The combined effects of man-made sea level rise, severe storm surges and tides could expose the coast to another 23 million people over the next 30 years, despite relatively ambitious reductions in greenhouse gas emissions.
In the worst case scenario, when emissions are constantly increasing and no efforts are being made to adapt to rising sea levels, coastal assets worth 14.2 tonnes could be jeopardized by the end of the century. USD ̵1; about 20% of global GDP.
Rising sea levels caused by global warming, expanding oceans and melting terrestrial ice could mean that floods that occur every 100 years could become floods in 10 years by the end of the century. Floods could affect up to 4% of the world’s population.
A study published in the Scientific Reports identified hotspot regions at risk of widespread flooding.
Southeast China, North Australia, Bangladesh, West Bengal and Gujarat in India are particularly at risk. In the United States, North Carolina, Virginia, and Maryland were considered the most exposed, such as the United Kingdom, northern France, and northern Germany.
However, the study also shows how the risk of damage from rising sea levels and storms will continue to increase, even if emissions are maintained to raise global temperatures to well below 2 ° C by the end of this century.
The new study is based on findings published by the UN Intergovernmental Panel on Climate Change in 2019, according to which predicted extreme sea levels could be almost annual on many coasts in the middle of this century.
Professor Ian Young, co-author of the study at the University of Melbourne, said: “We certainly need to mitigate our greenhouse gases, but that will not solve the problem.
“Sea level rise is already baked – even if we reduce emissions today, sea levels will continue to rise as glaciers will melt for hundreds of years.”
According to a study, about 148 million people worldwide are exposed to floods today.
If greenhouse gas emissions increase slightly – equivalent to 1.8 ° C to global warming by the end of the century – another 54 million people will be exposed. However, if spiral emissions are allowed in the worst case, this number will rise to 77 million.
According to the study, around 2100 tons of USD 10.2 t are exposed to coastal floods around 2100, even with emissions kept at a moderate level.
All data modeled in the study assume that no adaptation measures are taken to illustrate the benefits of early action to reduce the impact of floods.
Young said: “When most people think about sea level rise, they think about 3 or 4 mm a year, but when floods occur, it is even when you have a storm.
“It’s happening today and we saw it last week on the coast of New South Wales.” Sea level rise worsens the scale of these events and increases their frequency.
“There are significantly larger areas of flooding that will have a significant economic impact on infrastructure.
“Even if we reduce greenhouse gases, it doesn’t have much effect. We need to adapt to this – it has to happen by having to deal with either tough engineering solutions, or by looking at planned retreats and relocations, which is incredibly difficult, or there are coastal defense systems based on nature. “
Ebru Kirezci, a researcher at the University of Melbourne, said: “We need to adapt to sea level rise and climate change.
“Adaptation is the only way out and we need to adopt certain risk mitigation strategies, such as sea walls and dams, and to develop forecasting and warning systems or coastal retreats, which means moving coastal communities to safer places.”
Professor John Church, a leading sea level expert at the University of New South Wales Climate Change Research Center, who did not take part in the study, said the findings were valuable.
The study combined several elements to estimate extreme impacts, but more needs to be done to understand other impacts resulting from changes in the severity of storms and waves.
He said significant impacts were likely to occur along estuaries, and it was important to note that “sea level rise will not stop in 2100 in any scenario.”
He said: “The more emissions, the higher [sea level] rises with commitments of meters above sea level in the coming centuries to rise in higher scenarios. The impacts up to 2100 are an introduction to the future. “
Floods in coastal waters could affect 20% of world GDP, but said it was a reflection of a society that “loves the coast”.
“We need more thoughtful and forward-looking planning.”