End-To-End Probabilistic Impact Based Early Warning Systems for Community Resilience

Contributed by Dr. Bapon Fakhruddin, New Zealand

Recently I attended the Fourth Pacific Meteorological Council (PMC) and Second Pacific Meteorological Ministers Meeting (PMMM), which was held in Honiara, Solomon Islands, from 14 to 17 August.

Figure 1. Dr Bapon Fakhruddin at the meeting. Photo credit: Jenny Davson-Galle

Reaching communities and ensuring that those most in need are provided with effective communications and technologies are top priorities for the Pacific Meteorological Council (PMC). Science has in-build uncertainty and is highly probabilistic. The probabilistic ensemble forecasting approach exposes the range of uncertainty associated with different predictions. They also allow the adoption of a risk-based approach for decision making and contribute to building confidence to help operational forecasters. Effective early warning systems (EWS) require a complete understanding of the populations and assets exposed to threats linked to the probabilistic ensembles forecasts.

With present extreme weather events, risk-based early warning systems are essential. Practice shows that people and communities at risk need to be involved in the understanding of their exposure and the vulnerabilities of different groups, including the disabled, the elderly, children and pregnant women. An effective system also relies on expert risk assessment, interpretation and communication. Currently, in many places, we do not use probabilistic risk assessment. Since science information is probabilistic, risk assessment needs to follow the same path.

Figure 2. Participants at the meeting. Photo credit: Jenny Davson-Galle

Understanding the forecast

Research has shown that, before deciding to take a disruptive – and often expensive – action such as evacuation, people must understand the forecast; they must believe that it actually applies to their situation and, most importantly, they must feel that they need to act because people, including their loved ones, are at risk. However, in many cases, common practice has been to prepare and release forecast messages without adequate concern on how they are received, understood and/or interpreted. Accurate, appropriate information that translates early warnings into early actions at community level is essential.

“We’ve always been talking about reaching the last mile, and that means getting to the people who haven’t got the message we are relaying. We’re talking about people with disabilities as well. They need to be included in our conversations and awareness efforts too,” said the Secretariat of the Pacific Regional Environment Programme’s (SPREP) Climate Change Advisor, Espen Ronneberg. “We do this to prepare those who are vulnerable to disasters as well, and that includes people with disabilities.” was added.

Acting on the risks

Disabled and elderly people are particularly at risk from natural disasters as, even with strong family and community support systems, it takes longer for them to reach designated safety zones. Likewise, extra forward planning is required for the evacuation of hospital patients and other health care facilities. Ronneberg believes that the way forward lays in encouraging disabled people to join in on EWS (Early Warning Systems) discussions. “I think the best way to include them would be through the People with Disabilities’ Forum, and it will be great if we can get them to take an interest in meteorology as well,” he said.

The PMC session included a discussion on new forms of risk assessment, such as the shift from deterministic to probabilistic risk estimation. Deterministic approaches are used to assess the impacts of a specific natural hazard scenario, whereas probabilistic methods are used to produce more refined estimates of how often a hazard is likely to happen, and the potential damage it will deliver, with the help of modelling tools. Probabilistic assessments work with uncertainties, partly due to the random nature of natural hazards, and partly because of our incomplete understanding of natural hazards and the limited ways of measuring hazards, exposure and vulnerability (OECD, 2012).

Communicating probability information

As hazard information is always probabilistic, the risk information and risk communication also need to be probabilistic. When any new probabilistic forecast product is introduced, it can be mis-communicated to the affected people. For people to make good decisions, the capacity to generate an early warning with an acceptable lead-time is essential. For example, advances in tropical cyclone (TC) forecasts using ensemble methods have been widely used for operational TC tracking. By using simple, weighted, or selective methods, TC tracking forecasts tend to have smaller positional errors than single model–based forecasts.

Figure 3 End-to-end early warning systems.

The impacts of climate variability and change were also recognised at the meeting as major challenges to island nations. Of particular concern to the Pacific region were sea level rise, salt water intrusion, drought, flooding, coastal inundation, ocean conditions (tides, swells, waves, acidification) and impacts on health (e.g. malaria and dengue), water resources, agriculture and fisheries (invasive species, etc.).

WMO’s approach to Climate Risk and Early Warning System (CREWS) initiatives and the requirements for disaster loss data standardization is crucial for impact-based early warning system, which offers more accurate risk assessment. See also a summary the outcomes of both the Multi-Hazard Early Warning System and the Disaster Risk Reduction Global Platform Meetings (http://www.wmo.int/earlywarnings2017/) held in May in Cancun, Mexico.

The next Pacific Meteorological Council (PMC) meeting will be held in Samoa in 2019. The PMC consists of members of the Pacific National Meteorological and Hydrological Services supported by its technical partners, regional organisations, non-government organisations and private sectors.

The 14-17 August meeting was co-hosted by the Government of Solomon Islands, the Secretariat of the Pacific Regional Environment Programme (SPREP) and World Meteorological Organisation (WMO).



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