Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Politics : Foreign Affairs Discussion Group -- Ignore unavailable to you. Want to Upgrade?

To: Nadine Carroll who wrote (190652)	7/2/2006 2:21:47 AM
From: bentway	Read Replies (1) \| Respond to of 281500

"There didn't used to be six billion of us on the planet a hundred years ago, let alone the hundreds of billions cows, sheep, pigs, etc that we raise." This is just stupid Nadine. There were the millions of animals we've driven to near extinction. The buffalo used to be a black carpet to the horizon on the prairies, mowing the grass. Besides, ONE auto produces as much exhaust in a twenty mile drive as a human does in a year, at least.

To: Nadine Carroll who wrote (190652)	7/2/2006 6:16:09 AM
From: geode00	Read Replies (3) \| Respond to of 281500

"...The amount of CO2 we produce depends on (1) how many people there are and (2) how much energy they use. The poorer people on Earth will seek a bet-ter standard of living, and that will require more energy. Almost all of our energy now comes from burning fossil fuels and therefore involves adding CO2 to the atmosphere. The hope expressed at the UN Conference on Environment and Development (Earth Summit; Rio de Janeiro, 1992) was that the production rate of CO2 could be held to its 1990 level, but the production rate has already risen well above that level. Some politicians believe that the Earth Summit goal is achievable, but I don't. I suspect that we are going to generate 7 gigatons or more of carbon as CO2 every year. At this rate, the CO2 content of the atmosphere will rise at the rate of about 2 ppm per year (Fig. 6). fig. 6 The CO2 content of the atmosphere will continue to increase; how much it increases depends on many variables. Maybe there will be a miracle, and we'll find some alternate energy source that is socially acceptable and economically fundable. I have little doubt, though, that late in the next century, the CO2 content of our atmosphere will reach 560 ppm, twice the preindustrial level. Before we're free from dependence on fossil fuels, we'll probably drive the CO2 up to 700 ppm or more. For this rise in CO2, models yield a range of global warmings, because they differ in the extents of water-vapor feedback. As already stated, were there no such feedback, the warming would be only about 1.2°C and would not produce much difficulty. If the warming were 3, 4, or 5°C, as some models predict, then everybody would agree that there would be big trouble. What I've injected into this already complicated situation is the realization that in the past, climate changes haven't come gradually. Whatever pushed Earth's climate didn't lead to smooth changes, but rather to jumps from one state of operation to another. So the question naturally arises, What is the probability that through adding CO2 we will cause the climate system to jump to one of its alternate modes of operation? I contend that since we can't yet reproduce any of these jumps in computer simulations, we don't really know how many modes of operations Earth has, and we certainly don't have any idea what it might take to push the system from one mode to another. We do know, however, that a substantial warming would surely reduce the density of polar surface water and thereby tend to cut off deep ventilation. So we're entering dangerous territory and provoking an ornery beast. Our climate system has proven that it can do very strange things. Since we've only recently become aware of this capability, there's nothing concrete that we can say about the implications. This discovery certainly gives us even more reason to be prudent about what we do, though. We must prepare for the future by learning more about our change-able climate system, and we must create the wherewithal to respond if the CO2-induced climate changes are large, or, worse yet, if they come abruptly, changing agricultural conditions across the entire planet. We must think all this through. Even if there is only a 1% probability that such a change might occur during the next 100 years, its impact would be sufficiently catastrophic that the mere possibility warrants a lot of preparation. My lifetime study of Earth's climate system has humbled me. I'm convinced that we have greatly underestimated the complexity of this system. The importance of obscure phenomena, ranging from those that control the size of raindrops to those that control the amount of water pouring into the deep sea from the shelves of the Antarctic continent, makes reliable modeling very difficult, if not impossible. If we're going to predict the future, we have to achieve a much greater understanding of these small-scale processes that together generate large-scale effects. ... williamcalvin.com

To: Nadine Carroll who wrote (190652)	7/2/2006 10:42:19 AM
From: Wharf Rat	Read Replies (2) \| Respond to of 281500

"I read somewhere on the net an estimate that give 20% of the rise in co2 to respiration, and only 7% to fossil fuels" It depends on what you are trying to say. If you mean % of CO2 flux, 7% is about right. If you mean 7% of the change, you are way lowball. However, if you mean planetary respiration, and not anthropogenic, we do produce only a small amount of the CO2 flux.. The magnitudes of C fluxes are as follows (all in 1015 g of C per year): · Ocean uptake = 1.7 (x 1015 g C / yr) · Photosynthesis = 111 · Respiration = 110 · Fossil fuels = 6.3 · Biomass burning = 1.6 Now, that doesn't seem important,except that, without our input,there was a homeostasis. So we have taken a balanced system and have overwhelmed it with an a extra 7 GT of carbon a year. You can get a bigger picture here..http://www.cet.edu/ete/modules/carbon/efcarbon.html We are all familiar with how the atmosphere and vegetation exchange carbon. Plants absorb CO2 from the atmosphere during photosynthesis, also called primary production, and release CO2 back in to the atmosphere during respiration. Another major exchange of CO2 occurs between the oceans and the atmosphere. The dissolved CO2 in the oceans is used by marine biota in photosynthesis. Two other important processes are fossil fuel burning and changing land use. In fossil fuel burning, coal, oil, natural gas, and gasoline are consumed by industry, power plants, and automobiles. Notice that the arrow goes only one way: from industry to the atmosphere. Changing land use is a broad term which encompasses a host of essentially human activities. They include agriculture, deforestation, and reforestation. The adjacent diagram shows the carbon cycle with the mass of carbon, in gigatons of carbon (Gt C), in each sink and for each process, if known. The amount of carbon being exchanged in each process determines whether the specific sink is growing or shrinking. For instance, the ocean absorbs 2.5 Gt C more from the atmosphere than it gives off to the atmosphere. All other things being equal, the ocean sink is growing at a rate of 2.5 Gt C per year and the atmospheric sink is decreasing at an equal rate. But other things are not equal. Fossil fuel burning is increasing the atmosphere's store of carbon by 6.1 Gt C each year, and the atmosphere is also interacting with vegetation and soil. Furthermore, there is changing land use. cet.edu