Filed under: Altithermal, book, Hot Earth Dreams, Speculation | Tags: California High Altithermal, climate change, Hot Earth Dreams
For Part 3, I want to start with two numbers: 2,644,443 and 200,000-300,000. The first is what I predict, based on the formula in Hot Earth Dreams, would be California state population in 2100 CE, and I’ll get to how I calculated that in a second. The second is the estimate of how many Indians lived in California before European contact. The first I calculated by finding out California’s current population (rounded up to 39,000,000), it’s current annual growth rate (0.9%), and plugged the numbers into a compound interest equation and ran it out to 2050 (52,888,867. Please check my math). Then I applied the 95% dieoff from civilization collapsing between 2050 and 2100, and came up with a population of 2,644,443. The thing to notice is that this number is still ten times higher than what the state supported before Europeans came along. It’s also almost twice as high as the state population in 1900 (1,485,053), which suggests to me, sadly, that the scenario of a 95% population crash is probably too optimistic for California.
Why care about the precontact numbers? After all, California Indians were all hunters and gatherers. There was no food agriculture outside the Colorado River area (although many grew a tobacco species. Go figure). However, anthropologists consistently noted that the population density of California Indians was among the highest in North America north of Mexico, at least at Contact. California has been romanticized by many anthropologists as a Precontact Paradise, and so it’s worth looking at how many people the land could support under a sustainable non-agricultural, pre-climate change, regime. That number is almost certainly under one million people within the state. Oddly, this was a greater density than many other places achieved with agriculture, and we need to remember that.
How did the California Indians manage to have relatively dense populations without agriculture? The answer has to do in part with oaks, because when the acorn crop was good, an Indian family could gather a year’s worth of carbs with about three weeks of work. You want to farm under those circumstances? Still, the key point is “when the acorn crop was good,” because that didn’t happen every year. California Indians ate just about anything that was edible, including things like yellow jacket larvae and the larvae of brine flies at Mono Lake. The problem with California is that, while the climate is delightfully warm and dry (aka drought-stricken) for most of the year, rainfall is extremely unpredictable. In southern California, annual rainfall totals depend entirely on whether a few big storms hit or miss us. This is why I refer to the idea of Precontact Paradise as romantic. When California’s good, it’s very very good. When it’s bad, it’s horrid. And it’s bad pretty regularly, but seldom everywhere at once.
The Indians were undoubtedly exposed to agriculture (they regularly traded and occasionally settled with the agricultural tribes along the Colorado) and certainly they knew a lot about tending plants (Amazon link), but they didn’t go for agriculture because California is too unpredictable to bet your life on the rain in most places. It didn’t help them that they didn’t have access to Mediterranean crops that could hack the California climate, but California’s climate is a lot less predictable than the Mediterranean, and most California agriculture relies on irrigation rather than rainfall.
Going forward into the High Altithermal, one thing that won’t change is climatic unpredictability, even if it gets wetter and more tropical in northern California. Southern California will become even more chaotic, as storms stop arriving only in winter and show up randomly all year around.
I also think that California’s human population will drop below one million in the High Altithermal. Human manipulation of landscapes, with the exception of fire-starting, will correspondingly diminish, and many places will either rewild or feralize, depending on how you see it.
With that horribly extensive preliminary, let’s get to relandscaping California for the next 1500 years.
From 2100-2300, the average temperature will increase about 1°C every 40 years or so, and this strongly implies a lot of change. Plants seeds that require cold to germinate will disappear from areas that no longer get frost. Hot, La Niña-fired droughts will kill many trees. Migrating plants will occasionally get lucky with local climate and rainfall and sprout in huge numbers, resulting in thickets of young plants, especially around watercourses. Giant trees will increasingly become burned snags and fallen logs, and annual grasses and (hopefully) some wildflowers will spread, especially in the southern half of the state. Fires will be common, especially where drought, disease, or pests have killed large numbers of plants. Furthermore, many rivers will run dry in the summer and sometimes all year, as dams stop them, and downstream creeks run dry. Worse, many ancient springs will be long dry, because they’re currently being drained by wells, and they won’t be refilled (if at all) for many decades to millennia. Southern California in the 22nd Century will be a dry place.
