Scientists are probing the link between increased carbon dioxide levels and increasing amounts of algae known as "blood snow". They have been collecting laboratory samples on Le Brevent mountain in France. Source: Reuters

Video transcript

- Scientists are calling this phenomenon. Locals say it's becoming more and more prominent in early summer. The crimson color is caused by the presence of an algae.

- --to this because we don't have the proof--

- --phenomenon is accelerating snowmelt and--