Biogasoline's bad point

Researchers of Switzerland showed that "biogasoline"is not allways good for nature.They say that the biogasoline which is made from plant reduces over 30 persent of exhaust gas but it affect badly to the environment in process of making the gasoline.To make the gasoline,people use a lot of agricultural chemical so the soil will be bad.And people cut down many forests to expand places to raise the plant which will become materials of the gasoline .That's why they say "biogasoline" is not good. I thought "biogasoline" is a very good idea for the environment before I knew this topic.But I 'm now confusing about what is the solution of global warming.How about you?