6 Heat Vulnerability Index Development and Application in Medan City, Indonesia
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mentioned in the newest version of regional spatial planning called as RTRW 2011–
2031 (Medan Spatial Planning Agency 2011) and in the regional detailed spatial
planning called as RDTR 2015–2035 (Medan Spatial Planning Agency 2015a, b)
that the green rooftop is one of open green space component in the city. However,
the municipal target, technical guideline, and seedling assistance were not clearly
mentioned in those aforementioned documents. In addition, this initiative will be
applicable only for building with concrete roof type where only 5% for residential
roof and commercial building.
Re-establishing green spaces in the city, as it was shown in this study to be drastically reduced thought the time, would be another measure reducing the land surface
temperature in the central part of the city. As a reference, the increase of the green
coverage in New York City and Phoenix City showed significant improvement in the
city micro-climate (Phelan et al. 2015). In the mid-term regional planning document
of Medan City (RPJMD), increasing open green space was one of the strategies to
achieve a clean and healthy urban environment. Based on national regulation Law
No. 26 of 2007 on spatial management stated that the proportion of the open green
space in the urban region must be at least 30% of the total urban area where 20% is
public space and 10% is private space. However, the actual area of open green space
in Medan City was less than 10% (RDTR 2015–2035). This number is far from the
minimum requirement of national regulation. This condition also partly due to the
regional cluster in the RTRW document which stated that the downtown area was
focused on trade and services region while the southern region was focused on green
open land. Even though open green space is part of the adaptation to reduce heat
stress, but there is not yet a policy or legally binding instruments specifically designated for the implementation of urban climate adaptation measures, including Jakarta
as the capital city and benchmark development of Indonesia. As shown in Figs. 6.2
and 6.5, the number of extreme temperatures and the frequency of very strong heat
stress were gradually increased, particularly during strong El-Nino phenomenon.
This condition will be worse in the future when there is no policy regarding urban
climate adaptation. Urban climate including urban heat island is not yet included
in the national adaptation action plan (RAN-API) document. It is simply because
the scale of RAN-API is very broad and assesses climate change in general. For
regional planning document such as RTRW, RDTR, RPJMD, and REISTRA (midterm strategic master plan), there is no concrete urban climate adaptation intervention
yet.
The heat warning systems using UTCI considering especially for vulnerable
groups and the key actors (i.e., health agency, meteorological agency, spatial planning agency, disaster management authority, and scientist) employing the HVI to
design measures against extreme heat are recommendable for the city as part of
disaster preparedness plan. The UTCI also can be used as a quantitative indicator
to monitor the effectiveness of urban greening to reduce urban heat stress levels.
In addition, setting the warning threshold should be conducted in future research
in order to estimate when to issue a warning. There are four key elements of early
warning system: risk knowledge, technical monitoring and warning service, communication and dissemination of warning, and response capability (UNISDR 2006). The
103
mentioned in the newest version of regional spatial planning called as RTRW 2011–
2031 (Medan Spatial Planning Agency 2011) and in the regional detailed spatial
planning called as RDTR 2015–2035 (Medan Spatial Planning Agency 2015a, b)
that the green rooftop is one of open green space component in the city. However,
the municipal target, technical guideline, and seedling assistance were not clearly
mentioned in those aforementioned documents. In addition, this initiative will be
applicable only for building with concrete roof type where only 5% for residential
roof and commercial building.
Re-establishing green spaces in the city, as it was shown in this study to be drastically reduced thought the time, would be another measure reducing the land surface
temperature in the central part of the city. As a reference, the increase of the green
coverage in New York City and Phoenix City showed significant improvement in the
city micro-climate (Phelan et al. 2015). In the mid-term regional planning document
of Medan City (RPJMD), increasing open green space was one of the strategies to
achieve a clean and healthy urban environment. Based on national regulation Law
No. 26 of 2007 on spatial management stated that the proportion of the open green
space in the urban region must be at least 30% of the total urban area where 20% is
public space and 10% is private space. However, the actual area of open green space
in Medan City was less than 10% (RDTR 2015–2035). This number is far from the
minimum requirement of national regulation. This condition also partly due to the
regional cluster in the RTRW document which stated that the downtown area was
focused on trade and services region while the southern region was focused on green
open land. Even though open green space is part of the adaptation to reduce heat
stress, but there is not yet a policy or legally binding instruments specifically designated for the implementation of urban climate adaptation measures, including Jakarta
as the capital city and benchmark development of Indonesia. As shown in Figs. 6.2
and 6.5, the number of extreme temperatures and the frequency of very strong heat
stress were gradually increased, particularly during strong El-Nino phenomenon.
This condition will be worse in the future when there is no policy regarding urban
climate adaptation. Urban climate including urban heat island is not yet included
in the national adaptation action plan (RAN-API) document. It is simply because
the scale of RAN-API is very broad and assesses climate change in general. For
regional planning document such as RTRW, RDTR, RPJMD, and REISTRA (midterm strategic master plan), there is no concrete urban climate adaptation intervention
yet.
The heat warning systems using UTCI considering especially for vulnerable
groups and the key actors (i.e., health agency, meteorological agency, spatial planning agency, disaster management authority, and scientist) employing the HVI to
design measures against extreme heat are recommendable for the city as part of
disaster preparedness plan. The UTCI also can be used as a quantitative indicator
to monitor the effectiveness of urban greening to reduce urban heat stress levels.
In addition, setting the warning threshold should be conducted in future research
in order to estimate when to issue a warning. There are four key elements of early
warning system: risk knowledge, technical monitoring and warning service, communication and dissemination of warning, and response capability (UNISDR 2006). The