Wolf the western world is over indulging in all types of food not just meat. It is all about balance. The healthiest BMI readings are in the Asians. They eat plenty of meat but very little if any processed food.
I know cassie, it's true, Australians over indulge in everything which is why our obesity rate is over 50% of the population.
Asians eat a lot of rice, vegetables ect they don't base their meals around meat like we do. (and please don't base what asians eat off of what you see in asian restaurants because that is just westernized asian food)
i think we all know processed foods are bad anyway :p
as to answer your other questions, and this is just my opinion.
i don't think it is realistic for us to believe that the world will ever go vegan, however
if the rate at which we consume meat at the present continues we won't have enough land to sustain the demand for meat, so something has to give.
so if in fact say, the whole of australia started eating a mainly plant based diet
we would have no need for livestock, we could use that land and the water used for them to grow crops and vegetables to feed australians!
and if we plant alot of trees that will make it rain more, if you don't believe me look it up!