Maarten van Aalst

Declining vulnerability to river floods and the global benefits of adaptation

Significance Understanding the vulnerability of societies around the world is crucial for understanding historical trends in flood risk and for producing accurate projections of fatalities and losses. We reproduced historical river flood occurrence using daily climate data for the period 1980–2010 and quantified the natural and socioeconomic contributions to flood risk trends. We show that the fatalities and losses as a share of the exposed population and gross domestic product are decreasing with rising income. We also show that there is a tendency of convergence in vulnerability levels between low- and high-income countries. Projections based on a wide range of climate change and socioeconomic development scenarios demonstrate that amplified adaptation efforts have the potential to largely contain losses from future floods. The global impacts of river floods are substantial and rising. Effective adaptation to the increasing risks requires an in-depth understanding of the physical and socioeconomic drivers of risk. Whereas the modeling of flood hazard and exposure has improved greatly, compelling evidence on spatiotemporal patterns in vulnerability of societies around the world is still lacking. Due to this knowledge gap, the effects of vulnerability on global flood risk are not fully understood, and future projections of fatalities and losses available today are based on simplistic assumptions or do not include vulnerability. We show for the first time (to our knowledge) that trends and fluctuations in vulnerability to river floods around the world can be estimated by dynamic high-resolution modeling of flood hazard and exposure. We find that rising per-capita income coincided with a global decline in vulnerability between 1980 and 2010, which is reflected in decreasing mortality and losses as a share of the people and gross domestic product exposed to inundation. The results also demonstrate that vulnerability levels in low- and high-income countries have been converging, due to a relatively strong trend of vulnerability reduction in developing countries. Finally, we present projections of flood losses and fatalities under 100 individual scenario and model combinations, and three possible global vulnerability scenarios. The projections emphasize that materialized flood risk largely results from human behavior and that future risk increases can be largely contained using effective disaster risk reduction strategies.

Adapting development cooperation to adapt to climate change

Climate change can affect the efficiency with which development resources are invested and the eventual achievement of many development objectives. Drawing upon illustrative case studies in six developing countries: Bangladesh, Egypt, Tanzania, Uruguay, Nepal and Fiji, this article examines the synergies and trade-offs involved in integrating adaptation to climate change in development cooperation activities. Key barriers facing such integration are identified. An agenda is proposed for enhancing development efforts by mainstreaming climate risk management, organized around improving the usability of climate information, developing and testing climate risk screening tools, employing appropriate entry points for climate information, focusing more on implementation, and improving coordination and sharing of good practices.

Climate forecasts in disaster management: Red Cross flood operations in West Africa, 2008

In 2008, the International Federation of Red Cross and Red Crescent Societies (IFRC) used a seasonal forecast for West Africa for the first time to implement an Early Warning, Early Action strategy for enhanced flood preparedness and response. Interviews with disaster managers suggest that this approach improved their capacity and response. Relief supplies reached flood victims within days, as opposed to weeks in previous years, thereby preventing further loss of life, illness, and setbacks to livelihoods, as well as augmenting the efficiency of resource use. This case demonstrates the potential benefits to be realised from the use of medium-to-long-range forecasts in disaster management, especially in the context of potential increases in extreme weather and climate-related events due to climate variability and change. However, harnessing the full potential of these forecasts will require continued effort and collaboration among disaster managers, climate service providers, and major humanitarian donors.

Using Seasonal Climate Forecasts to Guide Disaster Management: The Red Cross Experience during the 2008 West Africa Floods

In 2008, the seasonal forecast issued at the Seasonal Climate Outlook Forum for West Africa (PRESAO) announced a high risk of above-normal rainfall for the July–September rainy season. With probabilities for above-normal rainfall of 0.45, this forecast indicated noteworthy increases in the risk of heavy rainfall. When this information reached the International Federation of Red Cross and Red Crescent Societies (IFRC) West and Central Africa Office, it led to significant changes in the organization’s flood response operations. The IFRC regional office requested funds in advance of anticipated floods, prepositioned disaster relief items in strategic locations across West Africa to benefit up to 9,500 families, updated its flood contingency plans, and alerted vulnerable communities and decision-makers across the region. This forecast-based preparedness resulted in a decrease in the number of lives, property, and livelihoods lost to floods, compared to just one year prior in 2007 when similar floods claimed above 300 lives in the region. This article demonstrates how a science-based early warning informed decisions and saved lives by triggering action in anticipation of forecast events. It analyses what it took to move decision-makers to action, based on seasonal climate information, and to overcome traditional barriers to the uptake of seasonal climate information in the region, providing evidence that these barriers can be overcome. While some institutional, communication and technical barriers were addressed in 2008, many challenges remain. Scientists and humanitarians need to build more common ground.

Factors Other Than Climate Change, Main Drivers of 2014/15 Water Shortage in Southeast Brazil

