Time traveler

I was walking down the street with my clock on my back wondering how the world had got this way and I thought "If I could, would I go back and change time? Make a difference to our environment? YES!" I remembered that there was a so called world's smartest mad scientist I went to him straight away and he made the clock I had found in a bin this morning and had chucked into my sack which that I always carry on my back he told me if I spin it and type the time into the new code pad I set off and sent the time back to when I had started my rein over the world polluting it and covering it in trash until was impossible to see the stars and the water dried up and plants died most of the people died of thirst and hunger and the survivors intent on my destruction carried as much weapons as they could most carried a MP5 which was their favourite for was a SAS fav gun I quickly ran up to my past self's mansion and unlocked it with my old key, rushed up to old me and when he noticed me he gave a yell and gave a leap to the alarm button and when he hit it and it didn't make a noise he looked up at me in fear as I lifted my hands that had the wire in them his voice trembled as he spoke "who are you" "I'm your future self and for your plans don't do them or you will cause the world to end he said ok and I zapped myself back to the present where the mad scientist was staring at me in shock I looked down at myself and was stunned I was slowly fading and I quickly ran to the window and knew my efforts were not in vain for everything was lush and green