New study reveals the costs of sanctions

UNIVERSITY OF WÜRZBURG

Facts and figures in brief

• In Iran, gross domestic product fell by 1.9 per cent as a result of the sanctions in 2012.
• In Russia, gross domestic product fell by 1.4 per cent in 2014 as a result of the sanctions.
• If all countries in the world were to participate in the sanctions against Iran, the economic consequences would more than double.
• Involving all countries in the world in the sanctions against Russia would increase the economic consequences by more than 70 per cent.
• China joining the sanctions coalition against Russia would increase the effect by a good 22 per cent.
• Economically strong countries would have to transfer around 5.4 billion US dollars to countries that suffer disproportionately large economic damage as supporters of the sanctions against Iran and Russia.

Economic sanctions can be a double-edged sword. On the one hand, they usually reduce gross domestic product and thus prosperity in the affected countries, as intended. On the other hand, however, they can also have a severe impact on the economies of the sanctioning countries. However, a skilful selection of the countries involved in the sanctions measures could significantly mitigate these undesirable negative consequences.

These are the key findings of a new study that has now been published in the journal Economic Policy. Economists Sonali Chowdhry (DIW Berlin), Julian Hinz (Bielefeld University & IfW Kiel), Katrin Kamm (IfW Kiel) and Joschka Wanner (University of Würzburg & IfW Kiel) are responsible for the study. The study focuses on the sanctions against Iran in 2012 in response to its nuclear programme and against Russia following the violent annexation of Crimea in 2014.

Analysing Prices, Prosperity and Trade Flows

"In our analyses, we focused on the economic effects of sanctions, for example on prices and prosperity in the target country, as well as on trade flows," says Joschka Wanner, Junior Professor of Quantitative International and Environmental Economics at Julius-Maximilians-Universität Würzburg (JMU), describing the approach. As a first step, the team analysed the extent to which these parameters have changed as a result of the sanctions.

In fact, the calculations for Iran show a real decline in gross domestic product of 1.9 per cent as a result of the sanctions. For Russia, the figure is 1.44 per cent - based on the sanctions from 2014. The sanctions following the attack on Ukraine do not yet play a role in this study. "1.4 or 1.9 per cent may not sound like much. However, from an economic perspective, this is a full-blown recession," says Wanner.

Maximum Sanction Potential not Reached

The group compared these real developments with the maximum potential of the sanctions under various conditions - either by including more countries in the sanctions or by extending them to all goods. "According to our calculations, in the case of Iran, the current coalition achieves around 39 per cent of what would be possible in terms of a decline in gross domestic product - compared to the case in which all countries participate in the sanctions," explains Wanner. For Russia, this figure is just under 58 per cent.

These figures are partly even more drastic if the current scenario is compared with the case in which the sanctions apply to all goods, i.e. there are no more exceptions. In this case, the current coalition only achieves 47 per cent of the possible decline in GDP for Iran. And 16 per cent for Russia.

High Costs for Some Stakeholders

When sanctions are imposed, it is not only the sanctioned countries that suffer - the study also shows this. However, there are major differences: "While larger economies such as the USA, Japan and Germany get off relatively lightly, smaller countries such as Malta, Estonia and Latvia suffer relatively drastic consequences," explains Wanner. This should come as no surprise: if a small country like Latvia restricts trade with its large neighbour Russia, this will inevitably have a greater impact than in the USA or Canada.

As a consequence, this means that Small countries pay a high price in this case, while the effects of their participation in the sanctions are only reflected in a small loss of welfare for Russia. The study also shows how things could be better: "Instead of the small countries, other states would have to join the coalition. Then the sanctions would have much greater consequences," explains Wanner.

In the case of sanctions against Russia, the economists have calculated that the participation of China, Vietnam, Belarus, Turkey and South Korea in particular would drastically increase the potential for sanctions. This would rise from 58 per cent under the current coalition to 71 per cent - simply by China joining the sanctions coalition.

