Connecting Global Priorities Biodiversity and Human Health

land. In addition to these detrimental impacts, IAS
pose risks of disease introduction and spread for
native wildlife, agricultural species and humans.
As global trade and travel continues to increase, so
do the health risks; changing climactic conditions
may also enable establishment of IAS where
climate would have previously limited survival,
demonstrated with alarming clarity in the case
of the pine mountain beetle invasion in western
Canada.
4.5 Climate change
The direct and indirect impacts of climate change
also pose risks for biodiversity and health;
for example, shifts in species ranges may also
facilitate changes in pathogen distribution and/
or survival, as projected for Nipah virus (Daszak
et al. 2013). Climate change also contributes to
ocean acidification, coral bleaching and diseases
in marine life, as reef-building coral species are
threatened with extinction. These in turn have
significant implications for the large biological
communities that coral reefs support and that
sustain human health (Campbell et al. 2009). More
extreme weather patterns and rising sea levels
(e.g. drought, flooding, early frost) may also be
detrimental to food and water security, especially
for populations dependent on subsistence farming
and natural water sources. Human populations
may also suffer acute health impacts from extreme
weather (e.g. heat or cold exposure injuries).
4.6 Demographic factors, including
migration
In addition to the direct drivers of biodiversity
loss, large-scale societal and demographic
changes, or intensified reliance on ecosystems
for subsistence or livelihoods, often linked to
biodiversity changes, may also impact vulnerability
to disease. For example, new human inhabitants
(recent immigrants) might not have immunity to
zoonotic diseases endemic to the area, making
them particularly susceptible to infection. Women
who are required to butcher harvested wildlife, or
men who hunt the game, may be particularly at
risk. Moreover, those sectors of society that lack
adequate income to purchase market alternatives
may be more likely to access forest resources
(including wildlife) for food and trade. Thus,
there are likely socioeconomic and gender-specific
relationships to these types of disease risks and
exposures (WHO 2008). Disease may also worsen
the economic status of a population; vector-borne
and parasitic diseases, the burden of which is
driven by ecological conditions, have been shown
to worsen the poverty cycle (Bonds et al. 2012).
4.7 Urbanization as a challenge and
an opportunity to manage ecosystem
services
Urbanization, the demographic transition from
rural to urban, is associated with shifts from an
agriculture-based economy to mass industry,
technology and service.⁹ With the majority of the
world’s population now living in urban areas and
this proportion expected to increase, it is expected
that urban health should become a major focus
at the intersection of global public health and
conservation policy.¹⁰ Urbanization is also closely
linked with the social determinants of health,
including development, poverty and well-being.
While urbanization is often associated with
increasing prosperity and good health, urban
populations also demonstrate some of the world’s
most prominent health disparities, in both lowand
high-income countries. Rapid migration from
rural areas as well as natural population growth are
putting further pressure on limited resources in
cities, and in particular, in low-income countries.¹¹
⁹ For the first time in history, the majority of the world’s population lives in cities, and this proportion continues to grow.
One hundred years ago, 20% of the people lived in urban areas. By 2010, this proportion increased to more than half. By
2030, it is expected that the number of people in urban areas will increase to 60%, and in 2050, to 70%. For example, see
World Health Organization Global Health Observatory (GHO) data: urban population growth. (www.who.int/gho/urban_
health/situation_trends/urban_population_growth_text/en/, accessed 30 May 2015).
¹⁰ To exemplify this trend and consequent shifts in health, WHO has been coordinating initiatives such as the “World Health
Day” and “Urban Health”.
¹¹ World Health Organization. Urban health. (http://www.who.int/topics/urban_health/en/, accessed 30 May 2015).
40 Connecting Global Priorities: Biodiversity and Human Health