I am suppose to write an essay where I need to "show" instead of "telling" in the essay, I am confused about this topic.
The best way to show rather than telling is having more examples to support your claims. Let's take each question;
What happens if the global warming is real and we take action?
Tell what you think will happen and give some evidence to convince the reader. You can google on this topic and find many ideas. try this link'; aip.org/history/climate/impacts.htm
Same way you can tackle other two questions too :)