Global warming - threat or benefit?

[stui magpie]

When I was recently in Darwin, the guy who was the guide for the kakadu tour I did is an archaeologist. He was fascinating to listen to as he could overlay knowledge of other other cultures he's researched with a scientific perspective.

When discussing how long Aboriginals have been in Australia and how archaeologists look to different evidences, he made the point that during the last Ice Age, 20,000 years ago, sea level was around 100m lower than today.

Let that sink in for a moment. 100 metres lower.

The reason he raised this was Aboriginal settlement occurred during the last ice age. With the sea level so low, many of the earliest areas that they inhabited are now under 50-100m of water, which makes it pretty frigging difficult to look for evidence of habitation.

Anyway, that led me off on a bit of research of my own, not into Aboriginal habitation, but into ice ages.

It seems there's a bit of a cycle over roughly every 100,000 years. Ice ages start when temperatures drop in summer in the northen hemisphere, the winter snow doesn't melt in summer but slowly turns into sheet ice. This increase in polar ice means sea levels drop (and salinity increases)and climate gets colder and drier with less rain.

Ice ages last for about 90,000 years (with a gradual lean in and lean out), with the warmer inter glacial period we're currently in only lasting around 10,000 years.

Can you imagine the impact of another ice age on a world population that has basically grown and thrived in the comparatively short period of 10-12,000 years? Whole tracts of land in the northern hemisphere would be permanently ice covered. A lot of that agricultural land currently used to grow food. Populations would potentially head to the equator where much of the worlds poor is already focused.

Vast tracts of new land would appear from under the receding water, but who owns this land? How usable would it be?

Now, it seems that we're about due for another ice age right now, but it seems that the increase of greenhouse gases in the atmosphere that first started around 5000 years ago with increased agriculture, is holding it at bay.

So, if all the efforts to reduce greenhouse gases is successful and the natural balance is restored, the result is likely another ice age sooner rather than later

Here's a good short simple article on the ABC

http://www.abc.net.au/news/science/2016 ... er/7185002

Another slightly more complex in The Conversation.

https://theconversation.com/ice-ages-ha ... -one-70069

It's an interesting dilemma in a way. The last ice age lead to the spread of the human race across the globe. The last 10,000 years have seen incredibly advances compared to the 90,000 prior to that. (well, as far as we know anyway. Evidence of past technologically superior civilisations could be 100m under water for all we know)

What would another ice age do to the world? It would certainly put a big dent in the population, with the poorest being the first to be dented. You could expect war over habitable land and natural resources and the environment as we know it now would be very different impacting all plant and animal life.

The world as we know it has evolved in a 10,000 year window that it seems we are holding open, for better or worse, whether temporarily or long term (in geological time)

Should we try to keep it open or work to allow it to close and let nature do her thing?

[Skids]

Interesting thoughts Stui.

I stick by what I've always said, the global warming brigade is a farce, to think humans can some how control the planets climate is stuff more suited to fairy tales.

We will have another ice age, the question is when and no matter how much Al Gore and his money leeches try to tell us otherwise, we can't do a thing about it.

[stui magpie]

Controlling the climate is indeed the stuff of fairy tales or science fiction, but influencing or impacting it, isn't.

The Aboriginals terraformed massive tracts of Australia over 10's of thousands of years, changing both the environment and the climate to the point where parts of it now rely on regular intervention.

Greenhouse gases have in impact on temperature, I think that's a given, but they don't impact planetary rotation and wobble, or the varying intensity of solar radiation.

Plus, whenever you make a change to a closed system, it has consequences.

It seems clear to me from what I've read that increased greenhouse gases in the atmosphere coinciding with the increased civilisation of man during this warm period has impacted the beginning of the next ice age. whether that's a "permanent" thing (inverted commas because in geological time human settlement is not going to be permanent) or short term like 100 or 1000 years depends not only on the greenhouse gases but on all the other factors that we have zero influence on.

[Dave The Man]

Interesting thoughts Stui.

I stick by what I've always said, the global warming brigade is a farce, to think humans can some how control the planets climate is stuff more suited to fairy tales.

We will have another ice age, the question is when and no matter how much Al Gore and his money leeches try to tell us otherwise, we can't do a thing about it.

Agree. I think it's not as bad as Some of the Crazies make it sound

[Mugwump]

It may be, but setting fire to your house is not a good way to deal with a cold snap that may come in across a hundred years.

