Friday, November 23, 2012

Earthquakes and Climate Change - Related?

Here is another example of a bright student trying to put things together. Sometimes there are things that are big and in the same place - but are still unrelated:

I am training to become a teacher, and my professor wants us to become more familiar with supplemental resources, such as this website. So he has asked us to generate a question and submit it to you and then give him the answer we get back. I thank you in advance for your feedback! Question: Are earthquakes, like storms are said to be, tied to climate change? Can you explain why or why not? Thank you so much! 
-Sarah S

No, earthquakes are not tied to climate change, and the main reason is because of they are not coupled (or very poorly coupled): Other than very temporary shaking of the ground, which is connected very poorly with the atmosphere, the huge energies involved in earthquakes are generated in, released in, and remain below the Earth's surface. Permanent surface manifestations of earthquakes (cracks or displacements) are uncommon except for the largest events, and are generally small and limited in scope, at least in terms of the scope of weather fronts moving across the Earth.

For a long time earthquake scientists have tried to find an association between earthquakes and syzygy (Solar and Lunar tides), but the correlation is just not there. Nor is there any apparent connection between volcanic eruptions and tides. Weather *IS* correlated with the orientation of the Earth's axis of course: when the north pole is oriented towards the Sun in the northern hemisphere summer, there is different weather than with the opposite orientation. Hurricanes and typhoons occur between June and November in the northern hemisphere, and the timing appears to be a heat latency effect. It takes awhile for the summer solar heat to accumulate in the upper ocean realm (water has a high heat coefficient, so it takes awhile to warm it up), and hurricanes derive their energy from the heat in warm ocean water. Hurricane Sandy was an unusual late-season event, because of the way pressure fronts interacted with each other to drive the storm backwards from the usual trade wind tracks and onto the New Jersey coastline.

Weather also correlates with the amount of CO2 and methane in the atmosphere, and also with the amount of energy that the Sun produces, but the critical geological record on the latter is distant in time and thus difficult to resolve clearly (see Among scientists, the anthropogenic (human-caused) contribution to climate is now widely accepted as the evidence keeps piling up: the increasingly severe weather events of the past half century are caused in no small part by fossil fuel combustion. Of the hottest 10 years in the past century, 9 of them have been since 2000, and that correlates well with the growing levels of CO2 in the atmosphere. A good article to pursue this topic further is here:

Interestingly, methane is approximately 37 times more potent than CO2 as a greenhouse gas, and the amount of methane produced/converted by a single cow from the vegetation it eats is quite large. With the burgeoning human population and its increasing affluence, more people seek protein, and thus the number of meat-producing animals has skyrocketed in the past century. By itself this new methane is frightening. However, there is a huge amount of sequestered methane in what are called methane clathrates or methane hydrates - methane bound up in water ice beneath the ocean seafloors (see This methane remains stable (and sequestered) as long as the pressure and cold temperatures around them don't change. However, with increasing temperatures caused by global climate change, it appears that these clathrates could become unstable, freeing more methane into the atmosphere, which will then get hotter, freeing ever more methane in a potential runaway feedback cycle.

Welcome to the increasingly interesting 21st Century!

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