 drought was the climax of a decade-long summer warming trend bearing comparison with that seen in the 1990s.

Unlike in 2003, the sunshine, warmth and dryness continued right until the end of the year in 1540:

Coherent narrative reports by independent contemporary chroniclers indicate that, unlike in 2003, the weather in the following months (October–December) was sunny and warm “like in April” until the end of the year, without any frost or snow (Brázdil et al. 2013a; Wetter and Pfister 2013).

How? The planet was in the grip of a little ice age. Nobody was driving around in gas guzzling 4x4s, yet somehow the hottest driest summer in a thousand years seems to have occurred, followed by an extended period of autumn and winter warmth.

The hydrological drought was far more severe than 2003:

Chronicler reports about the extremely low level of major water bodies confirm the record breaking precipitation deficits assessed for Western and Central Europe (Fig. 3a). Lake Constance, the second largest lake in Western Europe, dropped to such a low level in August 1540 that the lake floor, with its mountains and valleys, emerged close to the surface and the island of Lindau was connected to the coast so that people could walk around it.

Melting of the stored winter snow in spring and early summer usually fills the lakes at the foothills of the Alps, so that the extreme late summer low water level in 1540, also considering the summer precipitation maximum in the Alps, was indeed a record-breaking event. Chroniclers described low water levels of rivers all over Western and Central Europe (Fig. 3a). Major rivers, such as the Rhine, Elbe and Seine, could be waded through in some places (Supplementary Information, Table S1, section Germany I, source 86 and section Netherlands and Belgium, source 6). Often, like in Basel, Collogne or Meissen, the descriptive information of low water levels is given with such a degree of accuracy that the rivers’ low water level discharges can be reconstructed. In these cases they result, based on independent and different reconstruction and assessment methodologies, in only 10 % of the average instrumental period summer half-year discharge of each location (independent expertise according to methodologies by Herget and Meurs 2010;Wetter et al. 2011 and Prof. Dr. Uwe Grünewald; personal communication). In comparison, the discharge deficit of major German rivers in the hydrological summer half-year 2003 was only −47% for the Elbe and −37 % for the Rhine ( Bundesanstalt für Gewässerkunde 2006).

Unlike in 2003, no thunderstorm was observed in summer 1540

The authors conclude:

Based on widespread documentary evidence in Europe concerning weather in 1540, we demonstrated that the drought in 1540 was likely more extreme than similar events in the instrumental period. The meteorological drought was more persistent (11 months), leading to a cumulative annual deviation of NPD to about 90 to 95 days compared to the twentieth-century Western and Central European average. The hydrological drought was similarly extreme, with an assessed discharge deficit of about 90 % for rivers Rhine and Elbe and the complete desiccation of smaller watercourses. The record-breaking dimension of the Megadrought also corroborates the earlier result of Wetter and Pfister (2013) that the heat wave, respectively spring-summer temperatures in 1540, were likely more extreme than in 2003. Our analysis of CMIP5 simulations suggests that climate models are so far unable to simulate 1540-like droughts. Given the large spatial extent, the long duration and the intensity of the 1540 heat and drought, the return of such an event in the course of intensified global warming involves staggering losses, the dimension of which might be assessed by future economic analyses. In conclusion, the case of the 1540 Megadrought demonstrates that in particular palaeoclimatic evidence of the natural archives, such as tree-rings or grape harvest dates, may fail to detect record-breaking climatic outliers, whereas archives of society usually describe them in most accurate detail.

The last sentence is particularly relevant in respect of the recent nonsense published in the Washington Post and picked up by the rest of the global warming obsessed mainstream media. WaPo claimed that Tuesday July 4th was the hottest day on earth in 125,000 years! Yes, they really did:

Tuesday was the hottest day on Earth since at least 1979, with the global average temperature reaching 62.92 degrees Fahrenheit (17.18 degrees Celsius), according to data from the U.S. National Centers for Environmental Prediction.

As a result, some scientists believe July 4 may have been one of the hottest days on Earth in about 125,000 years, due to a dangerous combination of climate change causing global temperatures to soar, the return of the El Niño pattern and the start of summer in the Northern Hemisphere.

Tuesday’s global average temperature was calculated by a model that uses data from weather stations, ships, ocean buoys and satellites, Paulo Ceppi, a climate scientist at London’s Grantham Institute, explained in an email Wednesday. This modeling system has been used to estimate daily average temperatures starting in 1979.

Instrument-based global temperature records go back to the mid-19th century, but for temperatures before that, scientists are dependent on proxy data captured through evidence left in tree rings and ice cores. “These data tell us that it hasn’t been this warm since at least 125,000 years ago, which was the previous interglacial,” Ceppi said, referring to a period of unusual warmth between two ice ages.

Utterly absurd. First they use climate and weather models to generate output for individual hot days which they call ‘data’ and then they compare this ‘data’ to 125k years of paleoclimate proxies to conclude that July 4th, 2023 was the hottest day on earth since the last interglacial! This is desperation indeed from climate alarmists.