Climate change makes early flood warning more vital
With extreme weather conditions posing an increasing threat to lives and assets, South Africa’s disaster management capacity needs to include better early warning systems for key risks such as flooding.
The World Economic Forum has rated ‘extreme weather’ as the top global risk – in terms of likelihood – for the past five years. Floods have been cited as affecting more lives than any other type of disaster. The Centre for Researchon the Epidemiology of Disasters reported that around half of all lives impacted by natural disasters were attributed to flooding. However, according to Natasha Ramdass, senior civil engineer at SRK Consulting, early warning systems can significantly reduce the impact of flooding on our lives.
“The importance of early warning has been well demonstrated in terms of saving lives in the face of flood disasters,” said Ramdass. “Although the economic losses caused by flooding events have increased by 50 times over the past 50 years, the loss of life has reduced by a factor of 10.”
Underpinning this trend has been the paradigm shift away from post-disaster response, and toward to a more proactive risk reduction approach. This has required meteorological, hydrological and climate services to support science-based risk management decisions – alongside more investment in early warning systems.
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“Early warning systems for weather-related disasters such as flooding have been developed and tailored over the past decades across the world,” she said. “First world countries have invested time and resources on tailoring their early warning systems for their respective application, climatic conditions and data availability.”
Adapting to climate change
The need for these systems is no less urgent in South Africa, where the National Climate Change Adaptation Strategy has been developed in anticipation of both positive and negative rainfall trends. In Durban, for instance, the city’s rainfall is expected to increase by 500 mm a year by the period 2065 to 2100.
“In addition to that, average temperatures will rise by between 1,5 and 2,5 degrees Celsius by 2065, along with heat waves and higher intensity rainfall events,” she said.
She highlighted that government had raised national priorities for human settlements disaster risk reduction and management provisions, as well as calling for early warning networks for disaster management to be expanded.
“SRK has been engaging with disaster management issues for many years, applying our multi-disciplinary expertise in hydrology, hydraulics, geosciences, water quality management infrastructure development and other fields to help clients mitigate and adapt to the related risks,” she said.
Lightning is a related hazard that is attracting more attention in terms of disaster management and early warning systems, according to SRK Consulting hydrologist Byron Gray. It causes significant injury, death and damage to infrastructure annually – and South Africa has one of the highest incidences of lightning-related injuries and deaths.
“There has been considerable progress in developing facilities for early warning, with South Africa now equipped with a ground-based lightning detection network – one of only three in the southern hemisphere,” said Gray. “This is significant, as lightning is predicted to increase with climate change, raising the vulnerability of especially rural communities.”
Ramdass said the foundation of early warning systems for flooding comprised the specialised understanding of water engineering and meteorology data management paired with the knowledge of specific operations technology– to achieve acceptable confidence levels. It was also vital to deliver quality data to systems, requiring careful monitoring and checking procedures. This would underpin the four key functions in an effective early warning system: risk analysis, to understand what and who is going to be affected, and when; monitoring and warning, to understand what kind of warning is related to that risk; dissemination and communication, to warn the relevant people timeously; and the response capability, to ensure that action is planned and appropriate.
 Ref: World Economic Forum, The Global Risks Report 2021 16th Edition, p.14
 eThekwini Municipality 2014. Durban Climate Change Strategy. Available at :http://www.durban.gov.za/City_Services/energyoffice/Documents/DCCS_
 Environmental Affairs 2017. National Climate Change Adaptation Strategy – Republic of South Africa. Available at : https://www.environment.gov.za/sites/default/files/reports/themeC_vulnerabilities_risks.pdf