Well, it`s late and I`ve gone on far too long here. I hope you`re still reading this. I`m going to turn that earlier imagined toast into a real one and raise a glass to the successful landing of the Curiosity rover on Mars, which has me absolutely thrilled.
I`ll leave you with a link to the climate change section of NASA`s website. It`s a great resource and, frankly, makes me proud to be an American.
Lastly, RW, I apologize for the insults in my earlier posts. You didn`t deserve them and I should have been more civil.
You often hear the objection to AGW that goes like this: "Puny man can`t change the global climate. Nature is far more powerful than man."
The thought has some merit to it. After all, Earth`s been around a lot longer than we have and is likely to be here when we`re gone. Compared to natural processes, man does seem, in many ways, a minor factor.
But consider what`s happened with fossil fuels. Over tens of millions of years, carbon from fossilized organic materials was turned to coal and oil. In the past 100 years, man has extracted that carbon--millions of years worth--and dispersed it into the atmosphere. Carbon generated over EONS, thrown into the air in 100 years, the geological blink of an eye. Certainly, natural processes could cope with that much carbon in a suitable, geologic time frame. But to disperse that much carbon, this quickly? It`s an experiment, really, and a dangerous one at that.
What percentage of global warming do I attribute to solar variation? 10%-15%. That seems to me to be a conservative estimate (meaning, on the high side); I don`t know of any climatologists, in NASA or otherwise, who propose a greater role for solar variance than that.
So if rise in global temperatures we`ve seen this past century is not attributable to the ice age mechanism and it doesn`t seem possible that the Sun could be driving more than 15% of it, where is the majority of this heating coming from?
Well, since you`ve already stated that you accept anthropogenic climate change, I don`t think I need to explain the greenhouse effect. I`m sure you`ve seen the charts, including the "hockeystick graph." So I don`t think there`s any need to go over what you already understand.
I will pass on to you one realization I had a several years ago that helped me grasp why AGW is a serious problem.
But the warming we`ve been seeing now is on a completely different scale, unlike anything related to the temperature changes of the ice ages.
So if I don`t think the ice age cycle has anything to do with global warming, but I do think there is some natural component, what is it?
Our Sun exhibits some (not a lot) of variability in it`s intensity (aka, irradiance), its sunspot activity, and it`s output of UV (ultraviolet) light. While these solar variables are complex and not fully understood, one thing has emerged from the science: Earth is blessed with a Sun that has shown scant variability over millions, even billions, of years. If you stack all the solar variables I`ve mentioned above together, in a "perfect storm," they could account for perhaps 25% of the warming we`ve seen in the last 100 years. But, of course, we aren`t experiencing a perfect storm of solar variance. Yet temperatures continue to rise.
The theory you are proposing is pretty common, and I hear it frequently. There is something behind it but after looking into it, I find myself concluding (with NASA and the climatologists) that recurring ice ages is *not*, alas, an explanation for global warming.
To begin with, so far as scientists can tell, ice ages recur every 100,000 years or so, not 10,000 as you have it. These ice ages recur, as you probably know, due to anomalies in the Earth`s orbit and tilt.
So if there is that kind of a mechanism in place, as you say, why am I not attributing global warming to it? The answer is simple, really: The changes that occur in Earth`s temperature relative to ice ages are S-L-O-W. For an ice age to develop, it takes 5,000 to 10,000 years and a similar timescale to reverse. The attending change in temperatures occurs at about the same *glacial* pace (pun intended).