Seems kind of cruel to bring back mammoths just as we're in the process of cooking the planet.

As part of its effort to engineer mammoth-like elephants, Colossal and its collaborators are working to find gene variants that contributed to key mammoth traits, such as shaggy hair, cold tolerance and extra fat stores. To do this, they compare genomes extracted from the remains of dozens of mammoths and from other living and extinct relatives of the creatures, in search of protein-altering changes that evolved on the mammoth lineage.

That's not the same as what you're claiming.