PNAS – Climate- Science.press

Potsdam: Climate Change will Cut Sheep, Goat and Cattle Farming in Half by 2100

“… by the end of the century, there may not be enough suitable areas for cows, sheep, and goats to graze …”

“… by the end of the century, there may not be enough suitable areas for cows, sheep, and goats to graze …”

Climate Change Could Cut Land for Cattle, Sheep, and Goat Farming in Half by 2100

by Anastasiia Barmotina
March 3, 2026

As global temperatures rise, the vast grasslands that support billions of livestock and millions of people’s livelihoods are facing threats like never before. According to a recent Potsdam Institute for Climate Impact Research (PIK) study, by the end of the century, there may not be enough suitable areas for cows, sheep, and goats to graze. This alarming projection underscored the urgency to address climate change to safeguard food security and vulnerable communities.

The PIK study identifies the concept of a “safe climatic space” for cattle, sheep, and goat grazing. These systems, which cover about a third of Earth’s surface, rely on specific environmental conditions to thrive. Researchers defined this safe space based on ranges of key factors: temperatures between -3°C and 29°C, annual rainfall from 50 to 2,627 millimeters, humidity levels of 39% to 67%, and wind speeds of 1 to 6 meters per second. If the conditions don’t match, grasslands become less viable for sustaining large herds, leading to reduced productivity and potential ecosystem collapse.

As stated in the study, climate change could result in a net decline of 36% to 50% in areas suitable for grazing by 2100. This contraction would affect up to 1.6 billion grazing animals worldwide, and put the livelihoods of more than 100 million pastoralists at risk. Grasslands represent the world’s largest agricultural production system, making their decrease a critical concern for meat and dairy supplies, which already account for around 14.5% of global greenhouse gas emissions as mentioned by the UN Food and Agriculture Organization in their report.

…Read more: https://impakter.com/climate-change-could-cut-grasslands-in-half-by-2100/

The abstract of the study;

Climate change drives a decline in global grazing systems

Chaohui Li¹ https://orcid.org/0000-0002-3951-7141 lichaohui@pku.edu.cn
Maximilian Kotz
Prajal Pradhan https://orcid.org/0000-0003-0491-5489
Xudong Wu
Yuanchao Hu
Zhi Li
Guoqian Chen¹ https://orcid.org/0000-0003-1173-6796 gqchen@pku.edu.cn

Edited by Nils Stenseth, Universitetet i Oslo, Oslo, Norway; received November 27, 2025; accepted December 23, 2025

February 9, 2026

123 (7) e2534015123

Significance

Grazing systems form critical livelihood bases for hundreds of millions of people across diverse ecological and socioeconomic contexts, yet we lack a global understanding of their sensitivity to climate change. Applying a “safe climatic space” framework, we project a 36 to 50% contraction in suitable grazing areas by 2100 due to future climate change. We show the loss of safe climatic space for grazing overlaps significantly with regions already suffering from severe poverty, hunger, and political fragility. We estimate this could displace the livelihoods of over 100 million pastoralist and 1.4 billion livestock. These findings highlight how climate change will compound existing inequalities, threatening to destabilize the world’s most extensive food production system and the communities that depend on it.

Abstract

Grazing systems represent the most extensive production systems in the world and are highly sensitive to climate change. However, their global-scale sensitivity and vulnerability to climate impacts remain poorly understood. Here, we apply the safe climatic space framework to assess how changes in core climatic drivers of grazing suitability, including temperature, precipitation, humidity, and wind speed, will reshape global grassland-based grazing systems. Our analysis projects a net decline of 36 to 50% of areas in climate suitability for grazing by 2100, accompanied by inter- and intracontinental shift of grazing suitability. These changes are expected to negatively affect 110 to 140 million pastoralists and 1.4 to 1.6 billion livestock, with particularly severe impacts in Africa. We further show that 51 to 81% of these impacted populations reside in countries with low income, serious hunger, severe gender inequality, and high political fragility. Our study implies that future climate change will threaten grazing suitability across large portions of Earth, endangering the livelihoods of numerous communities and potentially triggering widespread socioeconomic consequences.

Read more (paywalled): https://www.pnas.org/doi/full/10.1073/pnas.2534015123

Unfortunately, the full study is paywalled, but I think we get the idea.

