![](https://247wallst.com/wp-content/uploads/2022/08/imageForEntry6-aCw.jpg)
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1993
> Carbon dioxide (CO2): 356.63 ppm
> Methane (CH4): 1,735.65 ppm
> Nitrous oxide (N2O): 310.25 ppm
1994
> Carbon dioxide (CO2): 358.20 ppm
> Methane (CH4): 1,741.66 ppm
> Nitrous oxide (N2O): 310.98 ppm
![](https://247wallst.com/wp-content/uploads/2022/08/imageForEntry8-i8n.jpg)
Source: Stefano Barzellotti / iStock via Getty Images
1995
> Carbon dioxide (CO2): 360.23 ppm
> Methane (CH4): 1,747.10 ppm
> Nitrous oxide (N2O): 311.78 ppm
![](https://247wallst.com/wp-content/uploads/2022/08/imageForEntry9-EdM.jpg)
Source: Stefano Barzellotti / iStock Editorial via Getty Images
1996
> Carbon dioxide (CO2): 362.01 ppm
> Methane (CH4): 1,749.86 ppm
> Nitrous oxide (N2O): 312.81 ppm
![](https://247wallst.com/wp-content/uploads/2022/08/imageForEntry10-BMW.jpg)
Source: Photos.com / PHOTOS.com>> via Getty Images
1997
> Carbon dioxide (CO2): 363.17 ppm
> Methane (CH4): 1,753.94 ppm
> Nitrous oxide (N2O): 313.53 ppm