A salty climate “bonbon”

Worried by Ross Garnaut’s claim in his revised review that sea levels are rising faster than even the U.N. predicted:

“Rising sea levels will continue to increase the frequency and intensity of coastal flooding events during the 21st century. Observations indicate that therehas been a significant increase in the frequency of extreme high sea levels within Australia”?

Well, if you look at the data instead of the models, the facts don’s support any such alarms. Here is a picture of sea levels at Sydney since 1992 from the JASON satellite (NASA) monitoring facility at the University of Colorado, that I hope will make you feel a lot better.

Sea Levels at Sydney from the NASA JASON satellite

That’s right: the latest satellite data shows over that period there has been a fall in sea levels at Sydney (longitude 151 E, latitude 33 S) at a rate of 0.14 cm per year. The grey line is the un-smoothed data.Here’s the data for the picture.

Global sea levels from the NASA satellite series

Over a wider geographic range of the sea there is a positive trend in sea-levels that the satellites measure for the period since 1992 at 3.1 mm/year (+/- 0.4 mm). That’s about 1ft per century in the old currency—paddling depth. Even the current slow rate of sea-level rise is likely to be higher than we’d see if we had such accurate measurements for a longer time-frame because this rise has been observed during a period of warming in the sea surface. Thermal expansion accounts for at least half (and in future maybe most) of the rise in sea levels.

GISS Sea Surface Temperatures

As it happens, global sea surface temperatures are falling, as the NASA (GISS) data show, perhaps reflecting the reversal of the Pacific decadal oscillation.

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