Archive for Thursday, March 19, 2009

Antarctica research shows Earth heading toward periodic thaw

March 19, 2009

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Scientists studying the geophysical mechanisms behind the periodic cycles of freezing and melting at the polar ends of the Earth reported Wednesday that Earth is headed toward another thaw, though it might take a thousand years or more for it to happen.

The research comes from cores drilled out of the ocean floor in Antarctica in 2006. The drilling project, co-directed by scientists from Northern Illinois University and known as ANDRILL, was one of the largest science projects ever undertaken on the continent.

In a report published on the cover of the research journal Science, the researchers found that during the Pliocene epoch 3 million to 5 million years ago — a time when conditions in Antarctica are similar to today’s — the ice in Antarctica collapsed and melted on a regular basis, raising world sea levels.

Polar ice began melting on a massive scale when atmospheric carbon dioxide levels were up to around 400 parts per million in the Pliocene, said Northern Illinois University geologist Ross Powell, one of the chief ANDRILL scientists.

“We are now at 386 parts per million and rising,” he said, and it grows by one part per million every year, thanks to carbon dioxide that human activity is putting into the atmosphere.

Scientists are particularly concerned about the West Antarctic Ice Sheet, which has collapsed with great regularity about every 40,000 years and is currently in an unstable state. If all the ice atop West Antarctica today melted, it would raise world sea levels 16 feet, inundating major cities and coastal areas where billions of people live.

Two climate modelers, David Pollard of Pennsylvania State University and Robert DeConto of the University of Massachusetts, say the ANDRILL data suggest it probably would take 1,000 or more years from the beginning of a warm-up until the ice sheet would melt away.

Over the Earth’s geologic history, polar freeze/thaw cycles have occurred about every 40,000 years because of a natural shift in the tilt of the Earth’s axis known as the Milankovitch Cycle.

“The tilting changes the amount of radiation absorbed into each hemisphere of the Earth, depending on which hemisphere is tilted closest to the sun,” Powell said. That leads to a gradual buildup of atmospheric carbon dioxide, he said, and eventually destabilizes and melts the ice shelves and ice sheets in Antarctica.

But human activity appears to be having its own effect on the world’s climate. Most climatologists believe that at today’s stage in the cycle, global temperatures should be cooling slightly, not warming, said geologist Ross Scherer, also a member of the ANDRILL team from Northern Illinois University.

“If something is an external cycle,” Scherer said, “it should be predictable. But it is much more complicated than that, and we seem to be throwing the pattern off balance now. It used to be that carbon dioxide rises were driven by the cycle. Now atmospheric carbon dioxide is driving the system.”

In the past, everything known about climate history came from geological data collected in the northern hemisphere and very little scientific data existed from Antarctica, which holds 90 percent of the world’s fresh water as ice atop the continent.

The ANDRILL core, extracted by a rig constructed atop an ice shelf in west Antarctica’s Ross Sea, is the first detailed geological data on Antarctic climate history, giving scientists and climate modelers a far more complete picture of world climate history.

Earth’s average annual temperature has risen 1.4 degrees Fahrenheit in the past 100 years, but over west Antarctica it has risen 4.5 degrees.

Comments

SettingTheRecordStraight 6 years, 5 months ago

Yet the environmentalists such as the Earth Liberation Front, Earth Justice, and the Natural Resources Defense Council would have us stifle industry (Holcomb power plants) and cripple the economy (cap and trade energy policies).

just_another_bozo_on_this_bus 6 years, 5 months ago

Yet STRS clearly didn't bother to read anything but the headline.

SettingTheRecordStraight 6 years, 5 months ago

Of course, I did boz. But you and I both know that humans cannot stop global warming.

Note, you should join me in refusing to eat at the downtown Ben and Jerry's because of their ridiculous "Stop Global Warming" sign in the window.

just_another_bozo_on_this_bus 6 years, 5 months ago

" But you and I both know that humans cannot stop global warming."

You've demonstrated that you know very little, if anything, about the subject, so I'd suggest speaking for yourself.

It very well may be that we've already pumped too much CO2 and other greenhouse gases into the atmosphere, and the feedback loops have already been set into irreversible motion. But unlike you, I'm not ready to assume that the human species has already committed collective suicide.

