285 – Measuring sea-level change caused by ice-sheet melt

Posted on March 29, 2014 by


There is no question that sea levels change over millennia. This is how Northern Europe looked about 15’000 years ago.



Without going into the issue of what causes current sea-level change (or what to do about it – if anything), we can use satellite data to assess in unimpeachable fashion current sea-level changes induced by ice-sheet melt. After 20 years of continuous reading, a clearer picture is emerging.
ESA has just put on its website a 3 minute video showing that since 1992 average sea-level has risen by over 1 cm due to ice-sheet melt worldwide:
here is the summarizing graph:

Source: ESA
To the ice-sheet contribution by melting, one has to add the expansion of sea-water as it heats up to get total rise in sea levels. Altogether, sea-levels are rising by about 3 mm per year – so ESA. We have no way of making accurate projections about the distant future, as all these phenomena are non-linear and often positively or negatively self-reinforcing.
The only thing I would venture is that we’ll be surprised. The relative stability of the climate in the last ten years has startled some: possibly it was due to a deep revolving of sea water that took warm water in larger quantities and deeper than expected.
The latest tweet about CO2 and climate change and is the role of iron fertilization as a trigger for phytoplankton bloom. Such blooms sequester enormous amounts of CO2 and may have had effects on climate eons ago – or in our future.
Beware: spreading iron fertilizer over the oceans is a simplistic approach to addressing the climate change issue. As in many instances of so-called “biological control” (remember the rabbits and cane toad in Australia), blow-backs are more than likely. In addition, the sea is a three-dimensional ecology. Add this twist: land-lubbers think in two dimensions only, and we are still unable to grasp the intricacies of three-dimensional sea ecology.

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