178
S. da Silva Neiva et al.
Table 2 (continued)
Main factors
Justification
Authors
Greenhouse gas emission Greenhouse gas emission are
50% higher than they were in
1990. This high number is a
reflex of the still high
deforestation rates, which
releases more carbon to the
atmosphere, and it is important
to look for ways to reduce this
emission, which is crucial for
world community
Emerging and Sustainable
Cities (2018), UN (2015),
Thornbush et al. (2013)
Energy
Energy efficiency is getting the
most from each unit of energy
purchased. It is mainly a
technical process, in which
newer, more efficient
technologies replace old
equipment. In general, energy
efficiency is a byproduct of
other social goals: productivity,
comfort, monetary economics,
or energy competition
Ribeiro et al. (2018), Martos
et al. (2016)
Water resources
Potable water is still a finite,
scarce resource and the
consequences of lack of water
are visible in many countries,
especially in Africa. Many
NGOs take the role of
promoting basic sanitation and
take potable water to the most
affected locations, but this
action can only help, not solve
the problem
Ribeiro et al. (2018), Welie and
Romijn (2018)
Fig. 1 Main factors in
sustainable cities