Every year humans add a little more land to the coastline, slowly but surely encroaching on the sea, filling small coastal water bodies with new developments. Occurs when extending to the sea. Since 2000, coastlines around the world, especially urban ones, have expanded by 2,530 square kilometers, according to a new paper.
A press release about the study said this was about 40 Manhattans, but the paper itself points out that this is about the size of Luxembourg. Neither source says this, but it’s also 4,000+ Dollywood.
The paper claims to be “the first global assessment of coastal reclamation” and examines how human development has built up land in the coastal zone, or filled parts of it. I checked. We can continue to build anyway, right?), as well as protecting inland areas from flooding and rising sea levels, and serving as habitat for countless species.
empty eyes
The researchers looked at satellite imagery taken from 135 large coastal cities (with more than 1 million people) around the world between 2000 and 2020. Of this number, 106 sites had an increase in shoreline land.
This process was most common in the Global South, especially in the growing economies. Cities in three countries—China, Indonesia, and the United Arab Emirates—lead the pack in terms of these developments. Shanghai, for example, increased by about 350 square kilometers, a notable increase compared to Los Angeles, the only US city that increased by 0.29 square kilometers in 20 years.
The most common type of development was the port expansion seen in 70 cities. This was followed by residential and/or commercial development in 30 cities. Dhritiraj Sengupta, a physical geographer at the University of Southampton and lead author of the paper, said in his press release that many of these changes have been driven by the increasing need for space in urban areas. But the city has also pursued some of these developments for prestige, like the islands of Dubai arranged to look like palm trees from above.
More than just sitting on a dock in the bay
However, these developments come with associated costs. The paper notes that about 70% of the expansion occurred in low-lying areas susceptible to rising sea levels. In some places, they compensate by building seawalls and other structures designed to protect against rising sea levels and flooding. For example, it is estimated that about 14% of the US coast is protected by such structures. However, these buildings can also affect nearby natural ecosystems, such as impeding migration of species. You may end up pushing water into the part.
The paper also notes that, in some cases, coastal growth is accompanied by increased pollution entering the sea. Including flowing. This can adversely affect nearby ecosystems and hurt industries such as tourism and fishing.
The paper focuses only on certain parts of the world’s coastlines, although they are highly populated. This is just a fraction of the estimated 620,000 kilometers of coastline for the entire planet. About 2.4 billion people live within 100 kilometers of the area. However, only 15% of the world’s coasts are in a natural state. Therefore, it is hard to say that unexpected changes are not seen even on sparsely populated coasts.
AGU, 2023. DOI: doi.org/10.1029/2022EF002927 (About DOI)
