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

95% of the greenhouse effect is caused by water vapour. The remaining 5% is composed of the 'greenhouse gases'. Human activity has raised that 5% to 6%. So now the total greenhouse effect is 101% of what it would be anyway.
Thinking that we can change the climate and ecosystems of an entire planet through carelessness is astonishing pride.

Whats been happening is that the earth is actually getting COLDER.

Stats posted on nation weather service show that since 1909 the temperater has gotten 2 degree's colder, and in some places there have been spikes that make it almost 15 degree's colder then then the coldest temperater
ever recorded in the area.

Now that IS interesting. Any info on why it's happening?
It's also been said that there was a clump of hot summers in the 1990's. Personally, I think people give too little credit to the randomness of weather!

*Thinking that we can change the climate and ecosystems of an entire planet through carelessness is astonishing pride.*

The problem with that, according to chaos/complexity theory, it doesn't take much to nudge a system out of equilibrium. And even if it's only an extra percent now, as countries like China modernise and start consuming much more fossil fuels, that figure will rise. So no, I don't think it's pride; it's just our best understanding of how global systems work. It would be astounding if we *didn't* affect our environment.

Hmm, true. Have we any evidence that the Earth was ever in equilibrium? Although it does seem pretty stable. I do think beleiving that human activity can send the planet into disaster is prideful. We are not so important as that.

What I've heard that I find most interesting is this:

Lets assume the worst case scenario is true and the current forecasts of global warming are true. It seems that even if we then took that on board and implemented the Kyoto treaty in full, and spent the 200 trillion dollars that would require (or whatever the figure) then we would only delay the predicted global rise in temperature by around six years.
Not much huh?

Of course doing *something* is better than nothing but this would apparently be not much better than nothing.

I've heard people from the Meteorological office predicting global rises in temperatures using their latest computer simulations. now this simulation has also been run forwards from data hundreds of years ago and it broadly predicts what has happens well. This seems to give some credance to its predictive power. I'd be interested to know of the source that claims we have had a global drop in temperatures in the last 100 years as this seems in direct opposition to the Met offices own figures (and this after all is their job).

I must say though that I largely go along with this statement...
*Thinking that we can change the climate and ecosystems of an entire planet through carelessness is astonishing pride.*
People used to blame the wrath of god on flash floods and the like. now it's taken as evidence of global warming...

>>The problem with that, according to chaos/complexity theory, it doesn't take much to nudge a system out of equilibrium<<
Possibly true but it doesn't mean the whole thing will necessarily spiral entirly out of control either. The earth's climate has survived far worse pressures on it than our activity for more than a few billion years. I expect we have less of an effect than some give us credit for.

>>I do think beleiving that human activity can send the planet into disaster is prideful<<

As I said, I broadly agree here but one must be aware of an important caveat. Remember the depletion of Ozone over the poles. This is most certainly caused by human activity, so potentially we do possess this power...

I don't think the whole thing will spiral out of control (like Venus). Evidence in glacier ice suggests that in the past, when the planet got too hot, an ice age followed. And it came on pretty quickly in geologic terms (like hundreds of years, not thousands). If we think the warming is bad, just wait for the encore...

Well the last Ice Age is largely responsible for the rise of Mankind as we know it today (at least if you believe the current anthropoligical theories) so it can't have been all bad

We'd survive it and it might make us a little humbler.

Just to follow up on the ice age thing, scientists think that what happens is that melting ice from the polar ice cap (fresh water) disrupts deep ocean currents in the Atlantic. These deep currents bring warmer water north and keep Europe's climate mild. Disrupt these currents, and Europe cools down quickly. And it takes a long time to restore the ocean currents to their former state - about as long as your typical ice age.

And - being a little ray of sunshine here - there is evidence that this process is already underway right now.

Maybe we should be cornering the market on warm woolies instead of sun screen...

In the same broadcast on the radio as I heard the Met Office people (here in the UK) mention their computer simulations they were asked about the Ice age switch possibility. They agreed that it is more than possible, it *will* happen. However, they were of the opinion that the timescale for this to happen was in about 1000 years. The predictions of this happening within a generation are a possiblity but are very much on pessimistic end of the worst case scenario...

Whew! I hate the cold...

Anyway, this is all the more reason to figure out how to generate energy without fossil fuels - we're gonna need it to stay warm.

