Background

Climate change may expand dengue transmission in space and season across Central America. In Costa Rica, complex topography and very small districts mean coarse global climate models can miss local conditions that drive outbreaks, creating a need for district-level, high-resolution climate–dengue assessments. This study aims to: (1) model the climate–dengue relationship at the district level using high-resolution data; (2) identify the best climate predictors for dengue incidence; and (3) provide mid-century (2035–2065) dengue cases projections under a pessimistic scenario (SSP5-8.5) with seasonal windows actionable by region.

Methods

Precipitation and temperature indices derived from the Climate Hazards group Infrared Precipitation with Stations (CHIRPs) and Climate Hazards Center Infrared Temperature with Stations (CHIRTs) were related to dengue diagnoses from Costa Rica’s public health centers using a linear model. An objective algorithm selected parsimonious climate–dengue predictors, with cross-validation to prevent overfitting. The resulting quasi-optimal models combined with downscaled projections from an ensemble of eight General Circulation Models (GCMs) to estimate future dengue incidence changes at the district level, Costa Rica’s smallest administrative division.

Results

Temperature and precipitation data are significantly related to dengue counts. Temperature dominates most district models during the dry season (December to June), while precipitation dominates during the rainy season (July–October). Mid-century projections indicate increases of up to 42 additional cases in some districts compared to the historical baseline, with the location of the most pronounced changes varying by month.

Conclusions

The projected dengue increases presented here are driven solely by climate change under the most pessimistic greenhouse gas (GHG) concentration scenario, and thus represent a potential upper bound on future risk. These findings offer actionable guidance on where and when dengue incidence may rise, and should inform adaptive health policies aimed at reducing the impacts of climate change in high-risk areas.

Ultrahot exoplanet, atmospheric differences: Researchers discovered clear differences in the atmosphere between the morning and evening sides of the ultrahot gas planet WASP-121 b using the James Webb Space Telescope (JWST).

Temperature and chemical variations: The evening side absorbs more infrared light due to higher temperatures caused by strong winds moving heat eastward, while water molecules decrease in the evening terminator due to high temperatures breaking them apart.

Planetary rotation and observation method: WASP-121 b’s synchronous rotation reveals different atmospheric regions during transit, allowing scientists to analyse changes in light absorption over time and longitude.

Over-reliance on chemical fertilizers to feed a growing population has often led to soil degradation and a decline in microbial diversity. Scientists are seeking sustainable alternatives that can maintain crop yields while revitalizing the soil. A new field study from the Chinese Academy of Agricultural Sciences offers a promising solution by demonstrating how biogas slurry—a nutrient-rich liquid byproduct of anaerobic digestion—can significantly enhance soil health and its ability to sequester carbon.

The investigation was conducted over three years at a dryland agriculture research station in China. Researchers compared the effects of applying biogas slurry topdressing (BST) against conventional chemical fertilizer topdressing (CFT) on maize crops. By collecting soil samples at three different depths and three distinct crop growth stages, the team performed a comprehensive analysis of soil chemistry and used 16S rRNA gene sequencing to map the changes in the bacterial communities over time and space.