While grasslands originally appeared around 40 million years ago, grassland expansion began around 23 million years ago, when the earth was in a cooling phase, though the early part of this period was significantly warmer than today.

The problem holding grass back was competition with trees – it’s hard for grasslands to thrive when competing for sunlight with a towering forest. The cooler, dryer conditions which prevailed when grasslands started to dominate killed vast tracts of forest, allowing hardier grasslands to thrive.

Since the evolution of humans, another way to encourage grasslands and tip the balance in favour of grass has emerged.

Native American imprint in palaeoecology

Marc D. Abrams and Gregory J. Nowacki

ARISING FROM W. W. Oswald et al. Nature Sustainability https://doi.org/10.1038/s41893-019-0466-0 (2020)

Southern New England in the United States had a long history of Native American habitation and land use and was dominated by vast expanses of oak (Quercus) and pine (Pinus) forests. A recent paper by Oswald et al. posits that: regional fires were mainly climate-controlled and played a minor ecological role; the region was dominated by closed-canopy, old-growth forests; and Native American land use had little impact on vegetation. We disagree with these conclusions because of limitations in palaeoecological methods, particularly in detecting lower-intensity surface fires, and in that they contradict extensive scientific research in multiple disciplines. Over the last decade or more, the palaeoecological view has become increasingly climate-centric, which contradicts the proud legacy and heritage of land use by Indigenous people, worldwide, and aims and methodologies of vegetation managers promoting natural ecosystems and fire regimes.

…

In southern New England, modern-day lightning-strike density is low and is normally associated with rain events (that is, a lack of dry lightning needed to sustain large fires). Moreover, lightning storms are largely restricted to the summer when humidity is high and vegetation flammability is low, making them an unlikely ignition source. Oswald et al. state that “During times when Native populations were relatively high, we found no evidence for forest clearance, elevated use of fire, or widespread agriculture”. In contrast, Patterson and Sassaman reported a substantial amount of Indigenous burning and agricultural fields in coastal areas. A book written on the subject concluded that Native American populations in southern New England practised extensive agriculture. Moreover, the human population increased in response to the widespread adoption of maize agriculture during the Late Woodland period

…Read more: https://www.nature.com/articles/s41893-020-0578-6.epdf?sharing_token=yAr3b7YXB1qGIa2U_3y7y9RgN0jAjWel9jnR3ZoTv0PVpvdv2U91vikhE9iUT0LIxbwdNYky5VTFe76VNDNpRu9I4n9VlwSf4asgm7W0rsBQnFL4YAdzEan7Rx4uM3EoHL6K2Gi4phI9-o138EmS1BZchxUyt0YQ-NwynlEgJhw%3D

Native peoples all over the world deliberately burnt dense forests to encourage more grass, either for fire stick agriculture or because large grassland herbivores provide more food than trying to survive in a forest.

My point is, grasslands have competed with forests for 40 million years. There is no evidence grass cannot thrive in much warmer conditions, the limitation is in benign climates, trees outcompete grass, unless someone burns the forest down.

There is no risk of the world running short of grasslands, because if forests start significantly encroaching on farmers’ fields in a big way, there’s going to be an “accidental” fire, even in places where forests are protected by law.

Storm Chasing with Michael Mann: How to Stay in the Climate Spotlight

It’s hard not to notice when Michael Mann’s name appears in the author list of a climate paper—after all, he’s about as synonymous with climate alarm as Al Gore is with PowerPoint slides. One could say spotting his name in a paper about “intensification of the strongest nor’easters” is like finding Waldo in a crowd where everyone’s wearing a red-and-white striped shirt—inevitable, but somehow still amusing.

From Watts Up With That?

By Charles Rotter

To the meat of the matter: this paper by Chen et al., published in PNAS in July 2025, claims that the strongest nor’easters affecting the U.S. East Coast are not only getting stronger in terms of maximum wind speed, but also producing more precipitation over time, especially since 1940. Naturally, this finding is attributed to—you guessed it— “a warming world,” though, as is tradition, the underlying uncertainties and methodological sleights-of-hand are tucked away in the statistical shadows.

