Rising carbon dioxide concentrations are already causing the planet to heat up. At the same time that greenhouse gases have been increasing, average global temperatures have risen 0.8 degrees Celsius (1.4 degrees Fahrenheit) since 1880.
Carbon dioxide is essential for the survival of animals. Oxygen is carried to body tissue during breathing and carbon dioxide is released. The gas protects the pH level of blood. Too much carbon dioxide, however, can kill animals.
