Questioning Tide Gauge ability to measure global mean sea level rise. (Thompson et al. 2016)

I came across this freshly released study that highlights the short coming of relying on Tide Gauges for estimating global mean sea level rise.  I'm posting this because it reminded me of my Virtual Debate with Dave Burton of NC-20 the North Carolina ocean science denial organization.  They are real estate focused folks who wanted the NC legislature to ignore climate science and sea level rise predictions when planning for the future.  A stellar example of willful ignorance in action.  Dave continues crusading for ignoring the facts at our disposal.

He has an obsessive focus on Tide Gauges and he claims that TGs prove that oceanographers don't know what they are talking about when they warn of accelerating sea level rise and it's consequences based on a combination of measurements.  Dave has particular contempt for satellite data, but never could explain why, in any meaningful manner.  {Dave, here's some more reasons that explain why you are wrong about your sea level claims.}

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http://onlinelibrary.wiley.com/doi/10.1002/2016GL070552/abstract

Tide Gauge Records May Underestimate 20th Century Sea Level Rise

Are long tide gauge records in the wrong place to measure global mean sea level rise? (Thompson et al. 2016) 

Abstract: Ocean dynamics, land motion, and changes in Earth’s gravitational and rotational fields cause local sea level change to deviate from the rate of global mean sea level rise. 

Here, we use observations and simulations of spatial structure in sea level change to estimate the likelihood that these processes cause sea level trends in the longest and highest-quality tide gauge records to be systematically biased relative to the true global mean rate. 

The analyzed records have an average 20th century rate of approximately 1.6 mm/yr, but based on the locations of these gauges, we show the simple average underestimates the 20th century global mean rate by 0.1  ±  0.2 mm/yr. Given the distribution of potential sampling biases, we find < 1% probability that observed trends from the longest and highest-quality TG records are consistent with global mean rates less than 1.4 mm/yr.

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Highlights include enriched and related content of notable journal articles presented on Eos org AGU org AGU On Demand and in AGU journals

Tide Gauge Records May Underestimate 20th Century Sea Level Rise

Leah Crane, September 26, 2016

From Eos.org: Research Spotlights—

Tide gauges can help measure sea level change, but their limited locations and short records make it hard to pinpoint trends. …