The paper leans heavily on reanalysis data (ERA5, 1940–2025) and cyclone tracking algorithms to cobble together a historical record, touting its “homogeneity” and “comprehensiveness.” Yet, buried within the technical details, there is acknowledgment that models and data sources are patchy at best, especially in the pre-satellite era—a recurring Achilles’ heel in this field. Indeed, the authors admit:

“The precise significance levels vary depending on the choice of statistical test, time interval, and effective storm radius… Of specific potential concern is the sensitivity of the trend to changes in input data sources during the transition from traditional surface and radiosonde observations in the early part of the record to multisensor observations in later years. However, we find that the trends of interest are even greater in magnitude… if confined entirely to the satellite era (1979–2025)…”

In other words: the “clear finding” that nor’easters are becoming more intense is more “clear” the shorter and more satellite-heavy the dataset. It’s a bit like insisting your cooking skills are improving because you swapped out a foggy bathroom mirror for an Instagram filter—suddenly everything looks better, but is it really you that changed, or the tool?

The authors do recognize the ambiguity and the wobbly ground their conclusions stand on. Previous studies, as they admit, have reached everything from “no significant change in median cyclone intensity,” to a decrease, or an increase.

“There is, as a result of these confounding factors, considerable divergence in future projections of ETC intensity in past studies, with findings ranging from no significant change in median cyclone intensity, to a decrease, or an increase.”

This is climate science in a nutshell: if you don’t like the answer, wait for another model run.

Quantile regression, the paper’s statistical hammer of choice, is used to hunt for trends in the upper tail of nor’easter intensity. The median shows no significant trend—no surprise—but the “upper quantiles” (think: the rare, nasty storms) show a “statistically significant” upward blip. Here, “significant” is a term of art, stretched nearly to the breaking point. As the authors write:

“Trends… become statistically significant at P < 0.10 for quantiles above 0.66. A similarly pronounced increasing trend at higher quantiles is also evident when applying the Mann–Kendall trend analysis… the results overall lead to a clear finding: the strongest nor’easters are becoming stronger.”

A P-value of 0.10, in case anyone’s forgotten, means there’s a 10% chance the result is due to random noise. For comparison, most scientific disciplines would require P < 0.05 (or even lower). Here, we’re invited to hang public policy on a confidence threshold that wouldn’t pass muster in most reputable poker games.

Then there’s the matter of reanalysis data, which the authors themselves acknowledge is a stitched-together Frankenstein’s monster of models and sparse measurements, especially in the first half of the twentieth century. If this is the bedrock for billion-dollar policy decisions, it’s no wonder taxpayers feel seasick.

The study’s discussion pivots to a familiar script, predicting more damage, more floods, and (curiously) “the counterintuitive possibility of increased winter cold air outbreaks in regions neighboring the U.S. East Coast.” It seems global warming, much like a Las Vegas magician, can pull any outcome from its hat—hotter, colder, drier, wetter, all roads lead to Rome.

And let’s not overlook the obligatory economic scare numbers:

“The total economic loss from [the Ash Wednesday storm, 1962] was estimated at approximately $3 billion (1962 USD). When adjusted for inflation, a storm of similar magnitude striking today would result in losses exceeding $21 billion (2010 USD)… Accounting for inflation, that would be equivalent to $31 billion, which is in proportion to the typical cost of a major landfalling hurricane.”

One almost expects the next sentence to warn of a biblical plague of frogs, with losses adjusted for inflation.

Now, about Michael Mann: his presence on this author list is not just a punchline, it’s a calling card. Mann, famous for the “hockey stick” graph that gave Al Gore a PowerPoint and generations of schoolchildren nightmares, has become something of a celebrity meteorologist—equal parts scientist, activist, and legal enthusiast. If his name’s on it, you can bet the conclusion will be that weather is getting worse, and humanity is to blame. It’s less a finding than a branding strategy.

Yet, let’s give credit where due. The authors stop short of outright libel or slander against skeptics, which is more than can be said for certain climate “debates” on social media. Instead, the rhetorical force is channeled into statistical acrobatics and economic extrapolations. The real comedy here is not in the intent to deceive, but in the perennial hope that just one more regression, one more reanalysis, will finally clinch the case for “unprecedented” danger.

In summary, this paper offers a case study in climate science as performance art. There’s an obligatory nod to uncertainty, a parade of statistical significance at thresholds so generous even carnival barkers might blush, and a supporting cast led by Michael Mann, the maestro of the climate anxiety industrial complex. For policymakers and the public, the lesson is simple: always read the fine print—and if the numbers look scary, check who’s holding the calculator.

