March 25, 2004
Last Ice Age Happened In South America Too

Researchers at UW-Madison including Michael Kaplan and Brad Singer along with researchers at Woods Hole Oceanographic Institution have show that the last ice age also happened in South America.

Using a technique to read the changes imposed by cosmic rays—charged, high-energy particles that bombard the Earth from outer space—on atoms found in the mineral quartz, the researchers were able to precisely date a sequence of moraines, ridge-like glacial features composed of an amalgam of rocks, clay, sand and gravel. Their results show that glacial ice in South America reached its apex 22,000 years ago and had begun to disappear by 16,000 years ago.

"The team has applied an innovative investigative technique to an untapped archive of data on natural climate variability to help reduce uncertainty in our knowledge of how Earth's climate works," said David Verardo, director of the National Science Foundation’s (NSF) paleoclimate program, which funded the research. NSF is the independent federal agency that supports fundamental research and education across all fields of science and engineering.

The work is certain to help researchers of past climates unravel the mysteries of ice ages that periodically gripped the planet, Verardo said, but it also will help those trying to understand current and future climate change by helping to determine the natural causes of changes in the Earth's climate system on a global scale.

"We've been able to get quite precise ages directly on these glacial deposits," says team leader Brad Singer, of UW-Madison. "We found that the structure of the last South-American ice age is indistinguishable from the last major glacier formation in the Northern Hemisphere."

And, said Kaplan, "During the last two times in Earth's history when glaciers formed in North America, the Andes also had major glacial periods."

The results address a major debate in the scientific community, according to Singer and Kaplan, because they seem to undermine a widely held idea that global redistribution of heat through the oceans is the primary mechanism that drove major climate shifts of the past.

The implications of the new work, say the study authors, support a different hypothesis: Rapid cooling of the Earth's atmosphere synchronized climate change around the globe during each of the last two glacial epochs.

"Because the Earth is oriented in space in such a way that the hemispheres are out of phase in the amount of solar radiation they receive, it is surprising to find that the climate in the Southern Hemisphere cooled off repeatedly during a period when it received its largest dose of solar radiation," says Singer. "Moreover, this rapid synchronization of atmospheric temperature between the polar hemispheres appears to have occurred during both of the last major ice ages that gripped the Earth."

There are big heat conveyor flows in the world's oceans. One fear of climatologists is that global warming might cause a halt to the flow of warm water into the North Atlantic due to a decrease in salinity caused by glacier melting and changing precipitation patterns. This would cause a dramatic cooling especially in Europe and even in parts of North America. However, while the possibility of that scenario still exists these researchers are arguing that a halt in the heat conveyor probably didn't cause the glacial periods. This research shows the glacial periods happened in South America as well and the halt in the conveyor would not have caused the same cooling effect in South America that it would have caused in Europe.

Most of the debate about climate change today is centers around the question of how is humanity changing the world's climate and how big an effort should be made to reduce the human impact on climate. However, if humanity survives long enough then eventually humans are going to have to decide whether to try to stop much larger climate changes that have non-human causes. When the Earth begins to descend into another ice age should humanity intervene to stop it? Some naturalists believe that processes that have non-sentient causes should be considered sacred and not to be tampered with. In their minds that which is natural is morally superior and changes caused by sentient minds are inherently sinful. My guess is that if humanity lives long enough to witness the beginning of the next ice age then artificial intelligences will ally with the majority of the human race in favor of an intervention to prevent the ice age.

Share |      Randall Parker, 2004 March 25 10:52 AM  Climate Trends

Stefan Jones said at March 25, 2004 12:18 PM:

"My guess is that if humanity lives long enough to witness the beginning of the next ice age then artificial intelligences will ally with the majority of the human race in favor of an intervention to prevent the ice age."

A move surely to be opposed by the winter-wear manufacturers and the uplifted polar bear community.

Randall Parker said at March 25, 2004 12:29 PM:

But the far more numerous uplifted dog community will be against the ice age. Uplifted primates will be similarly opposed to an ice age.

Also, the larger recreational boat industry can outbuy the winter gear makers for influence.

Stefan Jones said at March 25, 2004 12:51 PM:

Cut it out! You're going to make my World Builder lobes go into high gear.

There they go, damnit! AAAAAhhhhrrrrrgghhhh . . .

