Lorentz National Park

Two pieces of Earth's outer shell, called plates, push into each other here. That pushes the mountains up.

Ice has carved the mountains too.

The park lies where two of Earth's plates, the Australian and Pacific plates, collide. UNESCO says this collision built the main mountain range, and the mountains are still forming.

Glaciers have also carved the mountains, leaving lakes and moraines (ridges of rock left by ice). Fossil sites in the park show how life on New Guinea evolved.

UNESCO explains that the dominant mountain range is a direct product of the collision between the Australian and Pacific tectonic plates, with ongoing mountain formation, major sculpting by glaciation, and shoreline accretion along the coast; there is clear evidence of post-glacial shorelines.

The mountains show the classical glacial landforms, including lakes and moraines, and UNESCO says there is no better example in the world of plate collision combined with glacial and post-glacial sculpting. Fossil sites record the evolution of life on New Guinea.

The park is close to the Equator, but its highest mountains are cold enough for ice.

That ice is shrinking.

The mountains lie just south of the Equator, but NASA says they are high and cold enough to hold a few small areas of ice. UNESCO calls Lorentz one of only three tropical regions in the world with glaciers.

NASA's satellite pictures show the ice shrinking. In 1988 there were five masses of ice; by 2009 two of them had disappeared. In 2018, NASA reported that scientists estimated the rest could be gone within about a decade.

UNESCO's description of the site lists five small remnant glaciers, all retreating rapidly, and says no other tropical glacier fields show glacial evolution as well. NASA notes how rare they are: the nearest glacial ice is 4,500 km north on Japan's Mount Tate, and the nearest in the tropics is 11,200 km away on Mount Kenya.

Comparing Landsat images from 1988 and 2017, NASA reported five ice masses in 1988; by 2009 the Meren and Southwall glaciers had gone. In February 2018 it reported that scientists estimated the glaciers could be gone within about a decade.

Many animals live in the park, like echidnas and rare birds.

Some of them live nowhere else.

UNESCO counts some 123 kinds of mammals in the park, including two kinds of echidna, mammals that lay eggs. It also has 45 bird species with small ranges, such as MacGregor's bird-of-paradise and Archbold's bowerbird, and nine endemic species that live only in this region.

Scientists keep finding new species here. The Dingiso tree kangaroo was discovered in 1994.

UNESCO identifies 34 vegetation types and 29 land systems, about 123 recorded mammal species, and two of the world's three monotremes: the short-beaked echidna and the long-beaked echidna (Zaglossus bruijinii), a New Guinea endemic. The park covers substantial parts of two Endemic Bird Areas, with 45 restricted-range and nine endemic birds; Archbold's bowerbird and MacGregor's bird-of-paradise are considered rare and vulnerable.

The mountains gave temperate refuges to ancient Gondwanan plants as the climate warmed after the last ice age: Nothofagus beech forests grow here, while their closest relatives live in southeastern Australia, New Zealand and the southern Andes.

The mountains are very high, and high places can make your head hurt.

If that happens, tell a grown-up and go lower.

Lorentz rises from sea level to 4,884 meters, so its mountains are high enough to cause altitude sickness. The US Centers for Disease Control and Prevention (CDC) says children can get it just as adults can, a headache is the main sign, and going down at least 300 meters helps.

UNESCO notes the area also has high rainfall.

The CDC's Yellow Book says any unacclimatized traveler sleeping at 2,450 m or higher is at risk of altitude illness, children are as susceptible as adults, headache is the cardinal symptom of acute mountain sickness, and a descent of 300 m or more brings rapid improvement.

The park's high mountains reach 4,884 m (UNESCO), and UNESCO notes high rainfall along the transect from the mountains to the sea.