Sea level rising by ‘paddling’ levels over a century

NASA published data this week on a more recent series of satellite estimates that are six times higher than the ABC claims. But even they don’t add up to more than a wading-pool’s depth.

NASA recently announced that it is preparing to launch a second ocean surface measurement experiment (Jason-2). In the press release that accompanies the announcement, the actual rise in sea levels in the past 15 years, based on the current satellite data, is revealed:

From Topex/Poseidon and Jason 1, we know that mean sea level has been rising by about three millimeters (.12 inches) a year since 1993. This is about twice the estimates from tide gauges for the previous century, indicating a possible recent acceleration in the rate of sea level rise.

Let’s put that in perspective. Three millimeters a year is 33 centimeters per century, or a tad over 1ft in imperial measures.

The NASA division responsible for this ocean-surface experiment goes on to say, in their press release:

“Based on reconstruction of past sea level patterns using Topex/Poseidon and Jason 1 observations, scientists have found that the acceleration is likely to be part of the decadal variability of the ocean. But 15 years of data are simply not enough to determine long-term trends of sea level change. OSTM/Jason 2 will continue to monitor sea level changes and allow us to better understand its long-term variations“.[emphasis added]

You might also be interested to learn about the short-term and local variability of the sea-level that far outreaches the long-term trend:

Changes in the height of the global ocean due to ocean currents and thermal differences vary by as much as two meters (6.5 feet) from one place to the next. Before Topex/Poseidon and Jason 1, we didn’t know how much those heights fluctuated. We’ve learned that the height of sea surface over areas larger than the United States can move up and down by 20 centimeters (8 inches) in just 20 days.

If Kiribati or Tuvalu or the Seychelles reckon that they’re threatened by a century average rise of 33 cm (if that’s what it turns out to be), they must count themselves lucky they aren’t in the path of these much bigger day-to-day and place-to-place bumps in the ocean.

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