Rising seas, rising stakes: What increasing sea-levels mean to humanity

Land is being inundated, homes are flooding, livelihoods are being lost, driving significant hardships on people in search of a more secure future.

It is not just the environment that is being affected, rising sea levels also have a significant impact on human rights, economic development, health, culture, the future of many countries and basic human dignity.

Everyone and pretty much everywhere are affected across developed and developing nations. The ability to act and adapt today will prove decisive for whether rising seas become a manageable challenge or a generational crisis.

Simply put, sea levels are getting higher due to the effects of human-induced climate change. 

Between 2014 and 2023, the global sea level rose 4.7mm a year. In 2024, it jumped a record 5.9mm. 

Even under the most optimistic scenario, oceans will likely rise up to 0.55 metres by 2100; under the worst, over a metre. A small, but high-impact, chance exists under high emission scenarios, of nearly 2 metres by the end of the century.

Around 770 million people, roughly 1 in 10 humans, live less than five metres above the high tide line. 

That is uncomfortably close and its proximity is already being felt. 

Beyond the physical: cultural heritage, ancestral land and traditional ways of life are being lost, with real psychological toll

Many of the countries facing the most immediate risks contribute least to the emissions driving sea-level rise and often have the fewest resources to respond.

Not entirely, some rise is already locked in. 

But how much more happens depends on the extent to which the harmful emissions can be cut now. 

One flashpoint: Antarctica's Thwaites Glacier, covering around 190,000 sq km. Its collapse alone could trigger a sudden, irreversible sea-level jump of over half a metre a genuine and possible tipping-point from which there is no going back.

Moving away from climate-changing fossil fuels is the world’s most important priority to slow down global warming and thus the rise of seas, but adaptation measures are also needed now. 

Developing countries need an estimated $310-365 billion a year for adaptation, but global adaptation finance was only about $26 billion in 2023

Rising seas can feel like an unstoppable force, but how much damage is done, and to whom, still depends on the choices that people, communities and governments make today. 

Ultimately, boosting adaptation finance, ensuring that statehood is not affected by rising seas, and giving sea-level rise the standing and urgency of a permanent global priority is what is needed to protect people's homes, histories, livelihoods and identities.