“The floods have grown in intensity and turned into much stronger events that reach neighbourhoods, and areas that weren’t exposed before”, says Armando Calidonio, mayor of the large industrial city of San Pedro Sula, in Honduras.
“We’re seeing the concentration of rainfall into more aggressive storms that in general, even in the most developed areas, are causing the rainwater drainage systems to collapse”.
San Pedro Sula has always been prone to tropical storms and flooding, but the problem is getting worse, as climate change causes unprecedented changes to weather systems. The financial and human costs are only likely to grow.
To help people like Mayor Calidonio protect his citizens and best adapt to future climate change impacts, the UN University’s Institute of Environment and Human Security (UNU-EHS) utilizes a tool called Economics of Climate Adaptation (ECA), that identifies the most promising, and cost effective, strategies, tailored to specific regions.
© UNICEF/Martin Cálix/AFP-Serv
Using the ECA methodology, UNU-EHS and its partners projected that, by 2042 the annual damages caused by different climate hazards would double in the municipality of San Pedro Sula.
Working closely with the local administration, they looked at different options to address these risks, and identify the best solutions.
Following this process, a number of recommendations were made, such as improvements to the drainage system, reforestation along riverbeds, and the construction of vegetated swales (channels that store runoff) on the most flood-prone areas of the city.
Additionally, the study concluded that the municipality would benefit from further investments into climate risk-related data, improving the weather monitoring network, and early warning systems.
The work is also helping the local government to access financing for climate adaptation measures, because the analysis can serve as a guidance document to development banks, when they evaluate the worthiness of investment before rewarding grants.
Coping with droughts and floods
The ECA approach is being used in a variety of other settings, both urban and rural, in different parts of the world. For example, in the Afar and Somali regions of Ethiopia, which suffer from extreme drought, and some of the hottest temperatures in the world, the analysis showed that drought-related damage is likely to quadruple by 2050.
Recommendations for the regions included investing approximately $10 million into adaptation measures, such as the establishment of communal seed banks, improved forage storage, better management of protected areas, wetland restoration and the establishment of fodder tree and grass nurseries.
This $10 million investment would, according to the analysis, allow both regions to avoid some $500 million in damages, and protect around 90,000 people from drought over the next 31 years.
© UNICEF/Linh Pham/AFP-Services
In Can Tho, a city in southern Viet Nam, there are multiple climate challenges, including flooding and heat wave exposure. Here, an ECA study revealed that the annual damage from floods and heatwaves is expected to roughly quadruple by 2050.
However, a combination of measures such as mobile flood embankments, improving flood awareness, and rehabilitation of existing drainage systems, at a cost of less than $6 million, would prevent an estimated $300 million in damages and protect around 15,000 people over the next three decades from different types of flooding.
Similarly, by investing under $16 million in public cooling centres for vulnerable people, climate-smart agriculture, and the introduction of white rooftop surfaces, The Can Tho authorities would be able to prevent around $250 million in damages, and protect around 800,000 people for the next three decades.
© UNICEF/Truong Viet Hung
Overall, the three case studies show that investing in adaptation today, is far more cost-effective than having to address the damage that will likely occur in the next three decades.
“By using the ECA methodology, countries and communities have the data and information needed to develop more ambitious climate adaptation and mitigation plans”, says Dr. Maxime Souvignet, Team Lead of Economics Climate Adaptation at UNU-EHS. “These measures will support them in increasing their resilience against the impacts of current and projected future climatic conditions”.