Latest report on South-West Pacific a ‘climate wake-up call’

Experts are calling the findings of the latest State of the Climate in the South-West Pacific report a “wake up call” for stronger climate action in the region and globally.

Experts say climate change is “changing the water cycle quite significantly.”

According to the report, 2024 was the warmest year on record in the South-West Pacific region, at about 0.48°C above the 1991–2020 average.

“Extreme heat affected large parts of the region in 2024 with record breaking temperatures … posing serious risks to public health, livelihoods, and ecosystems,” says Ben Churchill, the director of the Regional Office for Asia and the South-West Pacific at the World Meteorological Organization (WMO) – the UN specialised agency for weather, climate and water.

WMO’s Dr Blair Trewin, a lead author of the report, warns that although 2024 was a record warm year “…within 5 years of current warming trends it will become an average year, and probably in 5 years after that it will become quite a cool one.”

The WMO’s annual report looks retrospectively at the extreme climate events and climate indicators, as well as their impacts and risks, across Australia, New Zealand, the Pacific, and parts of Southeast Asia.

It revealed that ocean warming in the Southwest Pacific reached unprecedented levels last year.

“Not only does the ocean bring us together in the region, but around 90% of the extra heat in the atmosphere and 25% of carbon dioxide (CO₂) emissions are absorbed by the ocean,” says Dr Thea Turkington of WMO, a lead author of the report.

2024 saw record-breaking sea-surface temperatures, near-record ocean heat content, and nearly 40 million km² affected by marine heatwaves – an area 5 times the size of Australia, and more than 10% of the global ocean surface area.

“Sea surface temperatures reach record highs in 2024 by a substantial margin,” says Tewin, who adds that it is due in part to continued influence from the 2023/2024 El Niño event.

“But a large part of it relates to the background [sea surface temperature] warming trend, which over the last 40 years is in the order of 0.13°C per decade.

“Much of the region saw at least severe marine heat wave conditions at some point during the course of 2024, particularly in areas near and south of the equator. That has significant implications for marine ecosystems, and in particular, corals, which are very sensitive to excess heat were quite significantly stressed … They also have influences on fisheries and other aspects of marine life.”

The report found that sea levels continue to rise across the region, exceeding the global average and threatening especially low-lying Pacific Islands with an increased frequency of coastal flooding and inundation.

“Half the population in this region live within 500m of the coast, putting them at a greater level of risk,” says Churchill.

The late 2024 tropical cyclone season in the Philippines was unprecedented, with 12 storms in that period. According to Trewin: “Philippines gets a lot of tropical cyclones already, but this is … off the scale.

In the southern hemisphere, the number of named tropical cyclones that formed in the South Pacific and Australian basins during the 2023/2024 tropical cyclone season was below average.

“Total number of cyclones is expected to remain stable or decrease with climate change, and we do see that in in the southern hemisphere regions … we have seen quite a noticeable decrease in the total number of tropical cyclones over the last 40-50 years,” explains Trewin.

“But the cyclones that do occur are expected to be, on average, more intense, and they’re expected to be capable of producing more rainfall.

“We’ve seen a number of episodes, particularly in Northwestern Australia in recent years, where cyclones [are] relatively weak in terms of cyclone intensity – they might only reach category 1 or 2 – but they produce enormous amounts of rain as they move inland and contribute to very significant flooding.”

Extreme rainfall and flooding caused deadly and destructive impacts across the South-West Pacific in 2024, with major events in Australia, New Zealand, Fiji, Malaysia, Indonesia, and the Philippines. Other parts of the region remained unusually dry.

“There were areas of significant drought during the course of the year, including in northern parts of New Zealand and in southern areas of Australia, particularly South Australia,” says Trewin.

For every one degree of warming in the atmosphere, Churchill adds, the atmosphere can hold an extra 7% of moisture.

“So, we’re seeing these extreme situations – both in terms of rainfall but also on the other end of the scale we’re seeing extreme drought.

“Global warming is actually changing the water cycle quite significantly, and so every fraction of a degree will have an impact, and it really highlights the importance of more ambitious climate action.”

According to the report, atmospheric concentrations of the 3 major greenhouse gases (GHGs), carbon dioxide (CO₂₎, methane (CH₄), and nitrous oxide (N₂O), reached new record observed highs in 2023 at 151%, 265% and 125% of pre-industrial (before 1750) levels.

When these molecules enter the atmosphere, they absorb and re-radiate heat back to Earth, rather than letting it escape into space, causing the greenhouse effect. Human activities, such as the burning of fossil fuels, continue to increase the concentrations of these GHGs in the atmosphere, warming the climate.

Churchill says the trend of increasing climate indicators has been driven by emissions, which are “continuing unabated.” The latest report by the Global Carbon Project found that global fossil fuel emissions were projected to reach a new record high of 37.4 billion tonnes (Gt) of CO₂ in 2024.

According to the Intergovernmental Panel on Climate Change’s (IPCC) Special Report: Global Warming of 1.5ºC, “Reaching and sustaining net zero global anthropogenic CO₂ emissions … would halt anthropogenic global warming on multi-decadal timescales.”

Net zero means reducing human-caused GHG emissions as much as possible and balancing the remaining emissions by removing GHGs from the atmosphere.

“What we want to see is that this report is spread far and wide … picked up by decision makers and policy makers and understood by sectors that are particularly vulnerable to climate, even the general community, so that they understand what’s at stake, what’s happening in their part of the world, at the national and regional level,” says Churchill.

“Perhaps they could use it to encourage their governments to take stronger climate action.

“To … reverse the global warming trend is going to take a significant shift, not just from sort of national, regional level, but even at the local and individual level.”