motörhead wrote on 03/07/10 at 17:41:43:
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Meaning based on this result, we can expect a total temperature increase of 1.4 degrees Celsius per CO2 doubling, based on current data.
I havn't recalculated your calculation. But some points came to my mind
- one cannot look a climate changes on earth as linear processes. Just take the ice shield in the north pole area plus Greenland (which infact recieved it's name from a warming period btw...). If it vanishes, and that can be measured by satellites, you have a double effect. First the area largely reflecting sun radiation back into space (albedo) shrinks. Second the area that absorps the sun radiation (warming up) increases.
So the total effect may well be exponential.
1.4 degrees Celsius per doubling of CO2 = 0.6 degrees C observed / log (380ppm CO2/280ppm) base 2.
Yes, it is possible the Earth's climate system works to amplify any small forcing through the mechanisms you discuss. In addition, CO2 becomes less soluble in water as temperature increases, so a slight increase in temperature due to CO2 could start a positive feedback loop.
Alternatively, the Earth's climate system could be primarily dominated by negative feedback mechanisms such as clouds, which may increase the albedo of the Earth and reflect sunlight back into space, in response to a higher temperature.
Really, the climate systems are hugely complex, and we don't really know. However, if the Earth's climate systems are driven by positive feedbacks, it's a good question as to why after 4.5 billion years, it did not find equilibrium in some kind of permanent Ice Age or Green House.
I would like to emphasize this point, mainly because most "warmers" I have encountered seem to think that the science is all so simple, that everything has been worked out.
The reality is that if you subscribe to the mainstream AGW theory, you are NOT just subscribing to the rather simple idea that CO2 is a greenhouse gas, and we are increasing the concentration, therefore temperature will increase. Even pro-AGW scientists admit the pure greenhouse effect of a doubling of CO2 is only 1 degree Celsius. In that case, you are subscribing to the idea that Earth's climate system is dominated by positive feedbacks that will serve to amplify this effect.
That, to me, is not so clear and all, and in light of the evidence we have, over the past 120 years and paleo-climatic evidence, in my view is quite dubious.
Quote:only 1.4° C ahh then... Well I take this figure. And I point out that this would also be only the average. The maxima may be much higher from here to there. So even starting from that seemingly meager figure that could have devastating effects on rainfall, wheather, harvest, rising sea level etc. Even 1.4 degrees is probably much too high simply because the warming prior to 1945 likely had a high solar component. The temperature increase from 1972-1998 may had cloud reduction and solar components as well.
But I would really like to address your point regardless. If humans can only prosper in a narrow band of approximately 2 degrees Celsius, then the geological record shows we're completely screwed because the climate varies by much more that all by itself, without our intervention.
Fortunately I don't share this view, in fact I believe it's little more than fear-mongering actually. One benefit of increased CO2 would likely be increased plant fertilization which could increase crop yields.
Quote:who are those bad guys behind the climate models espoused by the media and who are the bad guys in the media who espouse them? sounds like a big conspiracy by a chosen few against all mankind...
I only see thousands of scientists working on that theme and putting their results together. On the opposing side you have interest driven campaigns
I'd prefer to stay on issues of science, if you don't mind, the issues of human psychology are far more complex and grey really.
But if you want my short answer, my view is that it's largely a matter of self-selection in climate science -- people who don't believe in AGW don't enter this field, leave, or are forced out -- and mass delusions of crowds.
Quote:So it would help to answer the simple question "What if...?"
What if those campaigners from the oil or coal producing industry err an the majority of climate scientists are right? Ohh ouchh. Then good night where ever you are
What if the majority of climate scientists errs an those campaigners are right? Hmm... no...thing? Yoo, so or so we definitely have to find substitudes for carbon based energy in the near future. So why not begin right now?
If you take a look at the risks I think there is not a real choice at all. It is like in chess. You wouldn't sacrifice your queen just in the hope that your opponent may suffer a heart attack from this and you will win on time...
It is a good question but I think I addressed this already. In reality if the AGW theory were true there is not much that really can be done. We are Hydrocarbon Man -- with our current technology, without hydrocarbons, only a fraction of our current population could be sustained.
This isn't simply a matter of changing lightbulbs, and this is one my main issues with pro-AGW folk -- the sheer delusion as to the nature of the solutions.
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An example would be 650 million years ago when CO2 concentration was over an order of magnitude higher, yet the Earth was likely covered in ice.
Oh, no. Don't compare apples with stones.
650 million years ago earth offered a totally different picture. Life was yet in the kindergarten. The phanerozoic evolution of the fauna which is based on the flora took place about 500 to 550 million years ago. Besides it took some further 150 to 200 million years before nature left sea and took foothold on land.
So you cannot compare that early times (where our atmosphere was just evolving) with our days.
What does any of that have to do with climate PHYSICS? The issue is whether a model that predicts 3 degrees of warming per doubling of CO2 could reproduce an Earth covered in ice with over 10x as much CO2.
Quote: As before I repeat my important points:
- Every single year we combust carbonic resources (oil, coal) that took 500000 years to be build in the earth
More on the scale of 10s of millions of years, but I understand and agree with your point. Actually in my view this is a far greater issue. However I'm not convinced a focus on CO2 is an effective way to solve this. If it can be solved.
Quote:with that we crammed and cram on in only a few years our actual atmosphere with the carbondioxid of former eras in geological scale (!!)That is infact an unprecedented experiment on global scale. We, without knowing the effects, use our living room as laboratory.
Increasing the percentage of carbon in the atmosphere from 0.028% to 0.038% is hardly a geological scale when you consider the earliest atmosphere (4+ billion years ago) was likely majority nitrogen and CO2, and that it's really only the past few hundred million years that the CO2 concentration dropped below 0.4%.
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The cement you see all around you is probably made from limestone, which is the compacted remains of large number of coral reefs from hundreds of millions of years ago, when there was 10x as much CO2 in the atmosphere as there is today.
You don't know too much on zoology and palaeontology don't you?
Reefs can die, that took place more then once in earth history e.g. at the verge of the devonian to the carbonian. And the major reef builders may come extinct there. Later reefs may recover but then built by other species. Corals as dominating reef builders (as we know it from recent times) are a relatively new phenomenon and not known as being dominant "from hundreds of millions of years ago". The devonian reefs for example were dominated by stromatopores.
The overall importance of reefs cannot be overestimated. They are the craddle of many species. So if you like fish...
Limestone is by far not only built of "compacted remains of large number of coral reefs from hundreds of millions of years ago". Infact that is exeptionally seldom. Reefs aren't randomly distributed in the oceans. The need specific environments to develop.
Limestone is most often is a chemical sediment that was later compacted. The processes are complex.
That was more than a bit of a tangent.
I'm a geologist, so no zoology isn't my thing but I'm trained to know a little about fossils. I'm not going to argue most of your points, even though I'm biting my tongue a bit, because it's not necessary.
My casual remark regarding limestone was simply pointing out the rich diversity of marine life that existed for hundreds of millions of years in a period with 10x as much CO2 as now.
On that basis alone, I don't share your views on the impending doom of the ocean due to a 2x increase in CO2.
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Whether average temperature rises 1.4°C or 3°C is of minor importance, caus in an evolving population we can't afford it. It will result in wars on water, masses of refugies, starvation and rising instability.
It could be much less than 1.4 degrees, but anyways. As above, if a small temperature increase dooms humanity then let me assure you that we are doomed. Fortunately I don't share the view that this is the case, nor do I think temperatures will be rising dramatically in the next 100 years.
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