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Global sea levels rising higher than forecasted because of ice melting in Greenland and Antarctica

Tuesday, May 21st 2019 - 09:58 UTC
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The long-held view has been that the world's seas would rise by a maximum of just under a meter by 2100 The long-held view has been that the world's seas would rise by a maximum of just under a meter by 2100
Major global cities, including London, New York and Shanghai would be under threat Major global cities, including London, New York and Shanghai would be under threat

Scientists believe that global sea levels could rise far more than predicted, due to accelerating melting in Greenland and Antarctica, The long-held view has been that the world's seas would rise by a maximum of just under a meter by 2100.

This new study, based on expert opinions, projects that the real level may be around double that figure.

This could lead to the displacement of hundreds of millions of people, the authors say.

The question of sea-level rise was one of the most controversial issues raised by the Intergovernmental Panel on Climate Change (IPCC), when it published its fifth assessment report in 2013.

It said the continued warming of the planet, without major reductions in emissions, would see global waters rising by between 52cm and 98cm by 2100.

Many experts believe this was a very conservative estimate.

Ice scientists are also concerned that the models currently used to predict the influence of huge ice sheets on sea levels don't capture all of the uncertainties about how these are now melting.

To try to get a clearer picture, some of the leading researchers in the field carried out what is termed a structured expert judgment study, where the scientists make predictions based on their knowledge and understanding of what is happening in Greenland, West and East Antarctica.

In the researchers' view, if emissions continue on the current trajectory then the world's seas would be very likely to rise by between 62-238cm by 2100. This would be in a world that had warmed by around 5C - one of the worst case scenarios for global warming.

“For 2100, the ice sheet contribution is very likely in the range of 7-178cm but once you add in glaciers and ice caps outside the ice sheets and thermal expansion of the seas, you tip well over two meters,” said lead author Prof Jonathan Bamber from the University of Bristol.

The IPCC report in 2013 only considered what is “likely” to happen, which in scientific terms means they looked at 17-83% of the range of possibilities.

This new study looks at a broader range of results, covering 5-95% of the estimates.

For expected temperature rises up to 2C, Greenland's ice sheet remains the single biggest contributor to sea-level rise. However, as temperatures go beyond this, the much larger Antarctic ice sheets start to come into play.

“When you start to look at these lower likelihood but still plausible values, then the experts believe that there is a small but statistically significant probability that West Antarctica will transition to a very unstable state and parts of East Antarctica will start contributing as well,” said Prof Bamber.

“But it's only at these higher probabilities for 5C that we see those type of behaviours kicking in.” According to the authors, this scenario would have huge implications for the planet. They calculate that the world would lose an area of land equal to 1.79 million square kilometers - equivalent to the size of Libya.

Much of the land losses would be in important food growing areas such as the delta of the Nile. Large swathes of Bangladesh would be very difficult for people to continue to live in. Major global cities, including London, New York and Shanghai would be under threat.

“To put this into perspective, the Syrian refugee crisis resulted in about a million refugees coming into Europe,” said Prof Bamber.

“That is about 200 times smaller than the number of people who would be displaced in a 2m sea-level rise.”

The authors emphasize that there is still time to avoid these type of scenarios, if major cuts in emissions take place over the coming decades. They acknowledge that the chances of hitting the high end of this range are small, around 5%, but they should not be discounted, according to the lead author.

The study has been published in the journal Proceedings of the National Academy of Sciences.

Categories: Environment, International.

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  • :o))


    You summarized it ALL!

    May 23rd, 2019 - 08:49 am 0
  • Jack Bauer

    (cont. “Bzln Military cautions B”)
    1) comparing UK / Bzln pension rules doesn’t make sense; 2), too generous, compared to what ? what I can buy with it ? (not enough, ‘n I don’t splarge) ; 3) it’s 6 times less than Congressmen’s, who besides only having to contribute 8 years, have absurd benefits which no one in the private sector does…’n how about inflation ? does UK’s hover between 5 ‘n 10% /year ? Are yr pensions readjusted by full inflation ? here, private sector pensions aren’t, 'n usually way under, while the Congress adjusts its own salaries/benefits/pensions by 15% plus.
    It’s not that the system was generous to me, it’s under-generous to those on minimum wage (who alrdy work 40 years plus, ‘n retire after 65), ‘n over-generous to politicians ‘n civil servants; It’s far more complicated than you can imagine, th4 difficult for you to grasp.

    In my case, retiring at 61, i/o at 65, made sense, not only because of the mathematical advantage (revenue received in the 4 years would not be compensated by a higher pension 4 years later), the difference of which was not all that much, but because I could get out of the rat race.

    Equalizing public sector pensions to those of the private sector is one of the main proposals of the reform. “Good Lord” ? easy, when they start screwing around at age 13 or 14…promiscuity in the lower classes is pretty high…especially up in the NE, where until quite recently it was quite common to have 10 or more children. At the end of 1963, the government passed a law implementing the “salario família” (family salary), or an ‘extra’ for each kid. This simply added fuel to families having more kids, in the erroneous belief that it would benefit them…but as it was a mere pittance, it just aggravated the situation.

    Re Trump, the Laws are ‘already’ in place…what’s making Trump unpopular with rgds to immigration, is that he is trying to enforce the law. He’s not saying to kill them, just ‘don’t let ‘em in’.

    May 25th, 2019 - 07:30 pm 0
  • DemonTree

    1. Why not? It's the same principle when deciding whatever to retire early.
    2. Too generous compared to what Brazil can afford, as you've been saying all along. I did say people would be losing out as a result - even people like you.
    3. Obviously the special rules for Congressmen should be first on the chopping block, followed by evening up the public and private sector. After that, increasing the retirement age. In the UK the state pension is increased by inflation, more sometimes, but I don't know about workplace pensions. I think I have to buy an annuity with mine and can likely get it inflation-protected in return for a lower amount. I think public sector pensions get increases, but not sure.

    If you weren't already retired and the reform would force you to work until 65, would you oppose it? Or would you continue to support it for the overall good of the country?

    “easy, when they start screwing around at age 13 or 14”

    Even so, that's quick work. With several young kids, how the heck do they find time to screw around? But at least they've mostly stopped having 10 kids each. That's a textbook example of unintended consequences.

    Re Trump, it's the things he says that I was talking about, that have divided the country and set Americans against each other. Sure he didn't say kill them, but he's said some pretty unpleasant things, and he wasn't at all disapproving when that guy in the audience suggested the idea.

    May 25th, 2019 - 09:57 pm 0
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