These are some of the most urgent issues for the planet in 2024, according to scientists

According to the 15th annual analysis by the Cambridge Conservation Initiative, major issues for the planet to watch out for in 2024 include everything from melting ice sheets and the production of hydrogen from seawater to the disappearance of sea urchins and earthworms. Image: Johan Ordonez / AFP

According to the 15th annual analysis by the Cambridge Conservation Initiative, the most pressing issues across the planet to watch out for in 2024 range from melting ice sheets and the production of hydrogen from seawater to the disappearance of sea urchins and earthworms.

Every year since 2009, an international team of researchers known as the Cambridge Conservation Initiative (CCI) has come together to determine what will have the greatest impact on the planet over the coming year, whether in terms of global warming, greenhouse gas emissions or biodiversity preservation. This year, 31 scientists, practitioners and decision-makers drew up an initial list of 96 environmental issues, which they then narrowed down to 15 to highlight the most pressing and impactful.

Melting ice sheets top the list of threats to ecosystems, says the report, published in the journal Trends in Evolution & Ecology. "Recent studies suggest that reductions in water density caused by increased melting in the Antarctic and reduction in the concentration of salts may reduce abyssal overturning by 40% by 2050. These changes reduce the ability of the ocean to absorb carbon dioxide," the scientists of CCI outline.

The report's authors are also concerned about the massive decline of certain species, in particular sea urchin die-offs in the Caribbean and Mediterranean observed in 2022, which have "have highlighted potential ecosystem shifts in some of the most diverse seas across the world." In the Caribbean long-spined sea urchin (Diadema antillarum), mortality reached up to 99%, a rate similar to the mass extinction of this species in 1983 and 1984, which led to the coral reefs being overwhelmed by algal blooms, notes the study.

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The worrying disappearance of earthworms

The scientists are also issuing a warning about the disappearance of the earthworm, whose abundance has declined by an estimated 33% to 41% over the last 25 years in the UK as well as in many other parts of the world. Still poorly documented, this loss of biodiversity could nonetheless have serious repercussions for the planet. As ICC researchers remind us, "[e]arthworms (phylum Annelida) are ecosystem engineers that play important roles in nutrient cycling, soil fertility, and ecosystem condition, and contribute significantly to global food production."

But some of the pressing issues to watch out for in 2024 are also linked to technological innovations that are gaining momentum, according to the Cambridge Conservation Initiative. "In some cases, new issues arise directly from efforts to mitigate other issues," write the team of researchers, led by Cambridge University researcher William Sutherland. In particular, the report mentions new methods of producing energy sources using hydrogen extracted from seawater. While the report's authors point to the advantages of this technology in that it could reduce pressure on limited freshwater reserves, they also highlight the drawbacks associated with the production of "hypersaline brines and excess oxygen that are probably harmful to marine habitats in particular."

"We anticipate continuing to highlight novel emerging impacts of climate change and technologies aiming to mitigate climate change and transition to more sustainable pathways in future horizon scans," the researchers conclude.