ecology

A study published in Science shows a global increase in the toxicity and ecological harm caused by pesticides, contrary to the United Nations’ goal of halving pesticide-related risks by 2030. The authors analysed Total Applied Toxicity (TAT), which accounts for both pesticide use and toxicity, at a global scale between 2013 and 2019. The data covered the risks of 625 pesticides across eight species groups and 65 countries, representing 79.4% of global cropland. TAT increased in six of the eight species groups, including all invertebrate groups and terrestrial plants, and only Chile would meet the target of reducing pesticide risk by 50% by 2030.

The body composition index – used to estimate body fat reserves – of polar bears in Svalbard declined between 1995 and 2000, but then increased until 2019, despite the fact that the number of ice-free days in this Norwegian Arctic archipelago increased by about four days per year during that period. "Increases in some prey species, including harbour seals, reindeer, and walrus, may partly offset reduced access to seals," the authors write in Scientific Reports.

Lakes are considered sentinels of climate change, although most research has focused on temperate regions. An international team analysed 10 tropical lakes in the central Amazon during the 2023 drought, which caused high mortality among fish and river dolphins. Using satellite data and hydrodynamic models, the authors show how intense drought and a heatwave combined to raise water temperatures: five of the 10 lakes experienced very high daytime temperatures, exceeding 37°C. Specifically, temperatures in the shallow waters of Lake Tefé soared to 41°C—hotter than a thermal bath. The study is published in Science.

English ethologist Jane Goodall died on Wednesday at the age of 91 in California (United States), where she was participating in a lecture tour. This was announced by the Jane Goodall Institute on its social media. ‘Dr Goodall's discoveries as an ethologist revolutionised science and she was a tireless advocate for the protection and restoration of our natural world,’ the statement said. Her observations and analysis of chimpanzees in the wild over decades were a milestone in primatology.

The cyanobacterium Prochlorococcus, the smallest and most abundant photosynthetic organism on Earth, is an important producer of oxygen and is crucial to marine ecosystems. A team from the United States has collected data from ships sailing the Pacific Ocean over a ten-year period and concluded that these cyanobacteria could experience population declines of between 17% and 51% in tropical oceans by the year 2100, depending on the warming scenario. The results, which are the product of modeling work, are published in the journal Nature Microbiology and indicate that this microorganism is more vulnerable to climate change than previously thought.

A team from Stanford University (USA) has analysed the conservation status of 1,376 species of scavenger animals. The results, published in the journal PNAS, indicate that 36% of them are threatened or in decline, especially large species and obligate scavengers, which depend exclusively on carrion for food. In contrast, the number of small and facultative scavengers, such as rodents, for which carrion is not their only source of food, is increasing. According to the authors, this ‘could increase the risks of diseases that large scavengers have helped to mitigate’.

The changes caused by the climate crisis—such as its impact on rainfall and rising temperatures—are stressful for plants in both wild and agricultural environments. A special issue of the journal Science brings together five articles reviewing this issue, including the adaptations that plants can adopt and that could be applied to combat it.

Children will suffer more from the climate crisis than their grandparents. Fifty-two per cent of people born in 2020 will experience unprecedented heat waves throughout their lives, compared to 16 per cent of those born in 1960. This was calculated by a study published in Nature last month, assuming that temperatures rise 1.5 °C above pre-industrial levels. In this article, we analyse the profile of children who already suffer from heat in our country and explain how to adapt their environments to extreme temperatures. 

An international research project involving Spanish participation has analysed the distribution of brown bears in Europe and Turkey. To do this, the team studied more than three million locations belonging to some 3,000 bears, with data from 14 European and Turkish subpopulations in very different environments. The main conclusion is that bears occupy areas where the species that form part of their diet are distributed. The study, published in Global Change Biology, shows that the influence of climate change on these species also has an impact on the distribution of bears.

An international report by the Global Commission on the Economics of Water says the water crisis puts more than half of the world's food production at risk by 2050. It also claims that it threatens an average loss of 8% of GDP in countries around the world by 2050, with losses of up to 15% in the lowest income countries.