Long-term picture offers little solace on climate change

February 8, 2016 by David Tenenbaum
The Philippines is one of many densely-populated nations in and around Southeast Asia that are endangered by rising sea levels caused by global warming. Global average sea level is rising 3.1 centimeters per decade. Credit: Department of Foreign Affairs and Trade

Climate change projections that look ahead one or two centuries show a rapid rise in temperature and sea level, but say little about the longer picture. Today (Feb. 8, 2016), a study published in Nature Climate Change looks at the next 10,000 years, and finds that the catastrophic impact of another three centuries of carbon pollution will persist millennia after the carbon dioxide releases cease.

The picture is disturbing, says co-author Shaun Marcott, an assistant professor of geoscience at the University of Wisconsin-Madison, with a nearly inevitable elevation of sea level for thousands of years into the future.

Most climate projections now end at 2300 at the latest, "because that's the time period most people are interested in," says Marcott, a expert in glaciers and ancient climate. "Our idea was that this did not encapsulate the entire effect of adding one to five trillion tons of to the atmosphere over the next three centuries. Whereas most studies look to the last 150 years of instrumental data and compare it to projections for the next few centuries, we looked back 20,000 years using recently collected carbon dioxide, global temperature and sea level data spanning the last ice age. Then we compared past data to modeling results that extend 10,000 years into the future."

Climate—the interplay among land, ocean and atmosphere—has a long memory, Marcott says. "I think most people would tell you that temperature and sea level will spike as we continue burning fossil fuels, but once we stop burning, they will go back down. In fact, it will take many thousands of years for the excess carbon dioxide to completely leave the atmosphere and be stored in the ocean, and the effect on temperature and sea level will last equally long."

Chrisangel Nieto, age 3, rode his tricycle in front of the Valero refinery in Houston. This refinery processes almost 7 million tons of carbon per year, most of which will end up in the atmosphere as carbon dioxide. Credit: Earthjustice

The study looked at the impact of four possible levels of that would start in 2000 and end in 2300. The complex modeling effort was organized by Michael Eby of the University of Victoria and Simon Fraser University.

"Carbon is going up, and even if we stop what we are doing in the relatively near future, the system will continue to respond because it hasn't reached an equilibrium," Marcott explains. "If you boil water and turn off the burner, the water will stay warm because heat remains in it."

A similar but indescribably more complex and momentous phenomenon happens in the climate system.

New data on the relationship among carbon dioxide, sea level and temperature over the last 20,000 years was the basis for looking forward 10,000 years. "Now that we know how these factors changed from the ice age to today," Marcott says, "we thought, if we really want to put the future in perspective, we can't look out just 300 years. That does not make sense as a unit of geological time."

Current releases of the carbon contained in carbon dioxide total about 10 billion tons per year. The number is growing 2.5 percent annually, more than twice as fast as in the 1990s.

People have already put about 580 billion tons of carbon dioxide into the atmosphere. The researchers looked at the effect of releasing another 1,280 to 5,120 billion tons between 2000 and 2300. "In our model, the carbon dioxide input ended in 300 years, but the impact persisted for 10,000 years," Marcott says.

A 5- to 10-meter stream of meltwater flows on the Greenland icecap. Credit: M. Tedesco/CCNY/NASA

By 2300, the had soared from almost 400 parts per million to as much as 2,000 parts per million. The most extreme temperature rise—about 7 degrees Celsius by the year 2300 or so—would taper off only slightly, to about 6 degrees Celsius, after 10,000 years.

Perhaps the most ominous finding concerns "commitment," Marcott says. "Most people probably expect that temperature and carbon dioxide will rise together and then temperature will come down when the carbon dioxide input is shut off, but carbon dioxide has such a long life in the atmosphere that the effects really depend on how much you put in. We are already committed to substantial rises in temperature. The only question is how much more is in the pipe."

The warming ocean and atmosphere that are already melting glaciers and ice sheets produce a catastrophic rise in the ocean. "Sea level will go up due to melting, and because warming expands the ocean. We have to decide in the next 100 years whether we want to commit ourselves and our descendants to these larger and more sustained changes," Marcott says.