In northern California, summer rainstorms will become increasingly common, floods will be more common, and tropical plants (like guava) will escape gardens and take to the hills, as they have in Hawai’i. I suspect that the pattern we’re seeing now, where El Niño rains pound northern California, will become the norm (due to the edge of the Hadley cell moving north into southern California and forcing whatever remains of the Jet Stream north as well), so northern California will become wet tropical in El Niño years, dry tropical in La Niña years. Note that the weather becomes just as unpredictable as in southern California, but it will be predictably wetter.
Starting around 2150 (very approximately), the big dams will start failing, and the rivers will rewild themselves. One big effect of this will be that the Tulare Lake Basin (Tulare Lake and the lakes and sloughs that fed into and out of it) will refill in the southern San Joaquin Valley, and (hopefully) Owens Lake will refill in Owens Valley (this might happen even earlier). Both were dried out by diversion, to agriculture and Los Angeles respectively, over a century ago. With the diversions gone, these lakes should refill, as should rivers from the Colorado to the Klamath.
The floods from these dam failures will be catastrophic for those caught downstream at the wrong time, and that’s a problem for humans, because the best places to live will be where there’s dependable water–along rivers and around lakes. But humans are in the next blog entry.
After 2300, the temperature stabilize at +8°C, then it will very gradually decrease about two degrees over the next 1300 years, forcing the desert south a few hundred miles from wherever it got to in 2300. However, the melting East Antarctic Ice sheet will force sea level up to +65 meters above today, flooding (among other places) the Central Valley. The way this will play out is a gradual inland spread, with saltwater poisoning the soil ahead of the advancing ocean, storm waves destroying the dying vegetation, and mudflats forming where the rivers, chewing through centuries of dam sediments, dump them in the newly formed bay. Whether this bay is edged by salt marshes or mangrove swamps depends largely on whether people help mangroves migrate to California or not (currently they’re treated as weeds and removed when found). Both vegetation types are great sea-life nurseries, but if I understand correctly, mangroves support more species.
Moving away from the ocean, I almost hate to say it, but my model for future vegetation in northern California is the Hawaiian islands. In general, the lowland forests there are all imported plants, a minority brought by the Polynesians, a majority brought by the Haoles and by accident. This includes things like guava, figs, pepper trees, eucalyptus (argh!) and other tropical plants. Many of these now grow in California gardens. I’ve got a bougainvillea, for example, and they grow wild in Hawai’i. Some California native plants (I’m thinking here of things like mesquites) will adapt, but the plants that do so well in the current Mediterranean climate will probably survive, if at all, on the dry sides of the high Sierras.
The problem with this model is that most people have been conditioned to think of Hawai’i as a paradise, so they think this is a good thing. It is, sort of (it beats a Mad Max moonscape), but it’s also got a lot of issues. Unfortunately, the non-native forests of Hawai’i don’t seem to be studied with the same intensity that biologists have focused on the remnant native species, so it’s harder to talk about their ecosystem functions or even composition. Also, there aren’t any hunter-gatherers in Hawai’i, so we don’t have a model for how humans can exploit such landscapes to live year-round. Additionally, Northern California will probably experience more severe droughts than the Hawaiian Islands do now, so I’m not sure how good this comparison really is.
Southern California will become more like modern Baja and the Sonoran desert. More native species will survive. Plants that currently live inland and in the deserts will move towards the coast, while a lot of coastal species will go extinct, although we can’t yet guess which ones will survive and which will not. Oddly, some current weeds (like sahara mustard) will probably become rare in the future, simply because the droughts will get longer and deeper,. Many California plants already have a wide variety of mechanisms for dealing with this kind of chaos. Sahara mustard apparently can’t hack it.
As for animal species, many smaller birds and mammals will survive. This will especially include widespread generalists like coyotes, raccoons, crows, ravens, and pigeons. It’s harder to say whether deer, black bears, and mountain lions will survive. I suspect there’s going to be a lot of poaching in the late 21st Century, as people try to get food however they can. Deer especially were hammered by hunters in the 19th Century, and that may well happen again. Large mammals I expect to survive include feral cattle, feral horses (and donkeys), feral goats, feral pigs, and feral turkeys. The last two are currently spreading through California, and the others have been persistent features in the west for centuries. Indeed, in the Mission period, feral bulls were regarded as more dangerous than grizzly bears. Humans will keep these domesticated animals, and some will get loose, go feral, and survive. For all we know, there might be feral camels roaming the deserts and feral llamas in the mountains. They’re on ranches now, and if people breed camels to help them survive in the desert, some are bound to get loose.
What did I miss?
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