You never know, it might cause a much needed boost to the African Continent's economies.
Probably not the ideal scenario for such a shift in global economics though.

All of the ice age comments are interesting. Let me through a monkey into the works, rhesus is my current favorite. I recently read that on a geological time frame, the earth doesn’t have polar ice caps. This would mean that the last ice age hasn’t ended. The scientist who had written the work believed that, if the world climate continues to cool and more fresh water is trapped into the polar ice cap, the saline content in the oceans will rise to the point that the water will no longer support live.

Just some food for thought.

Just a question about the hole in the ozone over the pole, since it was brought up. I’m under the impression that we discovered the hole in the ozone. We didn’t watch it form. We have watched it change in size, but we have no way of knowing how long it’s been there or if there are natural fluctuations. Are we sure it isn’t natural. Maybe the ozone layer never completely formed. Or maybe whatever killed off the dinosaurs, created the hole in the ozone. Could a massive volcanic eruption that put enough ash into the atmosphere to create a world wide Pompeii be capable of burning a hole into the ozone? How about a planet killing comet or asteroid passing through the ozone layer prior to impact?

Is my understanding that we discovered the hole accurate?

I think the evidence for ozone depletion being caused by mankind is more or less conclusive, the atmosphere above the Antarctic was under observation long before the "hole" appeared. It's growth can be mapped pretty accurately to the growth in use of CFC's and other ozone depleting chemicals and we've seen it decline as we've stopped using them.
It doesn't map to volcanic activity (which on geological timescale is reasonably constant over long periods of time anyway) as far as I know although large eruptions do cause temporary depletion.

I'll reply to the rest later as I've w*rk to to

Reply to this post:

>>All of the ice age comments are interesting. Let me through a monkey into the works, rhesus is my current favorite. I recently read that on a geological time frame, the earth doesn’t have polar ice caps. This would mean that the last ice age hasn’t ended. The scientist who had written the work believed that, if the world climate continues to cool and more fresh water is trapped into the polar ice cap, the saline content in the oceans will rise to the point that the water will no longer support live.<<

I agree that we are currently in a warm period of an ice age. I'm not convinced that the earth doesn't have ice caps on a geological timescale. How do we know this? There have been many cold and warm ages aeons and eras during the existence of our planet, these must be controlled overall by the power output of the sun and changes in orbit of the earth, I doubt that there is an average temperature of the earth over its whol lifetime that could be agreed upon nor a frozen state where one could say "that's the typical earth during its lifetime."



As to the ice raising the salt concentrations in the sea until it cannot support life -that I'm going to have to strongly disagree with. Most life on earth (and I mean the *vast* majority of it) is bacterial, archea and viral (if you count these as life -certainly they are a manifestation of the biological process that underly life on earth). These can survive extremes in conditions that we are still not yet fully appreciative of I think.. There are bacteria than effectively eat rock as they get there minerals from rock formations and live within them. there are those that can survive at 80 degrees C, acid tolerant, base tolerant bacteria, those that survive on oxygen those that respirate anaerobically.
These are the powerhouse of life on earth and we *really do* overestimate our abilities if we think that we can end the existence of this plethora of creatures. Even a large increase in salt concentration would barely give them pause for breath I would imagine.
We live in a world where our general assumption is that large macroscopic life dominates merely because we can see it.

When was the ice age period when this happened anyway? Never I don't doubt. You'd probably have to turn off the sun for ice levels to get high enough to cause this I'd warrant.

For ' plethora of creatures', read plethora of organisms

From what I remember of my studies, a few years back now It seemed* to be a 'recognized' fact that we are still comign out of hte last ice age, hence why we managed a 'mini ice age' I think back about a hundred years ago in Victorian type age, oh dea I seem to have forgotten my history as well as my Geogrphy

I agree that there are bacteria and viruses that can survive conditions that would kill us instantly. Some have even theorized that some of them could survive the vacuum of space in spore form. There are also numerous insects, cockroaches for example, that can survive extremely severe conditions. The sea life I was thinking of though was the kind we eat. I think it is possible that the fish and mammal life in the sea, not to mention the oxygen creating algae and plankton, would start to die off as the salt levels rise. Not that I actually expect any of this to happen in a forseable future.

I’m not sure that we as a species can affect the planet to the extent that we think we can though. Mother nature is still in control. Just look at the tsunami in Asia. In one moment, whole regions were wiped clean of our “influence.”