Sea Level Rise

[Sunny and Warm]

This is broken out from the sunspot thread (strange that sea levels were discussed in a sunspot thread!!) The following is a blog story on WUWT. Interesting decelerating trend with regard to sea level rise. Yes, it is increasing, but at a decreasing rate. The first decade of this century shows only a one inch rise in sea levels. If we cool off over the next 30-40 years as many predict, then pronouncements of 1-2m rises this century cannot be supported, and look more and more as typical AGW crowd overreach.

Putting the Brakes on Acceleration

Posted on January 8, 2011 by Willis Eschenbach Guest Post by Willis Eschenbach

Various pundits and scientists keep talking about a threatened acceleration in the sea level rise. Here’s the IPCC Fourth Assessment Report:

Anthropogenic forcing is also expected to produce an accelerating rate of sea level rise (Woodworth et al., 2004).

The usual font of misinformation says:

Church and White (2006) report an acceleration of SLR since 1870. This is a revision since 2001, when the TAR stated that measurements have detected no significant acceleration in the recent rate of sea level rise.

Over at the inversely named “SkepticalScience” blog, which is inadequately skeptical, we find:

The blue line in the graph below clearly shows sea level as rising, while the upward curve suggests sea level is rising faster as time goes on. The upward curve agrees with global temperature trends and with the accelerating melting of ice in Greenland and other places.

The Guardian gets in their licks:

Sea levels are already on the rise as a result of increasing temperatures, because the oceans expand as they warm up, but until now scientists have had a poor understanding of how quickly ice sheets such as those in Greenland and Antarctica will begin to disappear.

Meanwhile, back in the world of reality we have the latest satellite data up to September of 2010:

Figure 1. Satellite-measured sea level rise. Errors shown are 95% confidence intervals. Data Source.

The smaller trend of the recent half of the record is statistically different from the larger trend of the first half. Will this reduction continue into the future? Who knows? I’m just talking about the past, and pointing out that we sure haven’t seen any sign of the threatened acceleration in the satellite record. Quite the opposite, in fact.

We now return you to your regularly scheduled warnings of global inundation from accelerating sea level rise …

link:

http://wattsupwiththat.com/

[salbers]

This is still faster than the average during the 20th century, so I wouldn't relax too much at this point.There are decadal variations in the tide gauge history, so this type of fluctuation perhaps can be expected. Is there a way we can link to some related threads over on Eastern Wx? Here also is a good summary where you can see a history of short term variations on a 5-year time scale in the tide gauge data: http://www.wmo.int/p...ws_20080221.pdf

[Sunny and Warm]

This is still faster than the average during the 20th century, so I wouldn't relax too much at this point.There are decadal variations in the tide gauge history, so this type of fluctuation perhaps can be expected. Is there a way we can link to some related threads over on Eastern Wx? Here also is a good summary where you can see a history of short term variations on a 5-year time scale in the tide gauge data: http://www.wmo.int/p...ws_20080221.pdf

What data or time period would you like to see prove matters one way or the other regarding whether sea levels are accelerating or decelerating? It is difficult to read that catastrophe is imminent on one hand, and then be told on the other hand to ignore the current data as inconclusive (since it doesn't agree with the overall premise). It seems you want it both ways. Believe the data that supports catastrophic global warming and question the trend of studies not in agreement with AGW. Not accusing you of deception or singling you out, but I note many on BOTH sides have the habit of discounting any unfavorable information, me included.

[salbers]

What data or time period would you like to see prove matters one way or the other regarding whether sea levels are accelerating or decelerating? It is difficult to read that catastrophe is imminent on one hand, and then be told on the other hand to ignore the current data as inconclusive (since it doesn't agree with the overall premise). It seems you want it both ways. Believe the data that supports catastrophic global warming and question the trend of studies not in agreement with AGW. Not accusing you of deception or singling you out, but I note many on BOTH sides have the habit of discounting any unfavorable information, me included.

I think it's easy to click on the link in my previous post and separate out the 5 year wiggles from the longer term trend. There's a good discussion with that link.

WIth sea level rise it seems to be the most apparent signal with a 50 year time scale (see the Church 2006 paper I think). We can look at shorter scales though and see (as I mentioned) that the most recent decade has a faster sea level rise than the mean of the 20th century (despite the slowing you are plotting). How does this relate to the polar ice sheet accelerating melt? We'll see over time, as this contribution starts to dominate more, compared with the other factors.

With the 5-10 year time scale we do have to consider various other factors with sea level that might not even be climate related.

This is more of a slow motion catastrophe that happens over long time scales, and it is very difficult to reverse once it gets going. So we should therefore endeavor to nip this catastrophe in the bud. Land temperatures though have already risen by about 2.5 degrees F. The oceans less so, because of the time lag and mixing of the heat.