Under the sea volcanic activity

25 Jun 2011

An interesting post at http://chiefio.wordpress.com/2011/06/24/megaplumes-and-volcanic-gasses/ is a bit of typical sleuthing by EM Smith, wondering just how much co2 might be produced by under the sea tectonics and volcanic activity. He takes it a stage further by speculating that it might influence the transfer of heat by the ocean circulation system that runs around the globe, an area of research that is poor in comparison with other palaeo-climatic endeavours. For example, it was reported a couple of years ago there was volcanic activity beneath the Arctic Ocean going on - presumably noticed by oil and gas research geologists. Nobody really knows the extent of the activity as the region is generally inhospitable as far as research boats are concerned, yet there is thought to be a wealth of fossil fuels under the sea bed that awaits exploitation. We do know that warm ocean water percolated into the Arctic Ocean in 2010 - via El Nino. However, did the volcanic activity contribute to the warmth? Whilst EM Smith does not raise that particular incident he does sniff around and ask questions about other bouts of sea floor venting, such as a hydrothermal 'megaplume' in the Indian Ocean, noticed in 2005. It stretched for 70km. Hydrothermal vents are volcanic hot spots that  emit gases and mineral enriched water as hot as 400 degres celsius. The heat is known to support unique eco systems. Once the plumes have formed they don't just disperse - they remain for years. This is how they may influence the heat dispersed by the ocean  circulation system - and nobody knows what really drives what is actually called the Ocean Thermahaline System (the transfer of heat). An average hydrothermal event might generate 500 megawatts but the 2005 megaplume produced, it is estimated, 100,000 megawatts - not to be sniffed at. Some 90 per cent of earth's volcanic activity actually takes place under the sea and oceans - out of sight and out of mind (and out of climate modelling). Now, here is the really interesting bit as far as catastrophism is concerned. Volcanoes and cold periods very often come along together. Volcanoes on the sea bed throw out heat which results in an overturning of cold ocean water, bringing it to the surface. The possibility is that it is this cold water that is percolated around the globe during La Nina events, which means the ocean circulation system goes into a change mode - or as Wally Broecker might say about the Heinrich and Dryas events, a switch is turned on. Hence, we immediately have the possibility the really big switch events are activated by ocean bottom seismic activity. Now, what might happen when the mid ocean ridges increase the flow of lava spreading more rapidly than the consensus will currently allow? It is assumed sea floor spread takes place at a constant uniformitarian rate but volcanic activity and pressure at the mid ocean ridge (as far as the Atlantic is concerned) may have proceeded much more rapidly at points of time in the past. Geologically, sea floor spreading may take place in a series of jerks and bumps, rather than in a slow but continuous way. Hence, if the Poles rocked for whatever reason the mid ocean ridge and volcanic vents just might be able to prompt a switch in the Ocean Thermahaline System - upwelling cold water from the deep rising to the surface very quickly and generating climate change. Is this the mechanism behind sudden coolings in the North Atlantic for example? Lots of questions and lots of unknowns. EM Smith asks, was there an observable increase in  volcanoes in 2010 and 2011 and if so is this reciprocated under the surface of the oceans - that we don't know about. Might this explain in part the massive dissipation of heat from the oceans to the upper atmosphere, and out into space, this year?

One commenter, Keith de Havelle, adds - some years ago microphones were dropped into the water off the West Antarctic peninsular with the object of recording the sound of whales and other marine life. The recording was dominated by seismic noise from underwater volcanoes. This section of the Antarctic Ocean subsequently became anomalously warm - assumed to be driven by warm tropical water flowing south from the equatorial Pacific. Might it also involve heat generated on the sea floor? Ian Plimer, in his recent book, much parodied by AGW puppets, actually said underwater volcanic activity was little understood by geologists (and he is a geologist). How much heat and co2 they might generate is completely unknown. The co2 involved, he suggested, might exceed anything humans are able to produce by burning fossil fuels. Plimer saw his role as essentially debunking the AGW doomsaying message and to a large extent many of the points he raised have been ignored as wishful thinking - but should they be ignored?

PS ... rapid changes in the ocean circulation systme, such as suddenly switching to a cold water (surface) situation might just be another marker of a catastrophic event. The fact they are perhaps a climate driver too is not at issue - it is what sets in motion increased volcanic activity, enough to spark into life a Heinrich or Dryas event. Although the seismic activity is internal to the earth the 'event' that triggers underwater volcanic vent activity remains the pea in the thimble. The ultimate driver of climate change could actually be external to the earth, raising stress along the mid ocean ridges and volcanic vents etc.