Volcanoes and global cooling

Found this amazing essay published on National geographic

Colossal volcano behind ‘mystery’ global cooling finally found

The eruption devastated local Maya settlements and caused crop failures around the world

Some extracts

The ices of Greenland and Antarctica bear the fingerprints of a monster: a gigantic volcanic eruption in 539 or 540 A.D. that killed tens of thousands and helped trigger one of the worst periods of global cooling in the last 2,000 years. Now, after years of searching, a team of scientists has finally tracked down the source of the eruption.

The team’s work, published in Quaternary Science Reviews, lays out new evidence that ties the natural disaster to Ilopango, a now-dormant volcano in El Salvador. Researchers estimate that in its sixth-century eruption, Ilopango expelled the equivalent of 10.5 cubic miles of dense rock, making it one of the biggest volcanic events on Earth in the last 7,000 years. The blast was more than a hundred times bigger than the 1980 Mount St. Helens eruption and several times larger than the 1991 eruption of Mount Pinatubo. It dealt the local Maya settlements a blow that forever altered their trajector……

el salvador


Ice cores from Greenland and Antarctica show spikes of sulfate, a byproduct of large volcanic eruptions, at 536 and either 539 or 540. The two volcanoes were so large and so violent, they launched sulfur gases and particles miles into the sky. Since this material reflected sunlight away from Earth’s surface, it triggered severe global cooling: One 2016 study found that the volcanoes decreased average global temperatures by as much as 3.6 degrees Fahrenheit……


geologists published new evidence that the historical “dust veil” of 536 was caused by a volcano. In the other, researchers announced that the Tierra Blanca Joven extended into marine sediments off the coast of El Salvador. The Tierra Blanca Joven eruption was even bigger than Dull and others thought.…….


Dull’s team also revised their estimate of Ilopango’s size, taking into account the thickness and spread of Tierra Blanca Joven deposits. They say that Ilopango may have even dwarfed the 1815 Tambora eruption, a huge volcanic event that ushered in “a year without a summer” because of the global cooling it caused. Ilopango likely launched up to a million tons of sulfur miles into the sky, high enough for stratospheric winds to spread the aerosols worldwide and trigger global cooling.…..

The actual Research paper

Radiocarbon and geologic evidence reveal Ilopango volcano as source of the colossal ‘mystery’ eruption of 539/40 CE







Are the Mount Sinabung eruptions ..effecting our weather?



Troposphere height

Links , pictures, research, information.

troposphere rheemoclineatmosphere temperature layers with,height

In no specific order.

Theory. Height of the troposphere


‘The height of the tropopause depends on the location, notably the latitude, as shown in the figure on the right (which shows annual mean conditions). It also depends on the season (1, 2). Thus, it is about 16 km high over Australia at year-end, and between 12 – 16 km at midyear, being lower at the higher latitudes. At latitudes above 60� , the tropopause is less than 9 -10 km above sea level; the lowest is less than 8 km high, above Antarctica and above Siberia and northern Canada in winter. The highest average tropopause is over the oceanic warm pool of the western equatorial Pacific, about 17.5 km high, and over Southeast Asia, during the summer monsoon, the tropopause occasionally peaks above 18 km. In other words, cold conditions lead to a lower tropopause, obviously because of less convection.

Deep convection (thunderstorms) in the Intertropical Convergence Zone, or over mid-latitude continents in summer, continuously push the tropopause upwards and as such deepen the troposphere. This is because thunderstorms mix the tropospheric air at a moist adiabatic lapse rate. In the upper troposphere, this lapse rate is essentially the same as the dry adiabatic rate of 10K/km. So a deepening by 1 km reduces the tropopause temperature by 10K. Therefore, in areas where (or at times when) the tropopause is exceptionally high, the tropopause temperature is also very low, sometimes below -80� C. Such low temperatures are not found anywhere else in the Earth’s atmosphere, at any level, except in the winter stratosphere over Antarctica.

On the other hand, colder regions have a lower tropopause, obviously because convective overturning is limited there, due to the negative radiation balance at the surface. In fact, convection is very rare in polar regions; most of the tropospheric mixing at middle and high latitudes is forced by frontal systems in which uplift is forced rather than spontaneous (convective). This explains the paradox that tropopause temperatures are lowest where the surface temperatures are highest.

The tropopause height does not gradually drop from low to high latitudes. Rather, it drops rapidly in the area of the subtropical and polar front jets (STJ and PFJ respectively in the Figure on the left), as shown in the Palmen-Newton model of the general circulation (Fig 12.16 or Fig on left). Especially when the jet is strong and the associated front at low levels intense, then the tropopause height drops suddenly across the jet stream. Sometimes the tropopause actually folds down to 500 hPa (5.5 km) and even lower, just behind a well-defined cold front. The subsided stratospheric air within such a tropopause fold (or in the less pronounced tropopause dip) is much warmer than the tropospheric air it replaces, at the same level, and this warm advection aloft (around 300 hPa) largely explains the movement of the frontal low (at the surface) into the cold airmass, a process called occlusion (Section 13.3) (4).




