How would humans likely go extinct on earth?

By not being able to breathe because of Global Warming. Heat rises faster and faster from the oceans as they heat up like Heat Batteries from the sun getting warmer here on earth through increasing Carbon dioxide in the atmosphere, especially where there is no ice and seas are blue or green. As heat rises faster and faster storms and winds of all kinds get worse and worse. Trees more and more blow down from winds between 100 and 300 to 400 miles per hour this century and the next. When most trees blow down from winds people start dying from a lack of oxygen because it is not only the trees that blow down but all the leaves blow away (that also convert carbon dioxide to oxygen blow off all the plants above about 150 mph like we saw in the Bahamas recently. So, it isn't just the trees blowing down.

Also, as oceans heat up plankton of all kinds dies which means there will be less and less oxygen from the oceans of the world too.

So, I'm thinking it won't be a lack of food that kills the last human beings but a lack of oxygen from trees and plants and plankton. I expect this will happen between 100 to 400 years from now on our present global warming trajectory.