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Another 150,000 Years of CO2 Data
An anonymous reader writes, "We've known since 2004 that the past 440,000 years have shown atmospheric carbon dioxide levels varying between about 200 and 300 ppmv, the difference in extremes being the difference between advancing ice sheets and our current clime. In 2005 the data were analyzed back to 650,000 years and were found to be much the same — Al Gore was proud to be able to show that then-new analysis in his 2006 movie An Inconvenient Truth. Now all 800,000 years of the ice column have been analyzed, and the data show much the same pattern, according to the researcher: 'When carbon dioxide changed there was always an accompanying climate change. Over the last 200 years human activity has increased carbon dioxide to well outside the natural range' — to 380 ppmv."
"You mean, we have no idea how to properly predict climatology? Any changes we attempt to make may be a moot point, because the planet in the end may have complete control?"
The climate scientists do appear to be making predictions. Those predictions aren't pleasant. Further, they are making these predictions based -- now -- on 800,000 years worth of ice core data (rather than ~600K years of data as before). There are other indicators, from tree ring data to a range of species from warmer regions migrating up north and down south as temperatures change. And then there's all that glacial freshwater being dumped into the sea due to arctic warming, as well as unprecedented permafrost melts.
There's plenty of data to back the assertion that human activity is the cause for increasing CO2 density in the atmosphere. --M
Carbon dioxide that's generated from metabolic proccesses come from carbon present in what we eat. Since all our food get's its carbon in turn from the air (plants via photosynthesis, animals via eating plants), the total carbon in the system remains in balance.
This is the same reason why biofuels aren't considered a greenhouse gas contributor - it takes as much carbon from the air to produce them as they release when burned.
Erotic is when you use a feather. Exotic is when you use the whole chicken.
As usual, what's good for the environment/consumer/voter takes a back seat to politicians' special interests.
Both the movie and the book An Inconvenient Truth were carbon neutral (via purchase of wind power carbon credits from NativeEnergy). According to various interviews, Gore also has offset his personal carbon consumption.
Using public transit is a good thing, but it's not a realistic option for everyone (particularly celebrities, given how the rest of us react to them).
By going Carbon Neutral in his personal life and business ventures, Gore is personally doing as much to fight global warming as anyone can reasonably do. I'm not going to judge him based on whether he uses compact fluorescent bulbs in his laundry room.
For those actually paying attention, there is no "ongoing debate" in scientific circles over human influence in climate change. The only people "debating" it are the conservative politicians and anti-environmentalist special interest groups, in order to seed doubt and to prevent any action to be taken.
Which "developing countries? As far as I can tell, the only developing countries that have not signed the Kyoto Protocol are the US and Australia.
Look at the map and list of List of Kyoto Protocol signatories. China, Russia, the EU, all of South America, Canada, Asia (inc both N. & S. Korea) have all signed and ratified the treaty. That means that those countries will be reducing their emissions to 55% of their 1990 levels.
Tell the truth and you won't have so much to remember.
It seems to me that, contrary to your strawman version of their claims, the realclimate article has a very valid point. Reading that summary, and also the linked references to published papers on the topic, there is a perfectly reasonable explanation: In the past carbon dioxide has not been the initial cause of climate changes, but rather a feedback mechanism. That is, Milankovitch cycles cause some initial warming. Warming is known to cause the oceans to be less able to sequester carbon, and hence carbon dioxide levels tend to rise when the planet warms. Once this initial kickstart has produced more atmospheric carbon dioxide (which takes, apparently, around 600 to 1200 years) a feedback cycle ensues with the increased levels of carbon dioxide producing yet more warming. The resulting warming continues for a period of around 4200 years, during which carbon dioxide is very likely to be a factor.
This seems very reasonable - one would hardly expect atmospheric carbon dioxide to necessarily be the initial driver for warming given that, historically anyway, there wasn't anything (other than warming) that could cause a significant enough change in atmospheric carbon dioxide to induce warming. Just because the intergalicials required orbital variation to kick off the warming and start the process of carbon dioxide induced warming hardly invalidates carbon dioxide potentially being a factor in warming. Rather, the burden of proof lies more with those who claim it doesn't: we know that atmospheric carbon dioxide, due to its absorption spectra, will trap heat by allowing incoming energy from the sun to pass (due to wavelength) while trapping and radiating back the reflected heat energy from the earth (due to its different waverlength to that of incoming energy from the sun); what is need is an explanation of why that effect is either of no significance, or why it in fact does not occur for some reason. No one has provided such an explanation.
In summary, instead of, as you claim, "...to them, apparently, man made CO2 causes instant warming, but natural CO2 takes up to 800 years to have an effect", it is the opposite: to them man made carbon dioxide can cause carbon dioxide levels to change and precede warming effects, but natural changes in carbon dioxide levels require warming to occur and thus lag behind warming events from other causes (such as Milankovitch cycles).
