By Borokini Joshua
The complex nature of climate change and its environmental and social manifestations result in diverse risks to human health. Our current, rather skewed knowledge of climate–health relationships has come from epidemiologic studies of health risks in relation to differences in temperature and from quasi-cyclical climatic events. However, most of the health risks arise from climatic influences on environmental systems and social conditions that affect food yields, water supplies, the stability of infectious disease patterns, and the integrity of natural and human-built protection against natural disasters (including forest cover, windbreaks, mangroves, vulnerable constructed seawalls, and urban water-drainage systems) and from the adverse health consequences of social disruption, displacement of communities, and conflict situations.
Global climate change is part of the larger Anthropocene syndrome of human-induced global environmental changes. These include land degradation, ocean acidification and disruptions, depletions of the stratospheric ozone concentration, soil fertility, fresh-water resources, biodiversity stocks and ecosystem functioning, and global nitrogen and phosphorus cycles. Greenhouse emissions from fossil fuel–based power generation and transport and from the agriculture and mining sectors also increase the heat-retaining capacity of the lower atmosphere, resulting in global warming. In addition, deforestation and ocean saturation have added to greenhouse warming by reducing the capacity of terrestrial and marine environments to absorb extra carbon dioxide (the main greenhouse gas) from the atmosphere. Also contributing to such warming are any ongoing natural variations in climate caused by cosmologic and geologic influences.
Populations living in diverse social, economic, and physical conditions will be affected differently by climate changes. Low income and remote populations are more vulnerable to physical hazards, undernutrition, diarrhea and other infectious diseases, and the health consequences of displacement. Populations on low-lying islands and in coastal areas, such as Nigeria, are vulnerable to increased storm surges and flooding as the sea level rises. This is visible, as recent flood incidents in Benue, Lagos and Ogun states go to prove this beyond doubts.
The likely future effects of climate change on various health outcomes have been modelled with the use of plausible scenarios of future climate change that have been agreed on internationally. The COP23 Paris Agreement in 2015 was one that was staged to change the world via global climate. For example, in temperate countries, as summers become hotter and heat waves more severe, modelling indicates that, from around mid-century, additional heat-related deaths will progressively overwhelm the number of deaths averted as a result of milder winters. Such estimates of the extreme effects of weather will improve as the modelling of changes in climatic variability under climate-change conditions improves and as researchers take better account of physiological, behavioural, and technological adaptation by populations over time. Meanwhile, an important research task is to identify ongoing changes in health risks and outcomes that can be reasonably attributed to recent climate change. Given the multivariate causation of most human health outcomes, attribution is rarely simple. Nevertheless, over the past decade, observed changes in some health outcomes, viewed collectively, suggest a climate signal.
Nigeria has a wide range of variety in energy production. The sunshine in the northern region is one that can kick out the use of fossil fuels if put into use. Hydro-power is an indispensible tool that can also aid in bringing a halt to this “wolf in sheep clothing” (crude oil). The Kanji Dam at Jebba has proved beyond doubt that Nigeria has what it takes to foster on renewable energy and discard fossil fuels. Sadly, health challenges have also been on the increase in some parts of Nigeria due to oil pollution and gas flaring. For example, Ogoni has been regarded as a write-off as oil spilling has rendered farmlands, water, aquatic habitat, infrastructures and other viable resources useless. This fossil fuel has shown to be a nail-in-the-tooth and unreliable, which is an indicator for the urgent need to embrace renewable energy.
One favourable aspect of efforts to mitigate climate change is that local health gains will quickly accrue to populations that undertake such efforts. Awareness of this potential health dividend in addition to the longer-term global health benefits should strengthen support for such actions. Health benefits will result from mitigating actions that address modes of transport, housing-design standards, energy generation, and agricultural systems (including livestock production). In many poor populations as Nigeria, improvements in environment-related technologies will help to replace indoor-polluting cooking fuels with low-carbon fuels, and improvements in reproductive literacy will lead to fewer, better-spaced pregnancies; both types of improvement reduce pressures on the climate system. All these actions will directly reduce well-known risk factors for disease and premature death (e.g., air pollution, sedentary living, and dietary excesses). Innovative urban design can have wide-ranging positive effects with regard to energy use, greenhouse-gas emissions, the effects of urban heat islands, patterns of physical activity, social relations, and community cohesion.
Joshua, an environmental activist, writes in from Lagos