HT/rhs

Hurricane Category 6?

The PNAS reasoning was that a few Pacific Hurricanes (aka tropical cyclones) have exceeded SF level 5. True, sort of. All 5 cited by PNAS only temporarily exceeded Cat 5. For example, quoting from the new paper, “The most intense of these hypothetical Cat 6 storms, Patricia, hit landfall in Jalisco, Mexico as a cat 4.” OOPS.

From Watts Up With That?

Rud Istvan

This simple guest post was prompted by an alarming WaPo report ‘today’ of a new PNAS study seriously proposing an expansion of the Saffir-Simpson hurricane scale to a ‘level 6’, (beyond the current peak of 5) because of intensified tropical cyclones caused by climate change.

The PNAS paper reached its new and alarming future ‘Cat 6’ conclusion by applying ‘bias corrections’ to CMIP5. Although it then states, “None of these high resolution climate model projection should be taken too literally.” Especially after PNAS ‘bias corrections’. But IPCC said CMIP5 was then the best and brightest.

There are two basic skeptical problems with this newly alarming ‘climate science’—albeit ‘not to be taken too literally’.

First, almost all the recent ‘worst satellite wind speed’ Florida hurricane alarms were not ground truthed by observations near eye wall ground wind speeds—by a lot.

Ian was an exception to this, unfortunately as bad as predicted. So the satellite and hurricane hunter CatX estimates are generally high compared to ground truth. That is probably OK when NHC warnings a threatened Florida populace to evacuate—but not for ‘climate science’ in PNAS.

Second, Ryan Maui’s ACE shows no such ‘Cat 6’ strengthening over time.

So PNAS published an alarming model speculation based on “corrections to climate model biases’, then failed to publish the observed facts.

Feynman is surely rolling over in his true science grave.

Leah Stokes, PNAS, and Conflicts of Interest

Leah Stokes blames White people for opposing wind projects.

From Watts Up With That?

By Andy May

Leah Stokes is the senior author of a new paper in PNAS, Prevalence and predictors of wind energy opposition in North America, in which she blames White people for opposing wind projects. She goes on to say that “…wealthier, Whiter communities [opposition] leads to continued pollution in poorer communities, and communities of color.”

There is evidence that offshore wind projects, or at least the geophysical site surveys required for building them, harm whales. The fact that these geophysical surveys can harm whales is well known and regulations prohibit the surveys, but numerous authorizations for surveys [waiving the rules] for renewable wind projects have been granted anyway. There is also evidence that wind turbines can harm our health, due to the low frequency sounds they produce. Thus, there are good reasons to protest wind turbine development, whether the protestor is White or not.

Stokes claims in her paper that she has “no competing interest.” This was accepted by the editor of the paper, Michael Mann. Yet her podcast, “A Matter of Degrees,” has received the following donations from organizations that support wind power:

The McKnight Foundation supports wind power and moving away from fossil fuels, the same is true of the William and Flora Hewlett Foundation, Bloomberg Philanthropies, and the Schmidt Family Foundation. Stokes is also a policy advisor to Evergreen Action, and a senior policy counsel to Rewiring America, an organization promoting the electrification of the USA.

As I asked Google Bard recently:

“A connection to the renewable industry is OK and not biased, but to the fossil fuel industry it is. This seems to be bias.”

This forced Google Bard to admit that:

“Both the renewable energy industry and the fossil fuel industry have a vested interest in the climate change debate.”

Thus, Stokes appears to have a competing interest, that could lead to bias in her paper. Advocates of wind are financially supporting her podcast. According to the PNAS rules, a financial interest may include:

“…membership on a standing advisory council or committee, service on the board of directors, public association with the company or its products, … compensation as a spokesperson, … or financial support.”

Do I need to ask why she left out her competing interests, or why Michael Mann accepted the paper with the “no conflict of interest” statement?

h/t Willie Soon and Matthew Nisbet.

Tag: PNAS

Potsdam: Climate Change will Cut Sheep, Goat and Cattle Farming in Half by 2100

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Hurricane Category 6?

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Leah Stokes, PNAS, and Conflicts of Interest

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