astrothad
Member
We now have tools that can split apart the molecules in the air and determine whether they came from cars, volcanoes, etc. by their chemistry composition. And the verdict is that most of them are CO2 from cars, so it's pretty hard coded in the science of what's happening....
Carbon dioxide is two oxygen atoms attached to a carbon atom, and there is no direct way to distinguish the last place any such molecule came from. They are - with the exception of isotopes ([SUP]13[/SUP]C instead of [SUP]12[/SUP]C, for example) - identical. If you can capture the CO[SUB]2[/SUB] at the source, you can look for relative amounts of the isotopes that give you clues to their origin. However, this is not possible in the open atmosphere due to the mixing of gases that occurs.
What we do have that allows climate scientists to state accurately the percentages of CO[SUB]2[/SUB] from various sources is a vast array of global monitoring from satellites and from the surface. We can, with greater precision than ever before, show how much is coming from geologic sources, from energy production, and from the burning of forests. We can also measure how much is being sequestered by plants and by the ocean. We also have more precise measurements of the changes to the land and water than ever before, largely due to satellite measurements.