What are mankinds worst inventions? I nominate three: the wheel, fire and sliced bread.

The wheel has enabled almost every man & woman on earth to mobilize a carbon dioxide spewing, oversized, heavy, inefficient and dangerous automobile, usually without carpooling.

Fire is the source of the carbon dioxide within those vehicles. It is also found within carbon dioxide spewing power plants, and beneath food....most often beef, which is also a major source of methane.

Sliced bread is a two-time offender. Firstly, the yeast used to make bread soft & fluffy does so by emitting carbon dioxide. Carbon dioxide is released during cellular respiration, which usually supports life, but in bread it merely makes an already edible food more palatable. Secondly, bread is found on both sides of a Whopper and Big Mac. People get in their carbon dioxide spewing, overside, heavy inefficient dangerous (wheeled!) cars to drive to a fast food restaurant that is probably only a block away. They eat a day's worth of food in one sitting, making them fatter and causing even more fuel to be burnt (fire!) in following car trips. If they get fat enough, they'll need a bigger car, even a SUV, which would make sliced bread a three-time offender.