Transfer Payments for Particularly Affected Countries

Of course, it is unlikely that China will join a coalition of Western states against Russia. So what could the coalition do to ensure that as many countries as possible side with it without suffering disproportionately large economic damage? "Financial transfers" is the research team's answer.

"Our results show that 591 million US dollars would have to be mobilised in connection with the sanctions against Iran and 4.8 billion US dollars in the case of Russia so that the members could compensate for their welfare losses due to the respective sanctions," the study states.

The largest contributor to this "compensation fund" would be the USA, whose combined transfers for both sanctions packages would amount to around 4.4 billion US dollars. They would be followed by the UK (770 million US dollars) and Canada (553 million US dollars).

---

JOURNAL

Economic Policy

DOI

10.1093/epolic/eiae019 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Brothers in arms: the value of coalitions in sanctions regimes

 

Promise green hydrogen may not always be fulfilled

Green hydrogen often, but certainly not always, leads to CO2 gains

RADBOUD UNIVERSITY NIJMEGEN

Green hydrogen often, but certainly not always, leads to CO2 gains. This claim is based on research published in Nature Energy by Kiane de Kleijne from Radboud University and Eindhoven University of Technology. “If you calculate the entire life cycle of green hydrogen production and transport, CO2 gains may be disappointing. However, if green hydrogen is produced from very clean electricity and locally, it can really help reduce emissions.”

It is thought that green hydrogen can make a major contribution to reducing greenhouse gas emissions. Dutch companies are currently investing in developing green hydrogen in countries where green power, needed to produce green hydrogen, can be easily generated, such as Namibia and Brazil. The EU is also aiming to produce 10 million tonnes of green hydrogen and importing another 10 million tonnes by 2030. “Green hydrogen has great potential as a technology due to its versatility and many applications. But unfortunately, I still foresee some bumps in the road”, says environmental scientist De Kleijne.

Entire life cycle

For over a thousand planned green hydrogen projects, De Kleijne calculated the greenhouse gas emissions associated with producing green hydrogen, including the production of, for example, solar panels, wind turbines and batteries to provide power, and the transport by pipeline or ship. “Green hydrogen is produced by splitting water into oxygen and hydrogen in an electrolyser using green electricity. You can then use that hydrogen as a raw material or fuel. Hydrogen made from natural gas is already widely used as a raw material, for example in the chemical industry to produce methanol and ammonia for fertiliser.”

The advantage of green hydrogen is that when splitting water, besides hydrogen, only oxygen is released and no CO2. “However, that does require large amounts of green power”, says the researcher. “You can only reduce emissions if you use green energy, such as wind or solar power. But even then, the emissions from manufacturing wind turbines and solar panels alone add up considerably. If you look at the entire life cycle in this way, green hydrogen often, but certainly not always, leads to CO2 gains.  CO2 gains are usually higher when using wind power rather than solar power. This will improve further in the future as more renewable energy will be used to manufacture the wind turbines, solar panels and steel for the electrolyser, for example.”

Hydrogen transport

Hydrogen production results in the lowest emissions in places where there is a lot of sun or wind, like Brazil or Africa. The downside is that this hydrogen must then be transported to Europe. That is technologically challenging and can create a lot of extra emissions. “Transporting green hydrogen over long distances contributes so much to the total emissions that much of the CO2 gains from production in distant, favourable locations is negated”, says De Kleijne. For short distances, transport emissions appear to be lowest for pipelines, while shipping liquid hydrogen is best for long distances.

Zero emissions

The key message, according to the scientist, is that we should not claim that technologies such as green hydrogen are completely emission-free. Current calculation methods that form the basis for regulations do not usually consider emissions from what needs to be manufactured to produce hydrogen, such als solar panels and electrolysers, or hydrogen leakage during transportation. In those cases, it might seem that green hydrogen does not produce many emissions, but that is far from the case. “By looking at emissions over the entire life cycle, we can make a better trade-off between technologies, and identify where improvements can be made in the chain. Furthermore, we can ask ourselves: what is important to produce in the Netherlands and Europe? And when might it be better to move an industry to somewhere else in the world?”

