Wetlands and oceans release a large amount of methane into the atmosphere. What is the relative contribution of methane to total global warming?

Q. Contribution of methane to global warming is

Q. Assertion :Methane is a component of greenhouse gases and contributing to global warming about 20 percent. Reason: Introduction of multi-point fuel injection engines in automobiles has decreased methane content in the exhausts.

Q. Assertion :Methane, component of green house gases, contributing to global warming is about 20 percent. Reason: Introduction of multi-point fuel injection engines in automobiles has decreased methane content in the exhausts.

Q. Assertion :Concentration of methane in the atmosphere has more than doubled in the last 250 years. Reason: Wetlands and rice fields are the major source of methane.