Examining Recent Climate Changes in Ghana and a Comparison with Local Malaria Case Rates

Abstract

This study investigated recent climate changes in Ghana and compared these changes to a new malaria case rates dataset for 2008–2022. The analysis was implemented at three spatial scales: national, regional, and by ‘climate zone’ (i.e., coastal, savannah, and forest zones). Descriptive statistics, qualitative discussion and correlation analysis were used to compare the climate variability to the malaria case rates. The climate analysis identified a general warming over the period with a mid-2010s maximum temperature peak in the forest and savannah zones, also associated with changes in the annual temperature cycle. Malaria case rates increased between 2008 and 2013, decreased sharply in 2014, and then decreased steadily from 2015 to 2022 for all scales. The sharp decline was broadly coincident with a change in the temperature regime that would provide a less favourable environment for the malaria vectors (precipitation and humidity showed no comparable changes). These coincident changes were particularly noticeable for an increase in maximum temperatures in the savannah and coastal zones in the key malaria transmission months after 2014. Correlation analysis showed statistically significant (p < 0.05) relationships between malaria case rates and mean and maximum temperatures at the national scale, and malaria case rates and mean, maximum, and minimum temperatures for the coastal climate zone (precipitation and humidity showed no significant correlations). However, more sophisticated methods are required to further understand this multidimensional system.