Carbon & Oxygen : the Earth's battery elements

[drbubb]

I remember a few lines from an old poem:

 

"... the wind decays in twilight,

And the leaves fall off the trees.

We all lie down in silence,

Frozen outside our dreams."

 

Chilling stuff. And it is an image of a future I still worry about sometimes.

 

BUT was this our past?

I just read an article which quotes the work of some Harvard scientists who believe that the earth was once covered by ice and snow. And it could have gone on being covered by ice and snow, but for one thing: CO2. An ice-covered world is a great reflector of sunlight, and so a world-so-covered might have stayed that way forever: going on reflecting a high proportion of the sun that hits its surface. But vulcanic action would have slowly released carbon dioxide, and CO2 in the earth's atmosphere would have helped to trap sunlight and heat through the greenhouse effect. This raised temperature to a level where the earth could begin to support life.

 

Once life thrived, the balance shifted. Plants captured the Carbon in the CO2, and put Oxygen into the atmosphere again, allowing animal life to rise in balance to the thriving plant life.

 

No we, the dominant animals, are busily plundering the energy treasure left by the plants. All that trapped carbon: in coal, in oil, in fossil fuels is being burned up, with the CO2 released back into the atmosphere. This is warming the earth, but threatened to upset the balance.

 

Will we learn to cope, or will the forces of nature find their own balance?

[brooki]

The last chapters of H.G Wells' "Time Machine" affect me in a similar way. Here the hero has travelled 30 million years into the future:

 

http://www.bartleby.com/1000/11.html

 

‘The darkness grew apace; a cold wind began to blow in freshening gusts from the east, and the showering white flakes in the air increased in number. From the edge of the sea came a ripple and whisper. Beyond these lifeless sounds the world was silent. Silent? It would be hard to convey the stillness of it. All the sounds of man, the bleating of sheep, the cries of birds, the hum of insects, the stir that makes the background of our lives—all that was over. As the darkness thickened, the eddying flakes grew more abundant, dancing before my eyes; and the cold of the air more intense. At last, one by one, swiftly, one after the other, the white peaks of the distant hills vanished into blackness. The breeze rose to a moaning wind. I saw the black central shadow of the eclipse sweeping towards me. In another moment the pale stars alone were visible. All else was rayless obscurity. The sky was absolutely black.

 

Interesting re the earth's icy past. What sort of time frame are they talking about - is there a link?

 

Man is undoubtedly having an effect on the planet, certainly with respect to the ozone layer and global warming. However, I think it is difficult to unpick genuine global changes from the mix. The earth has obviously gone through profound changes in it's recent (geological) history without man's help, eg the last glacial maximum was only 18,000 years ago:

 

http://www.scotese.com/lastice.htm

 

with Homo Sapiens arriving around 250,000 years ago, he must have been pretty resilient to survive.

 

Even in Victorian times you see pictures of people holding ice fairs on the frozen Thames. At this point in the industrial revolution, man's impact on the environment was still relatively low, but this demonstrates how planetary influences such as weather systems can vary. I believe that some extreme climate changes can be influenced by changes out of our control such as sunspot activity.

 

Mankind has obviously been through a lot in the past and won through. Has this been achieved by intelligence and the ability to adapt to even the most extreme and changing environments? Is it just sheer weight of numbers and the statistical probability that some will survive even the worst catastrophe, a sort of 'life will find a way scenario'?

 

Maybe it's sheer blind luck and ultimately self selecting. As man is the most intelligent/technological race (we know of, anyway), we look back and see our 'success' as inevitable, when it might be by the slimmest of chances that we are actually here. Deviating only slightly from a path we've been lucky to stay on for so long may lead to our demise. Another 'for example' is that the earth's core is iron, giving it a magnetic field like a bar magnet. Periodically the earth's magnetic field flips, every 200,000 years or so.

 

http://www.geomag.bgs.ac.uk/reversals.html

 

Last one was 780,000 years ago, so we're overdue for another. The effects are probably largely benign, but who knows....

 

The truth is, that apart from in the broadest sense, we don't really know what effect our actions have globally, although Man is no doubt causing some of these problems very rapidly. It's the 'butterfly flapping it wings in the Amazon rainforest causing hurricanes on the other side of the globe scenario'. Will the UK become get hotter with global warming, or will this affect the tides, so that we lose the warming effect of the Gulf Stream and are plunged into fierce winters - London being on the same latitude as Moscow.

 

It may be useful to look at other planets and moons in our solar system as models of planetary change. For example, the Cassini mission to the outer planets turned up fascinating information on the moons of Saturn and Jupiter, eg Europa, the ice covered moon of Jupiter has parallels with the earth's icy past DrB describes:

 

http://www.nineplanets.org/europa.html

 

and may conceivably harbour extremophile lifeforms, deep below the surface. Titan, the Saturnian moon that the Huygens probe recently landed on:

 

http://saturn.jpl.nasa.gov/news/press-rele....cfm?newsID=655

 

is of interest as one of the few planetary bodies with an atmosphere with some earthlike similarities. After these missions NASA had to bring a lot more geological scientists into the missions to analyse the surprise findings.

 

Maybe some of these discoveries may give us some clues to our understanding of the impact of both planetary and man made changes to the Earth. Ultimately, mankind is resourceful but will pay heavily for his mistakes. Maybe fossil fuels will expire before things get too bad - we will undoubtedly have to develop and refine carbon capture technology along the way, though.

 

TLM

[drbubb]

Grim, Wells' vision.

 

Was that the world before the belching out of C02 gas?

[brooki]

Nope, that's supposed to be 30 million years in the future, after he's left the time of the Morlocks and Eloi and is heading further into the future. I never really liked the main storyline, but the last chapters always gripped me in an apocalyptic way. Interestingly, air quality is probably far better in cities than it ever was in Wells' day, but the overall global problems are obviously far worse.

 

I sometimes wonder if as a race we actually welcome disasters in some perverse manner. It's like picking at a loose tooth or scab, you know you shouldn't, but it's irresistible. It's a car crash mentality that's balanced between shame for watching and morbid fascination.

 

You can taste the mood on HPC with people waiting for the economy to fall off a cliff.

 

Hmmm, maybe one too many whiskies on a wet Sunday afternoon....

 

TLM

[drbubb]

Back to the Future then- perhaps it WILL be cyclical.

[polo]

think melting glaciers are due to co2 emissions? then think again!!!!

 

May 23, 2005 THE COMING AND GOING OF GLACIERS

A New Alpine Melt Theory By Hilmar Schmundt

 

The Alpine glaciers are shrinking, that much we know. But new research suggests that in the time of the Roman Empire, they were smaller than today. And 7,000 years ago they probably weren't around at all............................................................

 

http://service.spiegel.de/cache/internatio...,357366,00.html