Extreme heat is intensifying due to climate change – heat whose hourly fluctuations are not captured by traditional daily temperature indicators. Research published in Nature Climate Change has analysed global hourly data from 1981 to 2023, alongside climate projections through to the end of the 21st century. More than 80 per cent of the world’s land surface showed an increase in heat. Under a high-emissions scenario, the authors predict that, for the period 2070–2099, each hot day could include more than four hours of additional high temperatures compared with current levels (2001–2023). They also predict that non-hot days could see a further three hours of high temperatures, which would likely go undetected by daily measurements. Low- and middle-income countries are the hardest hit, bearing more than three-quarters of current and future heat exposure.

Western Europe experienced its hottest June–July on record, according to data from the Copernicus Climate Change Service (C3S). July saw the third and fourth heatwaves since May, marking an exceptional spell of extreme heat this summer. Across much of the region, the drought observed in May and June also persisted and intensified, with exceptionally low rainfall and soil moisture in France, Spain, parts of Germany and the United Kingdom. These hot and dry conditions in Western Europe led to the spread and intensification of last month’s extreme wildfires in countries such as Spain and France, according to the report.

One of the main strategies for mitigating CO₂ emissions is the electrification of vehicles. Although taking vehicles that are still in good condition off the road has an environmental impact, a study published in the journal Science has shown that replacing them with battery electric vehicles brings long-term benefits, even when taking into account the emissions resulting from their manufacture. To address this issue, the authors estimated the life-cycle CO₂ emissions associated with keeping a combustion-engine vehicle in use, compared with scrapping it early and replacing it with an electric vehicle. The results show that the carbon footprint of manufacturing the new vehicle is reduced, as electric cars emit only a third of the greenhouse gases produced by combustion-engine vehicles.

A team of researchers has designed complete and functional genomes for bacteriophages — viruses that feed on bacteria — from scratch using generative artificial intelligence (AI), and has tested them against bacteria that had developed resistance to this type of virus. The study, published in the journal Science, represents a step forward towards generative systems capable of designing complete biological systems. The authors also state that it raises important questions regarding biosafety and biosecurity.

A study published in the journal Cell Host & Microbe analysed endometrial samples from 149 women aged between 20 and 45 who were undergoing treatment for infertility. The younger patients had a significantly higher abundance of a beneficial bacterium called Lactobacillus gasseri, the presence of which decreased with age. Furthermore, pregnant women had a higher abundance of these bacteria in the endometrium. In mouse models, older animals showed higher rates of embryo implantation when treated with L. gasseri derivatives. Despite these findings, the authors emphasise that further research is needed and warn women against self-medicating with over-the-counter L. gasseri products, as their effectiveness in treating infertility has not been validated.

A study published in JAMA Network Open has examined whether the colorectal cancer screening programme based on faecal immunochemical testing, launched in the Basque Country, was associated with lower mortality from this cause over a 21-year period. The study — a retrospective, population-based cohort study — included all residents of the Basque Country (2.2 million people) between 2004 and 2024. The screening programme, aimed at people aged between 50 and 69, was launched in 2009. According to the study, screening was associated with a 50 per cent reduction in mortality from this cause among adults in that age group. Furthermore, a significant change in the trend was observed just three years after the programme began.

OpenAI has stated in a press release that the internal version of its Astra AI model has found solutions to ten research problems in mathematics and computing, in areas such as geometry, group theory, operator algebras, quantum complexity, cryptography and combinatorics, amongst others. According to the company, the total number of tokens — basic units of information — required to solve these problems would cost around $2,000. OpenAI expresses “deep respect and understanding” for those concerned about the impact of AI on these disciplines, including the signatories of the Leiden Declaration on AI and Mathematics; and states that the attribution of results must honestly reflect how each one was obtained, whilst encouraging the mathematical community to review them. The company is publishing these results openly in a paper, accompanied by the model’s account of its reasoning process.

Pupils who set up a social media account in early adolescence appear to perform less well in subsequent standardised tests, according to a study published today in Nature Human Behaviour and based on a sample of 5,227 Italian pupils. The study is observational, so it does not allow for a causal link to be established between social media use and academic performance. Furthermore, it was carried out using questionnaires in which students had to recall and report on their use of these services when they were younger.

There are just a few days to go until 12 August, when we’ll be able to enjoy the first of the three eclipses we’ll see in Spain. This is a total solar eclipse — the Moon will completely cover the Sun’s disc — something not seen on the Iberian Peninsula since 1912. Experts from different regions of Spain with extensive experience in observing eclipses offer their recommendations. Choosing the right viewing spot, using approved eclipse glasses, coping with the heat and respecting the natural environment are key to observing the eclipse safely and enjoying the experience.

Currently, only 48 per cent of newborns are exclusively breastfed, according to the WHO. A narrative review published in the Journal of Maternal-Fetal & Neonatal Medicine analyses three clinical practices during the first 48–72 hours after birth that may negatively affect the initiation and continuation of breastfeeding in healthy newborns: the perception that the volume of colostrum in breast milk is insufficient, restrictions on the use of dummies in maternity wards, and the early introduction of electric breast pumps.