Yes there is. Specifically, the fact that CO2 is a gas. It's a basic mathematical rule.
You've got your discrete functions (such as integers) which are limited to specific values, and your non-discrete functions (such as temperature, gas density, and volume of a solid). The basic mathematical rule is that the value of a non-discrete property can never be measured perfectly. It can only be approximated. Next time you take your temperature, and the thermometer says 98.7? Your body temperature is never exactly 98.7. Ever. It's a little more or a little less. And, what's more, that's only the temperature inside your mouth. If you measured at the other end, I don't want to know about it. The temperature of other parts of your body is most certainly not 98.7--your arms and legs, for example, are almost always colder.
Ah, I think I see the problem now. There's something about measurement that I don't think you understand: measurements of these non-discrete functions are never exact, but that does not mean that those inexact measurements can't be useful. Take your thermometer example. You're right that my thermometer may say 98.7 F, but that's never exact. In fact, let's say it's kind of crappy - I take my temperature a hundred times in quick succession and I get a mean result of 98.7 F, with a standard deviation of 0.2 F, and the points appear to be distributed normally. Now what I can't say is that my body temperature is exactly 98.7 F; what I can say is that it appears that, with 95% confidence, my oral temperature is between 98.3 F and 99.1 F (I've used +/- 2 sigma). Furthermore, using established empirical relations between oral temperature and body temperature elsewhere, I can figure out approximations to what my temperature is in other parts of my body.
You seem to think that science is some sort of
exact endeavor. I hate to break it to you, but that's not actually true. We can't really know anything with 100% certainty; as an extreme example, we can't do anything that will prove that gravity won't just stop working tomorrow. All we can do is amass reams of evidence that shows that, in all situations we've seen so far, gravity works in a particular way and never simply switches off, or deviates from the predictions of Newton (except as corrected by Einstein).
In order to measure the Earth's temperature (or its CO2 levels) exactly, the measurement must be made at an infinite number of points--and all at the same time. Which is physically impossible. We can only guess. And today we can certainly measure more accurately than we could in the past. But we will never be able to measure perfectly. And the level of accuracy we need is a lot more than we're using, especially when it comes to measuring ocean temperature.
We can't have an infinite number of data points, but we do have far more data than I think you realize. There are thousands of meterological stations around the world, in all types of climates and levels of human habitation, and there have been for many decades. Many of these stations are in extremely rural locations that haven't seen any increase in human habitation. We also have satellite observations going back to the '70s. And basically all of the data we've ever seen indicates that an anthropogenic CO2 rise has happened, and that the global temperature average has also increased. And we can make extremely good predictions of what this global temperature average is based on all the data we've collected, even if it can't be known
exactly. Now the temperature increase has been nowhere near uniform; it's much higher in polar regions, and has been negative in a few isolated spots. But the overall trend is decidedly up.
One thing we have been able to measure is this: in and around cities, oxygen levels are lower and CO2 concentrations are higher than in rural areas. That has been verified. So we know that CO2 tends to linger around the emission point.
You're right that CO2 levels are higher near emission sources (e.g. cities) than they are in rural areas. But this has been satisfactorily corrected for. Even if you don't believe that, you should still note that measurements in extremely rural areas still show a marked increase in CO2 levels. Again, take a look at the
Keeling curve at Mauna Loa, and then note that this is just for illustration and that this has been demonstrated independently at a number of other locations.
And now for a comment: I'm actually not much of an environmentalist myself. Some of what the environmental movement has helped to do (e.g. getting DDT banned, opposing nuclear power plant construction, opposing intensive agriculture, etc) sickens me. If anything, I would tend to be skeptical of anthropogenic climate change without reams of evidence on its side. But the evidence is actually there, and I have to yield to that.
I just recently spent a term in a Ph. D. program in applied physics, and the people I had the most contact with were climatologists. I really hated research and discovered that I loved teaching, so that's why I quickly dropped out. But what was interesting was seeing some of this data for myself. I didn't even know about some other pieces of information backing anthropogenic climate change, such as the decrease in relative abundance of carbon-13 that comes from burning fossil fuels.
So the takeaway message is this: science is an inherently messy business, and we do have to make statistical inferences from limited data. But as data pours in, we can increase our confidence in certain hypotheses to the point where it's extremely unlikely that those hypotheses are correct. And AGW is something that has met those criteria in recent years. As somebody who thinks scientifically, I have to yield to the data and go with that. It doesn't necessarily mean that some of the behavior you see in environmentalists makes any sense. No, life as we know it is not going to end, and humans will almost certainly adapt to climate change, although it may cause some hardship and it will probably drive some more species extinct. But this is all just a cost of developing our economies in the way we have.
Unfortunately the mods would nail me for responding appropriately to your BS, but you made the claim and its your responsibility to support it. I'll take your refusal as evidence you screwed up and lack the honor to admit it. 
Bye bye...
A bit of trivia: ONE volcano spews as much carbon dioxide as the entire human race does in a YEAR.
