Human activity has increased the direct warming effect of carbon dioxide in the atmosphere by 50 percent above pre-industrial levels during the past 25 years, according to NOAA's 10th Annual Greenhouse Gas Index.
![Fossil fuel extraction in North Dakota's Bakken field in 2014. (Image credit: Jeff Peischl/CIRES/NOAA) Fossil fuel extraction in North Dakota's Bakken field in 2014.](/sites/default/files/styles/landscape_width_1275/public/legacy/image/2019/Jun/2014-Bakkenflaresatsunset%20-%20Peischl.jpg?itok=UzfanEhj)
Fossil fuel extraction in North Dakota's Bakken field in 2014. (Image credit: Jeff Peischl/CIRES/NOAA)