First author Peter Clark and co-authors calculated that ocean encroachment from just the lowest level of total carbon pollution would affect land that in 2010 housed 19 percent of the planet's population. However, due to climate's momentum, that effect will be stretched out over thousands of years.

"This is a stunning paper," says Jack Williams, a professor of geography and expert on past climates at UW-Madison. "At one level, it just reinforces a point that we already knew: that the effects of and sea level rise are irreversible and going to be with us for thousands of years," says Williams, who did not work on the study. "But this paper shows just how devastating sea level rise will be, once we look out beyond 2100 A.D."

The melting in Greenland and Antarctica from the highest level of carbon pollution "translates into a of 80 to 170 feet," Williams says. "That's enough to drown nearly all of Florida and most of the Eastern Seaboard."

For simplicity, the study omitted discussing other major drivers and effects of climate change, including ocean acidification, other greenhouse gases, and mechanisms that cause warming to accelerate further.

"It's worrisome, for sure," says Marcott. "I don't see any good thing in this, but my hope is that you could show these graphs to anyone and they could see exactly what is going on."

Marcott says a recent slogan of climate campaigners, "Keep it in the ground," is apt. "In the ideal situation, that is what would happen, but I can't say if it is economically or politically viable."

"The paper emphasizes that we need to move to net-zero or net-negative carbon emissions and have only a few more decades to do so," says Williams. "But the real punch in the gut is the modeled rise and its implications."

Explore further: Will warming records keep tumbling?

More information: Consequences of 21st Century Policy for Multi-Millennial Climate and Sea-Level Change, Nature Climate Change, DOI: 10.1038/nclimate2923

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37 comments

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marcush
4.7 / 5 (12) Feb 08, 2016
Ouch.
KipHansen
1.9 / 5 (13) Feb 08, 2016
This study makes the egregious error of extending a current short-term trend line (1800-2000s) indefinitely into the future -- on the order of "if the rise in obesity continues at the current rate, by 2100 150% of Americans will be obese."

Vietvet
4.2 / 5 (20) Feb 08, 2016
This study makes the egregious error of extending a current short-term trend line (1800-2000s) indefinitely into the future -- on the order of "if the rise in obesity continues at the current rate, by 2100 150% of Americans will be obese."



"New data on the relationship among carbon dioxide, sea level and temperature over the last 20,000 years was the basis for looking forward 10,000 years."

Read more at: http://phys.org/n...html#jCp
aksdad
2 / 5 (12) Feb 08, 2016
The earth has been cycling between ice ages for hundreds of thousands of years and humans can't do anything to stop it. So sad!

http://www.climat...20BP.gif

Notice that the cold periods with mile-thick ice covering lots of the northern hemisphere last for about 100,000 years and the warm periods for only around 10,000 years or so. We're optimally situated toward the end of the latest warm period right now; excellent for agriculture in the northern hemisphere and the flourishing of homo sapiens and other species.

Ancient sea-level data suggests we may have more warming in the future. According to the latest IPCC report (AR5 2013) sea levels were "at least" 5 meters higher at the peak of the last warming period 129,000 years ago. It will take another 1,600 years at the current rate of sea level rise, about 3 mm per year, to get there, but after that, it might become unseasonably cold for another 100,000 years.

Perspective. So refreshing.
drewstead81
1.4 / 5 (13) Feb 08, 2016
LIES LIES LIES!!!! What has happened at least the last 4 times the CO2 level got this high after a glacial period? SNOWBALL EARTH HAPPENED! Not just the usual 20K yr Ice-Age, THIS IS THE BIG ONE! All that ice will melt thanks to human intervention and sea level will rise this is true....but in the next 2,000 years we will see all the CO2 disappear as the ice sheet grows to mammoth proportions like it does every 100K yrs....
drewstead81
1.3 / 5 (13) Feb 08, 2016
ALSO,, they proved there's a another planet with a period of 20,000 years, you cant stop the Ice Age when Nibiru approches the sun it will be close to Neptune for a portion of its elliptical orbit pulling the Earth into an exaggerated orbit,
gkam
3.7 / 5 (9) Feb 08, 2016
Yup, and in about five billion years, the Aten will eat the Earth.

