As long-term average global temperatures rise due to climate change, the impacts of global warming on ocean levels are becoming increasingly visible. Sea levels are rising as glaciers and ice sheets melt due to higher temperatures, and although this may superficially appear to be a beneficial occurrence, the fact is that it represents an abrupt and potentially catastrophic change in the delicate balance of our planet’s ecosystems.
The Intergovernmental Panel on Climate Change (IPCC) reported that between 1870 and 2006, global sea levels rose by an average of 1.7 mm per year, which is the highest rate observed in recorded history. They have continued to rise even higher since: in 2019, the Global Mean Sea Level rose by 3.5 mm. This remarkable rate of change can be attributed to oceans warming and expanding, glaciers melting, and coastal ice melting from both land-based glaciers and ice shelves. In fact, over 85% of sea-level rise is caused by thermal expansion and melt water from ice sheets.
The effects of global warming on sea levels are far-reaching. The receding coastline leads to an increased risk of flooding, erosion, and storm surge in coastal areas. Currently, between 7 and 11 million people are at risk of flooding due to sea level rise, with varying levels of risk depending on the amount of rise in sea levels. Furthermore, a rise of 3.9 ft (1.2 m) has been forecast by the end of the century by the United Nations, raising the prospect of entire island nations being wiped out due to a lack of inhabitable land.
While the impacts of sea level rise on human populations have so far been mostly felt in developing countries, the wealthier nations are not immune. For instance, approximately 38 million people in the United States are at risk of flooding because of sea level rise. Predictions of a 10-foot sea-level rise by 2050 have caused certain areas of the US, such as Miami and New Orleans, to consider the possibility of relocating their populations due to the unsuitability of the land for residential areas.
In addition to the environmental and human impacts of sea level rise, there is also the potential for devastating economic consequences. As sea levels rise, so do the risks associated with flooding and storms, which can lead to increased insurance premiums, damage to public infrastructure, loss of coastal ecosystems, and damaging of fragile coastal habitats. For instance, in some areas, beach erosion and saltwater intrusion into freshwater aquifers can cause lasting damage and further destabilize populations and economies. The US has already issued a climate adaptation plan to tackle the potential economic damage associated with sea level rise by 2050.
Overall, global warming is having a profound effect on our planet, and the effects of sea level rise are being felt all over the world. While some impacts are already visible in coastal regions and can be addressed through adaptive management strategies, the scale of the issue is such that much more must be done to ensure effective mitigation and adaptation of our ecosystems. It is clear that immediate action is needed, both from governments and from individuals, to ensure that sea levels do not reach a tipping point which would be catastrophic for the livelihoods of the world’s people and the future of our planet.
