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."

Comments

Re:An Inconvenient Agreement: Bill O'Reilly &

[paranode]

Well there's that, and the fact that we get our ethanol from corn which is not nearly as useful for producing ethanol as Brazil's sugar cane is. And of course, our corn lobby is actually pretty big and have consequently placed nice restrictions on importing ethanol from such countries as Brazil as well as getting sugar cane into the business of producing ethanol. So it's not exactly 'big oil', though their lobby is plenty powerful on its own.

As usual, what's good for the environment/consumer/voter takes a back seat to politicians' special interests.

Re:My grip with "An Inconvenient Truth"

[theodicey]

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.

Re:Bad science

[Coryoth]

However AFAIK there is no solid proof that human activity is a major or even significant factor in the changes over the last 200 years.

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.

This claim has been made many times, but so has the claim that human activity is only responsible for some tiny fraction of global CO2 emissions.

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.

Our current cycle of global warming isn't natural. Note "hasn't happened before" isn't proof.

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.

Human activity is a major factor in global warming.

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.

dentify the other factors influencing global 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