© 2015–2025 Charles H. Pence and collaborators, content released under CC-BY-NC-SA unless otherwise noted
The local magazine for science students at UCLouvain, Cubix, recently asked me to contribute a piece on new efforts to resurrect the mammoth as a way to counteract climate change, pushed most strongly by George Church’s group. Here it is, in a slapdash translation.
The climate crisis is now a part of our daily reality, whether we like it or not. No solution will be easy to implement, and it’s no longer possible to dismiss a proposal as “too fantastic.” In one sense, the approach of George Church, geneticist and one of the founders of synthetic biology, is quite far from it. Indeed, it’s the sort of solution that you might hear from a child: let’s see what the Earth was like the last time the planet was colder, and make it like that today.
But in this case, we’re talking about the reconstruction of an ecosystem that’s today almost disappeared: the “mammoth steppe,” once one of the most common biomes in Europe and Asia. The existence of these massive herbivores kept the plains free of trees and cold, and also left undisturbed the permafrost, one of the largest sources of carbon in Eurasia. It’s not surprising to see, then, that reconstructing the mammoth step means reconstructing its key species, the mammoth. Much less clear, all of a sudden, that the idea of “winding back the clock” is as simple as it seemed.
Technically, it doesn’t seem impossible, even if it was first proposed six years ago, without many recent technological advances. (A parody of a reconstruction of a mammoth, an April Fool’s joke that was taken seriously in the media, dates all the way back to 1984!) We start with the new tool CRISPR-Cas9, a kind of easily reprogrammable genetic scissors that give researchers a powerful tool for modifying the genome more quickly and cheaply than ever. (This technology won its inventors the Nobel Prize for 2020 in chemsitry.) Church and his team chose a dozen genes from the mammoth and implanted them in cells from an Asian Elephant. Voila, mammoth genes, working once again in real life.
But a long way from a mammoth. These genes, for now, are only expressed in a few elephant skin cells, and we don’t know yet if they would result in the phenotypes (that is, the observed characters) of a real mammoth, or if these phenotypes will be those that make it capable to play its role on the steppe.
Even more difficult, even if the genes are well chosen, and one could really build a mammoth, that doesn’t mean we’ve given birth to an ecosystem. According to Church, it will take at least 80,000 mammoths to have a real possibility to recreate the mammoth steppe. And for that, we would outstrip our stock of elephants, themselves already members of an endangered species. Church already has plans for artificial uteruses, producing (can we still say “giving birth to?”) thousands of mammoths to populate the steppe.
And all this without having mentioned the ethical and legal aspects. Almost no law in the world covers the case of the resurrection of a species. What justifications might be offered? Of course, human curiosity and the progress of science justify, sometimes by themselves, scientific experiments. But it seems that the deployment of thousands of artificial uteruses and the reprogramming of an entire ecosystem require more argument than a simple appeal to curiosity or knowledge. One can certainly gather lots of scientific results in other areas (or from just one mammoth!) for the same amount of money, at the very least.
We thus have to balance, on the one hand, the side-effects of a possible replacement of an entire ecosystem and, on the other hand, the effects of climate change. One thing to mention straightaway: it’s not as though we don’t change or replace ecosystems here and now. The effects of climate change, just as much caused by use as would be a resurrection of the mammoth steppe, have already altered (and, of course, threaten to alter much more) the living world. While the effort of Church remains, for now, closer to science-fiction than to reality, it’s now that we should begin reflecting on it, to avoid a scientfiic, ethical, legal, and social surprise.