BTW, I really couldn't care less what brand of ice cream you buy.

Jaylee 6 years, 5 months ago

only reason to not eat ben and jerrys is if you were a member of that group trying to push for the sole milk provider to be human breast milk. THAT was a losing battle!

"Polar ice began melting on a massive scale when atmospheric carbon dioxide levels were up to around 400 parts per million in the Pliocene, said Ross Powell “We are now at 386 parts per million and rising,” he said, and it grows by one part per million every year, "

if this guy is such a genius, he might have noted that according to this math, we are all doomed in about 14 years, rather than "1000 or so".

here's an idea: pay ME tens of thousands every year to make random rounded off guesstimations concerning environmental disaster. i don't even require all the fancy lab equipment!

just_another_bozo_on_this_bus 6 years, 5 months ago

"if this guy is such a genius, he might have noted that according to this math, we are all doomed in about 14 years, rather than “1000 or so”."

I'd suggest improving your reading comprehension before you endeavor into climate science-- several different scientists were quoted in this article, not just one guy.

Christine Pennewell Davis 6 years, 5 months ago

snap you hit the nail on the head, we are all going to die.

Flap Doodle 6 years, 5 months ago

"...the periodic cycles of freezing and melting..." In other words, it's happened before and it will happen again.

just_another_bozo_on_this_bus 6 years, 5 months ago

"In other words, it's happened before and it will happen again."

Difference is, humans weren't around by the billions in past cycles, and humans weren't playing a major role in speeding up those cycles, or even creating new ones.

Your argument is a very poor one, snap. If a guillotine blade is dropped on an empty head rest, no harm is done. By your reasoning, there should be no reason not to put your head in there and see what happens.

cthulhu_4_president 6 years, 5 months ago

"It very well may be that we've already pumped too much CO2 and other greenhouse gases into the atmosphere, and the feedback loops have already been set into irreversible motion."

There is no way that you, or anyone, could know that this is true. It's equally likely (Occam would probably say "more likely") that our climate is constantly changing in ways that we cannot change.

Nor is there any indicator of how much CO2 is "too much". This is further complicated by the fact that "too much" may not actually be "too much". Our planet is a complex system made up of other complex systems. Changing one part of that can change the whole thing, and a degree of caution is required. Please see the unfortunate history of Yellowstone National Park during the 20th century, which relates, in great detail, the disaster that can unfold when people assume that they know what is "too much" or "too little" inside a natural system, when knowledge of that system is incomplete. There is also a video lecture by Michael Crichton about complexity theory which addresses this very issue. It is very pertinant and eye-opening, and easily found on youtube.

Chris Golledge 6 years, 5 months ago

Hmmm.

Jaylee's comment is more like saying that if you put a pot of water on the stove and turn up the heat, it will instantly come to a boil. That's why no one is paying Jaylee to make guesstimates.

Readers should also keep in mind that this article is William Mullen's interpretation of what was published in Science. I'm sure his interpretation is reasonably good, but things get lost when the information is condensed.

Chris Golledge 6 years, 5 months ago

Hey cthulhu,

You are right; the earth is a very complicated system and predictions with accuracy are difficult. So, what is your prediction; that we can alter the chemical composition of our atmosphere (and ocean) and therefore the earth's energy exchange, and exactly nothing will change?

Or is it that there have been climate changes which took place in past, on geologic timescales, and we are here today, therefore life will readily adapt to the changes we are making on a human timescale?

In general, change over the long run does not necessarily lead to things being worse, but change that happens too quickly can be hell to live through.

Flap Doodle 6 years, 5 months ago

bozo, by your logic, we should all be terrified to cross the street because people have died crossing the street. You could die the next time you cross the street! Stay on the couch where you are safe.

cthulhu_4_president 6 years, 5 months ago

Hi cig I'm not trying to pigeonhole the argument into one extreme or another, and I want to say that my prediction (since you asked for it) doesn't really matter. I would hope that people would research the issue objectively and decide. Actually, I think that both of those outcomes are partially likely. If the energy flow of this planet is changes, obviously things will change with it. I only argue that those changes, and the rate at which they are changing, may not be obvious for years, or decades, or ever, and just because we do see changes happening that are out of the cycle pattern doesn't mean that we can attribute it to man. There are many things that can affect global climate in the long term, and two of them aren't even on this planet! We simply don't know.

