NASA space lasers show sea levels have risen by 14mm in 17 years – but what’s the latest trend?

Posted: May 1, 2020 by oldbrew in climate, Measurement, methodology, sea ice, sea levels
Tags: , ,

Kangerlussuaq Fjord, Greenland [image credit: notsogreen.com]


Less than a year ago NASA was reporting from Greenland: Jakobshavn Glacier Grows for Third Straight Year, and ‘The glacier grew 22 to 33 yards (20 to 30 meters) each year between 2016 and 2019.’ So this new report may be, to some degree at least, already obsolete since it says: ‘The largest thinning rates were between 4 and 6 m a−1 in Jakobshavn and Kangerlugssuaq glaciers’.
– – –
Sea levels have risen by 14mm since 2003 due to ice melting in Antarctica and Greenland, scientists have said.

Nasa launched a satellite to measure global heights in 2018 and spotted the rise after bouncing laser pulses against sheets of ice, says the London Evening Standard.

The study found that Greenland lost an average of 200 billion tonnes of ice per year, and Antarctica lost an average of 118 billion tonnes.

One billion tonnes of ice is enough to fill 400,000 Olympic-sized swimming pools.

A team led by researchers at the University of Washington compared the data with measurements taken by the satellite between 2003 and 2009.

The findings, published in the journal Science, found the loss of ice from Antarctica and Greenland outweighs any gains from accumulated snow.

Lead author Benjamin Smith, a glaciologist at the University of Washington, said: “If you watch a glacier or ice sheet for a month, or a year, you’re not going to learn much about what the climate is doing to it.

“We now have a 16-year span between ICESat and ICESat-2 [satellites one and two] and can be much more confident that the changes we’re seeing in the ice have to do with the long-term changes in the climate.

“And ICESat-2 is a really remarkable tool for making these measurements. We’re seeing high-quality measurements that carpet both ice sheets, which let us make a detailed and precise comparison with the ICESat data.”

Full article here.
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AAAS Science report: Pervasive ice sheet mass loss reflects competing ocean and atmosphere processes.

Comments
  1. ivan says:

    Since they are measuring in mm what are they using as a calibration point near where they are measuring? If they don’t have such a calibration point then their measurements are meaningless although they may look good to the green slime.

  2. Graeme No.3 says:

    So, from their ‘measurements’ it will take 1215 years for the sea level to rise a metre.
    I thought we were going to see at least 3 metres by 2100. They will be in trouble with the alarmists.

  3. oldbrew says:

    What they did was to use ICESat-2 results to adjust the *problems* with the ICESat results. But ICESat-2 was only launched in late 2018, so most of the data was liable to be adjusted.

    NASA’s next generation laser altimeter ICESat-2 was designed to eliminate many of these problems. Launched 15 September 2018, ICESat-2 has a high sampling rate (0.7 m along-track), narrow footprint (~14.5 m), and near-global coverage (±88° latitude) repeating every three months, with a six-beam geometry that enables instantaneous cross-track slope determination (fig. S1).
    We compare ICESat-2 data (October 2018 to February 2019) to data from the ICESat mission (September 2003 to October 2008), which sampled a more coarsely spaced set of tracks to ±86° latitude (Fig. 1A) (25).

    https://science.sciencemag.org/content/early/2020/04/29/science.aaz5845
    – – –
    Graeme – yes, not very alarming, what a shame. Maybe coastal dwellers can get insurance after all 😎

  4. Curious George says:

    Did anybody check with tide gauges?

  5. ivan says:

    What they did was to use ICESat-2 results to adjust the *problems* with the ICESat results. But ICESat-2 was only launched in late 2018, so most of the data was liable to be adjusted.

    So basically they are correcting unverified data with unverified data which gives a very questionable accuracy – maybe a couple of metres.

    Without verified fixed height points they are never going to get accurate measurements. They are assuming the satellite is in a stable orbit – not falling down or leaving the earth but I question just how stable that is in relation to the earth surface – solar wind, moon position etc. Unless they can actually prove they get the same measurements each pass over a fixed position on solid ground, without having to add a fudge factor, I will question their mm height differences.

  6. Zoe Phin says:

    And if you look at a global map of ocean level rise, you will quickly realize it’s not CO2. It’s geothermal.

    P. S. Check out
    http://phzoe.com/2020/04/29/the-irrelevance-of-geothermal-heat-flux/

  7. Tom Williams says:

    Due to the Roman warm period and the Medieval warm epoch, there should be geological and archaeological evidence that seas have been this high prior to the Little Ice Age. The same applies on land where old Viking paths and artifiacts from the Warm period have just been discovered after glaciers receded. This info seems to have been suppressed by those with a stake in the “Manmade Climate Change” mindset. I hope that there are studies done in coastal areas regarding past sea levels and movements of humans related to them.

  8. stpaulchuck says:

    Ivan, I don’t know of any ‘stable’ land points. Perhaps one of the folks here can relate one or more.

    For instance, there are two slow but significant geological effects that mess up the ‘stable’ concept: continental rebound in the Midwest US/Canada since the kilometer of ice is gone, and every day tectonic forces at subduction zones causing mountains and general uplift. I’m sure in general something like that obtains around the world.

    And then there’s tidal effects of the moon which must have some effect on land mass. Consider they are talking about 1 mm steps (or less) per year, and like you say, compared to what exactly??

    How do they calculate the tidal effect of orbital height as the moon swings by?

    Any info out there guys?

  9. oldbrew says:

    Global Temps Drop Back (A Bit)
    Date: 01/05/20 Dr Roy Spencer blog

    In April 2020, the Northern Hemisphere extratropics experienced its 2nd largest 2-month drop in temperature in the 497-month satellite record.

    https://www.thegwpf.com/global-temps-drop-back/
    – – –
    Solar minimum.

  10. hunterson7 says:

    Since we have been told for years that the 3mm / year historical trend is actually dangerous, finding out that instead the SLR trend is much less is great news. That is if we weren’t living in a dark age this news would be seen for what it is: yet another line of evidence that the apocalyptic worldview of the popular climate consensus is wrong.

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