Until then, I am going to live, and keep postponing the inevitable. Okay?
Uncle Ira
4.3 / 5 (12) Feb 08, 2016
ALSO,, they proved there's a another planet with a period of 20,000 years, you cant stop the Ice Age when Nibiru approches the sun it will be close to Neptune for a portion of its elliptical orbit pulling the Earth into an exaggerated orbit,

Skippy I sure hope you get more interesting in a hurry.
gkam
3.9 / 5 (7) Feb 08, 2016
"you cant stop the Ice Age when Nibiru approches the sun"
-----------------------------------------

OMG, . . . and all this time I was worried about Xenu.
philstacy9
1.9 / 5 (9) Feb 09, 2016
Immediately defund all science except climate science since it is waste of time to advance science when climate change will soon exterminate the human race and erase that science.
Physics websites can be converted to pot growing tutorials.
Caliban
3.5 / 5 (8) Feb 09, 2016

Perspective. So refreshing.


Agreed, sackbag.

Too bad you'll have to wait the whole of your miserable existence to experience it for the first time --if ever.

Just a detail: Humanity is no better equipped to face the return of the Ice than it is to face the Fire.

What a maroon.

antialias_physorg
4 / 5 (8) Feb 09, 2016
"The paper emphasizes that we need to move to net-zero or net-negative carbon emissions and have only a few more decades to do so," says Williams. "But the real punch in the gut is the modeled sea level rise and its implications."

Looks like childhood is over. We made a mess, now we have to clean it up.
KipHansen
2.1 / 5 (11) Feb 09, 2016
""New data on the relationship among carbon dioxide, sea level and temperature over the last 20,000 years was the basis for looking forward 10,000 years."

Speculation about past causes and effects does not equal "new data" nor "new discovery" -- speculation is just speculation -- it can be interesting, but is no basis for making entirely untenable, unscientific "predictions" about the distant future.
gkam
3.4 / 5 (5) Feb 09, 2016
jeffensley
1.8 / 5 (10) Feb 09, 2016
We have no idea what the climate will look like in a century, much less 10,000 years. Why people put any stock in these predictions is beyond me. We don't even have the capability to see and accurately quantify all the variables of our existing climate, much less a future one.
Caliban
4.2 / 5 (10) Feb 09, 2016
We have no idea what the climate will look like in a century, much less 10,000 years. Why people put any stock in these predictions is beyond me. We don't even have the capability to see and accurately quantify all the variables of our existing climate, much less a future one.


Right jeffie.

But we do have a very clear understanding of what effect all that added GHG in our atmosphere is going to do to global average temperatures, and the persistence of those effects over very long timescales, in human terms.

Past, present and future climate all respond to the same forces. The only new input in the current era is the addition of massive amounts of GHGs into the atmosphere via human activity.

Further understanding of past changes in the climate system and their causes only adds weight to those projections --and with far greater authority than your simpleminded denial.

jeffensley
1.4 / 5 (9) Feb 10, 2016
You don't seem to understand the assumptions inherent in our projections. They are based on limited understanding of current and/or past phenomena. They are completely incapable of accounting for future changes and inputs to the ecosystem. How phytoplankton and terrestrial plant life responds to changing conditions is one of the more important unpredictables.
Caliban
4.2 / 5 (10) Feb 10, 2016
You don't seem to understand the assumptions inherent in our projections. They are based on limited understanding of current and/or past phenomena. They are completely incapable of accounting for future changes and inputs to the ecosystem. How phytoplankton and terrestrial plant life responds to changing conditions is one of the more important unpredictables.


You don't seem to understand that precisely the question you raise is an area --among many others-- of active and intensive research, and for exactly that reason, jeffie.

