Rising sea levels are threatening to push powerful seasonal waves towards Easter Island's iconic moai statues, according to a new scientific study.

Published in the Journal of Cultural Heritage, 15 of the human monolithic figures are at risk from flooding while 51 other cultural sites on the eastern Pacific Island are also in danger.

"Sea level rise is real," Noah Paoa, lead author of the study and a doctoral student at the University of Hawaii at Manoa's School of Ocean and Earth Science and Technology, said.

"It's not a distant threat."

Assessment of the island's coastal cultural sites has been a topic of growing interest in the scientific world, but the distribution of research has been "globally uneven and particularly scarce in Pacific Islands", the study reports.

Dr Paoa, who is from Easter Island – known to its Indigenous people as Rapa Nui – built a high-resolution "digital twin" of the island's most eastern coastline and ran computer models to simulate future wave environment's impacts under a range of sea level rise scenarios.

With his university colleagues, he then overlaid the results with maps of the cultural sites being flooded at the current mean high water level to pinpoint the locations that may be inundated in the coming decades.

The study said: "We find that cultural assets are within the reach of wave run-up at current sea levels, and the number of assets impacted could triple by 2100."

The site, home to the 15 towering moai, is a highly recognisable landmark and draws tens of thousands of visitors each year as the cornerstone of the island's tourism economy.

"This research reveals a critical threat to the living culture and livelihood of Rapa Nui," Dr Paoa said.

"For the community, these sites are an essential part of reaffirming identity and to support the revitalisation of traditions.

"Economically, they are the backbone of the island's tourism industry.

"Failure to address this threat could ultimately endanger the (Rapa Nui) island's UNESCO world heritage site status."

The findings show waves could reach Ahu Tongariki, the largest ceremonial stone platform on the island, within the next 50 years.

Beyond its economic value, the ahu is deeply woven into Rapa Nui's cultural identity.

It lies within Rapa Nui National Park, which encompasses a large slice of the island's land mass that is also recognised as a UNESCO World Heritage site.

The roughly 900 moai statues across the entire island were built by Rapa Nui Polynesian tribes sometime between the 10th and 16th centuries to honour important ancestors and chiefs.

"Unfortunately, from a scientific standpoint, the findings are not surprising," Dr Paoa said.

"We know that sea level rise poses a direct threat to coastlines globally. The critical question was not if the site would be impacted, but how soon and how severely.

"Our work aimed to set potential timelines by which we could expect the impacts to happen. Finding when waves could reach Ahu Tongariki by provides specific and urgent data needed to incentivise community discussion and planning for the future."

Such a threat to the cultural sites is not without precedent.

In 1960, the largest earthquake ever recorded – a magnitude 9.5 off the coast of Chile – sent a tsunami surging across the Pacific.

It struck Rapa Nui and swept the already-toppled moai statues further inland - which damaged some of the figures' key features.

The monument was not restored for more than three decades.

While the study focuses on Rapa Nui, its conclusions echo a wider reality for other cultural heritage sites worldwide that are increasingly endangered by rising seas.

A UNESCO report that was published last month found that about 50 World Heritage sites are highly exposed to coastal flooding.

Possible defences for Ahu Tongariki range from armouring the coastline with structures of breakwaters to block the waves from flooding Rapa Nui to relocating the monuments away from the island altogether.

Dr Paoa is hoping the latest findings will bring conversations forward to prevent irreversible damage in the future.

"It's best to look ahead and be proactive instead of reactive to the potential threats," he said.