(Press-News.org) The idea that irrigated agriculture underpins global food and water security—producing 40% of crops and using 70% of freshwater—has become widespread in science and policy. However, these statistics are not empirically supported, according to a new analysis. Arnald Puy and colleagues traced these figures through citations in 3,693 scientific documents published from 1966 to 2024. The authors found that 60–80% of citation paths led to sources without supporting data or that did not contain the claimed numbers. Only approximately 1.5% of cited documents provided original data. When the authors analyzed available data on irrigation's actual impact, the results showed much wider uncertainty ranges: irrigated agriculture produces 18–50% of the world’s grain and is responsible for 45–90% of freshwater withdrawals. The analysis revealed that the 40% and 70% figures spread through “amplification," in which sources without data are used, and “transmutation," in which uncertain claims are presented as definitive facts after repeated citation. The most cited basis for the statistics, FAO's Aquastat database, contains limited country coverage with mostly imputed rather than measured values. According to the authors, the wobbly nature of such oft-repeated statistics highlights the need to critically evaluate foundational claims in sustainability science. Regardless of irrigation's global impact, there are no shortage of specific, local irrigation problems to solve, and they can often be approached most fruitfully with place-based solutions.
END
Two major irrigation statistics may be wrong
2025-11-11
ELSE PRESS RELEASES FROM THIS DATE:
A ubiquitous architectural pattern in nature
2025-11-11
A database, collecting and classifying tile-like patterns in biology, aims to be a resource and research catalyst. The human eye is drawn to the rhythmic beauty of tiled patterns, which occur abundantly in nature. Jana Ciecierska-Holmes, John Nyakatura and Mason Dean led a project with colleagues, offering a classification of biological tilings—repeated patterns of geometric discrete elements found in nature. Tilings are found across the tree of life, in a wide variety of taxa and at many spatial scales from ...
The first four years of PNAS Nexus
2025-11-11
In an editorial, Editor-in-Chief Yannis C. Yortsos looks back at the journal’s first few years and considers the aptness of W. Brian Arthur’s 2009 definition of technology, “leveraging phenomena for useful purposes,” exploring how it might be applied across all scientific endeavors in the age of artificial intelligence, the acceleration of which has coincided with the launch of PNAS Nexus. Created to serve as a platform for scientific and technological ideas, enlightenment, and solutions, PNAS ...
Research alert: GLP-1 drugs linked to dramatically lower death rates in colon cancer patients
2025-11-11
A new University of California San Diego study offers compelling evidence that glucagon-like peptide-1 (GLP-1) receptor agonists — the class of drugs behind Ozempic, Wegovy and Mounjaro, for example — may do more than regulate blood sugar and weight. In an analysis of more than 6,800 colon cancer patients across all University of California Health sites, researchers found that those taking GLP-1 medications were less than half as likely to die within five years compared to those who weren’t on the drugs (15.5% versus 37.1%).
The study, led by Raphael Cuomo, Ph.D., associate professor in the Department of Anesthesiology ...
VR headsets may make dry eye less likely: World's first time-course observation during a VR session
2025-11-11
Virtual reality (VR) gaming has gained significant attention in recent years, with an increasing number of users integrating VR and immersive headsets into their daily lives. These devices provide highly immersive visuals, creating a strong sense of presence and disconnection from the real world. However, concerns have been raised about the effects of prolonged VR use—especially at short viewing distances—on eye health and its potential link to dry eye disease, an ocular condition characterized by tear film instability.
The tear film is a dynamic, multilayered system composed of lipid ...
CASIA-EXO: A novel exoskeleton for adaptive motor learning in post-stroke rehabilitation
2025-11-11
Stroke is one of the leading causes of non-traumatic disability worldwide, affecting more than 15 million people each year, with about three-quarters experiencing long-term functional impairments. This makes it crucial to develop long-term rehabilitation programs that can promote motor relearning, enhance neural plasticity, and restore daily motor function. Robot-assisted rehabilitation, which combines neuroscience, biomechanics, and advanced control systems, is emerging as a highly promising approach.
In recent years, exoskeleton-type rehabilitation robots that enable distributed ...
Topology-aware deep learning model enhances EEG-based motor imagery decoding
2025-11-11
Electroencephalography (EEG) is a fascinating non-invasive technique that measures and records the brain’s electrical activity. It detects small electrical signals produced when neurons in the brain communicate with each other, using electrodes placed at specific locations on the scalp that correspond to different regions of the brain. EEG has applications in various fields, from cognitive science and neurological disease diagnosis to robotic prosthetics development and brain-computer interfaces (BCI).
Different brain activities produce unique EEG signal patterns. One important example is motor imagery (MI)—a ...
Study sheds new light on how hormones influence decision-making and learning
2025-11-11
Researchers have long established that hormones significantly affect the brain, creating changes in emotion, energy levels, and decision-making. However, the intricacies of these processes are not well understood.
A new study by a team of scientists focusing on the female hormone estrogen further illuminates the nature of these processes. In a series of experiments with laboratory rats, it finds that the neurological mechanisms underlying learning and decision-making naturally fluctuate over the ...
Continents peel from below, triggering oceanic volcanoes
2025-11-11
Earth scientists have discovered how continents are slowly peeled from beneath, fuelling volcanic activity in an unexpected place: the oceans.
The research, led by the University of Southampton, shows how slivers of continents are slowly stripped from below and swept into the oceanic mantle – the hot, mostly solid layer beneath the ocean floor that slowly flows. Here, the continental material fuels volcanic activity for tens of millions of years.
The discovery solves a long-standing geological mystery: why many ocean islands far from plate tectonic ...
Where does continental material on islands come from?
2025-11-11
Many oceanic islands far from active plate tectonic boundaries contain materials that clearly originate from continents, even though they are located in the middle of an oceanic plate. Where do the continental remnants come from? Are they sediments that are recycled when oceanic plates subduct into the mantle? Or do they originate from the depths of the Earth's mantle and are carried upward by hot currents, known as mantle plumes? Both explanations are being discussed, but they fall short. This is because some volcanic regions show little evidence of crustal recycling, while others are too cool to be driven by mantle plumes.
Researchers at the University of Southampton and the GFZ Helmholtz ...
New drug target identified in fight against resistant infections
2025-11-11
The discovery of a new mechanism of resistance to common antibiotics could pave the way for improved treatments for harmful bacterial infections, a study suggests.
Targeting this defence mechanism could aid efforts to combat antimicrobial resistance (AMR), one of the world’s most urgent health challenges, researchers say.
Findings from the study reveal how a repair system inside some bacteria plays a pivotal role in helping them survive commonly-used antibiotics.
Many of these drugs work by targeting the production of proteins essential for bacterial growth and survival.
Now, researchers from the University of Edinburgh have identified ...