It has been mapped over centuries the Earth heats and cools. Global warming results in extremes [extreme heat in the summer extreme cold in the winter] while I do feel humans are causing global warming as a result of the pollution, we are not completely to blame, it's primarily nature.
The end of days [as described in the bible] is unknown to any man. Only God knows when that day is and he doesn't have a set date. He'll just wake up one day and hit the self destruct button. Don't worry too much though, as according to the new testament, Jesus died for our sins and God forgave us as a result. Therefore he's not going to go around killing us for no reason.
I do not believe in the bible however, so from a scientific perspective the Earth will not end in a few weeks/years. If we take care of the Earth, eventually the global heating/cooling will slow. As the sun ages however, the Earth will heat and the global heating/cooling will get stronger. Eventually the sun will either cook us, or it will explode [as stars do when they die] and the Earth along with the inner planets will be destroyed. This will not happen for millions of years. Best not to worry and live your life. To quote Homer Simpson 'People die all the time. Why you could wake up dead tomorrow.'