Increasing Temperatures
From a nearer distance, the time-travelers also discovered some traces of destruction on the planet Earth that worried them. By crossing the North Pole, they could see that the masses of ice were rapidly shrinking and when they came nearer, they could see a lonely polar bear on an ice flow, the last remnant of a once great ice sheet in this region.
In Antarctica and other polar areas there has been an increase in temperature causing animals threat and there is barely anywhere for them to go because the ice has melted. If this continues then in the near future the animals there would become endangered or extinct. The natural global warming is caused by the sun because sunlight passes through the atmosphere and warms the earths surface. Some of the man-made problems are caused by human activities like burning fossil fuels, deforestation and farming. When we burn fossil fuels like coal, oil and gas to create electricity or power our cars, we release carbon dioxide pollution into the atmosphere. This very bad because different species are becoming extinct in the warmer temperatures. Rising sea levels will make it so there is less space for people, plants, and animals. Unless our planet takes a turn for the best, big cities near the coast like New York and London will have to be abandoned because of floods.