Taking Stock: The 'green Sahara' of the past and the 'green growth' of the future

May 03, 2024

The hyper-arid desert of Eastern Sudan, the Atbai Desert, seems like an unlikely place to find evidence of ancient cattle herders. But in this dry environment, my new research has found rock art over 4,000 years old that depicts cattle.

‘In 2018 and 2019, I led a team of archaeologists on the Atbai Survey Project. We discovered 16 new rock art sites east of the Sudanese city of Wadi Halfa, in one of the most desolate parts of the Sahara. This area receives almost no yearly rainfall.

‘Almost all of these rock art sites had one feature in common: the depiction of cattle, either as a lone cow or part of a larger herd.

‘On face value, this is a puzzling creature to find carved on desert rock walls. Cattle need plenty of water and acres of pasture, and would quickly perish today in such a sand-choked environment.

‘In modern Sudan, cattle only occur about 600 kilometres to the south, where the northernmost latitudes of the African monsoon create ephemeral summer grasslands suitable for cattle herding.

The theme of cattle in ancient rock art is one of most important pieces of evidence establishing a bygone age of the “green Sahara”
Archaeological and climatic fieldwork across the entire Sahara, from Morocco to Sudan and everywhere in between, has illustrated a comprehensive picture of a region that used to be much wetter.

‘Climate scientists, archaeologists and geologists call this the “African humid period”. It was a time of increased summer monsoon rainfall across the continent, which began about 15,000 years ago and ended roughly 5,000 years ago.

This “green Sahara” is a vital period in human history. In North Africa, this was when agriculture began and livestock were domesticated.
In this small “wet gap”, around 8,000–7,000 years ago, local nomads adopted cattle and other livestock such as sheep and goats from their neighbours to the north in Egypt and the Middle East.

‘When the prehistoric artists painted cattle on their rock canvasses in what is now Sudan, the desert was a grassy savannah. It was brimming with pools, rivers, swamps and waterholes and typical African game such as elephants, rhinos and cheetah—very different to the deserts of today.

‘Cattle were not just a source of meat and milk. Close inspection of the rock art and in the archaeological record reveals these animals were modified by their owners. Horns were deformed, skin decorated and artificial folds fashioned on their neck, so-called “pendants”.

A strong relationship between human and animal: a cow with a modified ‘neck’ pendant and horns. Julien Cooper

‘Cattle were even buried alongside humans in massive cemeteries, signalling an intimate link between person, animal and group identity.

‘At the end of the “humid period”, around 3000 BCE, things began to worsen rapidly. Lakes and rivers dried up and sands swallowed dead pastures. Scientists debate how rapidly conditions worsened, and this seems to have differed greatly across specific subregions. . . .

‘Abandoning an animal that was very much a core part of their identity, and with whom they shared an emotional connection, cannot have been easy for their emotions and sense of place in the world.

‘For those communities that migrated and lived on the Nile, cattle continued to be a symbol of identity and importance. At the ancient capital of Sudan, Kerma, community leaders were buried in elaborate graves girded by cattle skulls. One burial even had 4,899 skulls.

‘Today in South Sudan and much of the Horn of Africa, similar practices regarding cattle and their cultural prominence endure to the present. Here, just as in ancient Sahara, cattle are decorated, branded and have an important place in funeral traditions, with cattle skulls marking graves and cattle consumed in feasts.

‘As we move into a new phase of human history subject to rapid climate oscillations and environmental degradation, we need to ponder just how we will adapt beyond questions of economy and subsistence. . . .’

theconversation.com | @TC_Africa | @cooper_julien

Are world’s 200 million pastoral herders a climate threat?—Michael Benanav

‘. . . Today, [the pastoralist] way of life is under threat not only from changing conditions on the ground. Pastoralist communities are also coming under pressure in some quarters as a contributor to the global climate crisis. A December 2023 report by the United Nations Food and Agriculture Organization, for example, seeks to provide “a comprehensive assessment of greenhouse gas (GHG) emissions from livestock agrifood systems.” Some researchers say the report, in effect, suggests that pastoralism is part of the emissions problem.

‘That idea may sound hard to imagine. Like other pastoralist communities I’d written about and photographed over the years—all of whom are experiencing impacts of climate change firsthand—the Afar rely little on fossil fuels. They eschew consumer culture—partly due to poverty, partly because everything they own, including their huts, must be portable.

‘But when researchers calculate the amount of greenhouse gasses generated by a livestock system, most compare the amount of methane and carbon dioxide that’s emitted to the amount of protein that’s produced. By that measure, animals raised by traditional pastoralists are less efficient than those raised with newer, more intensive methods, the report says.

