41 replies to this topic

[pdx5]

99% of Geologists agree that there was an ice age around 10,000 years ago.
Glaciers abounded as far south as Chicago. In fact the great lakes were formed
by retreating glaciers.

My question is what caused the ice to melt 10,000 years ago?

It had to be a serious magnitude of global warming to melt all that ice. Where
did that warming come from? Did the cave man burn enormous amounts of
chopped wood? Was there a worldwide cloud created by humongous volcanic
eruptions?

I am just curious.

My guess is the sun has cooling/heating cycles. Considering sun is a million times
bigger than earth, only it has enough power to cause climate changes. Human
activity is so insignificant, none of the human created structures are visible from
space except the great wall of China shows up as a faint and thin line, barely
visible.

But then I am just a mechanical engineer. Not a scientist. What do I know!

Edited by pdx5, 11 June 2006 - 11:37 PM.

[Rogerdodger]

I made this invisible to prevent trouble as we had below.

[ty250]

If you get the chance, there is a great program that runs on the history channel periodically. It is called "little ice age, big chill". According to the show there was a small ice age for about 500 years, ending in the late 1800's. It was enough to change the climate so that certain crops,grains, would not grow as abundantly as it had for centuries. Because it happened slowly and people were generally uneducated,they did not adapt. There is so much I can not begin to type all the information. In summary, we should be happy with the warming trend we are in because in the past these times are periods of abundance and wealth. Colder times have been times of disease and famine. If you don't agree don't kill the messenger, watch the show and decide for yourself. If anyone has seen it feel free to add, or if you have a specific ? ,I will try to recall what the show had to say about it.

[OEXCHAOS]

The key on this thread is that you keep it factual and avoid attacking the motives of the poster, their character, and simply stick to the facts. My read on global warming is that it may well be related to emissions, but that such is not the only cause and further major emissions reductions would have a negligible effect on the warming but a huge effect on global economies (not that the worst polluters would care anyway). We need growth and technology in order to deal with this issue and a neo-malthusian approach will do more harm than good. BTW, the creation of large heat sinks is an interesting aspect of global warming. That's something we can do something about fairly cheaply. Green Rooftops is one really interesting notion. So is aggressive urban reforestation, so is nuclear power. There are and will be others. Mark

[ty250]

Personally I don't think it has anything to do with emissions or any other man related reason. We have been through these cycles before and will again. The problem is these cycles are longer than our life times so it is difficult to grasp what is happening in the here and now. I believe our politicians love to alarm us about a looming disaster, they love to try to fix something that isn't broken instead of fixing what is broken where they can actually do something real other than redistribute wealth. Just look at newsletter writers who predict financial meltdown, people eat it up. You may ask what this has to do with sanity and health? Well it helps me to feel better to vent a little. Anyway watch the program ,I think it is fascinating. TY

[OptionTrading]

Of course its due to emissions.. theres no doubt man's impact on the globe is negative. There will be no disaster in our lifetime, but its a shame we cant be here in another 10k years.

[TechSkeptic]

We can argue about it all day, but I seriously doubt if anyone can conclusively prove one way or the other whether global warming is a result of human activity or a purely natural phenomenon, or some combination thereof. But why not give it the BENEFIT OF THE DOUBT that greenhouse gases may be a significant factor and do what we can not to accelerate this warming trend? We obviously can't transition immediately away from fossil fuels 100%, so the more we do now to promote the use of nuclear, solar, and other non-greenhouse energy sources (as well as conservation), the less painful it will be in the long run. And there are other obvious benefits such as reduced pollution and less reliance on politically unstable regions of the world, that moving in this direction should be beneficial regardless of who is right about global warming.

[Rogerdodger]

Wonder if this is hot?

[EntropyModel]

My question is what caused the ice to melt 10,000 years ago?

There are many theories of why the last ice age ended, here's new one:

http://news.national...7_iceshelf.html

It had to be a serious magnitude of global warming to melt all that ice. Where
did that warming come from? Did the cave man burn enormous amounts of
chopped wood? Was there a worldwide cloud created by humongous volcanic
eruptions?

All warming doesn't have to have the same cause. The 'warming' can come from accumlated feedback effects as explained below.

But then I am just a mechanical engineer. Not a scientist. What do I know!

Right, that's the problems with any of us trying to have opinions on subjects that even the worlds best scientists/climatologists disagree on, we are just blowing smoke frankly.

But at minimum to have an informed opinion, an understanding of feedback systems is required.

For example in case of last ice age. It needs to be understood that a 'system' remains in whats called a 'steady state', but feedback over time causes 'transients'. At some point those transients can cause a 'tipping point', like wings of butterly in choas, and a huge dramatic change in set in motion. Therefore, it doesn't require an event as such to change anything, its due to a cumulative feedback effect over thousands of years that appears to 'do nothing' until all at once those tiny changes play out all at once.

This is just how systems are - they like to stay 'steady' and make their changes dramatically, but the tipping point can be very small.



Global warming is a different issue entirely to ice age ending, as it has to with a known chemical effect. The issue of course is whether this chemical effect is actually happening on a scale to be responsible for the current warming, or whether its just a natural cycle.


As said, scientists can't agree, though the vast majority believe its human caused. But it cannot be proven, because of the complexity of the science involved. So you are left chose whether to believe in the majority or the few skeptics.


But this reveals a fundamenal ignorance of use of science by non-scientists [ as perpetuated by schools and media] . There is virtually no science that is 'provable'. Really science is just probabilities. So lets rephrase, and ask what are the odds it is man-made global warming. If you survery the worlds scientists, you'd get at least 70:30 odds in favour, whatever, make it 50:50 if we like.


So now its just a question of Risk like taking out household insurance - do you want pay to avoid potential disasters costs of global warming, with a 1 in 2 risk of needing it, and 1 in 2 you don't?


Personally I would take out the insurance[though how you do that is a big issue]. Especially I would do this since over time the 'costs' will pay back in growth in the economy.


Of course, we'd better hope it IS man made, because if its natural we have a bigger problem as we have no clue how to prevent it.



Mark.

Edited by entropy, 21 August 2006 - 02:23 PM.

[Rogerdodger]

Greenland's Glaciers Shrinking for 100 Years Link
Breitbart.com Aug 21, 2006
The most comprehensive study ever conducted reveals:
Greenland's glaciers have been shrinking for the past century, according to a Danish study, suggesting that the ice melt is not a recent phenomenon caused by global warming.
"70 percent of the glaciers have been shrinking regularly since the end of the 1880s at a rate of around eight meters per year,"



But...read my signature line below.