Between the international airport in Nadi, Fiji, and the capital city of Suva, the coastal road on the island of Viti Levu is lined with resorts and clogged with tour buses. It’s a route I took several times this spring when I visited friends in Suva, a bustling port city where cruise ships drop anchor year-round and deposit thousands of tourists.

The steady stream of hulking ships is emblematic of Fiji’s popularity, and a major source of income. But the country’s reliance on tourism, combined with vigorous development and the effects of rising global temperatures, have conspired against Fiji’s fragile environment.

The country now faces major environmental challenges, including deforestation, unsustainable fishing practices, and the introduction of invasive species, such as the crown-of-thorns starfish, that have led to the destruction of coral reefs. Rising sea levels has led to the erosion of Fiji’s coastal areas, and the intrusion of saltwater has destroyed farmland and forced residents to move to safer ground.

Before I arrived, I had read that Pacific Island nations were threatened by rising temperatures and sea levels, but it wasn’t until my fifth day there, when my friends and I flew 45 minutes on a small prop plane to the island of Kadavu, that the threat came into full view.