Due to increase in the inertia and velocity of the earth by the warming of air.
Explanation:
Due to the rise of global warming, the effects of GHG gases are increasing and the atmosphere warms and starts to expand with the length of the day.
This is due to the movement of the earth's expanding air cause the earth's inertia to increase which causes the mass to go or bulge outwards. The velocity increases with the movement of inertia and thus causes the day to lengthen.
