Flood has become a major problem in most part of the world. Flooding of the river and coastal systems are the most frequent and damaging climate-related hazard, affecting thousands of people and causing billions of dollars in losses each year. Human interference along with climate change causes a lot of human and financial losses every year following the occurrence of floods. Flood hazards and impacts are projected to increase in many regions around the globe. Future flooding hotspots are expected in Asia and Africa, owing to climate and socio-economic changes.

I. Introduction

Floods are more likely to occur due to more extreme weather patterns caused by long-term global climate change. Land cover changes such as vegetation removal and climate change increase the risk of flooding. Extreme flooding can be caused by heavy rainfall, prolonged rainfall, repeated rainfall, or a combination of these  ("How climate change is making record-breaking floods the new normal").  There are mostly three types of floods (i) Flash Floods are caused by rapid and excessive rainfall that raises water heights quickly, and rivers, streams, channels, or roads may be overtaken (ii) River floods are caused when consistent rain or snow melt forces a river to exceed capacity (iii) Coastal floods are caused by storm surges associated with tropical cyclones and tsunami.

Between 1906-2021, floods affected more than 3 billion people worldwide [EM-DAT data]. People who live in flood-prone areas, in non-resilient buildings, or who do not have warning systems and are unaware of the dangers of flooding are the most vulnerable to flooding. Depending on the socio-economic scenario, a 1.5°C increase in temperature compared to the period 1976-2005 would increase human casualties from floods by 70-83% and direct flood damages by 160-240% (Dottori et al., 2018).

Several global issues, such as increasing population pressures, continued degradation of ecosystem services, and climate variability and change, could further increase the risk of flooding around the world. In many parts of the world, this increase is exacerbated by poor flood planning and management. Flood management is very important in protecting people and infrastructure from floods and flooding.

II. World

Flooding has already caused more than $1 trillion in losses globally since 1980, and the situation is poised to worsen. Analysis from WRI’s Aqueduct Floods finds that the number of people affected by floods will double worldwide by 2030 (Kuzma & Luo). Climate change has increased extreme sea level events associated with some tropical cyclones, which have increased the intensity of other extreme events such as flooding and associated impacts. This has increased the vulnerability of low-lying megacities, deltas, coasts, and islands in many parts of the world ("Weather-related disasters increase over past 50 years, causing more damage but fewer deaths"). India, Bangladesh, and Indonesia, for example, have some of the largest populations affected by riverine and coastal floods each year. By 2030, these three countries will account for 44% of the world’s population annually affected by riverine floods, and 58% of the population affected by coastal floods ("The number of people affected by floods will double by 2030").

There has been an increasing trend in the events of flood disasters since 1980. More than 5000 disaster events (floods) were recorded worldwide during the period 1980-2021 by EM-DAT, one of the foremost international databases of such events. There were more floods in the period (2001-2021) as compared to the period (1980-2000). In the last 20 years, there were around 3518 flood disasters highest number of flood disasters was 226 which was recorded in the year 2006. In 2021 there were 222 flood disasters. Indonesia has the highest number of flood events in the year 2020 and 2021.

Number of Flood Events, World (1980-2021) ; Source: EM-DAT; Sanrachna Analysis
Number of Deaths due to Floods, World (1980-2021); Source: EM-DAT; Sanrachna Analysis

Around 2,61,000 deaths were recorded due to floods globally from 1980-2021. The highest is recorded in the year 1999. Since 2000 there were 1,14,898 deaths due to floods globally. In the year 2021, there were 4,166 deaths. India has had the highest number of death due to floods over the years.

III. Asia

Catastrophic floods have hit Pakistan recently . Nearly 2 million houses have been impacted by the devastated floods as of 19 September, with 788,000 houses partially destroyed and 7.8 million fully destroyed. In total, 1,559 people have died, and 12,850 have suffered injuries due to the devastating floods. Between 13-18 September 2022, floods on Kalimantan Island and in the western parts of Indonesia inundated some 8,300 houses and temporarily displaced 36,000 people. Heavy monsoon rains affected several States of India and caused severe weather-related incidents and floods that resulted in human loss and widespread damage. According to the National Emergency Response Centre (NDMI), on 9-10 September, at least 13 people died, nearly 1,400 have been affected and more than 1,200 were evacuated across the States of Assam, Gujarat, Karnataka, Maharashtra, Madhya Pradesh, Uttarakhand, and Uttar Pradesh.

The frequency and severity of floods in Southeast Asia have increased over the past several decades. Flooding in Southeast Asia is the result of many factors, including typhoons, heavy rains, and tropical storms. Flooding is a major problem that is currently affecting many regions in Southeast Asia, in particular Cambodia, Thailand, Vietnam, Laos, the Philippines, and areas surrounding the Mekong River (Torti, 2012). EM-DAT data shows that Indonesia had the highest number of flood events in the last 10 years in the South Eastern region.

Sea level rise of any magnitude will increase the frequency and duration of coastal flooding. Among the Asian countries, Indonesia has the longest coastline. Since 1880, the average global sea level has risen 8-9 inches with about 3 of those inches occurring since 1993.

Number of Flood Events and Death, Asia (1980-2021); Source: EM-DAT; Sanrachna Analysis

In 2021, South-Eastern Asia has the highest number of flood events but the number of deaths was highest in South Asia region.

Number of Flood Events and Death, South-Eastern Asia (1980-2021); Source: EM-DAT; Sanrachna Analysis
Number of Flood Events and Death, South Asia (1980-2021); Source: EM-DAT; Sanrachna Analysis

IV. Conclusion

Flooding has been the most common natural disaster globally. Between 1906-2021, floods affected more than 3 billion people worldwide. The severity of flooding has increased more in the South-Eastern region. People who live in floodplains or non-resistant buildings, or lack warning systems and awareness of flooding hazards, are most vulnerable to floods. There were more floods in the period (2001-2021) as compared to the period (1980-2000). In the last 20 years, there were around 3518 flood disasters. EM-DAT data shows that Indonesia had the highest number of flood events in the last 10 years in the South Eastern region.  An early warning system for floods.

V. References

1. How climate change is making record-breaking floods the new normal.  https://www.unep.org/news-and-stories/story/how-climate-change-making-record-breaking-floods-new-normal

2. Floods. https://www.who.int/health-topics/floods#tab=tab_1

3. Dottori, F., Szewczyk, W., Ciscar, J., Zhao, F., Alfieri, L., & Hirabayashi, Y. et al. (2018). Increased human and economic losses from river flooding with anthropogenic warming. Nature Climate Change, 8(9), 781-786. doi: 10.1038/s41558-018-0257-z

4. Floods. https://public.wmo.int/en/our-mandate/water/floods

5. Kuzma, S., & Luo, T. The Number of People Affected by Floods Will Double Between 2010 and 2030. https://www.wri.org/insights/number-people-affected-floods-will-double-between-2010-and-2030?utm_source=twitter&utm_medium=worldresources&utm_campaign=socialmedia&utm_term=ef803795-d35a-4691-a206-61250232f2a4

6. Torti, J. (2012). Floods in Southeast Asia: A health priority. Journal Of Global Health, 2(2). doi: 10.7189/jogh.02.020304

7. Weather-related disasters increase over past 50 years, causing more damage but fewer deaths.   https://public.wmo.int/en/media/press-release/weather-related-disasters-increase-over-past-50-years-causing-more-damage-fewer#:~:text=Climate%20change%20has%20increased%20extreme,many%20parts%20of%20the%20world.

The number of people affected by floods will double by 2030.  https://www.preventionweb.net/news/number-people-affected-floods-will-double-2030