Sea Levels, Then and Now

March 18, 2011 2 Comments

One of the relevant topics in conjunction with anthropogenic global warming (AGW) and something I mentioned in my presentation earlier this week is rising sea levels. This was the first effect of AGW that caught the imagination of the populace and media a couple decades ago and even inspired the apocalyptic movie “Waterworld” (which I thought was a halfway decent movie. I am not sure why it received so much scorn). Something I remind people of not only here in the blog but out in public is that the earth has already experienced something analogous to “Waterworld”. The consensus projections from climate models indicate a 2 to 3 foot sea level rise by the year 2100. This research projects 1 foot higher by 2050. The absolute worst case scenario, where all the ice on the entire planet melts, would result in a sea level rise of about 230 feet. Even in that implausible extreme worse case scenario, the sea level rise would not match what has happened since the last ice age. Human beings have had to deal with a sea level rise of over 200 feet since the end of the last ice age and some scientists figure that the sea level was 350 to 400 feet lower at the peak of the last ice age.

So 2 or 3 feet does not seem like too much in comparison. The problem is that our society has now built an impressive array of expensive assets near the coast and within a few feet of the current sea level. Two or three feet of sea level rise would force some though decisions for coastal mega cities like New York and for entire countries such as Bangladesh. This article shows areas of the southeast U.S. that are within 3 feet of sea level  and vulnerable to sea level rise – if it comes to pass. As a sign of the ongoing sea level rise (from past natural climate changes and possibly from AGW in the future), New England beaches erode a bit more each year.

If sea levels rise enough to threaten cities near the coast (especially one’s below sea level like New Orleans), then there will probably have to be some changes to current law. Currently, in the U.S, the government subsidizes insurance in risky coastal areas. When hurricanes strike, taxpayers pick up the tab for reconstruction, no matter if it is a one room shack or a million dollar mansion. If sea levels rise and more property on the coast is under threat, then I suspect taxpayers will revolt and not want to keep re-building the million dollar mansions on the coast.


If the skies remain clear tonight and tomorrow, be sure to keep an eye on the “super” moon. It might not look all that different but it will 14% larger than normal because it is at perigee. This has caused some astrologists to predict all kinds of calamities for the earth. It is highly unlikely that the miniscule increase in the gravitational pull  of the moon this weekend will cause earthquakes to rumble or volcanoes to explode. If something out of the ordinary does happen, WATCH OUT! I am sure we will hear about it from all of those predicting doom.


Lastly, how about some eye-candy so you can waste a little time at work (during break of course). Here is a neat picture gallery of farm fields  taken from space.

Have a good weekend! Meteorologist Justin Loew.

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  1. David says:

    If the sea level rose 1 foot or so how would that affect the great lakes?

  2. jloew says:

    Since the Great Lakes are well above sea level, the rise of the oceans would have little DIRECT effect on the Great Lakes. Lake Superior is 600 feet above sea level. There could be indirect effects. If the seas rise a foot or two, there will be more watery areas along the coast of the U.S., with perhaps more evaporation and moisture in the air, leading to heavier rain and snow in the upper Midwest (just hypothetical). More precipitation could raise the levels of the Great Lakes. Even if the Great Lakes went up a foot or two, it would not have too much effect on the shoreline/harbors in most areas. Thanks for the question David.

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