This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
According to the IPCC, 150 billion tonnes of carbon go into the atmosphere from natural processes every year. This is almost 30 times the amount of carbon humans emit. What difference will any reductions we try to do make?
Answer:
This is quite true that the natural fluxes in the carbon cycle are much larger than anthropogenic emissions. But in the natural process, for roughly the last 10K years until the industrial revolution, every gigatonne of carbon going into the atmosphere was balanced by one coming out. What we have done is to alter only one side of this cycle. We put approximately 6 gigatonnes of carbon into the air but, unlike nature, we are not taking any out.
Thankfully, nature is actually compensating in part for our emissions, because only about half of the CO2 we are emitting is staying in the air. Nevertheless, since we began burning fossil fuels in earnest over 150 years ago, the atmospheric concentration that was relatively stable for the previous several thousand years has now risen by over 35%. So whatever the total amounts going in and out on their own, humans have clearly upset the pre-existing balance and altered significantly an important part of the climate system.
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
"Natural Emissions Dwarf Human's" was first published here, where you can still find the original comment thread. This updated version is also posted on the Grist website, where additional comments can be found, though the author, Coby Beck, does not monitor or respond there.
Environment
Politics
Comments
Coby, which sources would you consider to be the more realistic example of human emissions? I've seen numbers ranging from 6 to 10 GtC/yr (I suspect land use changes are included in some of them while others may only mention fossil fuels, but I've been wrong on this before), and I'm trying to narrow down which ones I should cite when asked this. A citation would be useful, and I'm not having much consistent luck on Google Scholar.
Posted by: Brian D | October 22, 2008 2:23 PM
I've always used this as a primary source:
http://cdiac.ornl.gov/trends/emis/meth_reg.html
Posted by: coby | October 22, 2008 8:28 PM
Unless you mean one human is causing this problem, your title needs to say " Humans' " instead of " Human's ".
If you do mean one, please tell us his or her name (I'm betting it's a guy, probably in the midwest, probably a big sports fan)so we can go to his house and straighten him out.
Please correct your title, both here and where it's referenced (the list of denier points, etc.)
Posted by: J4zonian | March 17, 2009 3:27 PM
Thanks J4zonian, I have made the changes.
Posted by: coby | March 17, 2009 10:29 PM