---

JOURNAL

Nature Energy

DOI

10.1038/s41560-024-01563-1 

ARTICLE TITLE

'Worldwide greenhouse gas emissions of green hydrogen production and transport'

ARTICLE PUBLICATION DATE

21-Jun-2024

 

Up to 30 percent more time: Climate change makes it harder for women to collect water

POTSDAM INSTITUTE FOR CLIMATE IMPACT RESEARCH (PIK)

Climate change could increase the amount of time women spend collecting water by up to 30 percent globally by 2050, according to a new study published in Nature Climate Change. In regions of South America and Southeast Asia, the time spent collecting water could double due to higher temperatures and less rainfall. A team of scientists from the Potsdam Institute for Climate Impact Research (PIK) estimates the large welfare losses that could result from climate impacts and highlights how women are particularly vulnerable to changing future climate conditions. Worldwide, two billion people currently lack access to safe drinking water. The responsibility for collecting water typically falls on women and girls.

 

”Climate change leads to rising temperatures and alters rainfall patterns, affecting the availability of water. We show that for women in households without running water, the time spent for collecting water will increase in almost all regions analysed under future climate change,” says study author Robert Carr, guest researcher at PIK. On a global average, for the period from 1990 to 2019, women in households without running water spend 22.84 minutes every day collecting water – ranging from 4 minutes in parts of Indonesia to 110 minutes in regions of Ethiopia. “Compared to these numbers, we found that women will have to spend up to 30 percent more time each day collecting water by 2050 under a high-emission scenario. This can be reduced to 19 percent if global warming is kept below 2 degree Celsius,” says Carr.

“Regionally by 2050, daily water collection times could double under a high-emission scenario, for example, in regions across South America and Southeast Asia. For regions in eastern and central Africa that currently have the longest water collection times, temperature rises in a high-emission scenario would cause increases of between 20 and 40 percent,” says author Maximilian Kotz from PIK. Globally, women spend up to 200 million hours a day on this vital task (as of 2016), which can lead to major losses of time otherwise used for education, work or leisure and can sometimes be a physical and mental burden.
 

Cost of lost working time could reach tens to hundreds of millions of US dollars per country and year

Based on historical data from household surveys in 347 subnational regions across four continents from 1990 to 2019, the researchers first assessed how changing climate conditions have impacted water collection times in the past. “We find that higher temperatures and less rainfall have increased daily water collection times,” says Maximilian Kotz. There are several possible explanations for that, he adds: “From a purely physical perspective, higher temperatures and less rainfall change the balance between evaporation and precipitation, thus lowering water tables. This makes fresh water harder to access. In addition, the journey can also become more uncomfortable and thus take longer due to heat stress.” Combining the observed patterns with temperature and precipitation projections from state-of-the-art clime models (CMIP-6), the researchers then assessed the impacts of future changes in climate on daily water collection times under different emission scenarios.

“Our results shed light on a gendered dimension of climate change impacts,” states author and PIK researcher Leonie Wenz. “They show how strongly climate change will affect women's well-being, causing them to lose time for education, work and leisure. By 2050, the cost of lost working time, calculated at the country-specific minimum wage, would be substantial, reaching tens to hundreds of millions of US dollars per country and year under a high-emission scenario.”

 

Article:
Robert Carr, Maximilian Kotz, Peter-Paul Pichler, Helga Weisz, Camille Belmin & Leonie Wenz (2024): Climate change to exacerbate the burden of water collection on women's welfare globally. Nature Climate Change. [DOI: 10.1038/s41558-024-02037-8]

Weblink to the article, once published:
https://www.nature.com/articles/s41558-024-02037-8

---

JOURNAL

Nature Climate Change

DOI

10.1038/s41558-024-02037-8 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Climate change to exacerbate the burden of water collection on women's welfare globally.

