The lasting legacy of climate change

The lasting legacy of climate change
New research confirms the likelihood of a substantial rise in global sea-level in the future if greenhouse gas emissions continue, and highlights the moral significance of decisions made now about mitigating climate change.

An international team led by Dr Nicholas Golledge, who holds a joint position at Victoria University's Antarctic Research Centre and GNS Science, has published a paper in the respected scientific magazine Nature titled 'The multi-millennial Antarctic commitment to future sea-level rise'. The study predicts how the Antarctic ice-sheet will respond to future atmospheric warming.

Using state-of-the-art computer modelling, Dr Golledge and his colleagues simulated the ice-sheet's response to a warming climate under a range of greenhouse gas emission scenarios. They found that all but one of the scenarios (that of significantly reduced emissions beyond 2020) would lead to the loss of large parts of the Antarctic ice-sheet, which in turn would result in a substantial rise in global sea-level.

"The long reaction time of the Antarctic ice-sheet—which can take thousands of years to fully manifest its response to changes in environmental conditions—coupled with the fact that CO₂ lingers in the atmosphere for a very long time means that the warming we generate now will affect the ice-sheet in ways that will be incredibly hard to undo," says Dr Golledge.

In its 2013 Assessment Report the Intergovernmental Panel on Climate Change (IPCC) predicted that the Antarctic ice sheet would contribute only 5 centimetres to global sea-level rise by the end of this century even for its warmest ('business as usual') emissions scenario.

But Professor Tim Naish, who worked with Golledge on this latest study and who was also a lead author of the IPCC report, cautioned that at the time that report was written there was insufficient scientific knowledge on how the Antarctic ice sheet might respond to future warming, meaning the IPCC sea-level projections could have been too modest.

"Our new models include processes that take place when ice sheets come into contact with the ocean. Around 93 percent of the heat from anthropogenic global warming has gone into the ocean, and these warming ocean waters are now coming into contact with the floating margins of the Antarctic ice sheet, known as . If we lose these ice shelves, the Antarctic contribution to sea-level rise by 2100 will be nearer 40 centimetres," says Dr Golledge.

To avoid the loss of the Antarctic ice shelves, and an associated commitment to many meters of sea-level rise, the study shows atmospheric warming needs to be kept below 2°C above present levels.

"Missing the 2°C target will result in an Antarctic contribution to sea-level rise that could be up to 10 metres above present day," says Dr Golledge. "The stakes are obviously very high—10 percent of the world's population lives within 10 metres of present sea level."

The new findings therefore raise an ethical decision for us all, according to Dr Golledge. "Without significant reduction in greenhouse gas emissions over the next couple of decades, we will commit the Antarctic ice sheet to ongoing and widespread melting for the next few thousand years. Is that something for which we really want to be responsible?"

"In order to restrict global to 2°C, and prevent the more dangerous consequences of climate change, the United Nations meeting in Paris later this year must agree to reduce global CO2 emissions to zero before the end of the century," adds Professor Naish. "To be on track this will require a global commitment to 30 percent reduction, below year 1990 levels, by the year 2030."

Dr Golledge says the time has come for some serious questions to be answered. "It becomes an issue of whether we choose to mitigate now for the benefit of future generations or adapt to a world in which shorelines are significantly re-drawn. In all likelihood we're going to have to do both, because we are already committed to 25 centimetres by 2050, and at least 50 centimetres of by 2100."

Dr Golledge says the last time CO₂ concentrations in the atmosphere were similar to present levels was about 3 million years ago. "At that time average global temperatures were two or three degrees warmer, large parts of the Antarctic had melted, and sea-levels were a staggering 20 metres higher than they are now. We're currently on track for a global temperature rise of a couple of degrees which will take us into that ballpark, so there may well be a few scary surprises in store for us, possibly within just a few hundred years."


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The threat of global sea level rise

More information: N. R. Golledge et al. The multi-millennial Antarctic commitment to future sea-level rise, Nature (2015). DOI: 10.1038/nature15706
Journal information: Nature

Citation: The lasting legacy of climate change (2015, October 15) retrieved 18 July 2019 from https://phys.org/news/2015-10-legacy-climate.html
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Oct 15, 2015
The AGW terror tactics are becoming obsessive with several articles on this site just today.

The Antarctic ice shelves are already floating. If they break off or melt, the oceans will not suddenly rise up and obliterate the land.

Articles claiming doom from AGW are everywhere and repeated on all the news outlets. Articles showing a more moderate view, such as Freeman Dyson's commentary that Obama took the wrong side on climate change can hardly be found. You can find reference to his commentary on congress.

Oct 15, 2015
I wish I could edit on this site with my phone.

