How do you keep a city humming?
As we discuss the options for climate-smart reconstruction, this is a question that must be asked, over and over again. There are a number of things that immediately spring to mind: urban planning and systems that are in step with intensifying extreme weather events; tougher building codes,food security; water quality; a reliable energy mix; and air, land and sea access. Beyond that, all-weather telecommunications and key medical facilities are all a must. Essentially, we must figure out how to reduce downtime.
Let’s face it. Climate change is here. It is going to be highly variable from year to year. It is likely to be non-linear.
Back in May 2009, a WWF study about the effects of climate change on the Coral Triangle in Asia-Pacific posed six likely scenarios. The first was that the El Niño phenomenon will persist as a source of interannual vagaries. The second was that we should expect the rise in sea surface temperatures to continue.
This heating spawns the third and fourth scenarios — intense cyclones and storm surge, heavy rainfall and flooding. Heat also accelerates ice melt and thermal expansion. Both phenomena feed into the fifth scenario: sea level rise. NASA satellite altimetry data shows that sea levels rise occurs in mountains and valleys. Along the coastlines, there is no such thing as a “mean sea level.”
In 2010, the highest recorded peaks in sea level took place here in the Philippines. For the first time ever, each breath of air that we inhale contains 400 parts per million of carbon dioxide. This is increasing daily.
The sixth likely scenario is ocean acidification. As carbon dioxide levels continue to rise, episodes of ocean acidification are likely to spike more frequently. This will impact negatively on all forms of marine creatures whose life cycles involve calcium carbonate — fish, crustaceans, shellfish, and coral reefs.
Do we have 50 years? No. Since 2009, trends clearly show that all of these scenarios are on stream. How then should we retro-fit our cities and towns to make them climate smart?
Preparation should take place at four different scales: catchment, city, site and building. Our collective experience tells us that climate impacts do not recognize political boundaries. The appropriate scales for planning and management should, therefore, include catchment or river basin wide interventions. Cities and towns must work together.
Many of these things are already been done. These steps must, however, be standardized.
Catchment. The Leyte experience after Typhoon Haiyan tells us that interventions should include continuity planning, for both business and government. With heavy rainfall, the management of runoff starts with the enhancement of water recharge through forest plantations in the upper catchment. In order to spread risk, water impounding at mid-catchment levels could play a critical role. They can detain and slow down runoff, and possibly, reduce the amount of water that a city must drain. At the lower catchment, and along the coast, wetlands and natural environmental buffers should be encouraged to provide risk protection. All-weather land corridors should be established to ensure intra-catchment access.
City. Early warning systems and evacuation planning should be required. Updated comprehensive land use plans should clearly delineate risk zones and classify them as “no build” areas. Urban planning should pinpoint locations that can allow relatively lower risk expansion. All-weather road networks should be maintained accordingly. Echoing the engineered interventions at the catchment scale, each city should consider new flood storage areas, higher capacity flood drainage, barrier and barrage systems, as well as rock revetments that offer flood defense along river banks and the coastline.
Site. Private and government centers should invest in site scale interventions, as well. Each site should consider creating local redundancies that address flood defenses and soak away areas, wetlands and environmental buffers, underground rain storage, as well as site-specific flood conveyance measures. Proper site planning should identify flood zones, as well as safe havens. Building design standards should provide appropriate protection and disaster resistance. Solid waste management systems should be in place. And to make all of this work, the community should be actively engaged in the maintenance of these systems. It is, after all, in their own self-interest.
Building. There are several options that could make all the difference for the occupants of a structure. At this scale, building design features will be critical. Elements such as the application of disaster resistant concrete shell systems, external storm shutters, raised outlets and appliances, raised construction and safe havens in the upper floors, the use of water resistant materials, the installation of flood guards over doors in low areas, elevated fuel tanks and the use of backflow pipes could significantly increase a building’s survivability. After an extreme weather event, underground rainwater storage boosts the self-sufficiency of building occupants. The presence of swales or soak-away areas may help speed up the return to normalcy.
It is a mistake to leave these solutions entirely up to government. There are interventions that can and should be done at different scales. All of us should be part of the solution.
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