The earth's climate is a very highly tuned set of variables, change a variable, and the whole system adjusts. Man has impacted a variable, the earth will adjust, life will change. Could be many generations from now, but there will be consequences. Yes a super volcano could happen at any time, and the results to humanity would be devastating. I don't see the relevance that has to the issue of man's affect, except to cloud the issue. Why deny man's impact, it's a fact, the only argument is how much. Again it's too late to change anything, man has pretty much done as TUSKtimes quotes, "....I've just pissed in my pants.........and nobody can do anything about it."
How can 500 billion tons of human-produced carbon have no impact? Over the last 150 years, carbon dioxide (CO2) concentrations have risen from 280 to nearly 380 parts per million (ppm). The fact that this is due virtually entirely to human activities is so well established that one rarely sees it questioned. Since the industrial revolution, we have been burning fossil fuels and clearing and burning forested land at an unprecedented rate, and these processes convert organic carbon into CO2. Careful accounting of the amount of fossil fuel that has been extracted and combusted, and how much land clearing has occurred, shows that we have produced far more CO2 than now remains in the atmosphere. The roughly 500 billion metric tons of carbon we have produced is enough to have raised the atmospheric concentration of CO2 to nearly 500 ppm. The concentrations have not reached that level because the ocean and the terrestrial biosphere have the capacity to absorb some of the CO2 we produce. However, it is the fact that we produce CO2 faster than the ocean and biosphere can absorb it that explains the observed increase. We know that fossil fuel burning and land clearing specifically are responsible for the increase in CO2 in the last 150 years is through the measurement of carbon isotopes. Carbon is composed of three different isotopes, 14C, 13C and 12C. CO2 produced from burning fossil fuels or burning forests has quite a different isotopic composition from CO2 in the atmosphere. This is because plants have a preference for the lighter isotopes (12C vs. 13C); thus they have lower 13C/12C ratios. Isotope geochemists have developed time series of variations in the 14C and 13C concentrations of atmospheric CO2. One of the methods used is to measure the 13C/12C in tree rings, and use this to infer those same ratios in atmospheric CO2. This works because during photosynthesis, trees take up carbon from the atmosphere and lay this carbon down as plant organic material in the form of rings, providing a snapshot of the atmospheric composition of that time. Sequences of annual tree rings going back thousands of years have now been analyzed for their 13C/12C ratios. Because the age of each ring is precisely known we can make a graph of the atmospheric 13C/12C ratio vs. time. What is found is at no time in the last 10,000 years are the 13C/12C ratios in the atmosphere as low as they are today. Furthermore, the 13C/12C ratios begin to decline dramatically just as the CO2 starts to increase — around 1850 AD. This is exactly what we expect if the increased CO2 is in fact due to fossil fuel burning. Measurements of 13C/12C on corals and sponges — whose carbonate shells reflect the ocean chemistry just as tree rings record the atmospheric chemistry — show that this decline began about the same time as in the atmosphere; that is, when human CO2 production began to accelerate in earnest. Number of observations of carbon decreasing in the global oceans: zero. Number of observations of carbon increasing in the global oceans: more than 20 published studies using 6 independent methods. In addition to the data from tree rings and ocean chemistry, there are also measurements of the 13C/12C ratio in the CO2 trapped in ice cores. The tree ring and ice core data both show that the total change in the 13C/12C ratio of the atmosphere since 1850 is about 0.15%. The results show that the full glacial-to-interglacial change in 13C/12C of the atmosphere — which took many thousand years — was about 0.03%, or about 5 times less than that observed in the last 150 years. Now Doctor, please quantify your objection to AGW.
When I saw the thread topic red IMMEDIATELY came to mind. Happens to be one area he's an expert in. Most others he googles his azz off.
this is not an argument. what number of billion tons is alot? i could claim that music hurts the environment if i wanted. i could say "300 billion songs has to hurt the envirnment! its 300 billion! thats alot!" BUT THATS NOT AN ARGUMENT! I HAVE TO UNDERSTAND THE CORRELATION. caps lock came on by accident there but i left it on.
Bull. 56 Million years ago, at the end of the Paleocene epoc, the earth was hot and completely ice free. This was caused by a surge of carbon of unkown etiology. There were no humans injecting carbon into the atmosphere, yet it happened. The adverse impacts of humans are miniscule by comparison. What will be will be regardless of the existence of humans.
not unknown, red understands it well enough to rule it out. oh hey that is weird looks like we will need to grow the government with carbon cap and trade. weird that a "purely scientific" issue is being used to push political agendas. i cant imagine how that might ruin the science when people have political agendas.
Actually science is above political agendas, the scientific method is worldwide with no international borders. There is no science pope, no science president, just the scientific method. Individual scientists want to be heard, want to be published, they want fame and money. They strive to prove the established theories wrong, so they can make a name for themselves. And that's the beauty of it, every time an article is published, thousands of scientists try to discredit it. If the numbers don't add up, if there is any biased manipulation, it will come to light. Cheating scientists are kicked out of the club, no matter how respected they were. That's not to say science knows all, it doesn't, what science can't measure, science doesn't believe. Science can be corrupted, manipulated to fool the public. Industries such as oil, tobacco, pharmaceuticals, pervert science to make money. but scientists are skeptics, and they know poor science when they see it, science is not easily fooled. The public however is easily manipulated. It is wiser to listen to the scientist, and be wary of governments and corporations, they have ulterior motives, pure science just seeks the truth.