ARTICLE PUBLICATION DATE

21-Jun-2024

Disclaimer: AAA

WORD OF THE DAY

Navigating the Pyrocene: Recent Cell Press papers on managing fire risk

Peer-Reviewed Publication

CELL PRESS

As wildfires become more intense and the fire season grows longer across parts of the world, humans will need to adapt. In this collection of papers from Cell Press journals One Earth and Cell Reports Sustainability, an intersection of fire management researchers comment on what needs to change to ensure we can collaborate across stakeholders in a more fire-resistant future.

The papers are publishing in advance of a Cell Press 50th Anniversary sustainabiltiy forum on the topic of “Navigating the Pyrocene: Managing fire risk in a warming world.” The virtual event, free to register, takes place Thursday, July 11, 2024 at 11:00 am ET.

This collection of Cell Press journal content related to fire includes the following:

• Wildfires increasingly threaten oil and gas wells in the western United States with disproportionate impacts on marginalized populations (research article in One Earth) https://www.cell.com/one-earth/fulltext/S2590-3322(24)00256-2

University of California, Berkeley environmental health scientist David J.X. González (@davidJXgonzalez) and colleagues found widespread historical and projected future overlap between wildfires and oil and gas development in the western United States. Combined with recent increases in wildfire activity, this increases potential health risks for local populations, particularly in communities of color, and introduces new hazards.

• Reimagining a pathway to reduce built-environment loss during wildfires (commentary in Cell Reports Sustainability) https://www.cell.com/cell-reports-sustainability/fulltext/S2949-7906(24)00194-0

Civil and environmental engineer Hussam Mahmoud (@HussamN_Mahmoud) of Colorado State University argues that more can be done to mitigate against wildfire risks caused by communities expanding into forest-dense areas, which lead to changes in natural vegetation and increased human activity. Preparedness programs and related outreach initiatives can support neighborhood growth while enhancing residents’ ability to respond to these events.

• Technological solutions for living with fire in the age of megafires (commentary in One Earth) https://www.cell.com/one-earth/fulltext/S2590-3322(24)00260-4

Environmental engineers and scientists Marta Yebra (@Myebra12), Robert Mahony, and Robert Debus (@BobDebus1) of the Australian National University describe some of the high-tech options for early fire detection and rapid ignition suppression, ranging from sensors, cameras, aerial vehicles, and satellites, that can increase safety for firefighters or ground crews, but work is needed to assess the benefits and costs related to implementation.

• Model fires not ignitions: Capturing the human dimension of global fire regimes (commentary in Cell Reports Sustainability)
  https://www.cell.com/cell-reports-sustainability/fulltext/S2949-7906(24)00203-9

A team led by Matthew Kasoar and Oliver Perkins of the Leverhulme Centre for Wildfires, Environment and Society argue that global fire models overwhelmingly frame people’s ignition of fires as random events versus being actively planned and put out. Their data supports the idea that more useful models, while challenging to develop, would represent fires that spread naturally as well as those being managed by humans.

• Intense formation of secondary ultrafine particles from Amazonian vegetation fires and their invigoration of deep convective clouds and precipitation (research article in One Earth) https://www.cell.com/one-earth/fulltext/S2590-3322(24)00258-6

Ultrafine particles emitted from wildfire smoke are typically assumed to have little environmental consequence since they can be taken in by larger particles, but this study, led by Manish Shrivastava of the Pacific Northwest National Laboratory and Jiwen Fan of the Argonne National Laboratory, found abundant ultrafine particles in vegetation fires in the Amazon and that these may intensify cloud formation and heavy rain.

• A fire use decision model to improve United States’ wildfire management and support climate change adaptation (perspective in Cell Reports Sustainability) https://www.cell.com/cell-reports-sustainability/fulltext/S2949-7906(24)00200-3

US Geological Survey fellow Aaron Russell and colleagues explore use cases from New Jersey to California for intentionally setting fires as a method of harm reduction and risk mitigation. They recommend a framework that decision-makers can use to better collaborate among diverse stakeholders to plan and regulate burn events that considers each region’s unique goals, climate conditions, and social factors.

