Flood Risk for 36 Million In India

In News

According to a new scientific study, about 36 million people in India face flood risk. This is an increase from the previous estimates.

In-Detail

The study was conducted by Climate Centre, an independent organisation of scientists and journalists working on climate change, and is published in the scientific journal Nature Communications.
As per the study, the number of people affected by rising sea levels in India has been underestimated by as much as 88%.
With its new modelling approach, the study estimates that 36 million Indians will face annual flooding by 2050 and 44 million by 2100 if emissions are not reduced.
As against 2.8 million of the previous estimates, 21 million people are expected to live below the high-tide line. These are areas where the sea reaches the farthest into the land at high tide.

Methods

For the study, a new software called CoastalDEM has been used.
Currently, detailed maps of the globe taken by the Shuttle Radar Topography Mission (SRTM) are used to estimate flood prone areas.
The SRTM travelled aboard space shuttle Endeavour in 2000.
The images of the SRTM determined the elevation of the earth’s topography and helped in estimating the flood risk areas.
But, this approach overestimated the elevation as it uses more variables like vegetation cover, population indices etc.
But, as per researchers, CostalDEM is more accurate. It reduces the linear vertical bias from 4.71 m to less than 0.06 m.

More Live In BTL Areas

As per the study, nearly 110 million people across the world live in areas below the current high tide lines and 250 million live on land below flood annual flood levels.
SRTM based estimates put the numbers at 28 million and 65 million which are far lower.
Apart from India, there is an underestimation of numbers for countries like China, Bangladesh, Vietnam, Indonesia, and Thailand.

Conclusion

Globally, there is a mean sea level rise of 11-16 cm in the 20th century due to climate change.

This is expected to reach 2m by the end of the century. In such a scenario, this flood risk assessment study is important. It shows how cities, economies, regions and the world can get reshaped. It also raises the question of, how long countries can protect their people with coastal defences as the sea levels tend to rise drastically.