A lot of people are buying alternative fueled vehicles and so are cities, counties, major businesses etc.
On the one side, this is a good thing because it reduces pollution. Most of these vehicles are powered by propane (C3H8). There’s not a lot of other chemicals in propane (like sulfur and nitrogen and lead). The reason is that propane is naturally a gas. Most of the other compounds that make gasoline and diesel so polluting are liquids and solids at standard temperature and pressure.
Propane is cooled and compressed to a liquid for use in your bar-b-que or your alternative fueled truck.
On the other hand, propane is still a fossil fuel. Ironically, the pollutants from gasoline and diesel may actually be helping hold off global warming (very, very slightly) by reflecting some sunlight into space.
In that respect, propane is the worst of both worlds. It’s a super clean, but fossil fuel.
Even propane vehicles are combustion engines. That means fuel and oxygen go in. Energy, carbon dioxide, and water comes out.
C3H8 + 5 O2 –> 3 CO2 + 4 H2O + energy
So for every molecule of propane you burn, you use up five molecules of oxygen and produce three molecules of carbon dioxide. BTW: Water vapor is a greenhouse gas too, there’s just not very much of it in the air.
I freely admit that it is better than gasoline which is a mixture of various hydrocarbon molecules ranging from 4 carbons to 12 carbons (octane anyone?).
The problem is that carbon dioxide is persistent in the atmosphere. That means that any carbon dioxide emitted into the atmosphere will affect the climate not only now, but for (most likely) the next two-three thousand years. At least one model shows that, even if we stop all CO2 production now, the global temperature will only drop one degree every 12,000 years.
This won’t just affect us, but it will affect our children, grandchildren, great grandchildren, great great grandchildren and their great great grandchildren.
It’s really kind of stunning to know that the decision we make right now, will affect all life on this entire planet for the next 2,000 years. What’s more, we know it will. We can see the future. We just don’t have the political will and the cultural intelligence to do anything about it.