Sea-level rise faster than predicted

By Bianca

After I have just written the article about the use of satellite missions in monitoring the polar ice caps, I just came across the news that satellite measurements show a much faster sea-level rise than previous models have suggested. Satellite altimetry, such as the ICESat mission is the most common method used to monitor sea-level height changes over time. The study, by the German oceanographer and climatologist Stefan Rahmstorf, found that sea-levels are rising at an annual rate of 3.2 mm, which is 60% faster than the best estimate of 2 mm.

At the same time I found another article that has been just published, using the GRACE space mission, saying that ice sheet melting has been massively overestimated. Improved measurement analysis of the GRACE data suggest that the Greenland ice sheet is melting at a lower rate than expected, and is predicted to have melted completely in about 13,000 years (at the earliest) and to cause a global sea-level rise of 5 cm by the year 2130.

Now, just a day later, a new paper has been published with the news that Greenland is melting five times faster than it was in the 1990s. 47 scientists from 26 key labs have contributed to this study, using results from 10 different satellites. Their estimations are named to be the most reliable to date, providing the clearest evidence of polar ice sheet losses.

The amount of data that has contributed to the latest paper and the results that sea-level rose much faster than predicted leads to the assumption that the latter paper is more reliable on the results of ice sheet mass loss.

However, the errors on the estimated values still remain large and it actually is possible that the ice is decreasing more slowly than most scientists think. That in turn would rise the question; what other factors contribute to the intense sea-level rise? Could it be thermal expansion, as is suggested in the article?

After all, the publications just show once again how difficult the issue of ice mass loss and sea-level rise is and how important it is to undertake more research, especially with the study of polar ice sheet mass balance.

3 responses to “Sea-level rise faster than predicted

  1. kamikazewarrior

    Dear Friend,

    Fear not:

    If/when the ocean levels rise, we will know about it. Our worlds major coastal cities will be flooded.

    With Love,

    Matt

  2. Global sea level is rising – this is an observation, as noted by these articles. It isn’t rising so quickly that all of the sudden coastal cities will be flooded.

  3. Dear Matt,

    Please take the time to look at this link:

    http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/solact.html

    It explains the picture that is shown in the video clip and explains very well what is wrong with it!
    (If you pause the video at 6.30 min you can compare the pictures directly).

    The first thing you should wonder when seeing the graph in the video is, why does the orange line stop at 1980 while the blue line is shown till 1990? That would be the first thing I would be sceptic about…
    As explained on the website mentioned before, that picture is actually altered to correct their data but does not agree with the temperature increase after 1980!
    That means within the last two decades the solar activity went down, while the temperature increased further.
    The idea that global climate changes with the sun activity might have been true till 1980 but since then it has changed!
    We are living in 2012, you cannot simply use results that stop at 1980 and say nothing has changed! The main change in global warming/sea-level rise/ice sheet melting/extreme weather has occurred mainly within the past few decades and that is the part sceptic’s hide when convincing people like you that global warming is a myth. Unfortunately, it’s not and if we don’t want our major cities flooded it is time to change something!

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