Freeman Dyson's commentary can be found on Fox news.

Oct 15, 2015
Somehow we need to find a balance between the ability we now have to note the slightest variations in things like sea levels and temperatures and our reactions to this information. Almost invariably, the reaction is to panic.... we've seen something NEW , this has never happened before, and we should be worried. Unfortunately we forget that the abilities we currently have have only existed for a handful of decades which is nothing on the scale of geologic time. We don't have good context and we have amazingly unrealistic expectations such as when we build cities along the water, the shoreline isn't supposed to change.

Oct 15, 2015
Here we go again. 25 cm by 2050 means for the next 35 years we have to average 8mm / year. The current rise is 2-3mm/year. How do we get from 2-3 to 8? This guy is smart I presume. Does he just think we are all idiots? I realize a lot of people will just swallow this without thinking but in the long run won't he ever be accountable for saying things that are so improbable? The fact is that not only is sea level not accelerating it is not even clearly rising. Tide guages around the world haven't moved for decades. It is unclear how much rise is occuring but it could easily be much less than 2-3mm/year. It can't be much more because we would see things starting to disappear. It would be noticeable. The fact is all these threats of rising seas are not factually reinforced with actual rising seas observable by humans even over decades. There is factual evidence by physical observation of known landmarks that seas have not risen much in many places.

Oct 15, 2015
If there were physical evidence of such rising seas then after 50 years of 2-3mm we should see about 5 inches of rise. There should be physical evidence in places of things that were typically above water by 5 inches that are below however, I have never seen such evidence. If there were such evidence I expect the proponents of these sea rising scares would be pointing to it and it would be common knowledge. The sheer fact there isn't such common knowledge indicates it is unlikely that sea levels have been rising more than 2mm/year. Will they rise faster? That is what keeps being said but facts are that this is pure speculation. It is just not known but predicting an avg of 8mm for year for the next 35 years seems highly unlikely because unless sea levels start rising much faster very fast this becomes simply impossible very quickly. There is evidence there is a physical limit of 4mm to how fast seas can rise due to logical limits to melting and flows regardless of temps

Oct 15, 2015
Lastly his worry that over thousands of years rising seas will be a problem for mankind is absurd. It would be insane to spend a dime to forestall a modest cost 1000 years from now. Besides the obvious fact we don't have enough certainty to say anything about what will happen 20 years from now let alone 1000 years. It is pointless to speculate about that or any consequences, costs to children or such completely unknowable information. Mankind is incredibly adaptable and it is ridiculous to worry about mans problems 1000 years from now given that we have no idea what man's situation will be then. In the 70s we were polluting the atmosphere in the US. Today the skies are cleaner than they have ever been. Not saying they are perfect but the fact is anything we do whether putting up CO2 or whatever is something that given 1000 years man will undoubtedly have the ability to reverse or deal with little or no effort. So, it is not obvious that any prediction can be set in stone.

Oct 15, 2015
"Above all, as this revealing paper shows, the Professor has heard the keepers of the global satellite altimetry record of sea-level rise admitting – nay, proclaiming – that they
had tilted the sea-level record for the entire satellite era to make it show a rate of increase, for the raw data from the satellites show no sea-level rise at all. "
http://scienceand...sing.pdf

Oct 15, 2015
"Freeman Dyson's commentary can be found on Fox news."
--------------------------

Well, of course it can. And the real views of real scientists in the field can be found in peer-reviewed reports.

And in the recent news as well:

http://america.al...eas.html

Oct 15, 2015
gkam,
Perhaps you should read the article and follow the links to the published paper before you comment derogatorially?

Mr. Dyson has actually worked as a climate scientist.

Oct 15, 2015
He has? I read the summary of the report, (http://www.nature...6.html), the authors, looked at all the references, looked into the supplemental material, and searched for the name of Dyson, and found nothing.

Which links did you mean?


Oct 15, 2015
"Above all, as this revealing paper shows, the Professor has heard the keepers of the global satellite altimetry record of sea-level rise admitting – nay, proclaiming – that they
had tilted the sea-level record for the entire satellite era to make it show a rate of increase, for the raw data from the satellites show no sea-level rise at all. "
http://scienceand...sing.pdf


The Science and Public Policy Institute (SPPI) is a global warming skeptics website and blog now run by the Center for the Study of Carbon Dioxide and Global Change, which employs SPPI President Robert Ferguson; the SPPI website has drawn heavily on papers written by Christopher Monckton.

SPPI is not a separate 501(c)(3) nonprofit.

Oct 15, 2015


The Antarctic ice shelves are already floating. If they break off or melt, the oceans will not suddenly rise up and obliterate the land.

