Two recent studies, one from Harvard and the other from the Lamont-Doherty Earth Observatory, both conclude that there has been a very strong correlation between periods of increased worldwide volcanic activity and changes in major glaciations, usually referred to as ice ages*. Stated another way, geological forces influence climate.
This is a major confirmation of the Plate Climatology Theory detailed here.
Details of how historical increases in volcanic activity influenced ice ages are still being debated. The debate can be boiled down to one question. What came first, volcanic activity or atmospheric warming? It’s the old “chicken or the egg” conundrum. Harvard and Lamont-Doherty both believe that atmospheric temperature changes occurred first and that these changes led to / caused changes in volcanic activity.
What is more likely is that the opposite scenario is more correct. Increases in volcanic activity came first and these increases led to / caused changes in atmospheric temperatures. The details of each side of the debate are described below.
Harvard researched the interrelationship between historical increases in land-based volcanic activity and the end of ice ages. They limited the scope of their research to land-based volcanoes and land-based glacial ice sheets. The data showed that the end of ice ages when glacial ice sheets rapidly began to melt / retreat, coincided with dramatic increases in land-based volcanic activity. Based on this information, Harvard theorized that atmospheric warming occurred first and was therefore the root cause of deglaciation. Worked like this:
- The atmosphere was suddenly and somehow warmed by an unknown energy source.
- This warmed atmosphere acted to dramatically melt / thin worldwide glacial ice sheets.
- Thinned ice sheets reduced overburden pressure on previously ice sheet-buried land volcanoes effectively “uncorking” / activating them. The uncorked volcanoes spewed huge amounts of CO2 and heat into the atmosphere which acted to further increase atmospheric warming.
- Result? End of an ice age period.
The Lamont-Doherty folks researched the interrelationship between historical changes in sub-oceanic volcanic activity and sea level changes induced by atmospheric warming and atmospheric cooling. They limited the scope of their research to sub-oceanic volcanoes and worldwide sea levels. Data from this study showed that dramatic changes in atmospheric temperatures, both warming and cooling, coincided with changes in volcanic activity. Worked like this:
- When an unknown energy source suddenly and somehow warmed the atmosphere, glacial ice sheets were melted.
- Large amounts of meltwater acted to dramatically raise sea levels.
- Higher sea levels increased downward pressure on sub-oceanic volcanoes, which acted to “cork” / deactivate sub-oceanic volcanoes.
- Conversely, when the unknown energy source suddenly and somehow turned off the atmosphere cooled.
- Cooler atmospheric temperatures acted to rebuild worldwide ice sheets and in the process steal water from the oceans.
- As sea levels dropped, less pressure on sub-oceanic volcanoes acted to “uncork” / activate deep ocean volcanoes. These volcanoes began spewing CO2 and heat into the ocean.
- According to Lamont-Doherty the result of this complex series of events fits well with the Harvard research.
There are many problems with the integrated Harvard / Lamont-Doherty theory. Concerning land-based volcanoes, removing the overburden ice height-induced pressure has been conclusively proven to NOT “uncork” buried volcanoes.
Antarctica Ice core data clearly shows that many times in the past (12,000 and 43,000 years ago) deeply buried ice sheet volcanoes located along the West Antarctic Rift System violently erupted. These eruptions were not the least bit inhibited by overlying ice column pressure.
Secondly sub-glacial Antarctic volcanic systems are currently very active. They have created and maintained an entire present-day interconnected system of sub-glacial freshwater lakes and streams. Additionally, the heat flow from the West Antarctic Rift System is currently melting glaciers above it.
Concerning deep sub-oceanic volcanic activity, removing the overburden pressure induced by a raised sea level of a few hundred feet is insufficient to “uncork” deep ocean volcanoes, which lie at depths of 10,000 feet. Additionally, the sea level has not dramatically risen in decades, however, we are currently amid a dramatic increase in sub-oceanic volcanic activity.
There is a much better explanation for the correlation between ice ages and volcanism, one that fits nicely into Plate Climatology Theory. Geological and astronomical research shows that increases in global volcanic activity occur predictably in association with changes in Earth’s rotational/orbital patterns.
Scientists have known for many years that changes in the Earth’s axial rotation or its solar orbit put immense amounts of stress on the planet’s crust, inducing global increases in continental and sub-oceanic volcanic activity (Milankovitch Cycles). Resulting eruptions during these periods spew large amounts of heat and CO2 into the atmosphere and oceans.
Earth’s atmosphere suddenly and dramatically warms from a well-known / defined energy source. A warmed atmosphere acts to melt glaciers. Increased glacial meltwater raises sea level. When the increased volcanic activity cycle subsides the sea levels are at their highest level. This gives the false appearance, as per the Lamont-Doherty folks, that a higher sea level “corks” deep ocean volcanoes. This is not true. It’s just the end of the volcanically induced glacial melting cycle.
Other modern examples of how geological forces have influenced the Arctic, Antarctic, and Greenland Ice Sheets have been mentioned in previous postings: Update On Geothermal Heat And Arctic Ocean Sea Ice Melt, West Antarctic Ice Sheet Melting From Geothermal Heat, Not Global Warming, and Greenland Ice Melt Geothermal, Not Manmade.
Historical geological forces, primarily in the form of well-documented and well-understood cycles in volcanic activity, have driven global glacial cycles/ice ages. It is here contended that historical atmospheric warming is a side effect of increased volcanic activity, not the cause of increased volcanic activity.
The Plate Climatology Theory has come of age…Ice Age to be precise.
- Currently, we are in an interglacial period. The last glacial period/ice age ended 11,500 ago. Since that time glaciers have been melting at relatively predictable/steady rates, associated glacial melt water has predictably / steadily raised sea level, and atmospheric temperatures have predictably / steadily increased.
James Edward Kamis is a Geologist and AAPG member of 41 years and who has always been fascinated by the connection between Geology and Climate. Years of research/observation have convinced him that the Earth’s Heat Flow Engine, which drives the outer crustal plates, is also an important driver of the Earth’s climate.
References:
http://www.sciencedaily.com/releases/2012/01/120130131509.htm
http://www.ldeo.columbia.edu/news-events/seafloor-volcano-pulses-may-alter-climate
