What greenhouse gas has the largest effect on global warming

The greenhouse gas called water vapour has the largest effect on global warming.

Carbon Dioxide or Water Vapor.

Global warming is an effect on our planet that is caused by carbon dioxide being trapped in our atmosphere. When the carbon dioxide is trapped, it is bouncing off the bottom layer of the clouds. Some escapes into outer space, but most of it stays. We cause global warming, by using vehicles, making asphalt, burning fossil fuels, and many more.

An effect of global warming is our poles oceans are melting. When our polar caps melt most of the way, we will experience a lot of flooding for many coastal cities. We will also experience extreme weather, like stronger hurricanes, larger thunderstorms, and larger areas effected by other natural disasters.

One thing we can do to stop or slow down these effects is to use vehicles less (or make better vehicles for the environment), stop burning fossil fuels, and make a world-wide law to prevent certain things from commencing. Nuclear bombs are also a problem to global warming. We will hopefully never reach that problem.

i think its both a and b