Because their body-cooling mechanisms are limited to panting and a tiny patch of sweat glands on the pads of their feet, canines with large brains are going to face serious overheating problems. They'll probably favor cool climates.

Anyway, snow is just more fun.

It's simply easier for mammals to deal with cool climates than hot ones. Just grow fur.

By the time the next major potential ice age rolls around, I suspect the population will be a lot smaller, and/or located offworld. I say let it happen.

Randall Parker said at March 25, 2004 1:11 PM:

Stefan, As part of the uplift for dogs I assume they will be given a better cooling method.

However, you miss the real point of why the dogs will join in opposition against an ice age: huge amounts of land will be covered with ice. The dogs may like cool. But they want dirt underneath their feet, not ice that stretches for hundreds or thousands of miles.

Patrick said at March 25, 2004 11:09 PM:

More importantly, the dogs don't want vast areas of land with no trees.

Stefan Jones said at March 25, 2004 11:32 PM:

Baahhhhh, you're assuming a great-sheets-of-ice Ice Age. How about a moderate one that exposes the continental shelves a bit, turns the Sahara back into veldt, and brings good hard freezing winters to more of the world? They churn up the soil and kill off pests. We might end up with *more* trees.

Anyway, SmartDogs (versions 1.2 and up) use toilets. Or, in more canine-friendly urban area, designated pee-posts with piezo speakers that play specially targeted sponsor advertising in frequencies humans cannot hear.

michael vassar said at March 26, 2004 7:42 AM:

It is fun playing around with this sort of idea, but if ae get to a point where AIs are siding with people rather than doing what they are programmed to do then we will have an utterly different world, presumably one with a population of N = variable = moles of human equivalents and the very idea of natural will probably be moot. The Amish might still care about ice ages, but our intellectual decendants, if we have any, will not. Real AI may not happen for a long long time. Concievably it is even impossible, though I doubt it, but worlds with real AI that we can actually describe are pure science fiction.
I would not expect uplifted animals to have much political power, personally. Possibly some other sort of power though. Uplifted rats might be very physically formidably, and uplifted elephants very intellectually formidable.

cordell said at March 30, 2004 12:01 PM:

If it only takes 20 years to enter an ice age, we may not be talking about the distant future here. Ice ages are accompanied by droughts and crop failures over the lands which currently sustain most of the human population. Think massive human die-off.
Can an ice age even be prevented, given that no one really knows what causes an ice age that affects both northern and southern hemispheres. My guess is overlapping orbital cycles, Milankovich cycles and other cycles less well known.

Joseph Kaissis said at May 29, 2004 8:35 PM:

I found this a very interesting article, and a very hard one to come to a conclusion in regards to should humans intervene with the next ice age or shall we leave such sacred things. I believe that at the descend of the next ice age, humans will cherish life too much (maybe more than today) and will try with all they have to overcome and fight the ice age.
However, the outcome will be unknown.
I think that humans have already tampered enough with the environment, and if such an event were to come in my lifetime i would accept it and let nature take its place.
Thanks Randall Parker for you piece of work.

T A Smith said at July 25, 2004 8:05 AM:

If you think a blizzard in Atlanta, GA over a three-day period breeds havoc and a relatively high death toll due to freezing, accidents, and incidents related to snow removal and being snowed in, think how they might fare over a three-decade (three century?) period. Most likely they would cease to exist. Or think of increasingly catastrophic typhoons, tornadoes and hurricanes in Taiwan, Mexico City, flooding in most major coastal cities, the disappearance of Bangladesh and Holland and most of the towns ending in "Beach" in the USA. The melting of the Greenland icecap over a thousand year period would raise the sea level 7 m; that of the W Antarctic ice cap, another 3 m. all these would cool and effectively shut down the thermohaline engine of the Gulf Stream and in combination with a couple of severe winters would be enough to entirely negate the effects of greenhouse gases over England and N Europe, wh depend on the warm ocean currents for their relatively (considering their latitude) balmy weather and induce a new ice age in a relatively short period of time, if the melting is rapid enough. Effects of cooling tend to snowball; glaciers spread. Soon most of the northern temperate zones would be encased in ice, disrupting all normal life and probably putting an end to it. Don't cop to the knee-jerk reaction of most futurists by assuming our innate ability to cope no matter what. There was a long expanse of time before the advent of human life, and Gaea wasn't exactly waiting around for us to show up. There could very easily be a time when humans no longer exist on this planet.

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