Krakatoa’s climatic impact still not understood – Shocking?!
Posted 12th August 2017
The forceful eruption of Krakatoa, August 26-27th, 1883, darkened the sky worldwide for years afterwards. The final explosive eruption was heard 4,830 km (3,000 miles) away, 20 million tons of sulfur released into the atmosphere; produced a volcanic winter, reducing worldwide temperatures by an average of 1.2 °C (2.2 °F) for five years. Weather patterns were chaotic for years, and temperatures did not return to normal until 1888 (Wikipedia). A unique climatic event was offered to science for their better understanding. Did they used the opportunity?
Immediately a worldwide observation and research commenced in an unprecedented scale. “The year 1883 will take a remarkable place in the history of earth with respect to the effects of the earth’s interior on the crust and everything found upon it,” wrote Neumayer in January 1884. Unfortunately it didn’t happen.
More than 130 years later the Krakatoa matter is insufficiently understood and explained. For example a recent research by Zambri et al. 2017 claim, that “Observations show that all recent large tropical volcanic eruptions (1850-present) were followed by surface winter warming in the first Northern Hemisphere (NH) winter after the eruption”. In no way more convincing argues Willis Eschenbach (WUWT) saying “Krakatau, largest eruption in recent history, shows almost no effect on the winter. It’s just about average”. The use of statistics in this way is frightening.
Both views are shaky, if not outright misleading, and in any case of no help. Both views ignore that only a detailed assessment of temperature variations in different regions may reveal a picture, which offers valuable clues for climate research and understanding. Observing a pronounced difference between continental inland areas and close-to-the-ocean areas, would inevitable quickly highlight the significant role the oceans have played in the aftermath of the eruption of Krakatoa. An essay from 1992, explained it in detail as it follows:
Krakatoa – A Climatic Once-in-a-Century Event?
- State of Affairs
In the year following the three volcanic eruptions in 1883, including Krakatoa in August 1883, the circulation in the atmosphere was above normal and then sank to a powerfully developed minimum in 1888, wrote Artur Wagner in his discussion of climatic change in 1940. At the most, a reduction in solar energy could be caused only by fine dust at high altitudes. Other authors also refer to Krakatoa only from the standpoints of blockage of sunlight and as a cause of ice ages. Even today, the discussion of large-scale volcanic eruptions is limited to the determination that it can become colder for a short period of time. Little is left of Neumayer’s euphoria of January 1884 and – as it appears – there have hardly been any advances for science. Did Krakatoa really leave behind so few traces, or were they simply not recognized?
- b) The Observations after Krakatoa and the Stabilizer
Only a short time after the main eruption of Krakatoa on 21 August, 1883, unusual observations were reported, which were compiled by Neumayer.
Here are some examples from ship logs from all over the world in 1883:
- 3 September: During the past few days, there has been a fairly even gray cloud mass, normally covering the entire sky, above the cumulus and stratus clouds;
- 3 September: At midday hazy gray air. Hazy, gray air condensing into dew towards evening;
- 5 September The air appears yellow and watery;
- 7 September: The atmosphere appeared to be filled with very small, evenly distributed clouds of vapor;
- 13 September: The yellowish “haze” continues in the upper atmosphere;
- 11 October: Fiery atmosphere, cloudless sky;
- 5 November: Pale atmosphere;
- 10 December: The air was very clear and looked like the air in the southern Indian Ocean during the typhoon season;
- 13 December: Lead-colored sky.
The observations were continued, collected, evaluated, and thoroughly discussed.
Five years after the eruption of Krakatoa, the scientific work on the events of the year 1883 were temporarily brought to a close with the “Report of the Krakatoa-Committee of the Royal Society.” A summary by J. M. Pernter was given in the Meteorologische Zeitschrift of 1899. The following information is derived mainly from this summary.
The most amazing aspect of the report is that it does not contain any mention of possible relevance of the oceans. Furthermore, the question of a possible change in the average temperature of the atmosphere does not appear to have interested anyone. Although it was quickly determined that the amount of solar energy received was clearly reduced for a period of several years, little attention was paid to the development of the atmospheric temperature. The blockage must have fluctuated strongly and have varied greatly, depending on the observation point. In total, the blockage effect has been calculated at an average of approximately 10% over a span of four years, whereby the reduction of solar energy in the northern hemisphere (Paris) was at its greatest in fall of 1885, reaching a value of 25%.
