Thursday, December 30, 2004

Climate Change and Earthquakes

Prior to the current disaster, I was interested in the effects that climate change would have on the earth. The melting of glaciers can have profound effects on a region. The result is a major redistribution of weight. As I recall the shorelines of ancient Lake Missoula rose after the melting of the area glaciers. Conversely, there were localized earthquakes caused by the filling of Lake Powell.

Water is highly is heavy. The climate determines the distribution of this weight.

It seems to me that melting glaciers would have two effects: it would lighten the weight sitting on the areas once covered by the glaciers. It seems to me that a massive melting of glaciers would also increase the over all weight pressed down by the oceans. An unscientific guess would be that global warming would result in a downward force on ocean trenches and and upward force on mountains.

Unscientifically stated: I would not be surprised to see increased seismic activity as we turn this little blue planet of ours brown.


Annora said...

I was referred to your blog by my father Cary who has an interest in maths as well as currently noting the likelyhood of connection between global warming and seismic activity. To quote his email to me:

"I was googling for some clues on my current interest in the validity of Godel's theorems, so I entered 'self-referencing sets'. This came up with some very interesting views from someone called Kevin Delaney, who clearly shares my unhappiness with Cantor's diagonal method (work on which I have just about completed. A link from that site took me to his
blog which today deals with the link between climate change (he is an American) and earthquakes. It might be of interest to you in your project. It really is a Lewis Carroll world."

I am working on a project of visualising sustainable cities in the year 2055 and one of the possibility that we will be living in geologically unstable times is certainly not being taken into account when people think only of the ocean level rising against the land.

The heat exchange processes of the ocean, such as the gulf current and many other currents that function to move heat around the globe, are likely to alter along with the storm cycles that also act as a heat exchange. This will alter climates around the world, change the patterns of the seasons and impact on the growth cycles of plants in hard to predict ways.

Adding volcanic activity will even further change the surface of the world we live on, and perhaps how we build ourselves onto, or into that world.

Since seismic activity is localised along the plate edges the effect of geography change will be localised in various places around the world (often places that are currently densely populated) how do you see effects outside those local areas?

y-intercept said...

Thanks for the comment. Your interest in developing sustainable communities sounds intriguing.

I think you are correct that changes in ocean currents due to Global Warming will have dramatic effects on seismic activity. The Gulf Stream and other thermal currents obviously put a great deal of pressure on tetonic plates. The melting of the polar ice cap would completely change this dynamic structure. Changing thermal currents would have a more dramatic impact on seismic activity than simple movement of materials and water to which I referred.

I've read a few books on Lake Missoula. There is good geological evidence that there is increased seismic activity as glaciers advance and recede. Of course, it is completely impossible to attribute any particular earthquake to any given cause. A dam might cause seismic activity. It is also possible that a dam would releive pressure presenting earthquakes.

I do agree that the world should be prepared for increased seismic activity resulting from global warming. Change leads to more change.

Your interest in sustainable planning sounds intriguing. The catastrophy around the Indian Ocean will reveal a great deal of poor planning and hopefully people will learn from the lesson.

Several news reports on Indonesia indicate that recent decades had seen a sizeable migration of people from the highlands to coastal areas. Big mistake!

Oddly, one of the effects of the billion of so dollars in aid to the affected regions is that the aid money will probably create economic forces that draw even more people into the coastal areas.

Rather than rebuilding the destroyed communities, I think we should think seriously about abandonning many of the affected towns and moving the communities to safer areas.

The same things happens in the US. We spend billions on flood relief. Effectively what do is place a tax on living in highlands and subsidize living in flood plains. This transfer of wealth ends up moving mover people into harm's way.

Planning for geologic change sounds very interesting. Most planners seem to plan for a static world. What you propose is starting with the assumption that the world is dynamic.

It seems to me that planning for systemic geological and climatic changes should involve a willingness to complete abandon cities and regions affected by change. Allowing migrating and a mobile work force allows people to move from places that become less hospitible to places where there is more potential for a quality life.

I think our natural impulse is to want to save all communities. However, it seems to me that ultimately, the world needs a dynamic structure that makes it possible to abandon places.

Think of a town at risk like New Orleans. New Orleans is below sea level. The changes we made to the Mississippi River prevent it from adding new sediment to that part of the delta. What do we do if the Big Easy is hit by a Hurricane? or if the town continues to sink?

Annora said...

It is interesting to hear you encapsulating what I am saying as planning for a dynamic world. Reflected thinking often gains clarity.

The concept of abandoning communities - or responsing to what ecosystem different places are capable of supporting at different times is very interesting.

Your concept of using dams relates to something I worked on this afternoon. In the writing I was doing today I am afraid that I posited (almost as an aside because I am writing mainly about Australia) that prolonged violent activity on the San Andreas fault had rendered California unlivable. In my "news bulletin" I had geo-seismic scientists experiementing with a new process for controlled release of pressure along the faultline. I emptied the state because I thought that only on highly valued land in a technology valuing society would anyone try to control seismic activity. I am not sure if I will leave it in the final version.