How many tons of methane gas is added to the atmosphere annually by humans? and animals?

Answer 1

Well, here's a summary of what I managed to find online:
-~500 million tons of methane are put into the atmosphere each year, total, from all sources.
-each of the 1.3 billion cattle in the world today belch out about 1/2 lb of methane each day. All animals are responsible for about 15% of the total, cattle responsible for most of it (12%).
-the other main sources are landfills, coal mines, rice paddies, and peat bogs.
Couldn't find a specific amount attributable to humans.
Hope that helps.

Answer 2

Depends on the quality of baked beans that particular year.