This Atlantic article is about Pleistocene Park, an idea to restore functioning grassland ecosystems that existed during the last Ice Age, complete with woolly mammoths. The mammoths are supposed to keep the grassland from turning into forest, and the grass in turn is supposed to reflect more light and heat, thereby preserving the permafrost.

If this intercontinental ice block warms too quickly, its thawing will send as much greenhouse gas into the atmosphere each year as do all of America’s SUVs, airliners, container ships, factories, and coal-burning plants combined. It could throw the planet’s climate into a calamitous feedback loop, in which faster heating begets faster melting. The more apocalyptic climate-change scenarios will be in play. Coastal population centers could be swamped. Oceans could become more acidic. A mass extinction could rip its way up from the plankton base of the marine food chain. Megadroughts could expand deserts and send hundreds of millions of refugees across borders, triggering global war…

Research suggests that these grasslands will reflect more sunlight than the forests and scrub they replace, causing the Arctic to absorb less heat. In winter, the short grass and animal-trampled snow will offer scant insulation, enabling the season’s freeze to reach deeper into the Earth’s crust, cooling the frozen soil beneath and locking one of the world’s most dangerous carbon-dioxide lodes in a thermodynamic vault.

A lot of the article is about the process of genetically engineering the mammoths. Apparently, we know exactly what mammoths looked like because people have found plenty of intact frozen specimens. I didn’t know that some isolated pockets of mammoths survived until just 2,000 years ago, compared to tens or hundreds of millions of years for the dinosaurs. So there is really no comparison there – they are just cold-adapted cousins of elephants. The plan is not necessarily to clone extinct mammoths, but simply to edit the genes of modern elephants to give them the mammoth traits, then turn them loose and let them adapt and evolve a bit more in the wild.

In another interesting section, it talks about how nutrient cycling in temperate and cold-climate grasslands is much faster than in forests at the same latitudes, rivaled only by tropical forests. And large herbivores are critical both because their digestive systems are where a lot of that cycling takes place, and they also favor grass by keeping trees in check.

Another interesting claim is that Africa is the only continent with large herbivores left because the animals there evolved alongside humans for millions of years, whereas animals in temperate climates did not and were not prepared for humans when they came.

Finally, there’s this:

The park will need to be stocked with dangerous predators. When they are absent, herbivore herds spread out, or they feel safe enough to stay in the same field, munching away mindlessly until it’s overgrazed. Big cats and wolves force groups of grazers into dense, watchful formations that move fast across a landscape, visiting a new patch of vegetation each day in order to mow it with their teeth, fertilize it with their dung, and trample it with their many-hooved plow. Nikita wants to bring in gray wolves, Siberian tigers, or cold-adapted Canadian cougars. If it becomes a trivial challenge to resurrect extinct species, perhaps he could even repopulate Siberia with cave lions and dire wolves.

Yes, dire wolves are a thing.