Millions of people living in Small Island Developing States (SIDS), including Pacific nations such as Tonga, face escalating health risks from climate change despite contributing less than one per cent of global greenhouse gas emissions, according to a major report published in The Lancet Global Health.

The findings come as Pacific governments prepare for pre-COP climate meetings ahead of the UN Climate Change Conference (COP31) in Türkiye later this year.

The second annual Lancet Countdown SIDS report assessed 28 indicators covering health impacts, climate adaptation, emissions, finance and political action. Researchers found infants now experience seven times more heatwave days than in the early 2000s, while older adults face five times more.

In 2024, extreme heat contributed to an estimated 4.4 billion lost work hours across SIDS and increased the spread of climate-sensitive diseases such as dengue and chikungunya.

The report also found prolonged drought pushed an additional 2.7 million people into moderate or severe food insecurity, while warmer oceans continue to threaten fisheries and marine food security. Sea surface temperatures around SIDS averaged 0.61°C above the 1981-2010 baseline during 2022-2024.

Dr Georgiana Gordon Strachan, Regional Director of Lancet Countdown SIDS, said rising temperatures had become “one of the defining health challenges” for island nations and called for greater international support to implement proven solutions.

Researchers acknowledged progress, including expanded solar power, stronger early warning systems and fewer deaths from extreme weather events. However, they said climate finance and health adaptation remain inadequate, with only 10 of 58 SIDS having dedicated health and climate adaptation plans.

The report urges governments and international partners to strengthen investment before COP31 negotiations.