The correct statements are:
- higher temperatures;
In the essence of the global warming is the rise in the global temperatures, and this occurs because of increased amount of carbon dioxide in the atmosphere.
- penguins losing their natural habitat;
Because the temperatures are rising, the ice on and around the poles melts, so the penguins are losing their natural habitat with the loss of the ice masses in Antarctica.
- rising sea levels;
The melting of the ice because of the higher temperatures contributes to the releasing of large amounts of liquid water into the oceans, and that results in the rise of the sea levels.
- longer summers;
As the temperatures rise, the summers will become hotter, drier, but also longer, and lots of places will take in the shape of a steppe, savanna, or desert because of this.