New Zealand’s oceans are warming 34% faster than the global average, putting homes and industry at risk, report says | New Zealand
New Zealand’s oceans are warming 34% faster than the global average, and homes worth NZ$180 billion (US$104 billion) are at risk of flooding, a new report on the country’s marine environment has found.
The Ministry of the Environment and Stats NZ’s three-year update, Our Environment 2025, brings together statistics, data and research across five areas – air, atmosphere and climate, freshwater, land and sea – to build a picture of the state of New Zealand’s marine environment.
The latest in the series, Our Marine Environment 2025, paints a sobering picture of the nation’s oceans and coasts – a picture defined by warming and rising seas, intensifying marine heatwaves, and ocean acidification, driven by global warming.
“Climate change is not just something distant… it has impacts on our oceans and our coasts,” Dr Alison Collins, the department’s chief scientific adviser, told the Guardian.
“The coastal zone is under real pressure… and the importance of that coastal environment is absolutely crucial: it’s what we depend on in terms of our homes, our communities, our livelihoods and, ultimately, our connection to place. »
The report outlines a wide range of risks associated with marine change, including threats to native marine species, coastal flooding and flooding of homes, and stronger and more devastating storms, as well as risks to communities and the economy.
It noted that 219,000 homes worth $180 billion were located in coastal and inland flood zones, while more than $26 billion of infrastructure was vulnerable to damage. Around 1,300 coastal homes could suffer significant damage from extreme weather conditions.
Some areas will see 8 to 12 inches of sea level rise by 2050, a turning point for some communities, Collins said.
“If sea levels rise to this height, a coastal storm that used to occur every 100 years could start happening every year,” she said.
The planet’s oceans have absorbed about 90% of the extra heat created by the human-caused climate crisis.
New Zealand is most affected by warming seas due to its position in the ocean, making it more vulnerable to atmospheric circulation and changes in ocean currents.
Between 1982 and 2023, New Zealand’s sea surface temperatures in its four ocean regions increased by an average of 0.16 to 0.26 degrees Celsius per decade, and the rate of ocean warming exceeded global averages by 34%.
Coastal waters are also warming faster than the global average, the report said.
Meanwhile, the subtropical front – the boundary between cold subantarctic waters and warmer subtropical waters that is biologically and economically significant – moved 120 km westward, the report said, noting that it was the first time a change in large-scale ocean circulation around New Zealand had been observed.
This change, caused by warming water, will have “huge impacts” on ecosystems, the food web and on species such as corals, sponges, kelp and fish, Collins said.
Ocean acidification and warming also affects the country’s fishing and aquaculture industries – which contribute $1.1 billion to the economy – and can lead to toxic algae blooms in shellfish. Marine heat waves, for their part, are becoming more intense, longer and more frequent.
New Zealand has been hit by unprecedented marine heatwaves in recent years, linked to mass bleaching of sea sponges, southern kelp die-offs, large-scale fish strandings and penguin deaths.
Monitoring and research on the marine environment is growing, but gaps in understanding remain, the report notes, adding that deeper research would reduce risks to people, promote climate resilience and promote sustainability.
Of particular concern is the lack of understanding of how climate change, oceans, extreme weather events and ecosystems interact, Collins said.
“It’s a bit like pulling a thread from a fabric and everything could fall apart – understanding these interactions is perhaps the biggest blind spot for us. »
