Review and Critical Analysis of International UHI Studies

8 CONCLUSION
The research conducted has reviewed a total of two‐hundred and thirty‐eight papers across the
entire urban heat island value chain with the greatest interest (descending order) from the
following continents: North America, Asia, Europe, Australia, and Africa. The predominant focus
was in warm, arid and equatorial climate types with a majority of the seminal studies relating to
UHI emanating from the Lawrence Berkley National Laboratory, UHI Group.
The UHI phenomenon itself was well documented and universally interpreted by all research
groups and found to be a consequence of rapid urbanization and industrialization. It is apparent
that the focus of climate on the global scale has shifted from the global to local scale with most of
the research groups and studies addressing the urban climate. The research conducted to identify
the UHI causal factors and measuring the impact of UHI clearly demonstrates that the impacts
have greater implications than simply temperature increases. It is clear that the UHI problem is
not going to subside with time, if anything it is likely to increase in intensity as the population in
urban areas increases in the years to come.
It was clear in the literature reviewed and the analysis conducted that the evidence assessed
regarding the potential for energy savings and mitigation efforts from countermeasures to UHI
presents mixed findings. There are clearly cost effective energy and CO2 savings to be delivered
in many circumstances, however, still much uncertainty about the overall magnitude of those
savings and about how feasible it is to access them through public policy initiatives. The
recommendations made in this report reflect this pattern and were divided into research based
and policy/programmatic recommendations.
Despite existing uncertainties about the overall magnitude of savings that can be accessed
through public policy driven UHI countermeasures the latter are still justified in many cases
because the uncertainties are not so great as to require the delay in measures within urban areas
that clearly stand to derive significant benefits from commencing ameliorative actions. The
apparent potential scale of mitigation impacts from countermeasures targeting negative radiative
forcing are so large that they justify a significant policy and research effort to clarify the
phenomena and respond with policy efforts if the mitigation scales are validated.
Furthermore, it is important that local, national and international efforts consider the two key
UHI mitigation opportunities of reduced energy use and negative radiative forcing within a
common framework while appreciating the issues which are distinct to each. In particular, it is
significant that that the negative radiative forcing effect has no direct monetary value aside from
the value of equivalent‐carbon mitigated yet is apparently of much greater mitigation magnitude
than the direct/indirect energy‐related savings effect. This means policy dialogues would need to
consider whether or not to create dedicated policy vehicles to attribute value to the negative
radiative forcing effect so that municipalities have an incentive to apply UHI countermeasures
that are independent of the local energy savings they produce. It is therefore clear that policy
makers need a set of tools to enable them to act authoritatively, appropriately and in a
coordinated manner in response to the UHI issue; and of equal importance is that urban
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