No they are not, most rest on the sea bed , and their grounding lines are retreating inland.

They act as a brake to slow the flow of glaciers inland.


Oct 15, 2015
From wikipedia:
Around 1979, Dyson worked with the Institute for Energy Analysis on climate studies. This group, under the direction of Alvin Weinberg, pioneered multidisciplinary climate studies, including a strong biology group. Also during the 1970s, he worked on climate studies conducted by the JASON defense advisory group.

Oct 15, 2015
I read the references.

They are from dedicated pressure groups trying to argue against AGW, or even GW. They are political and economic players, not scientific interests.

Oct 15, 2015
gcam,
So you dismiss scientists of Dyson's caliber of their views are contrary to yours.

My point on this thread is that any scientist whose opinion is contrary to the politically correct position is ignored. You confirm my point.

Oct 15, 2015
No, doggie, I considered his point, but follow the news and the studies, and the arguments. I happen to disagree with him. I split with Dyson a long time ago, when he was excited and happy about nuclear weapons, and I wasn't.

Oct 15, 2015
gcam,
So you dismiss scientists of Dyson's caliber of their views are contrary to yours.

My point on this thread is that any scientist whose opinion is contrary to the politically correct position is ignored. You confirm my point.


Editorial Exxon's damaging denial on climate change

Before most Americans were even aware of global warming, Exxon was investing in high-quality research on the subject. According to reports in the Los Angeles Times and elsewhere, the oil company's scientists concluded in the 1970s, '80s and '90s that climate change was real, would transform the Earth's landscape and was driven by human activity — especially the burning of fossil fuels.

http://www.latime...ory.html

Oct 15, 2015
The AGW terror tactics are becoming obsessive with several articles on this site just today.

The Antarctic ice shelves are already floating. If they break off or melt, the oceans will not suddenly rise up and obliterate the land.

Articles claiming doom from AGW are everywhere and repeated on all the news outlets. Articles showing a more moderate view, such as Freeman Dyson's commentary that Obama took the wrong side on climate change can hardly be found. You can find reference to his commentary on congress.


Says someone who doesn't know the difference between land and sea ice and who quotes Freeman Dyson over actual climate scientists. Talk to the BAS, then come back.

Oct 16, 2015

The Antarctic ice shelves are already floating. If they break off or melt, the oceans will not suddenly rise up and obliterate the land.
.

That is obviously not what they implied, idiot. Firstly, nobody CLAIMS it will "suddenly rise"; that is just stupid straw man.
Secondly, the loose of the surrounding floating ice would mean a speed up of glacier movement from the ice sheet that is currently on top of the land to the oceans (because of reduction in back-pressure ) and it is THIS that will cause the GRADUAL, (over some decades ) NOT "sudden", sea rise. Get it?

Oct 16, 2015
The climate deniers are looking for a hero. Hence the obsession for Dyson. No other eminent scientist apparently fit the requirements.
Dyson is an excellent physicist, but when it comes to climate science he resembles other great scientists who were dead wrong.

Oct 16, 2015
gcam,
My point on this thread is that any scientist whose opinion is contrary to the politically correct position is ignored. You confirm my point.

Of course Dyson, an 85 retired scientist of great reputation, who retired decades ago,
does not get the same volume of attention as all active climate scientists combined during a conference to which Dyson does not participate as he is totally inactive.
How does that surprise you?

Oct 16, 2015
Hi all. Keeping in touch/commenting occasionally. Today, a reality check for Dogbert (and Shootist etc) re Freeman Dyson's actual stance re climate change:

https://en.wikipe..._warming

Dyson agrees that anthropogenic global warming exists, and has written that "[one] of the main causes of warming is the increase of carbon dioxide in the atmosphere resulting from our burning of fossil fuels such as oil and coal and natural gas."[55] However, he believes that existing simulation models of climate fail to account for some important factors, and hence the results will contain too much error to reliably predict future trends:
Unfortunate that the usual spamming of 'Dyson quotes' by shootist et al do not include the above.

Dyson's quibble is ONLY with climate 'modeling' reliability, and NOT climate change fact/causes per se.

So give it a rest dogbert/shootist etc. You misrepresent Dyson badly. :)

Bye.

Oct 16, 2015
RealityCheck is still here too! It's cool coming back and seeing the same stalwart user names.

I try and find a positive angle to the whole climate collapse thing. At least, if humanity survives, this will do for anti-intellectualism what Hitler and Mussolini did for philosophical dabblers in fascism : make it completely disgusting to several generations. If the human species holds together and keeps civilization open at least during business hours, science will be the new global way of human thinking, since the alternative will be extinction. Denying someone the tools of thinking will be seen as denying them a capacity to survive, because on a planet unadapted to humans it will be like sentencing them to death.

