Vulnerability to the Health Impacts of Climate Change in Kenya

The health impacts of climate change are not homogenous across low- and middle-income countries (LMICs) and as a result vulnerable communities need to be identified for resource allocation to support climate change adaptation initiatives. The Intergovernmental Panel on Climate Change (IPCC) has addressed this need by developing a framework of risk for the impacts of climate change. Additionally, in 2014, the World Health Organization (WHO) developed guidelines for the Health National Adaptation Plans (HNAPs) for adaptation to climate change in LMICs. Kenya is experiencing the effects of climate change nationwide, but the biggest threats are rising temperature, sea level rise, increased rainfall and floods in some areas, and droughts in others (Bauer and Mburu 2017, 74-79, Harison, Boitt, and Imwati 2017, Public Health & Environment Department World Health Organization 2010, Talisuna et al. 2020). Floods are projected to increase in frequency and intensity, posing a substantial risk to human life in Kenya (World Bank Group 2020, Romanello et al. 2021). In fact, every year since 2000, Kenya has experienced prolonged droughts and intense flooding (Thornton 2010). Additionally, riverine flooding in Kenya is projected to impact an additional 75,100 people by 2030, compared to impacting 29,600 people in 2010, with a high level of risk in Western Kenya (World Health Organization 2016, World Bank Group 2020). The Kenyan government considers waterborne diseases to be among the greatest health threats in the country in the near to long term future (World Bank Group 2020). It has been well documented that flooding and higher than average rainfall was associated with increases in the incidence of diarrheal diseases (Levy et al. 2016). Flooding and extreme rainfall can increase the already high burden of diarrheal disease in Kenya. Health National Adaptation Plans were promoted by the World Health Organization (WHO) to increase the capacity of LMICs to adapt to impacts of climate change on the health sector. Climate and its health impacts vary locally, yet frameworks for evaluating the adaptive capacity of health systems on the subnational scale are lacking. This is problematic, as the health impacts of climate change and climate change hazards vary considerably within many countries. In Kenya, counties prepare County Integrated Development Plans (CIDPs), which contain information that might support evaluations of the extent to which counties are planning climate change adaptation for health. This research aimed to develop and apply a framework for evaluating plans for public health adaptation to climate change at the county level in Kenya. While nearly all Kenyan CIDPs note climate change in the context of development, only about half mention health related to climate change. This suggests that some counties are planning for the health impacts of climate change while others do not appear to be making such plans. Currently, no risk index following the IPCC AR5 framework has been developed to address the association between weather and diarrheal disease. This is concerning, as diarrheal disease in children – which has been linked to recent rainfall – has substantial health and economic consequences. Prior indices have not included the system that is exposed, in this case the population that is exposed, and therefore do not take a systems-based approach to estimating risk. Additionally, health data is hard to obtain in low resource settings, but demographic and social data are more readily available. The IPCC did not provide guidance about how the AR5 risk index should be operationalized. For example, the types of data to be used and the ways that the index should be calculated were not spelled out, though researchers have developed their own approaches to this task, mainly driven by data availability. The aim of this research is to develop a risk index following the IPCC AR5 framework for the impact of climate change on diarrheal disease in Western Kenya for relatively small administrative units (sub- counties). Based on the literature and the IPCC framework, social and environmental factors that potentially relate climate change to diarrheal diseases were identified and principal component analysis was applied. The risk index of sub-county vulnerability varies on a subnational scale and does not follow a spatial gradient. The estimated local risks of diarrheal disease in the sub-counties should be useful to policymakers and health officials in Kenya. Moreover, our approach to implementing a risk index can be applied by climate and health researchers globally. Risk indices are useful tools to identify spatial regions highly vulnerable to the impacts of climate change to guide resource allocation and prioritization. Although a variety of vulnerability indices and a small number of risk indices have been created for climate change in LMICs, very few have been validated with epidemiological data. Assessing the predictive capabilities of vulnerability indices on the association between extreme rainfall and health impacts is relatively novel. The final aim of this research is to evaluate the predicted risk levels of weather-associated diarrheal disease to observed rates of weather-associated diarrheal disease in children. The risk index developed using the IPCC risk AR5 framework predicts diarrheal disease in children under 5, as do season and weather variables, though the correspondence between observed and modeled risk is limited. Surprisingly, high temperatures were directly associated with risk while precipitation was inversely associated with risk. These findings demonstrate the potential of the application of the IPCC risk framework to predict the future burden of climate-sensitive disease. Such information should be useful for policymakers and health officials in Kenya to prioritize efforts to prepare communities for health impacts of climate change.