The idea is to genetically engineer a species based on mammoth DNA, so that it would change the environment to slow down global warming. It sounds far-fetched, but respected scientists are working on different steps of this process. How much of this is scientists touting their research to get funding and how much is actually feasible is unclear, but it's very interesting stuff.
Here's the Genesis 2.0 trailer:
"God’s word is still imperfect, but if we work together, we can make God perfect." -- Dr. Huanming Yang.
Here's a TEDx talk explaining the craziness, by the author of Woolly: The True Story of the Quest to Revive One of History's Most Iconic Extinct Creatures:
Learn more about the Woolly Mammoth Revival Project here.