Google search.. ‘pictures tropopause height’









Volcanic activity correlated with prolonged solar minimum

Thought it was about time to start a post on this topic as it relates to earths climate

Click on the title to load all further entries and posts below

Volcanic activity erupts particulate matter and chemicals that have been associated with global cooling
diagram volcano

Salvatore Del Prete

a contributor from Tallbloke wordpresss has dished up some amazing findings

This preliminary study showed 80.6% of the largest eruptions took place during extended solar activity minimums. Significantly, the following list of the eight largest volcanic eruptions globally (VEI>6) since 1650, shows all but one took place only during a solar hibernation, or significant reduction in solar activity as measured by sunspot count.

source: Source: Smithsonian Institute.

Table 1.Volcanoes of greater than or equal to VEI of 5 from 1650 to 2009. This list of large volcanic eruptions since 1650 was used as the baseline list for comparison against solar activity, i.e. periods of reduced sunspot count to determine any apparent associations. 5* = a class five VEI with potentially large date uncertainty, P* = plinian large class eruption, assumed >VEI 5. The study did not include activity associated with geological hot spots or caldera (super volcano) sites. Source: Smithsonian Institute.
Volcano Location Year VEI
1. Shiveluch Kamchatka Penninsula 1650 5
2. Long Island N.E. New Guinea 1660 6
3. Usu Hokkaido, Japan 1663 5
4. Shikotsu Hokkaido, Japan 1667 5
5. Gamkonora Halmahera, Indonesia 1673 5*
6. Tongkoko Sulawesi, Indonesia 1680 5*
7. Fuji Honshu, Japan 1707 5
8. Katla So. Iceland 1721 5*
9. Shikotsu Hokkaido, Japan 1739 5
10. Katla So.Iceland 1755 5
11. Pago New Britain 1800 P**
12. St.Helens Washington State, USA 1800 5
13. Tambora Lesser Sunda Islands,Indo. 1815 7
14. Galungung Java, Indonesia 1822 5
15. Cosiguina Nicaragua 1835 5
16. Shiveluch Kamchatka Penninsula 1854 5
17. Askja N.E.Iceland 1875 5
18. Krakatau Indonesia 1883 6
19. Okataina New Zealand 1886 5
20. Santa Maria Guatemala 1902 6
21. Lolobau New Britain 1905 P*
22. Ksudach Kamchatka Penninsula 1907 5
23. Novarupta Alaska Penninsula 1912 6
24. Azul, Cerro Chile 1932 5+
25. Kharimkotan Kuril Islands 1933 5
26. Bezimianny Kamchatka Peninsula 1956 5
27. Agung Lesser Sunda Islands, Indo. 1963 5
28. St. Helens Washington State, USA 1980 5
29. El Chichon Mexico 1982 5
30. Pinatubo Philippines 1991 6
31. Hudson, Cerro So. Chile 1991 5+
Table 2.Volcanic eruptions that took place during major solar minimums and solar hibernations. This table establishes the strong relationship between the largest volcanic eruptions and solar activity lows on the order of the Centennial and Bi-Centennial Cycles defined by the RC Theory.
Volcano Location Year VEI Associated Solar Minimum
1. Long Island N .E. New Guinea 1660 6 Centennial: Maunder
2. Pago* New Britain 1800 P Bi-Centennial: Dalton
3. Tambora Lesser Sunda Islands 1815 7 Bi-Centennial: Dalton
4. Krakatau Indonesia 1883 6 Centennial: Year 1900
5. Santa Maria Guatemala 1902 6 Centennial: Year 1900
6. Lobobau New Britain 1905 P Centennial: Year 1900
7. Novarupta Alaska Peninsula 1907 6 Centennial: Year 1900

Salvatore DePrete suggests
“One item to remember is this period of below normal solar activity started in 2005 so the accumulation factor is coming into play.
Secondly it is not just solar activity within itself but the secondary effects associated with solar variability which I feel are extremely hard to predict as far as how strongly (to what degree)they may change and thus effect the climate in response to long prolonged minimum solar activity.
I strongly suspect the degree of magnitude change of the prolonged minimum solar activity combined with the duration of time of the prolonged minimum solar activity is going to have a great impact as to how EFFECTIVE the associated secondary effects associated with prolonged minimal solar activity may have on the climate. An example would be an increased in volcanic activity”
8. Pinatubo Philippines 1991