The Heard and McDonald Islands Are a Pristine Biological Wonderland
Trump’s tariffs put a spotlight on the uninhabited Heard and McDonald Islands, which comprise a remote volcanic refuge for penguins and seals and a UNESCO World Heritage site
A handout photo taken on November 21, 2012 and released on October 8, 2024 by the Australian Antarctic Division shows a waddle of King penguins standing on the shores of Corinthian Bay in the Australian territory of Heard Island in the Southern Ocean. Australia’s government moved on October 8, 2024 to protect a swathe of ocean territory by expanding an Antarctic marine park that is home to penguins, seals, whales and the country’s only two active volcanos.
Matt Curnock/Australian Antartic Division/AFP via Getty Images
Among the barrage of tariffs announced by U.S. president Donald Trump on Wednesday were those imposed (bafflingly to many) on a collection of remote, pristine and storm-battered islands with no human inhabitants: their main denizens are penguins and seals. Heard Island and the McDonald Islands, which were named a UNESCO World Heritage site in 1997 and represent Earth’s only volcanically active sub-Antarctic islands, were slapped with a 10 percent tariff.
Where are Heard Island and the McDonald Islands?
These islands are located in the Indian Ocean, about halfway between Australia and South Africa and 1,700 kilometers north of Antarctica.
On supporting science journalism
If you’re enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
Heard Island was discovered by American sailor John Heard in 1853. William McDonald, also an American, discovered the McDonald Islands the following year.
The islands are a territory of Australia, transferred from U.K. control in 1947, and cover an area about twice the size of Washington, D.C.
What are the geography and geology of the Heard and McDonald Islands?
The McDonald Islands are much smaller than Heard Island and are rocky. Heard Island is 80 percent covered by ice and features a large massif, or compact group of mountains, called Big Ben that has an active volcano called Mawson Peak at its summit.
A volcano on the McDonald Islands emerged from a 75,000-year period of dormancy in 1992. And lava from a 1996 eruption doubled the size of McDonald Island, the largest of the McDonald Islands. The most recent eruption of this volcano was in 2005. Both volcanoes are fed by a plume of magma from Earth’s mantle, akin to the plume that formed the Hawaiian Islands.
As the only volcanically active islands in the Antarctic regions, these islands “open a window into the earth,” according to their UNESCO entry, because they provide an opportunity to study how crustal plates form ocean basins and continents. They also allow researchers to study how glacial changes affect coastal and submarine environments, as well as the effects of climate change on the oceans and atmosphere.
The islands receive frequent rain, snow and other precipitation, along with strong winds, because of their latitude. Cloud cover is common.
Heard Island’s glaciers are relatively shallow and fast-moving. They have responded to rising global temperatures more quickly than glaciers elsewhere, retreating significantly in recent years, according to UNESCO.
What lives on the Heard and McDonald Islands?
These are also the only sub-Antarctic islands that have remained nearly free of nonnative species and have seen minimal effects from humans. This means they have enormous conservation value. There are no human settlements on the islands, and they are managed as a nature reserve by the Australian government.
The islands’ populations of marine birds and mammals number in the millions, according to UNESCO. They host major breeding populations of elephant and fur seals, petrels, albatrosses and penguins.
The islands are also home to species that are found nowhere else. These include the Heard Island Cormorant and a sheathbill subspecies called the Heard Island Sheathbill.
Do the islands have any exports that are now affected by the tariff or any other economic activity?
In the mid-19th century, hunters harvested elephant seal oil on the islands, killing off most of their seals before the practice was ended in 1877.
The first scientific expedition to the islands was made by a British ship called the HMS Challenger in 1874. Australia had a research station on Heard Island for a time, but it was closed in 1955, after the country opened a station on the Antarctic mainland. The Australian Antarctic Program is looking to do more research around the islands in the future.
A very small number of private yachts and tourist vessels have visited Heard Island, but few have landed because of the harsh weather.
No humans are known to have stayed on the islands for any substantial length of time since a winter research program in 1992, according to UNESCO. There are strict visitation and quarantine controls because of the islands’ nature reserve designation.
Limited commercial fishing of mackerel icefish (Champsocephalus gunnari) and Patagonian toothfish (Dissostichus eleginoides) is currently permitted in some of the waters around the islands. And interest in fishing there and elsewhere in Antarctic waters is expected to increase. Australian Defense Force vessels help enforce fishery rules.
