Studies have shown that the population affected by the flood is growing faster than expected
New satellite data reveal large areas of disaster-prone land
A new study shows that the number of people affected by floods is growing much faster than scientists previously thought, due to flooding and migration of people to flood-prone areas. The author’s use of direct satellite observations rather than standard model estimates shows that from 2000 to 2018, the population growth rate of flood-prone areas was 24% faster than other places-more than 10 times the previous estimate.This Research just published In leading journals nature.
Research “It will help policymakers understand where the impact of flooding is changing and how to best adapt,” said lead author Beth Tellman, a postdoctoral researcher at Columbia University’s International Institute of Climate and Society. She said it should “deepen our understanding of land cover changes. Understanding of how climate, climate, and flooding interact”. Tellman conducted most of his research during his Ph.D. Student at Arizona State University and Chief Scientific Officer of Global Flood Tracking Company Cloud to street.
Today, most flood maps rely on modeling floods based on ground data (such as elevation and rainfall records). This includes those used by the US Federal Emergency Management Agency. But the study authors say that these models have serious limitations. In fact, these maps often omit recent events in areas not affected by floods in history.
In many parts of the world, flooding is a fast-growing problem. A low-lying area near Khulna in southwestern Bangladesh has been flooded for a long time. (Kevin Krajic/Earth Institute)
On the other hand, the new Global Flood Database The 21st century floods used in the research allow researchers to directly observe the actual range, impact, and trends. The database is supported by global satellite imaging twice a day and has information on 913 flood events in 169 countries/regions since 2000.
New research shows that from 2000 to 2015, as many as 86 million people moved into the observed flood zone, resulting in a 24% increase in the proportion of people affected by floods. Between 2000 and 2018, approximately 2.23 million square kilometers (approximately 86,100 square miles) were flooded, affecting 255 million to 290 million people. Nearly 90% of mapped flood events occurred in South and Southeast Asia, with the largest basins—Indus, Ganges-Brahmaputra, and Mekong—with the most exposed. Satellite data revealed previously unknown increases in flood risk in South Asia, southern Latin America, and the Middle East.
Most of the floods in the database were caused by heavy rainfall, followed by tropical storms or tides, then snow or ice melting, and then dam failures. Although it accounts for less than 2% of the flood, the rate of increase in dam failures is the highest, accounting for 177% of the affected population.
For example, in August 2008, the collapse of the Koshi Barrage in Nepal left more than 3 million people homeless in Bihar, India. Over the past few years, the Bagre Dam in Burkina Faso has repeatedly overflowed with excessive water, flooding thousands of hectares of farmland in neighboring Ghana, destroying or destroying crops.
Researchers estimate that by 2030, climate and demographic changes will add another 25 countries to the 32 countries that have experienced more and more floods in the 21st century.
Research co-author Jonathan Sullivan, a postdoctoral scientist at the University of Arizona, said: “We found that economic development and people moving to flood-prone areas significantly increased the number of people affected by floods in these areas.” “Furthermore, flood risk. The increase is due to potential conditions that leave vulnerable groups with no choice but to settle in flooded areas.”
The author says that the information in the global flood database can bring immediate actionable lessons. For example, tracking population growth in flood-prone areas can help governments develop adaptation strategies and provide faster assistance to flood survivors.
Other co-authors of the study are from NASA, Google Earth Outreach, University of Michigan, University of Colorado, University of Texas at Austin, Dartmouth Flood Observatory, and University of Washington. Funding is provided by Google and NASA.
Adapted from Cloud to Street’s press release.
