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 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.