Devastating cost of future coastal flooding for many developing nations predicted in new study

Date:
February 7, 2023
Source:
University of Melbourne
Summary:
New global modelling predicts the devastating socioeconomic impacts
of future extreme coastal flooding for developing nations caused
by climate change, with Asia, West Africa and Egypt facing severe
costs in the coming decades.


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FULL STORY ==========================================================================
New global modelling predicts the devastating socioeconomic impacts
of future extreme coastal flooding for developing nations caused by
climate change, with Asia, West Africa and Egypt facing severe costs in
the coming decades.


========================================================================== Published in Frontiers in Marine Science,the study sought to determine
the expected annual costs and number of people impacted by episodic
coastal flooding across the globe as sea levels rise, rating the impact
of flooding for every country across specified scenarios. The study
found flooding would disproportionately affect developing nations,
given their reduced capacity to pay for improved coastal defences and
their geographic vulnerability.

Led by University of Melbourne Dr Ebru Kirezci and Professor of
Engineering Ian Young, the study found many developing nations would
experience expected annual damage costing over five per cent of their
national Gross Domestic Product (GDP) if no coastal defence adaptation
measures are taken to mitigate extreme coastal flooding impact.

By contrast, almost all developed nations would experience expected
annual damage of less than three per cent of national GDP because of
their capacity to undertake coastal defence adaptation measures.

Coastal defence adaptation measures include raising or building sea
walls or dykes as sea levels rise, and natural interventions such as
improving drainage and sand dunes or mangrove plantations.

"This research shows the human and financial cost of climate change and
how unequally its effects will be felt," Professor Young said.

"Developing nations will be devastated, both in terms of people impacted
and their economies. If the money to mitigate this impact in developing countries is not found, communities will be forced into coastal retreat
and there will be significant social disruption, including an increase
in climate refugees across borders." The researchers created a database
to model and analyse projected extreme coastal flooding in over 9000
locations for the years 2050 and 2100. Using 2015 data as a baseline,
two 'coastal defence' scenarios were modelled -- one with no additional
coastal defence adaptation measures, and the other with additional
coastal defence adaptation measures.

The modelling demonstrated that these measures will play a crucial role in reducing the impact of extreme coastal flooding for nations. The modelling predicted the most severe impacts by the year 2100 for Asia, West Africa
and Egypt, irrespective of the adaptation scenario. The nations and
regions likely to be most affected included Suriname, Vietnam, Macao
(Special Administrative Region of China), Myanmar, Bangladesh, Kuwait, Mauritania, Guyana, Guinea- Bissau, Egypt and Malaysia.

Dr Kirezci said episodic coastal flooding can be caused by storm surge,
high tides, breaking waves and climate change-induced sea level rise.

"Our model considers tides, storm surges, breaking waves and mean
sea level rising. It also accounts for different populations, GDP and greenhouse gas scenarios by 2100," she said.

Without adaptation measures, the modelling predicted the number of people affected by extreme coastal flooding could increase from 34 million
people per year in 2015 to 246 million people by 2100. The expected
annual global cost of extreme coastal flooding damage could increase
from 0.3 per cent of global GDP in 2015 to 2.9 per cent by 2100.

However, if coastal defence measures match the projected rise in sea
levels, by 2100, the number of people affected would be around 119
million people per year, with the expected annual global cost reduced by a factor of almost three, to 1.1 per cent of GDP. The researchers said that finding the funds to pay for these measures will be an enormous challenge.

"There is no doubt this is a wicked problem, which initiatives such as
the recent United Nations Climate Change conference COP 27, held in Egypt,
are grappling with," Professor Young said.

* RELATED_TOPICS
o Earth_&_Climate
# Floods # Global_Warming # Oceanography # Climate
o Science_&_Society
# Ocean_Policy # World_Development # Resource_Shortage
# Funding_Policy
* RELATED_TERMS
o Climate_change_mitigation o Global_warming o
Consensus_of_scientists_regarding_global_warming
o Global_warming_controversy o
IPCC_Report_on_Climate_Change_-_2007 o Climate_engineering o
Gulf_Stream o Kyoto_Protocol

========================================================================== Story Source: Materials provided by University_of_Melbourne. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Ebru Kirezci, Ian R. Young, Roshanka Ranasinghe, Daniel Lincke,
Jochen
Hinkel. Global-scale analysis of socioeconomic impacts of coastal
flooding over the 21st century. Frontiers in Marine Science, 2023;
9 DOI: 10.3389/fmars.2022.1024111 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/02/230207144251.htm

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