Your third paragraph is a very astute observation, and if changes are occuring very fast, they could be hell to live through. However, there is no evidence that man is causing those changes. What we have is correlations, but correlation does not equal causation. For example, It is statistically true that more births occur during the full moon than any other lunar cycle, but does the moon physically cause women to give birth? Maybe someday we'll know all the factors at work here, just like someday we'll know all the factors at work in the environment, until then, we can only intelligently guess.
Great point, and observations! Thanks for the discussion!

just_another_bozo_on_this_bus 6 years, 5 months ago

"bozo, by your logic, we should all be terrified to cross the street because people have died crossing the street. "

Not at all, Snap. The dangers of crossing the street are well known, and most people have learned them well by the time they are five years old, and on the whole, deal with them quite well-- for every person who gets killed crossing the street, there are probably hundreds of thousands, if not millions, who die from other causes than stepping out in front of a bus.

But the human race has not lived through multiple cycles of global warming, and during those previous cycles, we most certainly were not pumping billions of tons of greenhouse gases, released from carbon compounds sequestered over millions of years.

" However, there is no evidence that man is causing those changes."

Actually, there is a good deal of evidence. Is it 100% conclusive? No. But we make all kinds of decisions, everyday, based on information that's not 100% conclusive.

"What we have is correlations, but correlation does not equal causation."

"Causation" merely means that there is 100% correlation. Lower correlation doesn't mean there is no "cause-effect" relationship-- merely that we don't fully understand or know all the factors involved.

There is much we don't know or understand about the Earth's climate, but there is also much we do know and understand, and that tells us that our use of fossil fuels will very likely lead to dramatic changes in the climate of this planet, in our or our children's lifetimes.

cthulhu_4_president 6 years, 5 months ago

“Causation” merely means that there is 100% correlation. Lower correlation doesn't mean there is no “cause-effect” relationship— merely that we don't fully understand or know all the factors involved.

This is completely incorrect. Your lack of understanding is in the mathematical definition of "correlation". Example: 100% of all rapists have had at least one tooth in their lives. That's a 100% correlation, so does having teeth cause one to be a rapist (or vice versa)? I don't think so. Correlation is not a measure of a relationship between two things, nor does it measure the liklihood of a causal relationship, it is only an observation that as X changes, so does Y. There is no implied causal relationship. The way newspaper articles and biased studies are worded will make you think otherwise, but seeing past this alarmist language is the first step to looking at this issue objectively.

The first part of your second sentance is correct, lower correlation does not mean that there isn't a causal relationship, but it does mean that we can't assume that one exists, and that we just don't understand it yet, and so therefore have to act on it. The fault here is that you are assuming the truth of your conclusion as a premise to your argument, at which point any research stops being research, and starts being heavily biased cherry-picking, as you regard data that supports your premise (the conclusion) as "true" and all other data as "false". This bias keeps you from exploring all viewpoints objectively.

Didn't mean to rant, but I think that a couple of mathematical fundamentals will aid you in seeing the argument from all perspectives. I'm not trying to convince you of anything, I actually do consider myself an environmentalist, but a skeptical one, and I used to share many of your opinions until I realized that I was trying to debate a scientific issue with emotion, and that can have catastrophic results when carried out on the national level. You should really check out that Michael Crichton complexity lecture. I think you'd like it, as all open-minded people that I've showed it to have.

cthulhu_4_president 6 years, 5 months ago

" Correlation is not a measure of a relationship between two things,"

this sentance should be ignored, because correlation can determine a direct/inverse relationship. Instead of "a relationship" the above sentance should say "dependance"

Chris Golledge 6 years, 5 months ago

Cthulthu,

Thanks for the rational response; that's sometimes hard to find here.

I was offering a pigeonhole, but only to make the point that either you believe nothing will happen, or something will happen. The nothing option does not seem credible given what we know of thermodynamics. So, if it is something, why not give some credence to the thousands of people who have spent decades trying to make the best guess as to what that something is going to be.

