The Earth is not finished. Honestly, we tend to think of the world map as this static, laminated thing hanging in a geography classroom, but that’s just not reality. Right now, as you're reading this, molten rock is screaming up from the seafloor, hitting freezing seawater, and hardening into brand-new territory. It’s chaotic. It’s violent. And it means the question of how many of these islands are still forming isn't just a trivia point—it’s a look at the literal birth of the planet.
Most people assume the big tectonic shifts ended millions of years ago. They didn't.
While most of the world's 300,000+ islands are slowly eroding or sinking due to rising sea levels, a handful of "newcomers" are fighting back. From the black sands of Iceland to the bubbling cauldrons of the South Pacific, the map is being redrawn in real-time. We aren't just talking about coral reefs growing a few millimeters a year. We're talking about massive plumes of steam and the kind of geological power that can create a mile of land in a few weeks.
The Active Count: How Many of These Islands Are Still Forming?
If you want a hard number, it’s tricky. Geology doesn't work on a quarterly schedule. However, at any given moment, there are roughly half a dozen major sites globally where islands are actively being built by volcanic or tectonic forces.
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The most famous, of course, is the "Big Island" of Hawaii. Kīlauea has been pouring lava into the Pacific for decades, and while the flow stops and starts, the island is technically still in its growth phase. Then you have the newcomers like Niijima near Japan or the shifting sands of the Zubair Archipelago.
It's a constant battle between creation and the relentless hunger of the ocean.
The Life and Death of Surtsey
Take Surtsey in Iceland. Back in 1963, a fisherman noticed smoke rising from the water. He thought it was a boat on fire. Nope. It was a volcano. By 1967, a 2.7-square-kilometer island had emerged from the depths. Today, it’s a living laboratory. It’s one of the few places on Earth where we can watch life colonize a completely sterile environment. Moss came first. Then birds. Now, it’s a lush (well, for Iceland) little ecosystem.
But here is the catch: Surtsey is shrinking.
Since the eruptions stopped, the waves have been hacking away at it. This is the fate of many islands still forming; if the volcanic "faucet" turns off before the island is big enough to withstand erosion, the ocean wins. Most "new" islands disappear within a year. Only the heavyweights survive.
Where the Earth is Currently Growing
If you’re looking for where the action is right now, you have to look at the hotspots and the subduction zones. These are the "construction sites" of the world.
The Iwo Jima Expansion
Japan is effectively getting bigger. In late 2023, an undersea eruption near Iwo Jima created a tiny new island. It started as a jumble of rocks and ash, but it’s stayed above water longer than many expected. This area, part of the Ogasawara chain, is incredibly active. The Japanese Coast Guard has to keep updating their charts because the seafloor is basically a moving target.
The Hunga Tonga Phenomenon
You probably remember the massive Hunga Tonga-Hunga Ha'apai eruption in 2022. That was the loudest sound recorded in the modern era. Before that "big one," two separate islands actually merged together due to smaller eruptions starting in 2014. It was a fascinating case study in how many of these islands are still forming through consolidation. Unfortunately, the 2022 blast was so powerful it actually vaporized much of the land it had previously created.
Nature gives, and nature takes away. Fast.
The Canary Islands and the Atlantic Creep
Over in the Atlantic, the 2021 eruption of Cumbre Vieja on La Palma showed us that even "established" islands are still in the forming stage. The lava flows reached the sea, creating "deltas" of brand-new land. Thousands of square meters were added to the coastline. While the island itself isn't "new," its borders are still being negotiated by the magma underneath.
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Why Some Islands Stick Around and Others Vanish
It comes down to what they're made of.
If a volcano burps up a bunch of ash and "pumice," the ocean will dissolve it like a sugar cube in a cup of coffee. This happened with an island called Home Reef in Tonga. It popped up in 2006, 2022, and again recently. Every time, the waves just eat it.
To survive, an island needs pahoehoe or 'a'a lava—the thick, basaltic stuff that hardens into solid rock. Once you have a core of solid basalt, you have a fighting chance. Over time, the surface weathers into soil, seeds arrive via bird droppings or ocean currents, and suddenly you have a destination.
The Role of Tectonic Uplift
It isn't always about volcanoes. Sometimes, the Earth just pushes. In 2013, a massive earthquake in Pakistan caused a "mud island" called Zalzala Koh to rise out of the sea. It was basically a giant bubble of mud and methane gas. It lasted for a few years before the gas escaped and the mud washed away. It’s gone now.
But in places like the Solomon Islands, tectonic uplift is pushing coral reefs out of the water, creating "raised coral" islands. This is a much slower process than a volcanic eruption, but it’s arguably more stable.
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The Global Impact of New Land
Why should we care about a few acres of black rock in the middle of nowhere?
- Geopolitics: When a new island appears, everyone wants it. Why? Exclusive Economic Zones (EEZ). If a nation can prove a new island is "permanently" above high tide, they can claim 200 nautical miles of fishing and mineral rights around it.
- Biological Discovery: These islands are the only places where we can see how species migrate across vast distances without human interference.
- Climate Science: Watching how quickly these islands erode gives us vital data on wave power and rising sea levels.
Misconceptions About Island Formation
Most people think islands "float." They don't. Every island you see is the tip of a mountain that starts on the seafloor. When we ask how many of these islands are still forming, we are really asking how many underwater mountains are currently growing tall enough to break the surface.
There are thousands of "seamounts" (underwater volcanoes) in the Pacific alone. Many are just a few hundred feet from the surface. A single big eruption could turn any one of them into a new island tomorrow.
The most anticipated one? Lōʻihi (now officially Lōʻihi Seamount or Kamaʻehuakanaloa). It’s an underwater volcano about 20 miles off the coast of Hawaii. It’s currently about 3,000 feet below the surface. It’s growing. In about 10,000 to 100,000 years, it will be the newest Hawaiian island.
Actionable Insights for the Curious
If you’re fascinated by the fact that the Earth is still under construction, you don't have to just read about it. You can actually track it.
- Monitor the Smithsonian Global Volcanism Program: This is the gold standard. They provide weekly reports on volcanic activity worldwide. If a new island is popping up, they’ll be the first to document the "tephra" and "lava fountains."
- Use Satellite Imagery: Tools like Sentinel Hub or Google Earth Engine allow you to look at historical imagery. You can literally scroll back a few years and see the coastline of places like La Palma or Nishinoshima change shape.
- Visit "Young" Landscapes: If you want to feel the raw energy of a forming island, go to the Big Island of Hawaii or Iceland. Walking on a lava flow that is younger than you are is a humbling experience. You can see the heat shimmering off the rocks.
- Support Marine Conservation: New islands often form in volcanic arcs that are also biodiversity hotspots. Protecting the waters around these "birth sites" ensures that when life does move in, it has a healthy environment to thrive in.
The Earth is alive. It’s messy, it’s dangerous, and it’s constantly expanding in ways that defy our desire for a permanent map. We are living through a period of intense geological transition, and while the number of islands still forming might seem small, their impact on our understanding of life and our planet is massive.
Keep an eye on the horizons. The next piece of Earth could break the surface any day now.