‘This is partly because indigenous breeds of livestock, well suited to their often harsh environments, are less productive than so-called improved breeds that are raised on farms. Additionally, a diet of wild grasses causes livestock to create more methane than if they eat formulated feeds.

‘The FAO report stops short of condemning pastoralism outright. It notes that pastoralist emissions make up only a fraction of the world’s total methane output. And it recognizes that moving away from traditional grazing may be “unfeasible” for the world’s poorest countries due to “nutritional challenges and ... financial constraints.” But the report’s recommendations point away from pastoralism.

Is that pragmatism or a flawed narrative, like others that have pushed Indigenous and pastoralist peoples off their traditional lands?

‘The future of pastoralism may hinge on the answer. Climate policy experts widely agree that major changes are needed in agriculture, and notably the raising of livestock, to help tame the rise of heat-trapping gasses in Earth’s atmosphere. If policymakers believe traditional herds stand in the way of hitting methane targets, pastoralists may be pressured to stop herding. Age-old cultures could disappear, along with food systems that make resourceful use of marginal lands where crops won’t grow.

‘Already, for example, a 2021 policy brief by The Lancet has recommended that India, home to some 13 million to 20 million pastoralists, “needs to move away from the traditional animal husbandry practices” in order to reduce greenhouse gas emissions.

‘Some scientists, however, say there’s no environmental reason to turn away from pastoralism. The data behind the FAO report, and others like it, answers the wrong question, says ecologist Pablo Manzano, a fellow and rangeland expert at Spain’s Basque Centre for Climate Change.

‘Rather than looking only at methane levels produced by pastoralist herds, researchers should focus instead on how those compare with the emissions that would be produced by the same ecosystems if herds were absent, Dr. Manzano says.

‘“Many of those emissions are going to happen, whether or not livestock is there,” he says. Should pastoralist herds be removed from their landscapes, the void that they leave would likely be filled by other herbivores, he argues, which would produce similar amounts of methane.

‘Additionally, responsible grazing keeps grasslands healthy, increasing biodiversity and providing a natural carbon sink, while reducing the risk of wildfires, Dr. Manzano says. . . .’

“Pastoralism is basically a fossil-fuel-free, totally solar-powered production system that does not require feed inputs, fertilizers, or pesticides,” said Ilse Köhler-Rollefson, a veterinarian who has lived closely with the Raika tribe in Rajasthan, India, since 1990, and who is a co-founder of the League for Pastoral Peoples. “But it is under pressure worldwide, and has in many places already become extinct.” . . .

csmonitor.com | @csmonitor | @mbenanav

Bird flu's big question—Allison Snyder

‘The bird flu outbreak in dairy cattle that's swept across nine U.S. states is posing perplexing questions about how the virus is spreading between animals and the risk posed to humans.

‘Why it matters: Detecting viral spread early and limiting how long the flu circulates in a population of animals cuts the odds it will mutate and adapt to other species. . . .

‘Catch up quick: The current version of H5N1 avian flu has circulated around the world since 2021, killing seals from Chile to Russia to Maine, a polar bear in the Arctic, red foxes in Europe and the U.S. and other species. It's also being detected in wild birds and farmed poultry.

‘At the end of March, health officials announced they were investigating an outbreak of the virus in U.S. dairy cows, though it may have been circulating in cattle for months. It marked the first time avian flu was confirmed in cows, which become ill but recover with treatment.

‘There's been one mild human infection detected so far, in a person exposed to dairy cattle, but some researchers suspect not all cases are being spotted. . . .

The virus' jump to cows poses new questions about it despite being studied for decades.

‘. . . The big question is how it is spreading from one cow to another, Gillespie says. High amounts of the virus are being found in the udders of dairy cows and it's been detected in unpasteurized milk, suggesting it might be spreading through milking equipment.

‘Preliminary studies found pasteurization inactivates the virus, so milk is considered safe to drink, a Food and Drug Administration spokesperson said in a press briefing yesterday. (Raw milk and cheeses may be a gamble.) . . .

‘Flu viruses typically mutate a bit as they circulate and replicate. But when a virus moves into a new species there are opportunities to re-assort larger segments of genetic material. . . .

‘This flu has more chances to jump—and therefore potentially adapt—to humans because of the proximity we have to stricken livestock.

‘The big picture: The strain spreading among cattle now is different from previous H5N1 strains, Richt says, which were often fatal when they first emerged in humans.

"It shows higher virulence for a lot of mammalian species—except for humans," he says. . . .