• Fighting with fire: Historical ecology and community-based approaches to fire management, stewardship, and ecosystem resilience (commentary in One Earth) https://www.cell.com/one-earth/fulltext/S2590-3322(24)00259-8

A team led by paleoecologist Yoshi Maezumi (@yoshi_maezumi) of the Max Planck Institute of Geoanthropology presents how American and European cultures can draw inspiration from indigenous custodianship of land to bridge gaps with Western science that can often prioritize fighting fires over fostering resilience through fire management.

• Changing fire regimes: Ecosystem impacts in a shifting climate (commentary in One Earth) https://www.cell.com/one-earth/fulltext/S2590-3322(24)00264-1

A rise in intense fires requires new models that account for altered weather patterns and increased fuel flammability, argue climate-ecosystems interactions researcher Stijn Hantson, of the University of Rosario in Colombia, and colleagues. They say that resolving gaps between scientific research and policy application can lead to better frameworks to protect nature and people from the impacts of wildfires on at-risk communities.

• Remote sensing for wildfire monitoring: Insights into burned area, emissions, and fire dynamics (Primer in One Earth) https://www.cell.com/one-earth/fulltext/S2590-3322(24)00257-4  

Earth system scientists Yang Chen and James Randerson of the University of California, Irvine, along with Douglas Morton of the NASA Goddard Space Flight Center, examine how remote sensors are applied to produce fire event data. They compare the tools available that can effectively estimate burn areas, fire emissions, and fire spread and describe the promise of these technologies to establish global databases.

• Perspectives on fire risk in a warming world (Voices in One Earth) https://www.cell.com/one-earth/fulltext/S2590-3322(24)00263-X

Nine experts ranging from Australia, Botswana, Chile, Germany, Portugal, Sweden, and the United States answer questions related to what aspects of fire hazard, vulnerability, and exposure can be mitigated and what collaborations this requires

• Lara Steil on global fire preparedness and Wayne Cascio on adapting to a smokier world (two Q&As in One Earth) https://www.cell.com/one-earth/fulltext/S2590-3322(24)00262-8; https://www.cell.com/one-earth/fulltext/S2590-3322(24)00253-7

Laura Steil, a forestry officer at the Food and Agriculture Organization of the United Nations, and Wayne Cascio, director of the Center for Public Health and Environmental Assessment at the US Environmental Protection Agency, answer questions related to increasing fire risk, how it can be managed, affected communities, and how institutions are preparing.

• Bark Beetle Book Volume XIV: Ars datum est (Visual Earth in One Earth) https://www.cell.com/one-earth/fulltext/S2590-3322(24)00251-3

Artist Suze Woolf depicts the trails of mountain pine beetles in a book made of a tree log impacted by the insects. A bar chart on the piece represents affected forested areas in British Columbia and Alberta from 1999 to 2007 and illustrates how a warming world and increase in forest fires is causing the beetles, which feed on dead tree wood, to propagate.

###

One Earth (@OneEarth_CP), published by Cell Press, is a monthly journal that features high-quality research that seeks to understand and address today’s environmental Grand Challenges, publishing across the spectrum of environmental change and sustainability science. Visit http://www.cell.com/one-earth.

Cell Reports Sustainability (@CellRepSustain), published by Cell Press, is a monthly gold open access journal that publishes high-quality research and discussion that contribute to understanding and responding to environmental, social-ecological, technological, and energy- and health-related challenges. Visit https://www.cell.com/cell-reports-sustainability/home.

