Ice samples from glaciers provide evidence that today's atmosphere contains more carbon dioxide than ancient atmospheres on Earth did. Why is this increase in carbon dioxide a concern to scientists? A. It contributes to the rapid expansion of continental glaciers.
B. It contributes to the rapid cooling of the warm ocean currents.
C. It contributes to the gradual warming of the atmosphere.
D. It contributes to the loss of radiant energy from the Sun.​