Safeguarding the South Pacific's island nations from climate change


The current research project includes Micronesia. Image: norimoto - stock.adobe.com

A recently published report by the World Meteorological Organization (WMO) showing that 2023 was the hottest year on record highlights the need for more measures to safeguard vulnerable nations from the potentially devastating effects of climate change, a Federation researcher says.

The WMO State of the Global Climate 2023 report also confirmed that records were again broken for ocean heat and acidification, sea level rise, Antarctic Sea ice cover and glacier retreat, with more countries experiencing heatwaves, floods, droughts, wildfires and rapidly intensifying tropical cyclones.

These events affected millions of people and inflicted many billions of dollars in economic losses, the report says, while 2023 rounded off the warmest ten-year period on record.

Climate researcher Associate Professor Savin Chand says the report contained few surprises, as greenhouse gas concentrations in the atmosphere, particularly carbon dioxide, continued climbing.

Assoc Prof Chand says the South Pacific's island nations are among the most vulnerable on Earth to climate change, and as the temperature in the atmosphere rises, so does the risk of extreme events.

"As the temperature increases, sea surface temperatures increase, and this impacts what is referred to as acidity in the ocean – the increasing CO2 absorption in the ocean leads to a more acidic ocean," Assoc Prof Chand said.

"If the ocean's acidity rises, phytoplankton, chlorophylls, and other critical food sources for marine life will be at risk, which could have a huge impact on the food chain.

"We also see heat waves in oceans. We are familiar with heat waves in the atmosphere, which are persistent and abnormally high temperatures over a period of time, and the same thing happens in the oceans, referred to as marine heat waves. All these factors have adverse impacts in various ways, including a rising sea level."

Assoc Prof Chand is continuing a long collaboration with the CSIRO to develop disaster risk assessments associated with climatic hazards for specific Pacific Island nations. The current project's focus is on Tuvalu, Nauru, Niue, and the Federated States of Micronesia, which are atoll countries in the Pacific.

He says these and other South Pacific nations are more vulnerable because of their size, their lower capacity to adapt to a changing climate, and their location in a region more prone to tropical cyclones.

Researchers consider three key factors — hazards, exposure, and vulnerability — when examining the possible impacts on these nations.

"If there is a tropical cyclone, for instance, then these three factors can show us what the effect can be on that country in terms of the overall risk," he said.

"Based on my research, we have seen the number of tropical cyclones go down slightly in the Pacific — but their intensity is going up, and this is critical. To put this into context, these islands are subject to severe wind damage as a tropical cyclone develops. Next are the storm surges which bring waves that can inundate much of the island and its estuaries.

"The sea level is already 15 centimetres higher than in the 1950s, and some atolls rise just meters from ocean level. If there is high tide and heavy rainfall—and even weaker systems carry a lot of rainfall—these places are at a much higher risk.

"The characteristics of cyclones are changing, and the amount of rainfall associated with cyclones is increasing. That's why we see frequency and intensity of cyclone-related floods increasing over the past decades. Plus, winds are getting stronger, and all these factors combine to make those small island countries highly vulnerable to the impacts of climate change."

Assoc Prof Chand says it is important for research to focus on specific countries to identify the hazards that are crucial to those countries.

Kiribati, for instance, is near the equator and is less likely to get the direct impact of a tropical cyclone but can still be impacted by far-located cyclones in the region and a rising sea level, whereas Vanuatu has suffered from the direct effects of two of the strongest tropical cyclones ever recorded in the southern hemisphere, both in the last decade.

"Collaborating with the CSIRO, we have completed several projects in the region since 2016, and our role is to provide information about hazards—tropical cyclones, rain, and sea level rise — because this is important for these countries to make decisions about day-to-day activities, including food security, personal safety and tourism.

"We're already seeing how climate change is affecting Pacific Island countries. The Pacific is the hub of natural variability phenomena, including El Nino Southern Oscillation, and our climate model needs to simulate these phenomena well in order to better understand their impacts on climatic extremes such as cyclones.

"But models have biases in simulating these, and we need to improve our modelling capabilities to better judge how those climate variability and change will affect Pacific Island countries. We need to get the model right before we start looking at the impacts."

Related reading:

Research shows tropical cyclones have decreased alongside human-caused global warming – but don’t celebrate yet

Crunching the numbers on cyclone trends and global warming

There’s more to the wild weather than just La Niña


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