Regarding: "However, there is no evidence that man is causing those changes."

Well, we know the absorption spectra of CO2, the wavelengths of energy emitted by the sun, the wavelengths of energy emitted by the earth, and that information leads to the conclusion that more CO2 means more insulating effect keeping the earth's thermal energy from escaping to space. Equivalently, it means that a higher temperature is needed to achieve equilibrium. We also know that, because of radioactive decay, the isotope ratios of C in the air is different from that of the C in fossil fuels. We know that we are burning gigatons of fossil fuels every year, and we know that over the years of industrialization, the ratio of isotopes of atmospheric C has started to look more like the ratio of fossil fuel C. Maybe it isn't conclusive proof of causality, but it's one heck of a coincidence.

Chris Golledge 6 years, 5 months ago

AZH,

Here is a synopsis,

http://en.wikipedia.org/wiki/Ozone_depletion

Basically, CFCs were banned, the ozone layer depletion has been reduced, and your butt was saved despite your ignorance.

Meanwhile, sports programs continue to receive more funding than science programs and the fossil fuel corporations continue to make more money than Al Gore and all the other environmental extremists..

devobrun 6 years, 5 months ago

Isn't it fun reading bozo's scientific prowess?

Wiki is such a wonderful resource. http://en.wikipedia.org/wiki/Correlation

I particularly like the vector dot product idea. Bozo, a vector is a value, or magnitude, that also has a direction.

cthulhu gives a good example. Nice job. Confusion between cause and effect is what got Al Gore in trouble when he plotted CO2 and temperature together in his movie. Turns out that temperature precedes CO2. Thus, his graph implies that temperature increase causes CO2 rise, not the other way around. The correlation (with an 800 year time shift) is quite good. Is it a cause and effect relationship? Don't know. How do you answer that question?

Set up an experiment. Change the CO2 in the atmosphere periodically over a million year time. Hold all other variables fixed. See if raising or lowering the CO2 causes the temperature to rise or fall. The more times you cycle up and down, the more times you refine the sensitivity of temp to CO2, the closer you get to believing the causal relationship. Can't do that?

OK, look in proxy records. Can't hold other variables fixed? OK, use other proxies to estimate the values and do a multivariate correlation. Don't know all the variables? Don't know the cross correlation between variables?
Don't ever say that you don't know. Find creative ways to renormalize, average using new window functions, but most of all sophisticate.

Take crappy data, beat it to death. Correlate it with everything until you find a potential cause that suits your political agenda. Don't mention inconvenient correlations or lack of correlations.

Better yet, read this book by John Brignell:

http://www.numberwatch.co.uk/book.htm#Sorry

It is quite readable and points out the folly of bad science that abound in today's world.

just_another_bozo_on_this_bus 6 years, 5 months ago

What I said--

"“Causation” merely means that there is 100% correlation."

What cthulhu_4_president said,

"Example: 100% of all rapists have had at least one tooth in their lives. That's a 100% correlation, so does having teeth cause one to be a rapist (or vice versa)?"

I agree that a 100% correlation does not necessitate that there is causation. But that's not what I said, now is it?

just_another_bozo_on_this_bus 6 years, 5 months ago

"The fault here is that you are assuming the truth of your conclusion as a premise to your argument, at which point any research stops being research, and starts being heavily biased cherry-picking,"

This describes Devo's approach quite well. He throws out all data that doesn't support his belief system, along with the most of analytical tools we have at our disposal (no doubt expecting that we'll survive long enough to develop terraforming technologies, since computer modeling isn't "real science.")

gphawk89 6 years, 5 months ago

Remember back in the 1970's when the consensus was that we were headed for the next ice age? We have little or no clue what's happening, what's causing it, and what the future will bring. How can anyone look at a few years' data and make any kind of accurate prediction about the future of our climate?

just_another_bozo_on_this_bus 6 years, 5 months ago

The fossil fuel industries most definitely want us to throw up our hands and say, "We're hopeless ignoramuses, so let's keep throwing $billions at our favorite billionaires."

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