Your "understanding" is entirely one-dimensional and self-serving, as is all denierside maundering.

jeffensley
2 / 5 (8) Feb 10, 2016
You don't seem to understand that precisely the question you raise is an area --among many others-- of active and intensive research, and for exactly that reason, jeffie.

Your "understanding" is entirely one-dimensional and self-serving, as is all denierside maundering.


No, actually I'm quite aware of that and recent studies indicate that phytoplankton would not likely be impacted in the detrimental ways that we predicted... if the studies hold true of course. Just because we are studying something doesn't mean we understand it. And just because a short term study indicates phytoplankton are unaffected by increases in temperature or decreases in pH in a laboratory doesn't mean they will respond the exact same way when changes occur more slowly or in slightly different conditions. You could repeat the same experiment multiple times and get different results for each.
gkam
3 / 5 (6) Feb 10, 2016
" How phytoplankton and terrestrial plant life responds to changing conditions is one of the more important unpredictables."
----------------------------------------

Yes, and since our very existence depends on these critters, why are we taking the chance on killing them? That is one outcome we cannot risk. It is not like your "WMD!", but a real threat to OUR life on Earth.
jeffensley
2 / 5 (8) Feb 10, 2016
Call my arguments whatever you want and use childish insults to impress your middle school buddies, the fact is you all incapable of understanding (or truthfully acknowledging) the inherent limitations of our ability to predict change.
gkam
3 / 5 (6) Feb 10, 2016
jeff, there are some risks we do not take.

This is one.
Uncle Ira
3 / 5 (6) Feb 10, 2016
(or truthfully acknowledging) the inherent limitations of our ability to predict change.


I usually don't vote on your postums, I mostly disagree with them. But that little bit was worth the five I give you. I don't like the "all or nothing", "black-white but no grey", "this is the only trut", "Us-Them","Our Tribe versus Your Tribe" postums either.
jeffensley
2.3 / 5 (3) Feb 10, 2016
Well, thank you I guess. We don't have to agree on everything but all parties need to have a willingness to attempt rational discussion. To say decisively that something will/won't happen in the future is a practice of faith, not science.
gkam
2 / 5 (4) Feb 10, 2016
In this case, it is an act of reason.

As I said before, we cannot take the risk.
thermodynamics
4.6 / 5 (9) Feb 10, 2016
Unc said:
I usually don't vote on your postums, I mostly disagree with them. But that little bit was worth the five I give you. I don't like the "all or nothing", "black-white but no grey", "this is the only trut", "Us-Them","Our Tribe versus Your Tribe" postums either.


Let me put this in another way. All scientific evidence says that we are raising the heat content of the earth. The only question is how that heat will be distributed.

When people say that we should not act, they are saying that even though we know the heat content is increasing due to human releases of GHGs, we should not spend money on the problem because we don't know how bad it will be (although the majority of scientists have already indicated the oceans are rising, rain patterns are changing, and the ice sheets are melting). The issue is why not react when we know we are changing the earth? The gray area is how much risk are we willing to take on.
jeffensley
1.8 / 5 (5) Feb 10, 2016
I don't see anyone arguing for inaction. I certainly never have. But when any measurable (or calculated) change in our ecosystem can be used as justification for broad increases in governmental oversight and regulation, then you've got a recipe for corruption, wasted public money/resources, and loss of freedom. How much control are you willing to surrender to an unaccountable governing body in the name of preventing an arbitrary increase in average global temperature? When we enact carbon-reducing legislation and glaciers continue to melt and sea levels continue to rise, aren't activists going to say we haven't done enough yet and beg for more government control? You're unintentionally handing power to people who do not deserve it, just so you can have the illusion of control. If carbon-reducing legislation is to be passed, these projections should play no part whatsoever in the process and raw data for climate measurements need to be made publicly available.
Caliban
3.7 / 5 (6) Feb 10, 2016
Call my arguments whatever you want and use childish insults to impress your middle school buddies,[...] to predict change.


ok, jeffie

We all understand that we are to take your word for it, purely because that is what you want us to do.
We also understand that no form of chicanery is beneath you in this endeavor.

