5.3 Combining Climate Mitigation with Climate Adaptation in Honduras

LocationSula Valley, Honduras
ContextPost-disaster (2020 Hurricanes Eta and Iota)
Number of Houses Analyzed5 retrofit, 1 new construction
HazardsEarthquake, flood, wind
Building Type1 story, concrete block masonry, lightweight roof
Intervention ScopeRepair, retrofit, and vertical expansion to add a partial second story
Performance LevelLife safety (seismic)

Program Details

Build Change began working in Honduras after Category 4 Hurricanes Eta and Iota hit the country in quick succession in November 2020. In partnership with the Honduran Red Cross, we began working with homeowners in the Sula Valley, an area in the north west characterized by low-lying, alluvial plains prone to regular flooding. Expected damage in the area is anticipated to increase in the next decades due to economic and population growth, and climate change.[1]

The home improvement program offers homeowners technical and financial resources to repair the damage caused by the strong winds and flood water, while simultaneously strengthening their home against future events. Integral to this is the addition of a resilient partial second story, which will provide shelter and protection during hurricanes and a safe place for families to live while waiting for flood water to subside. Technically, this means providing additional reinforcement to the first-floor masonry walls, converting the existing lightweight roofs to reinforced concrete slabs, and building the partial second story as new construction. It also means providing systems for rainwater harvesting and solar panels for energy independence.

The Sula Valley is considered a rural, agricultural area, although population density is still relatively high. Houses are typically single-story, detached units built from concrete masonry blocks and lightweight roofs.

Before

After

Before and after Build Change and Honduran Red Cross technical and financial support for retrofit and expansion of Irma Mercedes Mardiaga’s home

Findings

Climate adaptation programs can also reduce emissions to mitigate the effects of climate change. The Honduras program was designed entirely for climate adaptation. However, the program’s reuse and improvement of existing houses has considerable emissions savings when compared with the only viable alternative—relocation and construction of new homes for the affected population. Each improved house saves, on average, 9.5 metric tons of carbon dioxide or 48 percent of the emissions of equivalent new construction.

Figure 16: Emissions Savings with Post-Disaster Programs in Honduras

Figure 17: Embodied Carbon by Intervention Type in Honduras

0.11

The emissions savings for repair, strengthening, and expansion of existing homes in Honduras are slightly below average compared to comparable global programs. The savings from the Honduras program interventions are on average 53 percent lower than all post-disaster programs with strengthening and vertical expansion. This is thought to be due to two reasons. First, because none of the existing houses have slab roofs—all have lightweight roofs that must be converted to slabs to support expansion. This considerably raises emissions because the steel and cement in reinforced concrete have very high associated emissions, and the slabs themselves are steel deck slabs. Secondly, the finishes on these homes were completed to a higher degree than other vertical expansion programs.

References

  1. UNU-EHS & Frankfurt School of Finance & Management (2021). Urban Flood Risk in San Pedro Sula – Honduras: Executive Summary. Bonn/Frankfurt: United Nations University / Frankfurt School of Finance & Management GmbH. 16pp.
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