Malaria is a long-standing public health problem in sub-Saharan Africa, whereas arthropod-borne viruses (arboviruses) such as dengue and chikungunya cause an under-recognised burden of disease. Many human and environmental drivers affect the dynamics of vector-borne diseases. In this Personal View, we argue that the direct effects of warming temperatures are likely to promote greater environmental suitability for dengue and other arbovirus transmission by Aedes aegypti and reduce suitability for malaria transmission by Anopheles gambiae. Environmentally driven changes in disease dynamics will be complex and multifaceted, but given that current public efforts are targeted to malaria control, we highlight Ae aegypti and dengue, chikungunya, and other arboviruses as potential emerging public health threats in sub-Saharan Africa.
ABSTRACT: Climate change will impact every aspect of biophysical systems and society. However, unlike other components of the climate system, the impact of climate change on the groundwater system has only recently received attention. This focus is due to the realization that groundwater is a vital freshwater resource crucial to global food and water security, and is essential in sustaining ecosystems and human adaptation to climate variability and change. This paper synthesizes findings on the direct and indirect impacts of climate change on the entire groundwater system and each component. Also, we appraise the use of coupled groundwater-climate and land surface models in groundwater hydrology as a means of improving existing knowledge of climate change-groundwater interaction, finding that most models anticipate decreases in groundwater recharge, storage and levels, particularly in the arid/semi-arid tropics. Reducing uncertainties in future climate projections and improving our understanding of the physical processes underlying models to improve their simulation of real-world conditions remain a priority for climate and earth scientists. Despite the enormous progress made, there are still few and inadequate local and regional aquifer studies, especially in less developed regions. The paper proposes two key considerations. First, physical basis: the need for a deeper grasp of complex physical processes and feedback mechanism with the use of more sophisticated models. Second, the need to understand the socioeconomic dimensions of climate-groundwater interaction through multidisciplinary synergy, leading to the development of better adaptation strategies and groundwater-climate change adaptation modelling.
Malaria interventions for seasonal outbreaks differ from managing year-round risk, so understanding where these patterns will change is important for both anticipating new regions at risk, and where to change health infrastructure and capacity. In Western Africa, there is a massive drop in the number of people at risk of year-round malaria transmission, but this is a function of increasing temperatures, putting much of the region at hotter temperatures than the mosquitoes best transmit. The region expecting the greatest risk increase by 2080, in terms of people, is the densely populated Eastern Africa, where seasonal risk will increase and push into novel areas, according to predictions.
This regional approach to thinking about where malaria transmission will change is important to global health policy. “It’s hard to communicate the intersection of demography and geographic risk, so aligning our scales with those at which decisions are often made is useful” Dr Ryan points out. Mapping disease risk is not enough, she continued, because we make decisions based on how many people, and when, not just where.
Malaria continues to be a disease of massive burden in Africa, and the public health resources targeted at surveillance, prevention, control, and intervention comprise large outlays of expense. Malaria transmission is largely constrained by the suitability of the climate for Anopheles mosquitoes and Plasmodium parasite development. Thus, as climate changes, shifts in geographic locations suitable for transmission, and differing lengths of seasons of suitability will occur, which will require changes in the types and amounts of resources.
The shifting geographic risk of malaria transmission was mapped, in context of changing seasonality (i.e. endemic to epidemic, and vice versa), and the number of people affected. A published temperature-dependent model of malaria transmission suitability was applied to continental gridded climate data for multiple future AR5 climate model projections. The resulting outcomes were aligned with programmatic needs to provide summaries at national and regional scales for the African continent. Model outcomes were combined with population projections to estimate the population at risk at three points in the future, 2030, 2050, and 2080, under two scenarios of greenhouse gas emissions (RCP4.5 and RCP8.5).
Estimated geographic shifts in endemic and seasonal suitability for malaria transmission were observed across all future scenarios of climate change. The worst-case regional scenario (RCP8.5) of climate change predicted an additional 75.9 million people at risk from endemic (10-12 months) exposure to malaria transmission in Eastern and Southern Africa by the year 2080, with the greatest population at risk in Eastern Africa. Despite a predominance of reduction in season length, a net gain of 51.3 million additional people is predicted be put at some level of risk in Western Africa by midcentury.
This study provides an updated view of potential malaria geographic shifts in Africa under climate change for the more recent climate model projections (AR5), and a tool for aligning findings with programmatic needs at key scales for decision-makers. In describing shifting seasonality, it was possible to capture transitions between endemic and epidemic risk areas, to facilitate the planning for interventions aimed at year-round risk versus anticipatory surveillance and rapid response to potential outbreak locations.
Professor & Department Chair, Department of Geography, The Ohio State University
Friday, 21 February 2020
3:00 – 4:30 PM
Reitz Union G330
University of Florida
There is greater recognition among IPCC and other scientific networks of the complex role land systems play in adaptation to and mitigation of climate change. Encouraging key shifts in land systems to more sustainable uses is necessary to food security, societal well-being, and the health of terrestrial ecosystems. However, policy interventions that do not address how and why current challenges reflect the profitability of environmental degradation, and that fail to prioritize social justice are unlikely to address root causes of unsustainable land systems.
Ohio State University, Department of Geography Professor & Department Chair, Dr. Darla Munroe will present her research in the second of two talks for the University of Florida 2020 Anderson Research Lecture series, in a talk titled Land Systems and Climate Justice.
Dr. Darla Munroe is an economic, and human-environment geographer specializing in landscape-level, long-run environment-economy relationships, with a particular focus on how political and economic restructuring manifest in local land-use change. She is a member of the Scientific Steering Committee for the Global Land Programme and Co-Editor-in-Chief of the Journal of Land Use Science. Her research is comparative, addressing land systems, particularly forests at the urban-rural interface in Eastern Europe, Central America, and Southeast Asia. Her current research focuses on boom-bust natural resource economies and forested community change in Appalachian Ohio.
ABSTRACT: Rainfall drives fishery fertility in Mweru-Luapula, thus rainfall variability contributes to frequent changes in fishing catches. Fishers and traders have adapted their institutions to this variable ecology in a variety of ways, including learning to read the fishery for productive periods and practicing multiple modes of income procurement. By accurately identifying inter-annual, inter-decadal, and longer spans of rainfall trends, future high and low yields can be forecast. This article presents and analyzes annual rainfall in the fishery from 1916-1992 and quantitative fish market data comprised of observed fish catch numbers by species in three markets from September 2004 to September 2005. It uses political ecology to better understand fish production, trade, and subsistence in this South-Central African freshwater fishery. We combine qualitative analysis of fisher and marketer perceptions of the fishery and knowledge of rainfall patterns to show how human behavior is not “tragically” driven, but instead based on the state of the ecological, sociocultural, and socioeconomic environment at a given time.