![](https://247wallst.com/wp-content/uploads/2022/08/imageForEntry26-YHj.jpg)
Source: Leonid Andronov / iStock via Getty Images
2013
> Carbon dioxide (CO2): 395.49 ppm
> Methane (CH4): 1,815.44 ppm
> Nitrous oxide (N2O): 326.53 ppm
![](https://247wallst.com/wp-content/uploads/2022/03/imageForEntry2-bBa.jpg)
Source: Ron and Patty Thomas / iStock via Getty Images
2014
> Carbon dioxide (CO2): 397.45 ppm
> Methane (CH4): 1,824.40 ppm
> Nitrous oxide (N2O): 327.61 ppm
![](https://247wallst.com/wp-content/uploads/2021/11/imageForEntry8-ueQ.jpg)
Source: Denis Doyle / Getty Images News via Getty Images
2015
> Carbon dioxide (CO2): 399.58 ppm
> Methane (CH4): 1,834.63 ppm
> Nitrous oxide (N2O): 328.51 ppm
![](https://247wallst.com/wp-content/uploads/2021/03/imageForEntry11-7t8.jpg)
Source: Allison Joyce / Getty Images News via Getty Images
2016
> Carbon dioxide (CO2): 402.87 ppm
> Methane (CH4): 1,842.40 ppm
> Nitrous oxide (N2O): 329.33 ppm
2017
> Carbon dioxide (CO2): 405.19 ppm
> Methane (CH4): 1,849.95 ppm
> Nitrous oxide (N2O): 330.31 ppm