Ice Age & Global Warming

[AJE]

AN INCONVENIENT TRUTH, book by Al Gore argues that global warming is not just about science, nor is it just a political issue: it is a moral issue and we have a responsibility to do something about it.

[kmfarm]

I believe global warming is happening, I simply wonder what's really causing it. I understand the issues with greenhouse gases, pollution and all, but here's something to think about: If glaciers formed the landscape and then receded, we must have had some warming for quite some time. So how much of the global warming is man-made and how much is naturally occuring? I ask this as a serious question.

Mark

[j10asen]

Originally Posted by kmfarm

I believe global warming is happening, I simply wonder what's really causing it. I understand the issues with greenhouse gases, pollution and all, but here's something to think about: If glaciers formed the landscape and then receded, we must have had some warming for quite some time. So how much of the global warming is man-made and how much is naturally occuring? I ask this as a serious question.

Mark

You are not the 1st person to pose this question many have inquired about this but we really do not have an answer. I think like most issues facing us today we need to deal with the knowns 1st and then perhaps the unknown will become more understood. Like any journey we begin on the known path and then venture into the unknown.

[AJE]

A Geological Brief History of Ice Ages and Warming

Global warming started long before the "Industrial Revolution" and the invention of the internal combustion engine. Global warming began 18,000 years ago as the earth started warming it's way out of the Pleistocene Ice Age. (A time when much of North America, Europe, and Asia lay buried beneath continental ice sheet.

Earth's climate and the biosphere have been in constant instability, dominated by ice ages and glaciers for the past several million years. We are currently enjoying a temporary reprieve from the deep freeze.

Approximately every 100,000 years Earth's climate warms up temporarily. These warm periods, called interglacial periods, appear to last approximately 15,000 to 20,000 years before regressing back to a cold ice age climate. At year 18,000 and counting our current interglacial vacation from the Ice Age is much nearer to beginning over again.

Global warming during Earth's current interglacial warm period has greatly altered our environment and the distribution and diversity of all life. Here is an example:

Approximately 15,000 years ago the earth had warmed sufficiently to halt the advance of glaciers, and sea levels worldwide began to rise.

By 8,000 years ago the land bridge across the Bearing Strait was drowned, cutting off the migration of men and animals to North America.

Since the end of the Ice Age, Earth's temperature has risen approximately 16 degrees F and sea levels have raised a total of 300 feet! Forests have returned to locations which I might add in geologic history was not so long ago.

During ice ages our planet is cold, dry, and inhospitable, supporting few forests but plenty of glaciers and cold deserts. Like a spread of colossal bulldozers, glaciers have scraped and pulverized vast stretches of Earth's surface and completely destroyed entire regional ecosystems not once, but several times. My best two example of the force from the recent Pleistocene Ice Age come from my hometown area; is Two Creeks Buried Forest in the northern section of Manitowoc County is an example of how fast the ice sheet extended into the region and also Valders Quarry which you’ll find several glacial striations going several directions to be able to count how many ice advances and to what directions they were advancing. Neat Huh!

Anyway, during the Ice Ages winters that went longer and became more severe. The ice sheets would advance and thus grew to tremendous size, accumulating to thickness of up to 8,000 feet! They moved slowly from higher elevations to lower-- driven by gravity and their tremendous weight. They left in their wake altered river courses, flattened landscapes, and along the margins of their farthest advance, great piles of glacial debris. I truly believe Wisconsin is one of the best places to see Glacial Topography left behind from the continental glaciations. Please feel free to see my definitions on my Journal.

During the Ice Age summers were short and winters were brutal. Animal life and especially plant life had a very tough time of it. Thanks to global warming, that has all now changed, at least temporarily.

Global warming over the last 15,000 years has changed our world from an icebox to a garden. Today extreme deserts and glaciers have largely given way to grasslands, woodlands, and forests.

Wish it could last forever, but . . .

[AJE]

Originally Posted by j10asen

You are not the 1st person to pose this question many have inquired about this but we really do not have an answer. I think like most issues facing us today we need to deal with the knowns 1st and then perhaps the unknown will become more understood. Like any journey we begin on the known path and then venture into the unknown.

Global warming alarmists like myself will sometimes jump to conclusions to advocate that global temperatures have increased since about A.D. 1860 to the present as the result of the so-called " Industrial Revolution," caused by releases of large amounts of greenhouse gases from manmade sources into the atmosphere causing a runaway "Greenhouse Effect."

Was man really responsible for pulling the Earth out of the Little Ice Age with his industrial pollution? If so, this may be one of the greatest achievements of the Industrial Age!

Unfortunately, we sometimes tend to overestimate our actual impact on the planet. In this case the magnitude of the gas emissions involved, even by the most aggressive estimates of atmospheric warming by greenhouse gases, is inadequate to account for the magnitude of temperature increases. Human additions to total greenhouse gases play a still smaller role, contributing about 0.2% to 0.3% to Earth's greenhouse effect. So what causes the up and down cycles of global climate change?

After digging through my notes from past geology courses here is my finale thoughts on what triggers an Ice Age...

