What is meant by global warming?

a.
it is the theory that water vapor increases earth's temperature through clouds.
b.
it is the theory that earth is warming due to greenhouse gas increases from human activity.
c.
it is the theory that the concentration of greenhouse gases is decreasing over time.
d.
it is the theory that the production of methane causes the greatest impact on the greenhouse effect.

The global warming is the uniform heating of the globe due to the effect of greenhouse gases.

Option B

Explanation:

Global warming is thus the theory that says that earth is warming up with an increase in temperature over time due to increment in the greenhouse gases.

These are greenhouse gases that are getting increased due to the human activity or say over exploitation of the natural resources. The heating of the globe has caused ozone layer depletion which is also causing warming.

at right angles to each other