Summary:Half of the world’s beaches could disappear by the end of the century due to coastal erosion, according to a new study led by the Joint Research Centre, the European Commission’s science and knowledge service.
Half of the world’s beaches could disappear by the end of the century due to coastal erosion, according to a new study led by the JRC.
Erosion is a major problem facing sandy beaches that will worsen with the rising sea levels brought about by climate change. According to the study, published today in Nature Climate Change, effective climate action could prevent 40% of that erosion.
Sandy beaches cover more than 30% of the world’s coastlines. They are popular recreational spots for people and they provide important habitats for wildlife. They also serve as natural buffer zones that protect the coastline and backshore coastal ecosystems from waves, surges and marine flooding. Their role as shock absorbers will become more important with the rising sea levels and more intense storms expected with climate change.
However, climate change will accelerate erosion and could make more than half of the world’s sandy beaches completely vanish by the end of this century. Fuelled by a growing population and urbanisation along coastlines, this is likely to result in more people’s homes and livelihoods being impacted by coastal erosion in the decades to come.
The findings come from the first global assessment of future sandy shoreline dynamics. JRC scientists combined 35 years of satellite coastal observations with 82 years of climate and sea level rise projections from several climate models. They also simulated more than 100 million storm events and measured the resulting global coastal erosion.
They found that reducing greenhouse gas emissions could prevent 40% of the projected erosion.
However, even if global warming is curbed, societies will still need to adapt and better protect sandy beaches from erosion. This is one of the main messages of the Paris Agreement on climate and the EU adaptation strategy.
Human presence makes sandy beaches less resilient
Sandy coastlines are extremely dynamic environments due to altering wave conditions, sea levels and winds, as well as geological factors and human activity. They are naturally resilient to climate variations, as they can accommodate higher seas and marine storms by retreating and adapting their morphology.
However, they face more and more pressure because of human development, a situation that could become worse if contemporary coastal urbanisation and population growth continues. As ‘backshores’ — the area of a coastline above the high-tide level — become increasingly built-up, sandy shorelines are losing their natural capacity to accommodate or recover from erosion.
At the same time, river dams and human developments retain sediment upstream that would naturally feed beaches. As a result, a substantial proportion of the world’s sandy coastlines are already eroding, a process that could accelerate with rising sea levels.
Climate mitigation and adaptation challenges ahead
The study shows that without climate mitigation and adaptation almost half of the world’s sandy beaches are under threat of near extinction by the end of the century. Apart from the loss of valuable ecosystems, socioeconomic implications can be severe, especially in poorer, tourism dependent communities where sandy beaches are the main tourist attraction. Small island nations are among the more vulnerable regions.
In most parts of the world, projected shoreline dynamics are dominated by sea level rise and moderate greenhouse gas emission mitigation could prevent 40% of shoreline retreat globally. Yet, in certain regions the effects of climate change are counteracted by ‘accretive ambient shoreline changes’ — the build-up of sandy beaches from sediments arriving due to other natural or anthropogenic factors. . This is true for areas of the Amazon, East and Southeast Asia and the North Tropical Pacific.
Commission is already working to address these challenges
The EU is committed to mitigating climate emissions. With the Green Deal for Europe it strives to achieve carbon neutrality by 2050.
The EU Strategy on Adaptation to Climate Change aims to make Europe more resilient and minimise the impact of unavoidable climate change. It stresses that coastal zones are particularly vulnerable to the effects of climate change, which challenges the climate resilience and adaptive capacity of our coastal societies. This requires a strong EU Strategy and preparedness actions by Member States aimed at reducing the vulnerability of their citizens and economies to coastal hazards in order to minimize future climate impacts in Europe.
The EC published the recommendations for Integrated Coastal Management. This policy instrument requires establishing a coastal setback zone, extending at least 100 m landward from the highest winter waterline, taking into account, inter alia, the areas directly and negatively affected by climate change and natural risks.
The EC Floods Directive requires Member States to assess if all water courses and coastlines are at risk from flooding, to map the flood extent and assets and humans at risk in these areas and to take adequate and coordinated measures to reduce this flood risk. Maintaining healthy sandy beaches is an effective coastal protection measure, and has environmental benefits.
Several sandy environments are included in the EC Habitats Directive as they are related to protected species and many of the NATURA protected areas include sandy coastlines.
Implementation of these actions should lead to rivers being more able than they are now to resume their natural function of sediment transport which, simply put, provides the material for natural processes to restore and retain sandy beaches.
The Sendai Framework for Disaster Risk Reduction 2015-2030, the Paris Agreement on Climate Change and the Sustainable Development Goals have set the agenda for reducing disaster risks through sustainable and equitable economic, social, and environmental development.
In this context, poorer low-lying countries remain particularly vulnerable to coastal hazards and huge investments or changes in these societies may be needed to close the vulnerability gap with richer countries.
More: Science Daily