Is the earth in danger of entering another Ice Age?

Question

I've just read an article where a scientist suggests that an Ice Age is something we should be more concerned about than Global Warming.

http://www.theaustralian.news.com.au/story/0,25197,23583376-7583,00.html

According to this article, our period of warm weather is an anomaly that usually doesn't last long. And a normal state of affairs is an Ice Age where about 1.5km of ice covers most of North America and Europe.

The interglacial periods such as ours in the past have lasted between 8,000 and 12,000 years followed by 100,000 years of ice age. And our present interglacial period is now 11,000 years old.

According to that article, such variation in earth's weather is probably caused by variation in the radiation from the Sun. And according to astronomical observations, now our Sun has entered a quiet phase with decreased sunspots and decreased radiation as a result.

http://www.spaceweather.com/

Answer 1

Yes, there is no doubt that the earth right now is pretty much as warm as it ever gets except for during mass extinctions.  On average, temperatures are colder for much more time than they are as warm as they heve been during the time humans have existed.  Life tolerates "colder" quite well, and "warmer" not well at all.  If there were no other factors at work we would enter another ice age in a few thousand years.

One thing to keep in mind is that UNLIKE scientific publications, the popular press is tasked with presenting both sides of an issue, no matter how inane, while the scientific press presents what the authors can support with facts while following strict protocols.

You will see posts that will say "Did you hear the scientists have changed their mind about Global Warming being caused by man made CO2? Now they say it's happening on Mars too, and is caused by natural variations in the sun. That shows you can't believe anything a scientists says". (but also disproves Global Warming!)

So what's wrong with that? Well when you look at the sources you don't find "scientists say" or "experts say". What you find is "Scientist Says", just like with the "ice age prediction" in the 1970's. So who is the scientist contradicting the experts? He is Habibullo Abdussamatov, head of space research at St. Petersburg's Pulkovo Astronomical Observatory . So he's not only not a household word, he is not a climatologist. So what else do the articles say?

" Abdussamatov's work, however, has not been well received by other climate scientists."

"His views are completely at odds with the mainstream scientific opinion,"

"the idea just isn't supported by the theory or by the observations."

"Perhaps the biggest stumbling block in Abdussamatov's theory is his dismissal of the greenhouse effect, in which atmospheric gases such as carbon dioxide help keep heat trapped near the planet's surface."

" He claims that carbon dioxide has only a small influence on Earth's climate and virtually no influence on Mars. "

"without the greenhouse effect there would be very little, if any, life on Earth, since our planet would pretty much be a big ball of ice,"

So the main thing wrong with his idea is that if it were true we wouldn't be here discussing it. Yet I guarantee you that 30 years from now (if we are still here) when the weather and climate scientists are trying to educate the world about some really important Global Warming issue there will be some guys saying "Well you can't believe what THEY tell you. Those same scientists said Global Warming was happening on Mars too back in aught-eight. How dumb can they get?"

Peace.

edit

{sigh}  Yes Jim.  On the questions that often get asked several times a day I don't always retype the entire answer, I copy portions of my previous answers to the question when I am busy.  I didn't realize this was a problem for you, but now that you mention it, I can see why.  I'm adding two links to other questions where my answer relates to the issues you raise.  I have no doubt you know of them anyway.  

Humans evolved at the height of the last Ice Age.  It's widely believed that the Ice Age triggered the divergence of Homo Sapiens from the Homo Erectus parent stock.  Homo Neanderthalensis  had been in place for 350,000 years with no significant competitor and no sign of change up to that point.  

Rises in temperature of 4 degrees or more above our current temperature have been associated with the six known mass extinctions, and no other periods that we know of.  Since you choose to argue about a point this elementary, I won't insult you by adding any links for it.  If you truly don't know, then you should look it up.  If I do it for you you probably wouldn't remember.

Answer 2

Unlike Bob, I know that the MIlankovitch cycles are not changes in the Sun, but changes in the Earth's orbit and axial tilt.

Many are starting to think that Milankovitch cycles are not the cause of the glacial/interglacial cycle, being that the forcing is so weak, even if you invoke a CO2 feedback. The newer theory describes changes in the sun's output as the driver, and here is a short primer on the subject: http://www.unisci.com/stories/20022/0606...

And regarding the Lockwood and Frohlich paper that Bob quotes, here is Svensmark's reply: http://www.spacecenter.dk/publications/s...

Answer 3

not for another 23 000 years apparently, according to analysis of the Milankovitch cycles;

http://www.globalwarmingart.com/wiki/Wik...

i too thought we were due for one, so i was looking at this just this morning. seems when you add up the eccentricity etc. we are in for a long warm period naturally, to which we are adding a huge amount of extra forcing.

this interglacial is most like the one 400 000 years ago, which lasted  30 or 40 000 years as you can see on this chart,

http://www.globalwarmingart.com/wiki/Ima...

Answer 4

Bob and Tuba simply give canned responses in a blind defense of global warming in my opinion.  It is nonsense to suggest that animals tolerate cold.  Most animals and plants do far better with warmth.  We are at the peak of the warmth or pretty close to it.  We may be heading for an ice age but these scales are on the order of thousands of years so I don't think there is much to worry about.  Short term cold periods such as the Little Ice Age might be another matter of great concern.  It would be far worse than a little warming IMO.

Answer 5

The theory of a comming ice age is highly speculative, but no less valid that the AGW theories.

Unlike Bob, most scientists don't claim to know what causes ice ages.  Milankovic cycles don't produce significant changes in the incident radiation of the Earth.  A lot of scientists prefer the explanation of a massive volcanic eruption or impact from an asteroid to cause ice ages.  Changes in the intensity of the sun also haven't been ruled out.  

AGW believers tend to believe ice ages are caused by Milankovic cycles as this implies that the sun is very constant in intensity and minute changes in incident radiation can have dramatic effects on climate.

Answer 6

Not likely...with Al Gores Hot Air .

Answer 7

No.  Ice Ages are due to changes in the Sun called Milankovic cycles (Google it).  We're simply not due for one.

And, if you work the numbers out (as the article below does), scientists can prove that global warming is, right now, more powerful than the observed changes in the Sun.  It's why we've been warming for the last 40 years even with the decrease in solar radiation.

"Recent oppositely directed trends in solar

climate forcings and the global mean surface

air temperature", Lockwood and Frolich (2007), Proc. R. Soc. A

doi:10.1098/rspa.2007.1880

http://www.pubs.royalsoc.ac.uk/media/pro...

News article at:

http://news.bbc.co.uk/1/hi/uk/6290228.st...

Answer 8

HECK YES!!!

We need to change our ways before we all die!!

Answer 9

This is logical, however, considreing that the last few times this happened, humans weren't in the equation, im sure we've made changes and considreing that in reality, the yearss are becoming hotter, the earth has a higher chance of heating even more that entering another ice age

Answer 10

i don't think we have to worry about another ice age ,we are not cooling down ,we are melting down.

Answer 11

Very Rare that the Ice Age will occur and it if it were going to happen the world will be way hotter

Answer 12

Some day grasshopper, but not today.

Answer 13

I believe the Ice Age theory more than global warming

With the oceans getting cooler and their warming currents not as strong it only makes sense