‘What to watch: One potentially alarming scenario is if H5N1 virus in cows mixes with influenza viruses that are endemic to pigs. . . . Swine are notorious mixing bowls for viruses that can eventually jump to humans, public health experts note. . . .

‘Right now, it is a dead-end host. But all it takes is one mutation.’

axios.com | @axios | @alisonmsnyder

+ Bird flu virus circulated in cows for four months before outbreak confirmed by USDA, analysis shows—STAT News

'Unprecedented': How bird flu became an animal pandemic—India Bourke (h/t Lynn Brown)

Bird flu is decimating wildlife around the world and is now spreading in cows. In the handful of human cases seen so far it has been extremely deadly.

‘. . . Relatively few people have caught the virus so far, but it has had a high mortality rate in those that do: more than 50% of people known to become infected have died.

‘Moreover, the impact on animals has already been devastating. Since it was first identified, the H5 strain of avian influenza and its variants have led to the slaughter of over half a billion farmed birds. Wild-bird deaths are estimated in the millions, with around 600,000 in South America since 2023 alone—and both numbers potentially far higher due to the difficulties of monitoring. At least 26 species of mammals have also been infected. . . .

‘Already the worst bird flu outbreak in wildlife on record, scientists . . . are now racing to track its journey—and so better understand how its further spread among humans might be stopped. . . .

‘H5N1 timeline
1996: detected in poultry in Guangdong, China
1997: first human deaths in Hong Kong
2005: Spilled over into wild birds in a major way. New strains emerge.
2020: A strain emerges that can sustain in wild bird populations year-round
2020–22: Becomes endemic in wild bird populations
2021: Arrives in North America
2022: Detected in South America
2024: Confirmed in Antarctica

‘. . . So can bird flu be stopped? Not in wildlife, experts say; transmission is too hard to prevent. But there are still things we can do to limit the harm to both wild and farmed mammals — as well as humans.

‘Dead wild birds should be left untouched and reported to authorities, experts encourage. Meanwhile, farms are also being urged to deploy biosecurity measures, from covering waste to reporting illnesses. And the World Organisation for Animal Health (WOAH) is pressing to ensure compensation schemes are in place for all farms that undergo mandatory culling. . . .

’HPAI is already a pandemic in global wildlife. . . . Reducing other pressures on wildlife could aid their survival as H5N1 becomes a new pressure on bird and mammal species. . . . Easing those human pressures could help give populations infected by HPAI more scope to recover. . . .’

bbc.com | @bbc | @india_bourke

+ Feds scramble amid bird flu crisis—AGree Newsfeed

‘“USDA has issued new guidance to states detailing testing requirements and restrictions on the movement of dairy cows under a new federal order that goes into effect today. The department told states that 'while it is still unclear exactly how virus is spreading, the virus is shed in milk at high concentrations.' The FDA said Friday that it hasn’t found any live virus in a limited batch of the milk samples that initially tested positive for bird flu particles. As we’ve reported, the CDC wants to deploy federal response teams to farms across the country in order to survey the health of dairy cows and farm workers in person, according to two state agriculture officials. The CDC has conveyed some flexibility in conducting those surveys, which are 20 pages long, amid feedback from several state agriculture officials who’ve made clear they’d like that work done in another setting, not on the farms. Sen. Tammy Baldwin of Wisconsin and other key Democrats in tough races this fall have raised concerns about the need for the federal government to readily address the outbreak and get its response right. The dairy industry across Wisconsin and the upper Midwest is already operating under razor-thin margins. The Dairy State in particular has already been hit by the loss of thousands of farms in recent years, leading to further consolidation in the sector. The response will likely be a major issue for Congress to tackle in the upcoming FY 2025 spending talks. USDA can also tap internal funding for new emergency spending on testing."‘

For your listening pleasure: Is Green Growth Possible?

The estimable Hanna Ritchie, deputy editor and lead researcher at Our World in Data and the author of Not the End of the World: How We Can Be the First Generation to Build a Sustainable Planet, is interviewed by the (equally) estimable journalist and podcaster Ezra Klein in this podcast session of The Ezra Klein Show: Is Green Growth Possible? (1 hr). Some quotes below.

Klein: ’A decade ago, I was feeling pretty pessimistic about climate change. The politics of mitigating global warming just seemed impossible: asking people to make sacrifices, or countries to slow their development, and delay dreams of better, more prosperous lives.

‘But the world today looks different. The costs of solar and wind power have plummeted. Same for electric batteries. And a new politics is starting to take hold: that maybe we can invest and invent and build our way out of this crisis. But some very hard problems remain. Chief among them? Cows.

