Much of the world as we know it might disappear or at least become uninhabitable in the coming decades — in some cases by as early as 2050, and almost certainly by 2100 — if the international community doesn’t take dramatic action to curtail the effects of climate change very soon.

Drought and other effects of increasing temperatures potentially render some parts of the globe unliveable, as do increasingly frequent and devastating hurricanes, typhoons, and monsoon rains. The main culprit, though, is the rise in sea level caused by melting ice sheets and other phenomena associated with global warming.

Some of the most vulnerable places in the world are islands whose elevations are at or below mean sea level, but alluvial plains and other low-lying places on every continent, even far inland, may be inundated too. Here are 20 islands that will disappear in your lifetime.

According to UNESCO, the places at risk include almost a fifth of the planet’s 720 World Heritage sites. But whole cities, including some of the world’s largest — Shanghai, Hong Kong, Mumbai, Bangkok, London, New York, Miami, Sydney, and Rio de Janeiro among them — are seriously threatened too. These are cities around the world that will soon be underwater.

24/7 Tempo based its list of countries, regions, and cities around the world that are at risk of flooding permanently over the next 30-plus years on projections of sea level rise and related data from Climate Central, FloodMap, Earth.org, ClimateLinks, the World Bank, the Union of Concerned Scientists’ Climate Hot Map, and UNESCO’s report on Climate Change and World Heritage. Editors then selected a representation of potentially affected areas in some 21 countries on six continents, and identified a total of 28 specific places of special interest in each of them.

Click here to see 28 amazing places that could be underwater by 2050