h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Pattern Chaser has prompted me to open up this new thread to discuss an issue which is of critical importance to our lives on this planet.

Is global warming caused mainly by man, or is it some type of natural phenomenon? What are your thoughts on Global Warming?

I'm a bit ambivalent on the subject, as it is often forgotten that the world has often gone through warm periods much warmer than the one we are in at the moment, when people could not possibly have had anything to do with this warming effect. The average world temperatures 1000 years ago were even warmer than they are today. Conversely global temperatures have also taken major dips, again without much intervention from mankind. People don't really know why these things happened in the past.

Nevertheless, we are burning up 70 million barrels of oil each day, cutting down the rainforests, and farming large methane producing animals (cattle) on a vast scale - surely all this must be having an effect, but how much?

Finally, it is obvious from looking at recent news stories that there is significant evidence of global warming. Temperatures continue to break records each year, ice caps are breaking off and melting, glaciers are flowing faster than expected. It appears to me that when governments deny that global warming is taking place, that they are not being realistic.

So what are your thoughts? Does it concern you? What do you think should be done? Do you think that people have sensationalised the Global Warming risk far more than necessary?

Woodpigeon

Personally I do beleive that humans have an effect on climate - I also beleive that regardless of the reasons behind the current increase (natural/man made) we need to recognise that an increase in global temperature is not good for us as a race and therefore do what is in our power to counteract this.

The precariousness (is that a word) of our position was brought home to me by a global sea level curve http://odp.pangaea.de/publications/166_SR/chap_16/c16_f2.htm
Today is at the top and as you go down you go back in time. The dotted line shows our current sea level. In the last 30 or so Ma (million yrs) sea levels have been predominantly high. All drops below our current sea level have been shortlived and it isn't unknown for the sea to rise by more than 100m.

As a geology student all the people I came into contact with agreed with global warming being accelerated rapidly by fossil fuel burning. The one lecturer who was being funded by an oil company also agreed (however he said that we should be grateful as we had avoided an ice age).

However as long as we continue to argue over the cause the solution will never be implemented - we can control our climate (global climate not day to day weather) but it isn't easy and would involve the entire human race cooperating for it's own continued survival (or at least survival of *civilisation* as we know it).

That's a facinating chart. Close to where I live there are extensive raised beaches indicating much higher sea levels than today.

Do you think though that it might be better to assume that world temperatures and sea levels are largely beyond our control, and that, rather than trying to tackle the causes (which might be futile), we might be better off preparing ourselves for the worst instead - coastal defenses, agricultural and social transition plans (preparation of highlands for new types of agriculture, movements of coastal populations to settlements on higher ground, tropical disease research, desert irrigation, etc.) You don't hear much about this.

I think a mix of the two would be ideal - there are huge amounts of greenhouse gases released through ignorance and laziness and a little effort by everyone would make a huge impact on this. Also I think looking into carbon sinks would be very worth while (either through artificial limestone (has to be feasable chemically), storing waste paper/wood where it wont decompose and get back into the cycle early, planting trees (but only because I like trees), making large areas of the ocean reserves for photosynthesizing plankton (and anything that eats them and then locks up the carbon in poo/rock), burning of methane (see below)).

Methane is 10 times more effective than CO2 as a greenhouse gas but in the atmosphere it will break down to CO2 naturally in 10 years or so. By burning methane before it is released into the atmosphere you accelerate its breakdown, prevent it doing any damage it could do and create energy out of waste - however this is only really any good for landfill type methane (again this has its drawbacks - the fact that the ammonia in the gas means that all components need to be made of gold being the most obvious) and is not much help when it comes to cows - maybe we should get them all on yakult?

When it comes to prevention I think you are right we have realised our effects too late to revers them - a bit of targeted effort could give us the time needed to prepare for the worst.

I'm wary of coastal defences - they have to be very well designed to only defend the coast and not cause worse problems elswhere. I think a good policy shift would be to ban building within xm of a coast meaning that if the worst happens we can sacrifice unpopulated coasts in favour of populated ones. Another thing I think we need to look into is possible artificial creation of aquifers (underground rocks that store huge amounts of fresh water) not only as water sources in dry spells but also as buffer zones in wet spells - at the moment higher ground tends to be on none aquifers but fractureing rocks along certain horizons/planes could theoretically solve this.

With a long term stratagy it is entirely possible for life to continue almost uninterupted along side global warming - and with some targetted research it should be possible to get to a stage where we can manage our atmosphere well enough to keep things stable.

The lack of O3 - ozone will kill us first. Methane is an ozone depleting gas and in my country, where skin cancer dwarfs all other cancers, cows are the worst culprit. There is a grass being developed to produce less methane. Unfortunately if ozone depleting gas production were to stop tomorrow the hole would continue to grow for about 50 years.

So on the origional question. I'm not afraid of the global warming bogey man.

Are people sure about the size of the hole continuing to expand? I though that one of the problems with the ozone hole controversy was that records were still very recent. I take your point though. Darn cows.