Major Causes of Global Temperature Shifts
--------------------------------------------------------------------------------
(1) Astronomical Causes
:arrow: 11 year and 206 year cycles: Cycles of solar variability ( sunspot activity )
:arrow: 21,000 year cycle: Earth's combined tilt and elliptical orbit around the Sun ( precession of the equinoxes )
:arrow: 41,000 year cycle: Cycle of the +/- 1.5° wobble in Earth's orbit ( tilt )
:arrow: 100,000 year cycle: Variations in the shape of Earth's elliptical orbit ( cycle of eccentricity )

(2) Atmospheric Causes
:arrow: Heat retention: Due to atmospheric gases, mostly gaseous water vapor (not droplets), also carbon dioxide, methane, and a few other miscellaneous gases-- the "greenhouse effect"
Solar reflectivity: Due to white clouds, volcanic dust, polar ice caps

(3) Tectonic Causes
:arrow: Landmass distribution: continental drift causing changes in circulatory patterns of ocean currents. It seems that whenever there is a large land mass at one of the Earth's poles, either the north pole or south pole, there are ice ages.
:arrow: Undersea ridge activity: "Sea floor spreading" (associated with continental drift) causing variations in ocean displacement.

[j10asen]

Originally Posted by AJE

After digging through my notes from past geology courses here is my finale thoughts on what triggers an Ice Age...

Wow impressive.
I am not that well educated, I never even went past 9th grade geology!!

I do have a question.

If you had two water sources to choose from with one being pure and the the other containing " about 0.2% to 0.3% e coli" which water supply would you drink ?

[Crys]

Really, I can't be more clear than saying you should go to http://www.climatecrisis.net, which is the website for Al Gore's presentation. He's got all his facts straight, and he's far more eloquent on the subject than I'll ever be. He'd better be after studying it for forty years.

Yes, there's a natural fluctuation in avg temperature. Yes, there are natural processes that can cause these same changes OVER HUNDREDS OF THOUSANDS OF YEARS. We went from a little warming and cooling here and there to the sharpest spike in a million years over just the last hundred and some odd years in direct correlation with our physical effect on the world. There is no debate over this in the scientific community. The public at large only thinks there's a debate because a small minority of non-scientists with a political or economic agenda have been given equal airtime in a misguided attempt at "balance". Facts are facts. You don't give equal air time to the antithesis of a fact and call it BALANCE! (Yes, this makes me angry. I was a journalist once and all things considered I'm often ashamed to be associated with what passes for journalism now).

You can think of it like a tetherball. It swings around a little bit without you touching it, because of wind or other natural reasons. If you hit it, it makes the same motion but more quickly, violently and so much farther than the natural process ever did. Would you debate why the tetherball swung so much farther now than it was when you weren't hitting it? No.

[talleyJudy]

Thank you AJE for a factual and concise presentation of the topic of 'global warming'.

The media tend to ignore the fact that science has data that would lead one in differing directions and the direction of "human activity" caused global warming is the only one the media chooses to present. The natural viewpoint would not be sensational news or have any public moneys for study/solution grants. *follow the money*

Between the eventual ageing of our Sun and the possiblilties of super volcanoes like Yellowstone and remote but real chance of a large metior impact, global warming is way down there on my list of things to 'worry' about.

Judy

[Crys]

There is no _scientific_ debate about global warming other than whether we've already passed the point of no return. In fact, all you have to do is walk outside right now to see the effects of it, or look at all the extreme weather we've been having and notice the increasing frequency of extreme weather.

The only debate about global warming is made up out of whole cloth by corporate interests who don't care if they make the planet uninhabitable by humans within fifty years as long as they can make a big profit today.

The FACT is, we may already be beyond the point of stopping it. But we can't be sure that's true, and we HAVE to TRY to reduce our impact. The survival of humans AS A SPECIES depends on it.

The aging of the Sun is something that's on a scale of billions of years (but certainly advocates for a space program today!). Super volcanoes and meteors are something we cannot control, though we should try to monitor them to get as much warning as possible. Global warming is OUR FAULT and entirely in our control. We may deserve the extinction we're aiming for with our irresponsibility, but the rest of the world doesn't.

[talleyJudy]

In my simplistic way I see the debate about global warming being about the causes; natural causes vs. man-made causes.

The raw pollitically unbiased science points to natural cycles of the sun and the efects of our volcanic earth.

:wink:

[Crys]

No, that's not the case. The corporate media tries to sell that in the name of looking "balanced" but this is not a two sided thing. The increase and change we are seeing now is man made. Period. It's like putting salt on a patch of ice when the temperature stays below freezing. That ice will melt, because of the salt. Saying that the current greenhouse effect we're seeing "might" be natural is identical (and I mean, the argument itself is identical too) to saying that the patch of ice in question "might" not have been affected by the salt at all, just because when it's above freezing the sun melts the ice, even though it didn't get above freezing when the ice melted this time and the sun didn't come out. Because natural cycles happen, over thousands and millions of years, does not change the fact that NOW we see thousands of years of change compressed into a couple decades, coupled with the knowledge that the pollution we create causes exactly those chemical effects. These are physical, chemical effects that you can reproduce in a lab. X pollutant plus Y physical environment equals Z effect.

[pk]

Ancient ice shelf breaks free in Canadian Arctic
Breakaway may 'signal the onset of accelerated change,' researchers say

TORONTO - A giant ice shelf has snapped free from an island south of the North Pole, scientists said Thursday, citing climate change as a “major” reason for the event.

a comment in the story reads:

“This is a dramatic and disturbing event. It shows that we are losing remarkable features of the Canadian North that have been in place for many thousands of years,” Vincent said. “We are crossing climate thresholds, and these may signal the onset of accelerated change ahead.”

FULL STORY: http://www.msnbc.msn.com/id/16390346/

[MrKhay]

I did'nt attend kindergarten