The mountain pine beetle Dendroctonus ponderosae, is a species of bark beetle native to the forests of western North America from Mexico to central British Columbia. It has a hard black exoskeleton, and measures approximately 5 mm, about the size of a grain of rice. It may be the largest forest insect blight ever seen in North America. Climate change has contributed to the size and severity of the outbreak, and the outbreak itself may, with similar infestations, have significant effects on the capability of northern forests to remove greenhouse gas (CO2) from the atmosphere.