In some way pretty much everything you do contributes greenhouse gasses to the environment, but we aren't concerned about the little dribbles from jogging or blowing farts while you sleep. We are only concerned about large scale things such as transportation and power supplies.
The fact is that nuclear energy is actually the most environmentally friendly power supply when looked at over a plants lifecycle, which includes construction, decommisioning, operation, and harnessing the fuel supply. I include hydro, wind and solar in that statement. My reasons are below:
1. Nuclear is very prolific.
2. Greenhouse gases are nil.
3. Wastes are contained in drums neatly stored rather than emitted into the air and stored in you lungs and the food you eat.
4. Extremely safe. Chernobyl is not going to happen again folks.
5. Nuclear wastes are greatly reduced with more efficicient plants built today.
You may wonder how nuclear can be cleaner than hydro and wind and solar. The answer is to look at the whole story behind a power supply. It's lifecycle. Wind, solar, and hydro rely on the right weather and they are inefficient. Furthermore, they cause a lot of pollution during construction and decommissioning.