"Without sea ice, arctic plants and animals must either adapt or migrate. If they can’t, they will go extinct."
"If that isn’t enough, people who live in coastal communities within the Arctic Circle are also battling erosion along their coastlines."
"(These communities must relocate inland or their homes and land could be washed out to sea.)"
"(For ice in the Arctic, it’s a race against time. If humans do not change what we are doing to the global climate, the ice will continue to disappear and life as we know it will be altered.)"
This is a simile as it compares two things using the word like. It compares her running across the grass to a cheetah chasing its prey, implying she is running very fast
“By donating just a dollar a day, you could help millions of shelter animals in need.” Is one example.
The tone should be serious/alarming but since the tone should also be happy.