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Issue32: July - August 2004


Two billion will be in flood path by 2050, UNU expert warns

The number of people worldwide vulnerable to a devastating flood is expected to mushroom to 2 billion by 2050 due to climate change, deforestation, rising sea levels and population growth in flood-prone lands, a UNU expert warns.

One billion people – one sixth of the global population, the majority of them among the world’s poorest inhabitants – are estimated to live today in the potential path of a 100-year flood and, unless preventative efforts are stepped up worldwide, that number could double or more in two generations, said Dr. Janos Bogardi, director of UNU Institute for Environment and Human Security (UNU-EHS).

Floods affect more than 520 million people per year worldwide, resulting in 25,000 deaths, extensive homelessness, disaster-induced disease, crop and livestock damage and other serious harm. Unsustainable land use and other human actions aggravate the situation.  

The greatest potential flood hazard is in Asia. Every year for the past two decades, more than 400 million people on average have been directly exposed to a flood.  Between 1987 and 1997, 44 percent of all flood disasters worldwide affected Asia , claiming 228,000 lives (roughly 93 percent of all flood-related deaths worldwide). Economic losses in the region in that decade totaled US $136 billion.  

The fast-growing cost to the world economy of floods and other weather-related disasters (now $50 to $60 billion per year, much of it in developing countries) is roughly equal to the global development aid provided by all donor countries combined.  The flood-related death toll represents 15 percnet of all natural disaster-related loss of life.

Bogardi estimates that the number of people living in flood-prone areas will roughly double due to:

  • more extreme weather systems that accompany global climate change,

  • rising sea levels; and

  • continuing deforestation, especially in mountain regions. 

He also predicts that pressure to live and work in flood-prone areas, which typically feature attractive rich soils, abundant water supplies and ease of transport, will increase as the world’s population continues rising to a projected 10 billion by 2050.

Janos Bogardi

The growing frequency and magnitude of extreme environmental events worldwide has intensified research interest in natural disasters as well as regional vulnerability and response capabilities,” said Bogardi. “In the warmer, wetter world predicted by science today, the northern part of the Northern Hemisphere will likely see more storms while some continental areas might have drier summers and more risk of drought. Sea levels could rise, fed in part by melt-water from glaciers and ice caps. Along with this, extreme high-water levels may occur with increasing frequency.  Higher sea levels could inundate small islands, flood coastal lowlands, and erode sand dunes.  

“Most urgently needed to adapt to the growing risk of flood disasters is greater global capacity to monitor and forecast extreme events,” Bogardi said. “Armed with better information, superior early warning systems and infrastructure can be installed, and new planning strategies devised.  

“It is also necessary to ensure that increasingly freakish climate variability and the gradual forces of climatic change and deforestation are factored into the total picture.”  

There needs to be a shift in the international mindset – from reaction and charity to anticipation and preemption. Countries are generous with post-disaster relief but less so when it comes to pre-disaster preparedness, spending $100 in relief for every $1 in preparedness. 

Recent studies have also shown the cost of constructing disaster-resistant buildings adds only 2 to 12 per cent on average to the final costs.  Meanwhile forecasting and warning systems commonly show a cost-benefit ratio of 10 or 15 to 1.

Mortality is often highest in rural areas of poor countries where disaster preparedness and early warning is virtually non-existent and where health coverage is usually weak or not easily accessible.  In such areas, people are less likely to evacuate from flood prone areas – and in some cases fear leaving and potentially losing their possessions or their property claim.


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