Flooding from rising sea levels could cost $14 trillion worldwide annually by 2100, if the target of holding global temperatures below 2ºC above pre-industrial levels is not achieved, as per a study led by the UK National Oceanographic Centre (NOC).
The study was published on July 3, 2018 in a science journal - Environmental Research Letters.
According to the study’s lead author, Dr Svetlana Jevrejeva from the NOC, "More than 600 million people live in low-elevation coastal areas, less than 10 meters above sea level. In a warming climate, global sea level will rise due to the melting of land-based glaciers and ice sheets and from the thermal expansion of ocean waters. So, sea level rise is one of the most damaging aspects of our warming climate."
Study: Key Highlights
• The researchers have revealed that upper-middle income countries such as China would see the largest increase in flood costs, whereas the highest income countries would suffer the least, due to existing high levels of protection infrastructure.
• The sea level projections exist for emissions scenarios and socio-economic scenarios.
• However, there are no scenarios covering limiting warming below the 2°C and 1.5°C targets during the entire 21st century and beyond.
• The study team explored the pace and consequences of global and regional sea level rise with the restricted warming of 1.5 ºC and 2 ºC, and compared them to sea level projections with unmitigated warming following emissions scenario Representative Concentration Pathway (RCP) 8.5.
• Using World Bank income groups (high, upper middle, lower middle and low-income countries), the team then assessed the impact of sea level rise in coastal areas from a global perspective and for some individual countries using the Dynamic Interactive Vulnerability Assessment modelling framework.
Speaking on the findings, Dr Jevrejeva said that they had found that with a temperature rise trajectory of 1.5°C, the median sea level will have risen by 0.52m (1.7ft) by 2100. But, if the 2°C target is missed, then the world will witness a median sea level rise of 0.86m (2.8ft), and a worst-case rise of 1.8m (5.9ft).
Jevrejeva stated that if the warming is not controlled and follows the RCP8.5 sea level rise projections, the global annual flood costs without adaptation will increase to $14 trillion per year for a median sea level rise of 0.86m and up to $27 trillion per year for 1.8m. This would account for 2.8 per cent of the global GDP in 2100.
• The projected difference in coastal sea levels is also likely to mean tropical areas will see extreme sea levels more often.
• These extreme sea levels will have a negative effect on the economies of developing coastal nations, and the habitability of low-lying coastlines.
• The most vulnerable nations would be small, low-lying island nations such as the Maldives. It would mount more pressure on the natural resources and environment of such nations.
• Hence, the results place a high emphasis on putting even greater efforts in controlling the rise in global temperatures.