# What percent have we raised CO2?

Preamtjeopogenic (1850 AD) concentration of CO2 in the atmosphere was 280 ppm. Today(2015) the level is 400 ppm. What was the percent of atmospheric CO2 if it was 280 ppm? CO2 is increasing in the atmosphere at the rate of approximately 22 ppm/ yr due to human interaction; in 2014 we emitted 10 GT of carbon. In 2014 ad, CO2 i the atmosphere was 400 ppm

Dirac

The question is somewhat ambiguous. The number of moles of CO2 in the atmosphere have gone up (400-280)/280 x 100 = 43% The molar percentage has gone from 0.028% to 0.040%, an increase of 0.012% The percentage by weight has gone up about 44/29 x 0.012% = 0.018%, since CO2 is heavier than most other gases in the atmosphere. For the greenhouse effect, though, it's not the atmospheric fraction, it's how much CO2 there is along a vertical column and how it is distributed vertically (higher means more greenhouse effect). In comparison, water vapor has a molar percentage of about 0.4%, or about 10 times as much. "Anonymous" points out that CO2 has a diminishing warming effect as its concentration increases, that is true for CO2 and for all the other greenhouse gases present in the atmosphere (at least in the concentrations currently seen). That's why methane is sometimes misleadingly referred to as a "stronger" greenhouse gas, it's not that it's stronger on a molecule by molecule basis, it's just that it's present in much smaller concentrations, so you don't have to add as much to get a big change.

Jim

Dirac is correct, except that the question is not ambiguous. Percent cahange is always the ratio between the change and the initial value, multiplied by 100%.

Daro

Gov. wants to keep the issue as vague as possible. Simplified "give us your money or dies". Hence the continued calls for a global tax collected by the U.N. Purely political issue.Earth has warmed many many times before, and CO2 has been at dramatically varied levels, far above the paltry numbers they are trying to scare us with. The Yellow vests indicate that even hardcore socialists are not impressed with the supposed "solutions". .

JimZ