design a poster on global warming??
A few pointers are given at the link mentioned below that will help you to frame your answer.
https://www.meritnation.com/ask-answer/question/format-of-poster/english/5616196
https://www.meritnation.com/ask-answer/question/can-u-please-tell-me-about-how-to-make-posters-poster-making/english/5846559
https://www.meritnation.com/ask-answer/question/format-of-poster/english/5616196
https://www.meritnation.com/ask-answer/question/can-u-please-tell-me-about-how-to-make-posters-poster-making/english/5846559