I'll use the old "appeal to authority" fallacy to illustrate just how ludicrous your above comment is:
If a whole panel of specialist doctors tell me that I have advanced, lethal cancer, will be dead in 6 months and to get my affairs in order, am I going to tell them that they are lying practitioners of pseudoscience and unqualified to make the diagnosis --much less the prediction-- or do I put my affairs in order?

Your argument is 100% denierside horseshit, just as has been pointed out over and again.
Anyone requiring further proof of your duplicitous chicane has only to read your comment preceding mine to grok your actual Agenda.

Filthy troll.
jeffensley
2.1 / 5 (7) Feb 11, 2016
It's sad that you (and apparently anyone that would give such a childish post 5-stars) think that insults somehow advance your argument. That you can equate the lethality of cancer (something we have a multitude of observational data for) with PREDICTED climactic change (something Nature is equipped to adapt to) speaks volumes as well. You're in need of a better analogy. I'm right in assuming you do understand the difference between past, present, and future aren't I?
gkam
2 / 5 (4) Feb 11, 2016
jeff, you take all the chances you want. We will not.
Caliban
3.9 / 5 (7) Feb 12, 2016
It's sad that you (and apparently anyone that would give such a childish post 5-stars) think that insults somehow advance your argument. That you can equate the lethality of cancer (something we have a multitude of observational data for) with PREDICTED climactic change (something Nature is equipped to adapt to) speaks volumes as well. You're in need of a better analogy. I'm right in assuming you do understand the difference between past, present, and future aren't I?


Lacking, as you are, jeffie, any semblance of scientific literacy --much less rationality-- it really doesn't apper that you are capable of seriously entertaining anything --AT ALL-- that lies outside of your cloisterd little fossilfuel libertatrandite worldview.

I'll add, as well, that no one posting here even expects you to, since there's a good chance that it provides some fraction of your daily bread.

No, jeffie-- my comments are for anyone reading who might confuse your trollblatt with Reality.
jeffensley
1.8 / 5 (5) Feb 12, 2016
Whatever makes you're fragile ego feel better, callie. If a couple goofs giving you 5-star ratings for insults makes you feel secure, who am I to deny you that pleasure?
philstacy9
1 / 5 (3) Feb 13, 2016
Religious change models show rising of Islam destroying civilization before climate change so climate change can be ignored.
Caliban
4 / 5 (4) Feb 13, 2016
Whatever makes you're fragile ego feel better, callie. If a couple goofs giving you 5-star ratings for insults makes you feel secure, who am I to deny you that pleasure?


I challenge YOU, jeffie, to deny me ANY pleasure.

ANY.

In the mean time, jeffie --do try to at least honor your fictional educational achievement and science literacy at least to the point of correct spelling, grammar and syntax, since your repeated failure in that regard has a highly corrosive effect upon your already minimal credibility.
howhot2
5 / 5 (2) Feb 15, 2016
It doesn't take much research to find how much carbon dioxide is released into the air from fossil fuel combustion. And it doesn't take much to extrapolate how much fossil fuel is left to burn (while it's economically viable as an energy source). In this article, It's fun watching all of the climate change denier's head explode one at a time.
antigoracle
1 / 5 (5) Feb 15, 2016
It doesn't take much research to find how much carbon dioxide is released into the air from fossil fuel combustion. And it doesn't take much to extrapolate how much fossil fuel is left to burn (while it's economically viable as an energy source). In this article, It's fun watching all of the climate change denier's head explode one at a time.

It takes even less to see how ignorant you are.
howhot2
5 / 5 (2) Feb 15, 2016
It doesn't take much research to find how much carbon dioxide is released into the air from fossil fuel combustion. And it doesn't take much to extrapolate how much fossil fuel is left to burn (while it's economically viable as an energy source). In this article, It's fun watching all of the climate change denier's head explode one at a time.

It takes even less to see how ignorant you are.

How so dick weed?

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