# Slicing the greenhouse gas pie: Where from?

*Published:* 2007-04-26
*Author:* Bill Chameides

In the previous post, I described [which gases are important and what activities they come from](https://blogs.edf.org/climate411/2007/04/26/slicing-the-greenhouse-gas-pie-what-gases/). But we can also learn a lot by looking at regional patterns in how those gases are emitted.

For example, most deforestation occurs in poor tropical countries (in fact, in many of these countries deforestation is a much larger source of CO2 than fossil fuel use). In contrast, most CO2 emissions from fossil fuel use come from the developed countries.

As I described in an earlier post, the [U.S. is the largest emitter in the world](https://blogs.edf.org/climate411/2007/03/21/us_emissions/), both today and historically. Next let’s take a closer look at the U.S. greenhouse gas pie.

As one might expect in a developed country, virtually all our CO2 emissions come from burning fossil fuels. We use relatively more natural gas than the rest of the world – which is good because [natural gas is the cleanest of the fossil fuels](https://blogs.edf.org/climate411/2007/04/24/should-we-fill-our-gas-tanks-with-coal/). The percentages are: about 40 percent coal, about 40 percent petroleum, and about 20 percent natural gas. Worldwide, deforestation is a net source of CO2, but in the U.S., forests and urban trees are growing. They are taking CO2 out of the atmosphere and storing it. That growth cancels out about 11 percent of U.S. fossil fuel emissions.

Forty percent of our country’s CO2 emissions come from electricity generation. Half of our electricity comes from coal-fired power plants, which produce 32 percent of America’s CO2 emissions. Because of that, utilities will play a huge role in our fight against global warming, but everyone will need to cut emissions because every sector contributes to greenhouse gas pollution:

***U S. greenhouse gas pie:** Sliced by economic sector*

It is interesting to note that residential and commercial emissions – coming from our homes and offices – together make up almost 40 percent of our emissions. What the chart doesn’t show is that commercial and residential emissions are growing about twice as fast as the overall average.

These statistics suggest that there are multiple sources to worry about in our fight against global warming. Clearly, coal is a major challenge – almost one-third of our emissions come from coal-fired power plants. But the good news is that there are [clean coal technologies](http://www.environmentaldefense.org/article.cfm?contentID=5434&campaign=583) that would allow us to use our huge coal reserves without harming the climate.

Transportation is another biggie – also about one-third of our emissions. Here again [there are solutions](http://www.fightglobalwarming.com/page.cfm?tagID=268) – more [fuel efficient cars](http://autos.yahoo.com/green_center/;_ylt=ArDjWPEf7136fLZp9GvQvykEc78F;_ylv=3) come to mind. And for commercial and residential sectors, building green buildings and improving the efficiency of our existing ones will help stem the flow of greenhouse emissions.

As I’ve said before, it’s [not going to be one silver bullet](https://blogs.edf.org/climate411/2007/03/28/green_technologies/); the solution is going to be more like silver buckshot.