no. the earth's axis is an "imaginary" line to represent where the earth is spinning along. global warming is caused by greenhouse gases which are emitted from various things such as automobiles and industry, which get trapped and thicken the atmosphere. the suns rays come in and would normally bounce back outwards towards space, but since the atmosphere has thickened and the ozone is being depleted, the suns rays are staying in the atmosphere, thus heating it more so than in the past.