About 17,000 years ago, during the last Ice Age, sea levels were significantly lower, allowing people to walk from Russia to America and from Australia to Tasmania. However, since the end of the Ice Age, sea levels have been rising at an alarming rate due to factors like global warming. A recent study published in the journal Nature highlights the impact of sea level rise on coastal habitats and the potential devastation it could cause to coastal agriculture worldwide.
Coastal Habitats and Rising Sea Levels
Coastal habitats such as mangroves, marshes, and coral reefs form in the low-lying areas that are flooded and drained by tides. The study suggests that these habitats can adapt to a certain extent to rising sea levels. However, they could reach a tipping point when global warming causes sea levels to rise more than 1.5 to 2 degrees Celsius.
Mangroves: Tropical Guardians
Mangroves are typically found in tropical regions like southeast Asia, northern Australia, equatorial Africa, and low-latitude Americas. These unique ecosystems play a crucial role in preventing erosion and are hotspots for biodiversity. However, smaller mangrove colonies can also be found in unexpected places such as Olympic Park in Sydney and Towra Point in Botany Bay.
Marshes: Guardians of the Intertidal Zones
Coastal marshes, on the other hand, are found in intertidal zones that are further away from the equator, such as along the Atlantic shores of North America and Northern Europe. Australia boasts approximately one million hectares of coastal marshes. These marshes act as a buffer between the ocean and the land, absorbing wave action and preventing erosion. They are also home to a diverse range of plant and animal species.
The Vulnerability of Coastal Habitats
Both mangroves and tidal marshes depend on oxygen reaching their roots to survive. During low tide, when the water drains out, they receive necessary oxygen. However, global warming has led to waterlogging, causing these plants to die out. Scientists have already witnessed this phenomenon at Sydney Olympic Park. Additionally, coral reefs, which form a coastal ecosystem protecting coral islands, will disappear underwater beyond 2 degrees Celsius of global warming, losing their ability to safeguard coastal ecosystems.
The rising sea levels due to human-caused global warming pose a significant threat to coastal agriculture. Coastal habitats like mangroves, marshes, and coral reefs are already experiencing the adverse effects of sea level rise. It is crucial to address climate change and take necessary measures to mitigate its impact on these habitats to ensure the sustainability of coastal agriculture and the overall health of our planet.