Abstract
The global human population growth is growing rapidly and is expected to surpass 9
billion people by the year 2050. The sub-Saharan African region is one of the fastest
growing regions where the population is expected to reach 2.7 billion people by
2060. Given the rapidly increasing population in the sub-Saharan region, it is
predicted that 50% of the global population growth between 2022 and 2050 will take
place in Africa. At a more local scale, South Africa is ranked the 6th most populated
country in Africa. The growing population is becoming a threat to social, economic,
and environmental sustainability. Furthermore, predictions suggest that the
environment is nearing its carrying capacity and consequently natural forces will
bring down the population growth rates to sustainable levels. Such forces may take
diverse forms, including pandemics, e.g., COVID-19. In return, humans will have to
develop innovations to circumvent nature’s fight back which include building and
boosting their resilience against COVID-19. Then arise interesting research
questions: 1) How is the population growth related to indicators of sustainability?
This is a key question to investigate if we want to understand how to remain within
nature’s carrying capacity and ensure sustainable development. 2) Are green spaces
an effective innovation to build human resilience against COVID-19? Several studies
highlight the tremendous benefits that green spaces provide to humans especially in
improving their health and ensuring their wellbeing. However, such evidence in the
context of COVID-19 is scant. If green spaces boost human resilience against
COVID-19, we expect people in greener neighbourhoods to exhibit lower COVID-19
infection and severity rates. Then, 3) what is the mechanism underlying this
beneficial effect of green spaces on human health in the context of the COVID-19
pandemic? It is only when the mechanism is well understood that informed decisions
can be made by policymakers regarding planning, implementing, and achieving
sustainable development (SDGs 3 and 11). Against this background, the present
study aimed to investigate the sustainability value of green spaces in the context of
the COVID-19 pandemic. The following objectives were set: (i) to test the Malthusian
Theory of population dynamics in the South African context; (ii) to determine the
contribution of Africa to knowledge generation on the link between green spaces and
human health conditions; iii) to test the hypothesis that people living in greener areas
are less likely to suffer from COVID-19 consequences; iv) to meta-analyse the
iii
existing data on the link between green spaces and COVID-19 to generate a global
stand on the topic; and (v) to determine a mechanism driving the link between green
spaces and COVID-19 infection and severity in South Africa. To achieve these
objectives, relevant data were collected in South Africa, Africa and globally covering
several years of data collection, and these data were analysed using different
statistical approaches, e.g. Structural Equation models, generalized linear mixed
effects models, meta-analytical approach, etc.) depending on the objectives. Results
showed that the human population change in South Africa is strongly associated with
the environmental and economic indicators of sustainability, but not the governance
indicators. Furthermore, we found that a human-biodiversity conflict exists which
may undermine sustainability efforts considering the reliance of humans on
biodiversity for sustenance. This conflict is regarded as one of the natural forces
against the rising human population. The analysis reveals that, first, Africa makes
very little contribution to the debate on the topic of the relationships between green
spaces and human health. Second, the analysis shows that green spaces exhibit a
negative correlation with COVID-19 infection but not with COVID-19 severity,
implying that greener neighbourhoods are more resilient to COVID-19 infections.
These results highlighted the need to integrate green spaces in spatial planning to
benefit from the health services they provide. Furthermore, such correlation is also
supported globally as revealed by the meta-analysis done in this study, which,
however, reveals several factors of heterogeneity in the studies interested in the
topic. Finally, to promote the integration of green spaces in spatial planning for the
benefit of public health, we defined mechanisms through which the health benefits of
green spaces are realised. The analysis revealed that the benefits of green spaces
against COVID-19 are strongly associated with the level of human exposure to green
spaces, but not the amount of green space provided. This suggests that intensive
exposure to green spaces is one of the primary drivers of the health benefits of
green spaces.
Collectively, these findings suggest that economic and environmental improvement
promote population growth and that green spaces are an effective innovation to
boost human resilience against the effects of COVID-19 but only if these green
spaces are used for physical or intense activities, suggesting that any initiative to use
green spaces as a tool to enhance human health needs to focus on maximising
intensive exposure, and not just the provisioning of green spaces. These findings are
iv
key to decision-making. First, the observed human-biodiversity conflict points to the
need to limit population growth for the benefit of biological diversity. The significance
of biodiversity conservation is apparent given the crucial role it plays in the
sustenance of humans and the natural environment. Second, the establishment and
maintenance of green spaces are crucial for the benefit of human health, especially
in the face of global pandemics. Green spaces offer a solution to the public health
sector with significant benefits against the COVID-19 pandemic. Last, green spaces
must be designed to encourage physical or intense activity to maximise the health
benefits against COVID-19.