---

JOURNAL

One Earth

DOI

10.1016/j.oneear.2024.06.001 

ARTICLE TITLE

The burning challenge: Seeking a sustainable path for people and fire

ARTICLE PUBLICATION DATE

21-Jun-2024

 

Restoring the Great Salt Lake would have environmental justice as well as ecological benefits

CELL PRESS

 

IMAGE: 

KITE FLYING AT THE GREAT SALT LAKE IN UTAH

view more 

CREDIT: SARA GRINESKI

Inland seas around the world are drying up due to increasing human water use and accelerating climate change, and their desiccation is releasing harmful dust that pollutes the surrounding areas during acute dust storms. Using the Great Salt Lake in Utah as a case study, researchers show that dust exposure was highest among Pacific Islanders and Hispanic people and lower in white people compared to all other racial/ethnic groups, and higher for individuals without a high school diploma. Restoring the lake would benefit everyone in the vicinity by reducing dust exposure, and it would also decrease the disparities in exposure between different racial/ethnic and socioeconomic groups. These results are reported June 21 in the journal One Earth.

“People here in Utah are concerned about the lake for a variety of reasons—the ski industry, the brine shrimp, the migratory birds, recreation—and this study adds environmental justice and the equity implications of the drying lake to the conversation,” says first author and sociologist Sara Grineski of the University of Utah. “If we can raise the levels of the lake via some coordinated policy responses, we can reduce our exposure to dust, which is good for everyone's health, and we can also reduce the disparity between groups.”

The Great Salt Lake has been steadily drying since the mid-1980’s, exposing its dry lakebed to atmospheric weathering and wind. Previous studies have shown that dust emissions from drying salt lakes produce fine particulate matter (PM2.5), which is associated with numerous health effects and is the leading environmental cause of human mortality worldwide.

“We know that the dust from these drying lakes is very unhealthy for us, so the question becomes, what does that mean in terms of people's exposure to the dust, and what does it mean in terms of inequalities in exposure to that dust,” says Grineski. “Are some people more likely to have to suffer the consequences to a greater degree?”

To answer this question, Grineski teamed up with a multidisciplinary group including atmospheric scientists, geographers, and biologists. They started by using a model to investigate how dust pollution would change if the lake became even dryer, or if its levels rose to a healthy level. The model simulated how much dust would be created by erosion under different lake-level scenarios  and how wind would distribute this dust in three counties surrounding the Great Salt Lake. Then, the team combined the model’s outputs with demographic data from the 2020 U.S. Decennial Census and American Community Survey to examine whether the severity of dust exposure is associated with racial/ethnic groups or socioeconomic status.

During a typical dust storm, the team found that at the lake’s current level, people in the Great Salt Valley are exposed to 26 μg/m3 of dust PM2.5 on average, which is higher than the World Health Organization’s threshold of 15 μg/m3 (though lower than the less stringent U.S. National Ambient Air Quality Standards threshold of 35 μg/m3). If the lake were to dry up completely, average exposure during dust storms would increase to 32 μg/m3, but restoring the lake to a healthy level would decrease the average exposure to 24 μg/m3.

 

They also showed that some groups within the population are exposed to disproportionate levels of dust. Exposure was highest in Pacific Islanders and Hispanic people, and higher in people without a high school diploma (one metric of socioeconomic status), though there was no association between the risk of dust exposure and income level or home ownership.

Raising the lake’s level would decrease the disparities between groups, thus helping to alleviate one form of environmental injustice within the region, though Grineski notes that the valley is home to other social disparities in pollution exposure.

“If the lake’s level rises, the dust drops, and the disparity in exposure narrows for race/ethnicity and education,” says Grineski.

In the future, the team would like to investigate how potential future changes to the region’s population size and shape might influence who is most exposed to dust from the lake. Ultimately, they hope their results will help guide local policy makers to prioritize re-filling the Great Salt Lake.

“If we were to enact policy and conservation measures to raise the lake, we would benefit not only in terms of decreased dust, but in terms of less dramatic disparities between who is breathing in more of this dust,” says Grineski. “It’s important to consider the environmental justice implications of different choices that we might make in the policy arena when we think about different strategies for adaptation and mitigation to climate change.”

###

This research was supported by the National Science Foundation.