[stui magpie]

^

Not sure I follow your logic there.

[HAL]

Does that remind you of it? ?

[Mugwump]

^

Not sure I follow your logic there.

I mean that things on a geological time scale, such as ice ages, take place very slowly, and an adaptable species will have time to adjust. Global warming seems to be happening in decades, much faster than an ice age would, so the sequencing is unlikely to align helpfully.

[stui magpie]

^

Did you read either of the articles I linked? Once the conditions are right for an ice age, it can start relatively quickly. One summer in the northern hemisphere where the snowfall doesn't melt is a trigger event. It then has a form of self fulfilment about it unless you get a hot burst that melts it. Once it starts it will creep south but not over thousands of years, more decades to get started.

As far as greenhouse emissions, we've been putting greenhouse gases into the atmosphere for thousands of years, really spiking upwards since the industrial revolution.

I don't think we have the ability to reduce greenhouse emissions back to what they were pre the last ice age, even if we stopped burning all fossil fuel. Agriculture plus over 7 million people breathing out CO2 and farting methane (even if those 7 million are all 2 legged carbon sinks) means we're producing greenhouse gases.

I suppose my point was, the overall equation isn't as simple as people like to think it is. We're due for another ice age, so rather than people spouting memes, we should all look at the bigger picture.

[Mugwump]

[stui magpie]

^

Yup, when you look at it, more than 10,000 years ago humans were all pretty much tribal and had been for 100,000 years with little progress. All the progress has happened in a small window.

The human races grip on it's ongoing future is tenuous at best.

[Pa Marmo]

[roar]

Controlling the climate is indeed the stuff of fairy tales or science fiction, but influencing or impacting it, isn't.

That's an excellent way of putting it, stui. I am really dumbfounded how people can think that emitting so much pollution won't have an effect.

[Skids]

Controlling the climate is indeed the stuff of fairy tales or science fiction, but influencing or impacting it, isn't.

That's an excellent way of putting it, stui. I am really dumbfounded how people can think that emitting so much pollution won't have an effect.

Like termites do?

An article from before Al Gores scare tactics.....

TERMITE GAS EXCEEDS SMOKESTACK POLLUTION 1982

For several years scientists have been warning that carbon dioxide added to the atmosphere by increased burning of fuel is likely to alter world climates, like a greenhouse, by inhibiting the escape of heat into outer space.

Now researchers report that termites, digesting vegetable matter on a global basis, produce more than twice as much carbon dioxide as all the world's smokestacks.

Termite gas production has become particularly high, the researchers say, because widespread clearing of land has offered them abundant food in the debris of felled forests. By digesting this debris, they are adding not only carbon dioxide but also methane to the atmosphere. Other researchers have found that methane in the atmosphere is increasing 2 percent a year.

The possible significance of increased methane in the atmosphere touched off a debate in 1971 on whether supersonic transports might alter the stratosphere. Dr. S. Fred Singer, then at the University of Maryland, suggested that other human activities, including intensive cattle-fattening, were more important. He cited an estimate that bovine flatulence added 85 million tons of methane to the atmosphere each year. The new estimate for termites is 150 tons.


https://www.nytimes.com/1982/10/31/us/t ... ution.html


Then this.... 12 years later, 1994 ... still way before Gore and his fairy tale....


Could termites be the world's terminators?: A humble forest insect may be emitting dangerous amounts of methane.

Termites may also contribute to greenhouse gases in another way. Termite mounds appear to contain denitrifying bacteria which release nitrogen from the soil. Small amounts of two particularly potent greenhouse gases, nitric and nitrous oxide, are also emitted. Although this goes on in mounds in undisturbed forest, the bacteria seem to be stimulated when the forest is disturbed, especially when fertilisers are used on cleared land.

While it remains uncertain exactly how much termites contribute to greenhouse gases, it is certain that for millions of years termites have existed in tropical forests and have done no harm. The danger lies in upsetting the natural balance of the forest eco- system. Dr Bignell concludes: 'Termites are the ultimate guardians of the gas exchange between the soil and the atmosphere. Destroy the natural habitat of these guardians, upset the system and the consequences could be very serious.'

https://www.independent.co.uk/news/scie ... 94135.html

[Pies4shaw]