It's impossible to predict exactly how much time humanity has left. The future of our species is dependent on a wide variety of factors, including advances in technology, the actions of individual people and governments, and the state of the natural environment.
While some scientists have predicted that humanity has only a few decades or centuries left, others believe that we could continue to thrive and evolve for many thousands of years.
Ultimately, the fate of humanity is in our own hands, and it will be up to us to determine our own destiny.