Monday, March 11, 2013

Is The 1/10 Inch Per Year Rise In Sea Level A Big Deal?

One of the most the maddening aspects of the global warming debate is the challenge in pinning down facts. As an example, the question of whether the oceans are rising should seemingly be a question that is easily answered by hard facts. However, the skeptics and alarmists make conflicting claims over the data. A key issue is that the change in sea level is not uniform; the ocean is rising in some parts of the world and falling in others. Thus, any aggregated measurement of the ocean's rise conflicts with local observations. Also, the differences in measured change in differing locations creates lots of issues prompting attacks upon the methodology used in determining the aggregated rise in sea levels.

The most frequently referenced source of data on annual sea level change is provided by the Colorado University Sea Level Research Group. Viewing their sea level graph derived from the TOPEX satellite data published last year shows a key factor fueling the debate. As shown in the chart below, as of last year, it seemed as if the rise in sea level had stalled. The skeptics jumped on this result as proof that the sea level had stopped rising.

Global Mean Sea Level By Year (Year Ago)

However, there was significant rise in sea level in the past year, and the trend in the increase in sea level rise is once again intact. Notably, the global warming skeptics have tended to ignore the updated results that weaken their case that the sea level is not rising. Here is the updated chart.

Global Mean Sea Level By Year (Current)

Thus, based on this evidence, the proposition that the sea level is rising by about 1/10 inch per year or more seems to be the most likely conclusion. It also seems likely that the sea level will continue to rise. Based on the results from the past couple of decades this increase will be about 1/10 inch per year (although some researchers predict that rate of rise in sea level will accelerate in the future). 

The consequences of a continuation in the trend of rising sea levels largely depends upon time frame. If the sea level rises by 1/10 inch per year, the consequences over the next decade or two is vastly different than the consequences over the next 60 years. An inch or two rise in sea level will not be nearly as damaging as a 6 inch or greater rise in sea level. Thus, for those with an expected life span of 20 years or less, the rising sea level may not be a big deal during their lifetime. However, for those with a 60 year expected lifespan, and those that are concerned about their children and grandchildren, the rise in sea level is likely to be a  very big deal. A study by Climate Central suggest that 3.7 million people in the U.S are vulnerable to flooding over the course of the next century. The damage from future hurricanes could be even more severe than from Katrina and Sandy. And the consequences on a world wide basis could be life changing for hundreds of millions of people

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