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Care to cite a source on this? The whole region (the Sahara) was much greener in the past, this is true, but desertification started long before the advent of agriculture, and has been creeping along for the last 30,000 years or so. Egypt, at least as long as it has held civilization, always been mostly desert, which is why the largest population centers there (now, and thoughout history) have been next to the Nile. Also do a brief refresher of Egyption mythology to see the importance of annual Nile flooding for their agriculture thoughout the ages. 60,000 years ago Egypt indeed might have been more grassy than today, or even 30,000 years ago, but it changed previous to the advent of heavy agriculture.
I think Brazil is doing much better ecologically than we are, even if this "risk" to topsoil is real. Top soil can be managed through intelligent farming techniques, it can even be retained and replenished thanks to modern farming technology. Even fertilizers can be used to replenish mineral and nitrogen content of the soil, and while if used unintelligently this can lead to enviromental impacts, this is not a necissary consiquence.
In the end, the enviromental consiquences of ethenol is much much less than using fossil fuel (which, BTW, has nothing to do with dinosaurs, or even prehistoric fauna, it is the result of ancient, but much after dinosaurs, swamps and boglands decaying).
I really don't see how Brazil is destroying their economy. All indicators say that their succesfully applying a socialist model to it, with great results. Granted, their not quite up to "first world" standards, but in light of the region, and history, they're doing great for an progressive emerging economy.
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good thing they found water on mars. No, just kidding, but seriously, there's water on mars.
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I would have to disagree. Aside from the simple correlction of timing of changes, and accounting of carbon dioxide emissions, there is the analysis of carbon isotopes in atmospheric carbon dioxide. In summary, by measuring the ratios of different carbon isotopes in the atmosphere, and knowing that carbon from fossil fuels will have different isotope ratios than carbon from natural sources, it is possible to establish how much of the recent change in atmospheric carbon dioxide levels are due to human activities through burning of fossil fuels. The results are that the rise in carbon dioxide levels of the past 200 years are almost entirely anthropogenic.
I have never seen any credible evidence to support the counter claim that the change in atmospheric carbon dioxide levels is not due to human activity. It is true that in terms of the total carbon dioxide produced in the carbon cycle, human produced carbon dioxide is just a fraction, but if I have a tank that is draining water at 10 liters per minute and having water added at 10 liters per minute then adding more water, even at a small fraction of that rate, will cause the otherwise stable tank to overflow. In terms of change human factors are very relevant, and quoting other figures about total carbon produced is, while accurate, disingenuous and misleading with regard to the actual issue at hand.
Well this isn't something that can be "proved", but in terms of history (last 800,000 years) we are in the middle of an interglacial which peaked some time ago, so we shouldn't be expecting further increases in temperature from the galcial/interglacial cycles. From a more recent historical perspective (last 200 years or so) the recent warming is quite unprecedented according to almost all historical temperature reconstructions (and there are many). In terms of our current understanding of climate and all the things that could effect it, without including atmospheric carbon dioxide changes, we cannot properly account for the present warming. That is, to the best of our current knowledge the warming is not natural. That could change, but we would have to learn some significant new informnation to change our understanding of the climate for that to occur.
As noted above, recent increases in carbon dioxide levels are the only way to account for the recent warming given our curent understanding of climate. Also noted above is the fact that human activity has been a major factor in increasing levels of atmospheric carbon dioxide. If you want more details on how attribution of recent warming has been determined so far the IPCC TAR attribution chapter is a good place to start - it summarises a number of different studies using a variety of techniques to attempt to determine the most likely factors driving the current warming.
That is certainly being worked on. I'll again refer to the IPCC TAR for a figure showing various radiative forcings, which is to say factors affecting global warming (both positive anmd negative effects). There are several besides atmospheric carbon dioxide. One of the most s
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Before irrigation, Egypt was green. GREEN! Now it's a fucking desert.
I'm sorry, but this is exactly the kind of falsely alarmist crap that's causing so many people to be skeptical of the environmental movement.
Egypt and the surrounding desert was green about 6,000 BP because of an period of unusually heavy precipitation in the region called the Neolithic Subpluvial. It supported agriculture in what is now desert, yes, and also a pastoral economy. Desertification resumed about 5,000 BP not because of these activities -- there were, for example, no forests to cut down -- but because the rain stopped. (And this was also not due to human activity, which was at a relatively low level at the time.) Agriculture in the Nile Valley has ever since, and until the construction of the dams at Aswan, been reliant on the annual Nile flood. This flood irrigates fields all by itself, without human intervention. There was a degree of artificial irrigation, true, but it had little effect on the progress of desertification.
Stick to the truth; you'll be more convincing.
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OTOH, [plants] also require loads of sunlight, water and soil
Mean distances from Sun:
Mars:Earth ratio of sunlight per square metre: 1:1.542^2 = 1:2.378
The sunlight issue alone is not all that difficult - a sealed environment with sufficient biomass and prudent management could be brought into range by an arrangement of lenses and mirrors. Now you might say that if you're talking about a sealed environment, you can do that on Earth too, but let's see how long your environment remains sealed when you have crowds of starving, desperate people on the outside of your bubble.