Global Tropical Cyclone Damages and Fatalities Under Climate Change: An Updated Assessment

Impact of uncertainty induced by fatality function on future tropical cyclone risk assessment

Tropical cyclones (TCs) are among the deadliest extreme events occurring under a warming climate. Future TC risk assessment depend on TC projection from climate models and impact function relating TC to its possible consequence. Few studies have explored the uncertainty of impact function in future TC risk assessment compared to uncertainty in future TC characteristics. In this study, we investigate the uncertainty in TC fatality risk assessment induced by geographic and TC category-dependence of fatality function. We focus on all provinces in the mainland of China with historically recorded TC-induced fatalities and examine their TC fatality risks by assessing the difference in the annual average fatalities between current and future climate conditions. Synthetic TCs derived from four climate models and fatality functions parameterized from three grouped historical TC disaster datasets are used to observe the uncertainty induced by climate model and fatality function. Results show that the changes in the TC frequency, wind, TC-induced rainfall intensity, and exposure due to climate change in each province are dependent on the climate models. And the changes in the annual average fatality of each province are dependent on both the climate models and fatality functions. Climate models play a dominant role in determining the spatial pattern of future risk, while the fatality functions can alter the direction and magnitude of the risk change for certain provinces. Our results highlight the role of fatality function in detecting future TC risk under climate change, and inspire further TC impact studies that consider the heterogeneity of both climate conditions and geographical locations.

Empirical analysis of Chinese overseas power plant investments: Likelihood of suspensions and associated environmental risks

Power sector investment is crucial to accelerate a sustainable energy transition, but not all investments are successful. We examine 1,393 Chinese overseas electric power projects across 78 countries over the past two decades. We identify 5% that have been canceled or delayed, with coal and hydro projects having much higher suspension rates than solar and wind projects. We find electric projects with higher environmental risks are more likely to be suspended. Specifically, coal projects located in more densely populated areas where more people are exposed to air pollutants, in countries with more fatalities from extreme weather events, and in places with a record of environmental protests, are more likely to be suspended. Additionally, hydro projects closer to protected areas have a higher suspension rate. Our results suggest that refraining from investing in environmentally risky projects helps mitigate environmental damages and prevents financial losses due to cancellation and postponement.

Unveiling four decades of intensifying precipitation from tropical cyclones using satellite measurements

Increases in precipitation rates and volumes from tropical cyclones (TCs) caused by anthropogenic warming are predicted by climate modeling studies and have been identified in several high intensity storms occurring over the last half decade. However, it has been difficult to detect historical trends in TC precipitation at time scales long enough to overcome natural climate variability because of limitations in existing precipitation observations. We introduce an experimental global high-resolution climate data record of precipitation produced using infrared satellite imagery and corrected at the monthly scale by a gauge-derived product that shows generally good performance during two hurricane case studies but estimates higher mean precipitation rates in the tropics than the evaluation datasets. General increases in mean and extreme rainfall rates during the study period of 1980-2019 are identified, culminating in a 12-18%/40-year increase in global rainfall rates. Overall, all basins have experienced intensification in precipitation rates. Increases in rainfall rates have boosted the mean precipitation volume of global TCs by 7-15%/year, with the starkest rises seen in the North Atlantic, South Indian, and South Pacific basins (maximum 59-64% over 40 years). In terms of inland rainfall totals, year-by-year trends are generally positive due to increasing TC frequency, slower decay over land, and more intense rainfall, with an alarming increase of 81-85% seen from the strongest global TCs. As the global trend in precipitation rates follows expectations from warming sea surface temperatures (11.1%/°C), we hypothesize that the observed trends could be a result of anthropogenic warming creating greater concentrations of water vapor in the atmosphere, though retrospective studies of TC dynamics over the period are needed to confirm.

Linking soil phosphorus with forest litterfall resistance and resilience to cyclone disturbance: A pantropical meta-analysis

While tropical cyclone regimes are shifting with climate change, the mechanisms underpinning the resistance (ability to withstand disturbance-induced change) and resilience (capacity to return to pre-disturbance reference) of tropical forest litterfall to cyclones remain largely unexplored pantropically. Single-site studies in Australia and Hawaii suggest that litterfall on low-phosphorus (P) soils is more resistant and less resilient to cyclones. We conducted a meta-analysis to investigate the pantropical importance of total soil P in mediating forest litterfall resistance and resilience to 22 tropical cyclones. We evaluated cyclone-induced and post-cyclone litterfall mass (g/m² /day), and P and nitrogen (N) fluxes (mg/m² /day) and concentrations (mg/g), all indicators of ecosystem function and essential for nutrient cycling. Across 73 case studies in Australia, Guadeloupe, Hawaii, Mexico, Puerto Rico, and Taiwan, total litterfall mass flux increased from ~2.5 ± 0.3 to 22.5 ± 3 g/m² /day due to cyclones, with large variation among studies. Litterfall P and N fluxes post-cyclone represented ~5% and 10% of the average annual fluxes, respectively. Post-cyclone leaf litterfall N and P concentrations were 21.6 ± 1.2% and 58.6 ± 2.3% higher than pre-cyclone means. Mixed-effects models determined that soil P negatively moderated the pantropical litterfall resistance to cyclones, with a 100 mg P/kg increase in soil P corresponding to a 32% to 38% decrease in resistance. Based on 33% of the resistance case studies, total litterfall mass flux reached pre-disturbance levels within one-year post-disturbance. A GAMM indicated that soil P, gale wind duration and time post-cyclone jointly moderate the short-term resilience of total litterfall, with the nature of the relationship between resilience and soil P contingent on time and wind duration. Across pantropical forests observed to date, our results indicate that litterfall resistance and resilience in the face of intensifying cyclones will be partially determined by total soil P.