It would seem that a reduction of solar radiation of such proportions would necessarily have a long-lasting effect on atmospheric dynamics. But supposedly the average temperatures fell only slightly and the atmospheric circulation in 1884 was above normal and did not sink to a strongly developed minimum until 1888. While the equilibrium of the world of statistics may not have been disturbed by Krakatoa, events were rather different in the world of nature. Without the stabilizing effects of the ocean, the effect of Krakatoa would have been catastrophic. A person sitting in warm bath water does not experience any discomfort when the heating is turned off – at least, not right away. But what can possibly happen to the higher latitudes of the earth if the warm water from the tropics is already on the way? A cooling-off effect will only become noticeable after the passage of some time and continued blockage of solar radiation. The influence of the oceans was shown clearly by the fact that coastal areas had above-average temperatures in 1884, whereas continental land masses such as Russia, Siberia, India, China, Canada, and the USA (inland areas far from the Atlantic) recorded very cold winters in the years up to 1888.
This could be dismissed as coincidence if the time until 1886 had not been accompanied by another phenomenon, a “hazy fog”, a strange, smoky cloudiness in the atmosphere which was observed both in the tropics and in other areas. When Pernter further states (P. 410): “The hazy fog appears as a constant companion of the extraordinary optical phenomena in the atmosphere during the entire period of the atmospheric-optical disturbance”, then one can say – speaking non-technically – that Nature had “popped a lid over it” and so protected the oceans from cooling off too quickly. The lid consisted of ingredients provided by Krakatoa and water vapor provided by the ocean. As a result of the “dirtying” of the atmosphere by the volcano’s eruption, the atmosphere displayed characteristics and behavior deviating from the norm. Just as fog over a water surface sharply limits the transfer of heat energy, the hazy fog must have had a long-lasting effect. The dispute at the time as to whether Krakatoa had provided the water vapor (Pernter, P. 414) would most likely not have occurred if it had been assumed that the upper ocean water level (statistically speaking) was about 30° C. warmer than the atmosphere. The fact that the air circulation did not reach its minimum until 1888 is not surprising. From the middle of the 1880s on, a “weakening” of the oceans in the higher latitudes must have become noticeable. The less heat energy the ocean feeds into the atmosphere, the weaker become the dynamics in the atmosphere. This also becomes clear when it is seen that three years after Krakatoa the temperatures above land rose more sharply than above the oceans.
- c) The Missed Opportunity
If climate is explained by average weather conditions and the oceans are allowed only a static place in events in Nature, as was the case until recently, then we really could go on with our daily affairs and regard Krakatoa as no more than an interesting event in Nature which gave us some beautifully dramatic sunsets. But when the oceans temporarily cool off, it does not mean that heat is withdrawn in equal measure everywhere from the upper ocean layer. As the oceans comprise a chaotic system, it must be assumed that the tendencies in the entire system change when an event such as the eruption of Krakatoa takes place and has an effect over a period of three to four years. The fact that the sum of the statistical values (particularly the global average temperature) showed little or no deviation cannot be proof that the event did not have any climatic quality whatsoever. An event which reduced the solar radiation by about 10% for more than three years cannot have failed to influence ocean currents and must have had to one extent or another short- as well as long-term consequences. In addition, the possibility that the oceans reacted in some way to a three-year “cleaning of the sky” of volcanic ash, pumice dust, and sulfuric acid, more than 2/3 of which landed in the seas, cannot be categorically excluded.
After the eruption of Katmai in 1912, the temperatures in the low and middle latitudes also rose by up to 1° C. and even more in the higher latitudes. Wexler of the US Weather Bureau wrote of this in 1951: The warming in the middle and lower latitudes can be a result of clearer air and increased transport of solar energy, but the warming in winter in higher latitudes during the Arctic night will have to be explained in another way. Naturally, someone should have thought of the oceans. [Link to the ABTRACT]