Scientists

Childhood vaccination coverage has declined in most European Union (EU) countries in recent years, reversing some of the significant progress made since 1980, according to a study published in The Lancet Regional Health – Europe. The researchers analysed data from the World Health Organisation and UNICEF on coverage rates for seven childhood vaccines – diphtheria, tetanus and pertussis; hepatitis B; Haemophilus influenzae type b; measles; pneumococcal; poliomyelitis and rubella – across the 27 EU countries between 1980 and 2024. Most of the recent declines began between 2019 and 2022, coinciding with the COVID-19 pandemic. In Spain, the data point to a decline in vaccination rates for five of the seven childhood vaccines – whilst rates for rubella and measles increased.

According to a report published by the World Meteorological Organisation, 2025 has been one of the driest years in more than three decades for rivers worldwide. Global water reserves have been declining for more than 10 years, and this is the fourth consecutive year in which glacier losses have been recorded across all regions. Although rainfall in the Iberian Peninsula was above normal in the summer, the west and north-west of Spain experienced a reduction in rainfall of up to 75 per cent below average.
  

A combination of geological and climatic factors — the latter influenced by anthropogenic climate change — lay behind the catastrophic rock and ice avalanche last August on Nepal’s northern border, according to a review carried out by World Weather Attribution and glaciology experts. The team carried out an attribution analysis to examine the role of climate change in the rise in temperatures in July and August preceding the collapse, as well as in the region’s rainfall. According to the study, human-induced warming has raised the freezing line by around 100 metres per decade, leading to the thinning of glaciers and the thawing of the permafrost that held the mountain together. These factors, together with the destabilisation caused by a magnitude 7.8 earthquake in 2015, are believed to be the main causes of the landslide, which left more than a thousand people dead and thousands missing. 

A US-based team with Spanish participation has successfully transplanted cortical organoids—self-organizing fragments of lab-grown human brain tissue—into modified mice lacking most of their cerebral cortex, the brain layer responsible for functions ranging from cognition and language to attention and decision-making. The research, published in the journal Nature, shows that the human tissue survived, grew, and developed functional connections with the mice's brains and, extending beyond that, with the spinal cord. According to the authors, this could help generate new models for studying disease-related alterations in human brain circuits.

A meta-analysis has examined the relationship between four environmental exposures – air, noise, light and water pollution – and the risk of death by suicide, suicide attempts and suicidal thoughts. The research shows an association between these three events and exposure to various air pollutants. Specifically, the study, published in the Journal of Epidemiology & Community Health, links these three events to short-term exposure to particulate matter (PM2.5 and PM10) and long-term exposure to PM2.5 and nitrogen dioxide. The research encompassed 45 studies, 29 of which were included in the meta-analysis and 16 in a systematic review. In the review, the authors found possible associations between suicide and other air pollutants (including sulphur dioxide and ozone) as well as noise pollution. By contrast, no significant associations were found with either light pollution or water pollution.

A team from the Teruel-Dinópolis Joint Palaeontological Foundation has discovered, at the La Tejería site in El Castellar (Teruel), the remains of what could be the first diplodocus found outside North America. The research, published in the Journal of Vertebrate Palaeontology, describes 14 exceptionally well-preserved caudal vertebrae from the tail and several cheurones (tail bones). According to the authors, “osteological comparisons and phylogenetic analyses consistently placed the specimen within the genus Diplodocus”. The specimen, which dates back some 150 million years, provides the first intercontinental evidence for this genus and constitutes one of the most robust pieces of palaeontological evidence for episodes of faunal dispersal and exchange between the two continents across the proto-Atlantic Ocean during the Late Jurassic.

A team from Harvard University (United States) and the University of Ghana has analysed the meteorological factors that can most significantly affect cocoa crops, the raw material used to make chocolate. In addition to low rainfall during the dry season – a long-standing concern – heavy rainfall during the wet season has emerged as a key factor. This pattern was observed in all three countries studied, which are major cocoa producers: Ghana, Ecuador and Indonesia. The authors, who have published their findings in PNAS, emphasise that rainfall harmful to cocoa is linked to larger-scale climate patterns, such as El Niño or variations in sea surface temperature in the Atlantic; consequently, it is possible to predict some poor harvest years before the damage occurs, with sufficient advance warning to alert farmers.

Rivers around the world discharged approximately 263,000 tonnes of microplastics into the oceans in 2022, with 96 per cent of this originating from the Global South. This is the main finding of a study that has analysed various data sources showing that extreme rainfall events can substantially increase this transport of microplastics, particularly in regions with high plastic use and poor waste management. The authors, whose findings are published in Science, warn that climate change could exacerbate the problem as extreme rainfall becomes more frequent and intense.

Cities’ adaptation to climate change is not progressing fast enough to protect their inhabitants from increasing heatwaves, infectious diseases and exposure to pollen, which are having an ever-greater impact on the urban population. This is the main conclusion of a study published in The Lancet Public Health, based on 28 indicators from more than 850 European cities, including many in Spain such as Madrid, Barcelona and Valencia. The greatest improvements were observed in cities that increased their green space. The study also suggests that risks are rising more rapidly in southern and eastern Europe.

A study published in Science Advances suggests that the use of betel nut as a drug has older origins than previously thought. Bone remains from two pre-agricultural hunter-gatherers — dated between 25,000 and 16,000 years ago — from Sulawesi (Indonesia) show dental pathology associated with the consumption of these whole nuts. Considered one of the world’s oldest known drugs, when consumed, this nut releases arecoline, the plant’s main neuroactive alkaloid. According to the research, it is possible that the hunters-gatherers’ sole motivation for using it was not merely as a drug, but also for its analgesic and digestive properties.