So even though I am philosophically opposed to there being a machine that saves us from the consequences of our actions, please make a machine that eats CO2. I would rather live in stupid no consequence world. I say this as a critical thinker, and a comedian.

Oct 16, 2015
RealityCheck,

Dyson's quibble is ONLY with climate 'modeling' reliability, and NOT climate change fact/causes per se.

So give it a rest dogbert/shootist etc. You misrepresent Dyson badly. :)


I did not misrepresent Dyson at all. I noted that he said Obama took the wrong side on climate change -- and he did say that.

Then I provided links to Dyson's commentary -- which was Dyson's commentary.

Why don't you try the truth sometime instead of misrepresenting what others say?

Oct 16, 2015
Hi dogbert. :)
I noted that he said Obama took the wrong side on climate change -- and he did say that.

Then I provided links to Dyson's commentary -- which was Dyson's commentary.
Ok, mate, Sorry if I misrepresented you on this. :)

Does this mean you and shootist etc AGREE that anthropgenic global warming is real and becoming an urgent issue as climate change/warming nears the 'tipping point' stage which triggers release of massive, previously 'geologically sequestered', CO2/Methane (like in hydrates/clathrates and permafrost)?

If so, then time for quibbling about accuracy of various 'models' is over.

I long ago pointed out the inadequacies of various modeling with GIGO potential. But I ALSO warned that arguing about incomplete 'modeling' was a 'distraction' from the main point...to take serious action asap before it's too late.

See? Why quibble over 'models'. By the time 'models' ARE 'accurate' it WILL be too late. Dyson quotes won't help. Good luck. :)

Oct 17, 2015
Dogbert, bugger yourself until you bleed to death and stop spamming this site. This is a source? Yeah, do just go fuck yourself and leave Gloria alone. Godamned xtians again. Surprise.

Dyson considers himself a non-denominational Christian and believes in non-overlapping magisteria; some of the material he has written on metaphysics, though, is much less Christian than it is reminiscent of various theories of quantum consciousness, panentheism, panpsychism, and other sorts of New Agey science woo.

Dyson has succumbed to old age crank syndrome as well, becoming a global warming denier. Dyson's support for deniers seems to be the result of wanting to stick it to the scientific man:

""My objections to the global warming propaganda are not so much over the echnical facts, about which I do not know much, but it's rather against the way those people behave and the kind of intolerance to criticism that a lot of them have. I think that's what upsets me.

Oct 17, 2015
RealityCheck4.8 / 5 (4) 15 hours ago
Hi dogbert. :)
I noted that he said Obama took the wrong side on climate change -- and he did say that.

Then I provided links to Dyson's commentary -- which was Dyson's commentary.
Ok, mate, Sorry if I misrepresented you on this. :)


Why are you apologizing to a spammy troll? Do you think he ever exercises any consideration before cutting and pasting the exact same youtube links over and over and over and over? These are sadistic little mental cases and weakness encourages them. The only way you'll ever see consideration from that ilk is when you start talking about knocking their teeth down their throat.

gkam is right. The *only* reason one makes a youtube video is to cover having to cite facts/references. In the age of the habitual gen X liar it has become the go-to resource for every confidence scammer wannabee.

Oct 17, 2015
We should not be discussing Dyson here. If he really said "My objections to the global warming propaganda are not so much over the technical facts, about which I do not know much, but it's rather against the way those people behave and the kind of intolerance to criticism that a lot of them have. I think that's what upsets me." then he is irrelevant.
Lets talk about Exxon instead. They had established AGW as a fact in 1978, but opted for denial, in the mean time upgrading arctic investments motivated by the coming thaw.
http://www.thegua...-warming

Oct 17, 2015
Lets talk about Exxon instead.

Let's talk about you first.
Tell us the date you stopped using electricity and fuel derived from fossil fuels?

Oct 17, 2015
two cents is right: Investigation for prosecution is warranted.


Oct 17, 2015
http://science.nasa.gov/science-news/science-at-nasa/2013/08jan_sunclimate/


"If there is indeed a solar effect on climate, it is manifested by changes in general circulation rather than in a direct temperature signal." This fits in with the conclusion of the IPCC and previous NRC reports that solar variability is NOT the cause of global warming over the last 50 years."Much has been made of the probable connection between the Maunder Minimum, a 70-year deficit of sunspots in the late 17th-early 18th century, and the coldest part of the Little Ice Age, during which Europe and North America were subjected to bitterly cold winters. The mechanism for that regional cooling could have been a drop in the sun's EUV output; this is, however, speculative."

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