United Nations Secretary-General Antonio Guterres has sounded an urgent climate warning, urging nations to "Save Our Seas" as he highlighted the catastrophic threat posed by greenhouse gas emissions and rapidly increasing sea levels.

Addressing a summit of Pacific Island leaders on Tuesday in Nuku’alofa, the capital of Tonga, Guterres stressed that there was “no escape route,” warning that the situation was dire.

“We’re facing a perilous situation: Rising seas represent a disaster entirely of our own making. A disaster that in the near future could escalate to a scale few can imagine,” he remarked. “The cause is crystal clear: Greenhouse gases – largely produced from fossil fuel combustion – are heating up our planet. And the oceans are bearing the brunt – quite literally.”

Nuku’alofa is currently hosting over 1,000 global representatives for the Pacific Islands Forum Leaders Meeting, which runs until August 30. Tackling climate change and its devastating effects on the Pacific’s vulnerable coastal populations is a primary focus of discussions among leaders from some of the planet’s most at-risk nations.

Guterres, who last attended the Leaders Meeting in 2019, pointed out that with roughly 90% of the population living within 5 km (3 miles) of the shore and the average altitude sitting between just one and 1-2 meters (3.2-6.5 ft) above sea level, the “Pacific islands are especially vulnerable.”

During this trip to the Pacific, Guterres is also expected to visit Samoa.

“Without urgent cuts to emissions, Pacific Islands could be facing at least a 15-centimeter [6-inch] rise in sea levels by mid-century, alongside more than 30 days a year of coastal flooding in some areas,” he cautioned. “But saving the Pacific isn’t just about saving these islands, it’s about saving all of us. The global community must respond to this SOS before it’s too late.”

One of the Pacific Islands' most forward-thinking responses to climate change is the Pacific Resilience Facility. This locally governed initiative is designed to help communities strengthen their defenses against climate impacts and aims to be fully operational in 2025. However, the project is facing significant financial hurdles as it awaits support from international donors.

Reiterating his ongoing plea, Guterres called on the world’s largest polluters, the Group of 20 (G20) nations, to provide financial aid to those countries most vulnerable to the effects of climate change.

“We need an influx of funds to combat the rising tides,” he stated.

Guterres’s comments followed the release of two sobering reports published by UN agencies on Monday. One, from the World Meteorological Organization, examined rising sea levels in the Pacific, while the other, from the UN Climate Action Team, focused on the broader issue of surging seas in a warming world. Guterres remarked that these reports “vividly underline” the pressing nature of the crisis.

The Climate Action Team’s findings showed that between 1990 and 2020, sea levels in Nuku’alofa increased by 21 centimeters (8.3 inches), more than twice the global average of 10 centimeters (3.9 inches).

“These reports confirm a troubling reality: Sea levels in the Southwestern Pacific have risen even faster than the global average – in some locations, by more than double in the past three decades,” Guterres emphasized.

The UN General Assembly has scheduled a special session on September 25 to examine the existential threat posed by rising sea levels.