Impact of Cyclone Yaas 2021 Aggravated by COVID-19 Pandemic in the Southwest Coastal Zone of Bangladesh

The severe tropical Cyclone Yaas hit on 26 May 2021 in 16 coastal districts of Bangladesh and affected 1.30 million people. Moreover, the study areas are highly affected by the COVID-19 pandemic, which has increased the vulnerability of the people. Therefore, the objective of this study is to assess the impact of cyclone Yass aggravated by the COVID-19 pandemic in the southwest coastal zone of Bangladesh. COVID-19-aggregated Cyclone Yaas impact data at the household level were collected from Kalapara Upozilla of Potuakhali district, the area most affected by Cyclone Yaas. A total of 196 households were surveyed, and a quantitative approach was applied to analyse the data. The results show that households in the study area were severely affected by Cyclone Yaas in terms of income, housing, food consumption patterns, and water sanitation and hygiene. The outcome also revealed that the affected households received relief from the government, international/non-government organizations, donor agencies, as well as adopted coping strategies such as obtaining credit, selling assets, reducing daily meal intake, and tapping into savings. These strategies may be useful for a temporary recovery but not for the long term. The results of the study will help policymakers to reform policies.

Flood Impacts on Dairy Farms in the Bay of Plenty Region, New Zealand

Flood damage assessments provide critical information for flood hazard mitigation under changing climate conditions. Recent efforts to improve and systemise damage assessments have focused primarily on urban environments with few examples for primary industries such as dairy. This paper explores the adverse consequences of flooding on dairy farms in the Bay of Plenty region, New Zealand. Ex-tropical Cyclone Debbie in April 2017 caused prolonged riverine and surface water flooding on over 3500 hectares of dairy farmland. The event provided an opportunity to develop and apply a participatory approach for collecting information about on-farm flood damage, and both response and recovery actions implemented by dairy farmers. Semi-structured interviews and transect walks with farmers revealed a range of direct and indirect damages to production and capital assets, influenced by duration of inundation, silt deposition and seasonality. Results highlight the need to identify on-farm and off-farm asset interdependencies of dairy farm systems to estimate long-term socio-economic consequences at farm-level. Enhancing dairy farm flood resilience in a changing climate will rely on farm-level response and recovery plans, proactively supported by emergency management agencies, farm service suppliers and support agencies.

Economic vulnerability to tropical storms on the southeastern coast of Africa

Climate change will hit Africa economically hard, not least Southeast Africa. Understanding the impact of extreme climatic events is important for both economic development and climate change policy. Global climatological summaries reveal high damage potential pathways for developed countries. Will countries in Africa, especially in the southeastern board of the continent, be vulnerable to loss-generating extreme climate events? This study examined for countries in the sub-region, their vulnerability and damage costs, the impact of climate change on tropical storm damage, as well as the differential impacts of storm damages. An approach using a combination of physical and economic reasoning, as well as results of previous studies, reveals that in Southeast Africa, the economic response to the key damage parameters of intensity, size and wind speed is significant for all the countries. Damages in Kenya and Tanzania are sensitive to wind speed. Both vulnerability and adaptation are important for Madagascar and Mozambique - two countries predicted to be persistently damaged by tropical storms. For Mauritius and South Africa, inflictions from extreme events are expected to be impactful, and would require resilient public and private infrastructure. Reducing the physical and socio-economic vulnerability to extreme events will require addressing the underlying socio-economic drivers, as well as developing critical public infrastructure.

Tropical cyclone risk assessment using geospatial techniques for the eastern coastal region of Bangladesh

Tropical cyclones frequently affect millions of people, damaging properties, livelihoods and environments in the coastal region of Bangladesh. The intensity and extent of tropical cyclones and their impacts are likely to increase in the future due to climate change. The eastern coastal region of Bangladesh is one of the most cyclone-affected coastal regions. A comprehensive spatial assessment is therefore essential to produce a risk map by identifying the areas under high cyclone risks to support mitigation strategies. This study aims to develop a comprehensive tropical cyclone risk map using geospatial techniques and to quantify the degree of risk in the eastern coastal region of Bangladesh. In total, 14 spatial criteria under three risk components, namely, vulnerability and exposure, hazard, and mitigation capacity, were assessed. A spatial layer was created for each criterion, and weighting was conducted following the Analytical Hierarchy Process. The individual risk component maps were generated from their indices, and subsequently, the overall risk map was produced by integrating the indices through a weighted overlay approach. Results demonstrate that the very-high risk zone covered 9% of the study area, whereas the high-risk zone covered 27%. Specifically, the south-western (Sandwip and Sonagazi), western (Patiya, Kutubdia, Maheshkhali, Chakaria, Cox's Bazar and Chittagong Sadar) and south-western (Teknaf) regions of the study site are likely to be under a high risk of tropical cyclone impacts. Low and very-low hazard zones constitute 11% and 28% of the study area, respectively, and most of these areas are located inland. The results of this study can be used by the concerned authorities to develop and apply effective cyclone impact mitigation plans and strategies.