‘Hannah Ritchie . . . [has] pored over the data on this question and has come away more optimistic than many. “It’s just not true that we’ve had these solutions just sitting there ready to build for decades and decades, and we just haven’t done anything,” she told me. “We’re in a fundamentally different position going forward.”

‘In this conversation, we discuss whether sustainability without sacrifice is truly possible. How much progress have we made so far? What gives her the most hope? And what are the biggest obstacles?’ . . .

Ritchie: ‘When people think about the vast array of environmental problems that we face, they get really overwhelmed. And they get really overwhelmed because they assume there are 50 solutions to 10 different problems, and therefore we need to find a way of implementing 500 different solutions.
. . . [T]he reality is that when you bring it down to the basics we need to stop burning stuff for energy. And we need to find a way of feeding people on much less land. And I think we are getting closer and closer to the solutions we need, and the solutions are getting better and better for us to do that every year. . . .

‘I think people underestimate the contribution of food to climate change. So if you look at the breakdown of emissions, around a quarter to a third of emissions come from food systems. I think if you take emissions from livestock alone, it’s somewhere in the region between 14 percent to 18 percent of greenhouse gas emissions.

Without any change in this trajectory in food that we’re on, emissions from food alone would take us past 1.5 degrees. . . . [I]t’s just very clear from the data that we just cannot continue on a business as usual in food systems. . . .
[I]t’s really food production that is the biggest driver of biodiversity loss by far . . .

‘I’m just way more optimistic about the energy transition than I am about the food transition. Overall, people might have some biases towards what energy source they like. Ultimately, they just want cheap energy coming out of the plug. And if you can give them that, they’re not that bothered.

That’s not the same for food. Right? People are actively making decisions about what they eat three or four times a day, and they really care about what they eat. And they will push back if you try to tell them what to eat. . . .

Klein: ‘I’ve known many people who see this data and decide to give up red meat. They decide to give up beef. But from the animal suffering perspective, that’s very, very, very bad if you substitute with chicken or fish or other smaller animals. Cows are known for living better lives even in industrial agriculture than, say, chickens.

‘And a family can eat a chicken and a night. It takes them a year to eat a cow. So in terms of the total numbers of animals that you are killing or raising in very difficult conditions, cows mean fewer of them.

‘So there is also this other difficult tension of, well, you don’t want to substitute into these other animals. But then people don’t want to be told to become vegetarians. It’s a genuinely very hard political problem. . . .

Ritchie: For me, a chicken packed into a cage or a barn just seems to have a lower standard of living than a cow in a field, even if it has a much, much lower environmental impact.

‘So I couldn’t handle that trade-off and that dilemma, so I opted out and went completely vegan. But it is really hard to communicate this to people. And my approach to this is to give people good information, and then hope that they then make the right decision for them. But I’m not going to pretend that this is going to move very quickly, because I don’t think it will. . . .

‘The land footprint of humans is really not about where we live or where we build stuff. Urban land area is about 1 percent of global land, maybe a few percent if you add in stuff like roads and other infrastructure. But you’re talking about a few percent for where we live and nearly half of habitable land for the food that we eat.

Ultimately, the land footprint of humans is very much what we eat. . . .

‘I think many of the things that we assume to be green or feel are green, when you actually break down the data, the alternatives are often better. And I think the conflict there is that we see natural as good and synthetic is bad. . . .

[T]he key thing is not to get discouraged that we don’t have all of the solutions now and let that hold us back from deploying the technologies that we have and we urgently need to roll out. . . .

‘I think individual behavioral change is really hard. And there are a bunch of studies that would support that shifting people’s behaviors on stuff like climate is just really, really difficult to do.

‘If we’re relying on that to get out of this climate crisis, I would have very little optimism about our ability to do so. People always frame me as a kind of techno optimist. But I think I lean that way because I’m just more optimistic about the substitution effect rather than a stop doing this effect. . . .’

podcasts.apple.com | @ezraklein

Arresting headlines

How far should we carry the logic of the animal-rights movement?: People who think seriously about the use and abuse of nonhuman creatures often end up calling for changes that might seem indefensible—at least, at first—New Yorker

‘ChatGPT for CRISPR’ creates new gene-editing tools: Some of the AI-designed gene editors could be more versatile than those found in nature—Nature

Pasteurization inactivates H5N1 bird flu in milk, new FDA and academic studies confirm—STAT News

Opinion: The workers at the front lines of bird flu—New York Times (summarized by AGree NewsFeed)

Confirmed: Pasteurization inactivates H5N1 bird flu in milk—STAT News