News24

Global warming to devastate glaciers

2011-01-10 07:24

Paris - Global warming may wipe out three-quarters of Europe's alpine glaciers by 2100 and hike sea levels by 4m by the year 3000 through melting the West Antarctic ice sheet, two studies published on Sunday said.

The research places the spotlight on two of the least understood aspects of climate change: How, when and where warming will affect glaciers on which many millions depend for their water, and the problems faced by generations in the far distant future.

The glacier study predicts that mountain glaciers and icecaps will shrink by 15% - 27% in volume terms on average by 2100.

"Ice loss on such a scale may have substantial impacts on regional hydrology and water availability," it warns.

Some regions will be far worse hit than others because of the altitude of their glaciers, the nature of the terrain and their susceptibility to localised warming.

Computer model

New Zealand could lose 72% (between 65% and 79%) of its glaciers, and Europe's Alps 75%, meaning a range of between 60% and 90%. At the other end of the scale, glacial loss in Greenland is predicted at around 8% and at some 10% in high-mountain Asia.

Melting water will drive up world sea levels by an average of 12cm by 2100, says the study.

This figure - which does not include expansion by the oceans as they warm - largely tallies with an estimate in the landmark Fourth Assessment Report by the UN's Intergovernmental Panel on Climate Change (IPCC) in 2007.

Geophysicists Valentina Radic and Regine Hock of the University of Alaska base these calculations on a computer model derived from records for more than 300 glaciers between 1961 and 2004.

The model factors in the middle-of-the-road "A1B" scenario for greenhouse-gas emissions, by which Earth's mean surface temperature would rise by 2.8°C during the 21st century.

The tool was then applied to 19 regions that contain all the world's glaciers and icecaps. But - importantly - it does not include the ice sheets of Antarctica and Greenland, where 99% of Earth's fresh water is locked up.

If either of these ice sheets were to melt significantly, sea levels could rise by an order of metres, drowning coastal cities.

Collapse


That very scenario emerges in the second study, which focuses on the inertial effect of greenhouse gases. Carbon molecules emitted by fossil fuels and deforestation linger for many centuries in the atmosphere before breaking apart.

Even if all these emissions were stopped by 2100, the warming machine would continue to function for centuries to come, says the investigation.

It largely bases its forecast on the "A2" emissions scenario, which sees greater carbon pollution by 2100, stoking Earth's temperature by an average 3.4°C by century's end.

Warming of the middle depths of the Southern Ocean could unleash the "widespread collapse" of the West Antarctic ice sheet by the year 3000, it says.

"The inertia in intermediate and deep ocean currents driving into the southern Atlantic means those oceans are only now beginning to warm as a result of CO2 (carbon dioxide) emissions from the last century," said Shawn Marshall, a professor the University of Calgary in Canada.

"The simulation showed that warming will continue, rather than stop or reverse, on the thousand-year timescale."

The two studies are published online by the journal Nature Geoscience.

Comments
  • GLOWER - 2011-01-10 08:44

    This might sound like a very cynical thing to say, but global humanity have for so long put it’s own greed and wants first, that it might not be a bad thing if the global disasters ultimately results in it’s demise. Even if it means wiping out populations, bringing governments to knees, devastating economies. Of course humanity first reaction will be to retaliate on this post. This just goes to proof that we are selfish and really do not care about anything else, but our own prosperity and comforts, first and foremost.

      thundacat - 2011-01-10 09:46

      couldn't agree with you more. Humans are responsible for the earth's demise and we deserve exactly what mother nature throws back at us.

      Irené - 2011-01-10 11:35

      agreed! we have only ourselves to blame. I say, just make sure you know about selfsufficient and sustainable living, it might come in handy in the near future.

      Baloo - 2011-01-10 12:11

      We are so arrogant to say that humankind is killing the earth. We are not. We are killing ourselves. The earth has been there for billions of years and will be there for another billions years. But us arrogant humans are killing ourselves as we make it increasingly impossible for humankind to survive. We are poisoning our water supplies, the very air we breath and the ground we depend on to produce food. After we killed ourselves Mother Earth will recover.

  • JudithNkwe - 2011-01-10 09:26

    Humanity will walk over everything including its fellows to ensure its greed is met. I completely agree with you Glower. We are looking at complete loss of potable water in South Africa because the govt refuses to accept the facts that have been reported on since 1963! Whole communities will be wiped out and so will our economic hub - but it's not a crisis!

  • hkwebified - 2011-01-10 09:41

    This coming from people that cant even predict the weather for next week properly!

      G.O.D - 2011-01-10 12:06

      Always at least one douche in every article willing to unleash his stupidity on the rest…How boorish…

      Dave - 2011-01-10 13:16

      I don't blame you for your scepticism as this is a very common criticism, but what they don't know is that there is a huge difference between forecasting for meteorology (ie next week) and for climatology (40+ years).

      CTScientist - 2011-01-11 07:06

      Operational meteorologists aren't the only scientists involved in working out the effects of global warming. While they predict the weather using tools developed by Meteorologists and Synoptic meteorologists, they are not always at the forefront of the climate debates. In any regard, we're also using ice cores/deep sea cores to measure oxygen isotopic levels for the past few hundred thousand years in order to compare today's changing environment to other points in the Earth's history. As far as I was aware.. meteorologists didn't do this?

  • Chewbacca - 2011-01-10 13:25

    Global warming is a natural phenomenon. It will happen whether we speed it up slightly or not. Agree with hkwebified, these guys are as good as predicting the future as our economists.

      Dave - 2011-01-10 13:49

      Natural climate change happens BUT it occurs on the order of 1000's of years. The rate at which things are changing means the both flora and fauna can't adapt as they would naturally, the fynbos biome is being constricted by the change in temperature and rainfall as a very simple example. Yes, as humans we will more then likely survive at the expense of the natural world, but it's not going to be a world that will (climatically) recognise, and what of those communities that can't adapt. Bangladesh is for the most part on a massive river delta that is less then 1m above current sea level. You can't just think that a speeding up of things will end up as the same result in the long run. Environmental thresholds will be broken, species will die and the world will not be the same. The head in the sand tactic wont work.

  • IceBlaster - 2011-01-10 13:49

    Whether global warming is a myth or not, we should all live smarter greener lifes,(eg dont buy a prius just drive more economically and keep your car for longer). Dont go greener and do stupid things like spend millions of rands on something that they not sure will work. 1. clean the water surplies. 2. recycle!!

      Kunikos - 2011-01-10 22:20

      You forgot one: Stop the prolific human breeding cycle, soon it will be anti-social to have more than a single child.

  • pawsaw - 2011-01-10 14:08

    Less is more. Natural phenomena are beyond our control. We can see something coming some of the time but we can't put a date on it or even an exact location. I am with Glower on being cynical. Knowing that these things will happen won't be able to stop them. We may not even be here when it happens. Future generations will have to think of very differentscenarios and survival will depend on the most prepared and the most resourceful and intuitive not necessarily the richest or the smartest.

  • BLACKsoWHAT! - 2011-01-10 14:54

    Everything is subject to change, whether we pay Carbon Tax or not.

  • Rajty - 2011-01-11 10:03

    I think you miss the bigger picture Glower- it's fine to philosophise about our demise as a species, but history has shown that it is generally the poor who carry the brunt of these things- they won't have the means to migrate to safer areas, will not be able to afford rising prices of fresh water etc....perhaps we should just erradicate those people in the devloped world- after all they are the reason that we are heading down this slope.

  • Jakob - 2011-04-18 09:46

    kill the system

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