Introduction. The southeast region of Brazil (SEB, defined as the area between 15°–25°S and 40°–48°W; Fig. 9.1a) experienced remarkably dry conditions from January 2014 to February 2015, comprising the 14-month period that includes two rainy seasons investigated here. This region includes Sao Paulo, Brazil ś most populated city, which suffered impacts due to water shortages, and the watersheds and reservoirs feeding the city’s water supply system. The wet season occurs during austral summer and the dry season during austral winter. The South Atlantic convergence zone (SACZ) is the main mechanism responsible for the region’s austral summer rainfall. During summer 2014, there was a complete absence of SACZ episodes (Coelho et al. 2015). Previous major droughts occurred in the region in 1953/54, 1962/63, 1970/71, and 2001. While droughts have very complex criteria, these were all characterized by large rainfall deficits while the effect of the SACZ needs further investigation. The 1953/54 rainfall deficit prompted construction of the largest water supply system (Cantareira) used for Sao Paulo (Porto et al. 2014). The 2014/15 drought had major impacts in Sao Paulo due partly to a four-fold population increase since 1960 (Fig. 9.1b). Although new water supply systems were constructed after Cantareira, it is still by far the largest in terms of capacity and number of people supplied (until early 2015) and hence is used as an indicator of the impacts of the SEB drought on water supply. In January 2015, Cantareira, which used to supply 8.8 million people in Sao Paulo, sank to a water volume of just 5% of capacity (Fig. 9.1c), and currently supplies just 5.3 million people. Other systems (Guarapiranga and Alto Tiete) started to supply the excess population, those previously supplied by Cantareira, after the water crisis was established. In this analysis, we investigate potential changes in the hydrometeorological hazard, defined by accumulated precipitation and the difference between precipitation and evaporation (P − E) in the SEB region. The true impact, however, is due to a combination of a physical event with vulnerability and exposure, in this case on millions of people in the affected area (Field et al. 2012). The current drought reflects increasing trends in exposure. Sao Paulo’s population grew by 20% in the past 20 years. Water use has increased at an even faster rate over the same period (Fig. 9.1b). Vulnerability of water supply systems remains high. Recognizing that water governance is key to reducing vulnerability, Southeast Brazil experienced profound water shortages in 2014/15. Anthropogenic climate change is not found to be a major influence on the hazard, whereas increasing population and water consumption increased vulnerability.

Development & Climate Days at COP 18 meeting report

The Development & Climate Days celebrated its 10th anniversary at the United Nations Framework Convention on Climate Change COP 18 in Doha, Qatar (1–2 December 2012). With a vision of re-energizing the original purpose of bringing together policy-makers, practitioners and researchers for intensely participatory learning, dialogue and networking, this event convened over 200 negotiators, policy-makers, scientists, funding agencies and development practitioners. A highly interactive, out-of-the-box programme featured ‘speed networking’ icebreaker sessions, experiential learning games about climate risk management and development, sharply moderated discussions, high-level panels and a ‘Beyond the Film Festival’. Without support from the habitual Powerpoint presentation format, each of these sessions aimed to foster an environment of collaboration among participants, and inject serious fun into the climate and development dialogue processes. Key messages emerging from the event included: (i) considering ways to reduce social exclusion and generating ‘constituencies of demand’, in order to place the injustice of climate change in a political agenda guided by science, (ii) addressing the role of sub-national governments in delivering climate and development financing at community level, (iii) integrating climate services into climate-smart development, and (iv) improving understanding of Loss and Damage from the research, policy and practice perspectives.

Climate change adaptation: integrating climate science into humanitarian work

A changing climate means more work for humanitarian organizations. In the face of rising dangers, science-based information about likely threats can be used to reduce risk and improve resource allocation. By doing so, humanitarian organizations can enhance their work even in the face of the rising risks of climate change.

Managing health risks in a changing climate: Red Cross operations in East Africa and Southeast Asia

While climate variability and change affect global patterns of disease, there are few examples of methods that effectively integrate climate into health programming. This study examines a Red Cross Red Crescent pilot project in Kenya, Tanzania, Vietnam, and Indonesia that incorporated climate information and considerations in health operations. Our investigation looks at three elements of programming: baseline community perceptions of climate and health, integration of climate information in operations, and resulting community-level risk reduction behaviour. (1) Through community focus groups, semi-structured interviews, and household surveys, our research reveals that potential health effects of climate variability and change are a key concern at the community level. (2) Project implementors used climate information to design educational materials and health contingency plans to inform when and where disease prevention activities should be concentrated. This climate-based disease anticipation and improved sharing of incidence data aimed to quickly detect and respond to changing disease patterns in a variable climate. (3) Subsequently, community-level risk reduction behaviour significantly increased in project locations. This pilot is evidence that climate information and considerations can be readily integrated into health programming to account for changing risks, using existing disease prevention techniques to address priority concerns of vulnerable communities.

Scalable and Sustainable: How to Build Anticipatory Capacity into Social Protection Systems

Climate shocks contribute to a significant share of the humanitarian burden, and are a key factor in increasing poverty and food insecurity. Social protection is increasingly recognised as an instrument to help build resilience to climate risks through long-term, large-scale national systems. However, most experiences to date have focused on social protection’s role for chronic needs, or at best, shock-response, rather than on anticipation and prevention. This article argues that social protection can support more effective resilience building at scale by integrating early action and preparedness. We propose a concrete solution, namely linking a Forecast-based Financing mechanism to a social protection system to enable anticipatory actions based on forecast triggers and guaranteed funding ahead of a shock. Such a system may enhance scalability, timeliness, predictability and adequacy of social protection benefits. Key considerations for success of this emerging approach include sound analysis of forecast, risks, cost and benefits, and ring-fenced funding.

International Conference on Climate Risk Management, inputs for the Intergovernmental Panel on Climate Change’s Sixth Assessment Report

ABSTRACT In April 2017, over 70 scientists, policymakers and practitioners from 32 countries convened at the International Conference on Climate Risk Management in Nairobi, Kenya. This conference utilized innovative approaches to facilitate a process of constructive, critical reflection of the existing climate risk management knowledge base, as well as its relevance to decision-maker needs and views of the most vulnerable people. The conference articulated recommendations to the Intergovernmental Panel on Climate Change (IPCC) in the development of their Sixth Assessment Report (AR6) – in support of the Chair’s vision for AR6 to have a strong focus on solutions. This report highlights key recommendations distilled from these discussions in areas such as risk-framing approaches and risk metrics. The meeting also suggested that the next IPCC assessment could be strengthened by stronger interaction with practitioners and policymakers working at the forefront of implementing global climate and development agreements, especially in the most vulnerable contexts, and identified associated research priorities.