I disagree, the planet is not going to die in 50 years. What is going to happen is life is going to get harder, more and more of our resources are going to be used to deal with the results of climate change. Over the next hundred years we are likely to see significant increases in seal levels forcing us to rebuild most of our coast cities further inland. Hurricanes and tornadoes will increase in strength and number. Most our wheat production and corn will move north, possibly into Canada as temperatures and rain patterns change. Russia will become the new breadbasket of the world as it becomes the largest producer wheat and other grains. Forest fires will spread further east in the US requiring a major increases in resources needed to fight forest fires. Many species will become extinct such as Polar Bears, to toads to seat turtles to staghorn coral to North Atlantic Cod which will have both foreseen and unforeseen effects on the environment and man.
However, the planet will continue in it's orbit around sun, days will still be 24 hours, the sun will rise and set as it has for hundreds of millions of years. And yes, man's life will continue, although far different than we might expect today.