One Earth, Grineski et al. “Harmful dust from drying lakes: Preserving Great Salt Lake (USA) water levels decreases ambient dust and racial disparities in population exposure” https://www.cell.com/one-earth/fulltext/S2590-3322(24)00249-5 

One Earth (@OneEarth_CP), published by Cell Press, is a monthly journal that features papers from the fields of natural, social, and applied sciences. One Earth is the home for high-quality research that seeks to understand and address today’s environmental Grand Challenges, publishing across the spectrum of environmental change and sustainability science. A sister journal to Cell, Chem, and Joule, One Earth aspires to break down barriers between disciplines and stimulate the cross-pollination of ideas with a platform that unites communities, fosters dialogue, and encourages transformative research. Visit http://www.cell.com/one-earth. To receive Cell Press media alerts, contact press@cell.com.

---

JOURNAL

One Earth

DOI

10.1016/j.oneear.2024.05.006 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Harmful dust from drying lakes: Preserving Great Salt Lake (USA) water levels decreases ambient dust and racial disparities in population exposure

ARTICLE PUBLICATION DATE

21-Jun-2024

 

Study challenges popular idea that Easter islanders committed ‘ecocide’

Inhabitants found Ingenious ways to adapt to a harsh environment

COLUMBIA CLIMATE SCHOOL

 

IMAGE: 

SO-CALLED ROCK GARDENS WERE KEY TO FEEDING THE POPULATION OF RAPA NUI, TODAY COMMONLY KNOWN AS EASTER ISLAND. ROBERT DINAPOLI, COAUTHOR OF A NEW STUDY ON THE GARDENS, INSPECTS ONE. 

view more 

CREDIT: PHOTO BY CARL LIPO

Some 1,000 years ago, a small band of Polynesians sailed thousands of miles across the Pacific to settle one of the world’s most isolated places—a small, previously uninhabited island they named Rapa Nui. There, they erected hundreds of “moai,” or gigantic stone statues that now famously stand as emblems of a vanished civilization. Eventually, their numbers ballooned to unsustainable levels; they chopped down all the trees, killed off the seabirds, exhausted the soils and in the end, ruined their environment. Their population and civilization collapsed, with just a few thousand people remaining when Europeans found the island in 1722 and called it Easter Island. At least that is the longtime story, told in academic studies and popular books like Jared Diamond’s 2005 “Collapse.”

A new study challenges this narrative of ecocide, saying that Rapa Nui’s population never spiraled to unsustainable levels. Instead, the settlers found ways to cope with the island’s severe limits, and maintained a small, stable population for centuries. The evidence: a newly sophisticated inventory of ingenious “rock gardens” where the islanders raised highly nutritious sweet potatoes, a staple of their diet. The gardens covered only enough area to support a few thousand people, say the researchers. The study was just published in the journal Science Advances.

“This shows that the population could never have been as big as some of the previous estimates,” said lead author Dylan Davis, a postdoctoral researcher in archaeology at the Columbia Climate School. “The lesson is the opposite of the collapse theory. People were able to be very resilient in the face of limited resources by modifying the environment in a way that helped.”

Easter Island is arguably the remotest inhabited spot on Earth, and one of the last to be settled by humans, if not the last. The nearest continental landmass is central Chile, nearly 2,200 miles to the east. Some 3,200 miles to the west lie the tropical Cook Islands, where settlers are thought to have sailed from around 1200 CE.

The 63-square-mile island is made entirely of volcanic rock, but unlike lush tropical islands such as Hawaii and Tahiti, eruptions ceased hundreds of thousands of years ago, and mineral nutrients brought up by lava have long since eroded from soils. Located in the subtropics, the island is also dryer than its tropical brethren. To make things more challenging, surrounding ocean waters drop off steeply, meaning islanders had to work harder to harvest marine creatures than those living on Polynesian islands ringed with accessible and productive lagoons and reefs.

