"Most of the carbon dioxide emitted by human activity does not remain in the atmosphere, but is instead absorbed by the oceans and terrestrial ecosystems. In fact, only about 45 percent of emitted carbon dioxide stays in the atmosphere....To assess whether the airborne fraction is indeed increasing, Wolfgang Knorr of the Department of Earth Sciences at the University of Bristol reanalyzed available atmospheric carbon dioxide and emissions data since 1850 and considers the uncertainties in the data. In contradiction to some recent studies, he finds that the airborne fraction of carbon dioxide has not increased either during the past 150 years or during the most recent five decades." - bob

This is very easy to misunderstand! They're not saying that CO2 *levels* haven't increased, but that the *fraction* of human-generated (anthropogenic) CO2 which isn't reabsorbed hasn't changed -- even if that fraction remains constant at 45%, increased anthropogenic output still leads to increased atmospheric CO2 levels. This is about fine tuning climate models, not denying anthropogenic global warming. I find the phrase "airborne fraction of carbon dioxide" actively misleading. - ⓞnor

I read that wrong the first time too. I wonder how long before it starts getting cited as a "global warming debunking" paper... - Joel Webber

@nor++ - Andrew C (✔)

That's kind of exactly the opposite of what @nor wrote. - Andrew C (✔)

Let's try that again, MVB: "only about 45 percent of emitted carbon dioxide stays in the atmosphere" (article quote) means that ~half of the CO2 emitted by humans stays in the atmosphere, the rest being absorbed by oceans and plants. 1 unit more CO2 emitted means 0.45 units more in the atmosphere. This does *not* say "the contribution as a percentage by humans to carbon dioxide levels has not changed" (your quote). It's a confusing but important distinction, which is what ⓞnor was pointing out. - Joel Webber

Also from the article: "However, some studies have suggested that the ability of oceans and plants to absorb carbon dioxide recently may have begun to decline and that the airborne fraction of anthropogenic carbon dioxide emissions is therefore beginning to increase." If that turns out to be true, then each additional unit of CO2 we emit will translate into *more* atmospheric CO2 than it would have in years past. Not a good thing. - Joel Webber

Good luck with that sobriety thing... I'm hanging at home tonight, still recovering from a couple of days partying with my brother-in-law, who's ~10 years younger, and with a commensurately higher tolerance :) - Joel Webber