Pacific Earthquake / Tsunami connection to Climate Change?
This morning’s devastating 8.9 earthquake off Japan reminds us again of the mysterious tsunamis. This time there was high quality real time television coverage; even better than the Indonesian event in 2004.
Tsunamis are unique among the ocean phenomena and crises. Everything else, pollution, overfishing, increasing temperature and levels of acidity are all caused by, or greatly impacted by us.
Even long term hurricane activity is now associated with the warming ocean temperatures, particularly powerful Category 4-5 versions — to be covered in another post.
On the other hand, tsunamis are caused by an earthquake underwater. Today it is widely understood that earthquakes are caused by movement of the massive plates of the earth’s crust that are in constant slow movement. There is no evidence that they are affected by the same forces as weather, i.e. the normal patterns of heating and cooling, combined with the spin of the earth, and the dynamics of the atmosphere and the oceans.
Interestingly, however, there is at least one theory that could connect climate change and earthquakes, and therefore tsunamis. Presently it is only conjecture.
The earth’s crust — those massive plates — do respond to the ice ages. The weight of the ice sheets, more than 2 miles thick (3 km) is so great that it depresses, or pushes down the continents.
The peak of the last ice age was about 20,000 years ago. Even though we have been in what we consider the “normal” situation with ice caps at the poles for more than 10,000 years, North America is still rebounding, particularly at the higher latitudes in Canada and Alaska. The land is moving upward, less than an inch a year, as a result of the ice disappearing more than ten thousand years ago. Remember that most things move VERY slowly in geology, at least compared to our human timescale.
As a result of those sections moving upwards, areas further south are moving downward, somewhat like a see-saw. This is the reason that areas like Norfolk Virginia are experiencing almost double the effective rate of sea level rise. The land is going down.
The question has been raised as to whether there is any connection between the increased earthquake activity and the rapidly melting ice sheets in Greenland, Antarctica, and the mountain glaciers. In other words, could the melting of ice, at rates that are unprecedented in known geologic history, be causing some kind of effect on the plates?
If the forces on the plates changes, it is conceivable that the location and frequency of earthquakes could be affected.
So far it is just a provocative question. My sense is that it is POSSIBLE, but very UNLIKELY, to have a substantial impact.
Like many questions of science, however, it is worth asking and exploring. The more we try to “connect the dots” the better we will understand the systems of this amazingly complex and mysterious planet.