To cope, the settlers used a technique called rock gardening, or lithic mulching. This consists of scattering rocks over low-lying surfaces that are at least partly protected from salt spray and wind. In the interstices between rocks, they planted sweet potatoes. Research has shown that rocks from golf ball–size to boulders disrupt drying winds and create turbulent airflow, reducing the highest daytime surface temperatures and increasing the lowest nighttime ones. Smaller bits, broken up by hand, expose fresh surfaces laden with mineral nutrients that get released into the soil as they weather. Some islanders still use the gardens, but even with all this labor, their productivity is marginal. The technique has also been used by indigenous people in New Zealand, the Canary Islands and the U.S. Southwest, among other places.

Some scientists have argued that the island’s population had to have once been much larger than the 3,000 or so residents first observed by Europeans in part because of the massive moai; it would have taken hordes of people to construct them, the reasoning goes. Thus in recent years, researchers have tried estimating these populations in part by investigating the rock gardens’ extent and production capacity. Early Europeans estimated they covered 10% of the island. A 2013 study based on visual and near-infrared satellite imagery came up with 2.5% to 12.5%―a wide margin of error because these spectra distinguish only areas of rock versus vegetation, not all of which are gardens. Another study in 2017 identified about some 7,700 acres, or 19% of the island, as suitable for sweet potatoes. Making various assumptions about crop yields and other factors, studies have estimated past populations might have risen as high as 17,500, or even 25,000, though they also could have been much lower.

In the new study, members of the research team did on-the-ground surveys of rock gardens and their characteristics over a five-year period. Using this data, they then trained a series of machine-learning models to detect gardens through satellite imagery tuned to newly available shortwave infrared spectra, which highlights not just rocks, but places of higher soil moisture and nitrogen, which are key features of gardens.

The researchers concluded that rock gardens occupy only about 188 acres—less than one half a percent of the island. They say they might have missed some small ones, but not enough to make a big difference. Making a series of assumptions, they say that if the entire diet were based on sweet potatoes, these gardens may have supported about 2,000 people. However, based on isotopes found in bones and teeth and other evidence, people in the past probably managed to get 35% to 45% of their diet from marine sources, and a small amount from other less nutritious crops including bananas, taro and sugar cane. Factoring in these sources would have raised the population carrying capacity to about 3,000―the number observed upon European contact.

“There are natural rock outcrops all over the place that had been misidentified as rock gardens in the past. The short-wave imagery gives a different picture,” said Davis.

Carl Lipo, an archaeologist at Binghamton University and coauthor of the study, said that the population boom-and-bust idea is “still percolating in the public mind” and in fields including ecology, but archaeologists are quietly retreating from it. Accumulating evidence based on radiocarbon dating of artifacts and human remains does not support the idea of huge populations, he said. “People’s lifestyle must have been incredibly laborious,” he said. “Think about sitting around breaking up rocks all day.”

The island’s population is now nearly 8,000 (plus about 100,000 tourists a year). Most food is now imported, but some residents still grow sweet potatoes in the ancient gardens―a practice that grew during the 2020-2021 lockdowns of the Covid pandemic, when imports were restricted. Some also turned to mainland farming techniques, plowing soils and applying artificial fertilizer. But this is not likely to be sustainable, said Lipo, as it will further deplete the thin soil cover.

Seth Quintus, an anthropologist at the University of Hawaii who was not involved in the study, said he sees the island as “a good case study in human behavioral adaptation in the face of a dynamic environment.” The new study and others like it “provide an opportunity to better document the nature and extent of strategies of adaptation,” he said. “Surviving in the more arid subtropics on the more isolated and geologically old Rapa Nui was a heck of a challenge.”

The study was also coauthored by Robert DiNapoli of Binghamton University; Gina Pakarati, an independent researcher on Rapa Nui; and Terry Hunt of the University of Arizona.

# # #

Hundreds of huge stone statues known as moai built by earlier residents are taken by some as evidence of a onetime much larger population.

CREDIT

Photo by Stephanie Morcinek via Unsplash

---

JOURNAL

Science Advances

METHOD OF RESEARCH

Imaging analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Island-wide characterization of agricultural production challenges the demographic collapse hypothesis for Rapa Nui (Easter Island)

ARTICLE PUBLICATION DATE

27-Jun-2024