Scientists are exploring the possibility of using biotechnology to bring back extinct species. One species that could help fight climate change is the woolly mammoth, which could help restore grasslands in the Arctic tundra, preventing permafrost from melting and releasing carbon into the atmosphere.

Dr. George Church, a founder of Texas-based company Colossal Biosciences, plans to create an elephant-mammoth hybrid that can survive in the Arctic tundra. Church will remove DNA from a female Asian elephant's ovum and replace it with mammoth-like DNA, creating an elephant-mammoth embryo that will be placed in an African elephant surrogate. Colossal Biosciences claims it will have an elephant-mammoth calf by 2027.

Another species that could be brought back is the thylacine, also known as the Tasmanian tiger, which became extinct due to persecution by farmers in Australia. Its extinction caused trophic downgrading, leading to the spread of diseases and invasive species. Colossal Biosciences has teamed up with the University of Melbourne and research center TIGGRR to de-extinctify the Tasmanian tiger using preserved DNA. However, the process of bringing back extinct species raises moral concerns and faces significant technological challenges.