Venu Menon
Wellington, October 4,2023
In a disquieting coincidence, as the three main political parties of New Zealand debated climate action in the lead-up to the general election set for October 14, scientists attending an emergency summit in Wellington on Tuesday sounded the alarm over record low sea ice in Antarctica this year.
More than 40 researchers released a joint statement calling for urgent cuts to climate pollution as the warming of the Southern Ocean was causing unprecedented loss of Antarctic sea ice.
“We are missing between seven and 10 New Zealands’ worth of sea ice,” National Institute of Water and Atmospheric Research (NIWA) marine physicist Natalie Robinson said.
She feared the record ice lows “could flow into another devastating year in 2024.”
“Personally that would be my expectation, if we end the winter season and enter the summer season with less sea ice, I would expect to see a similar pattern emerge next year.”
While the Wellington summit did not echo the view of some Australian researchers that the Antarctic sea ice was “at a tipping point of ‘new normal’ lows,” there was “plenty of cause for alarm without needing to use those words,” according to NIWA principal scientist in marine physics Dr Craig Stevens.
The summit based its findings on 44 years of research, but Stevens said a longer period of research was needed to understand the complex processes driving sea ice depletion.
“We don’t all agree on all the nuances and details around this because there is still a lot of work to be done,” he said.
New Zealand’s proximity to Antarctica
The researchers noted that, being among the nations closest to Antarctica, New Zealand’s climate was strongly influenced by the ice continent.
The Southern Ocean with its floating ice sheets “has far- reaching effects on the planet’s climate,” the scientists noted.
Sea ice provided a habitat for penguins while the algae growing underneath it sustained marine life.
Controlling carbon dioxide levels
Ice formation resulted in pushing carbon dioxide from the surface to the bottom of the ocean.
“Sea ice keeps the global climate system running the way we like it. It pulls heat out of the atmosphere and into the deep ocean when it is formed, and mirrors energy back out to space,” Robinson said.
She said the Southern Ocean ice area hit a peak in 2014 before it started shrinking.
Antarctic vs Arctic
For many years, Antarctic sea ice was growing, even as Arctic sea ice shrank, Robinson noted.
She explained: “They are fundamentally different systems… the Arctic is a basin contained by land masses, whereas at the other end of the globe we have a continent surrounded by ocean. The ocean completely circulates around the continent and helps keep the continent cool.
“Oceans have taken up almost all the extra heat that has been put into our climate system by human activities, and of that about two-thirds was taken up by the Southern Ocean on its own.”
Robinson expressed surprise that the Southern Ocean had managed to retain its ice for so long.
“You would expect in a warmer ocean and stormier environment that sea ice would reduce, as it did in the Arctic, so the fact it hasn’t until now is the more surprising thing. That’s the thing we would like to understand,” Robinson said.
In 2022, the ice in the Southern Ocean was at record lows.
“But then we’ve had an even more dramatic reduction in this current year,” Robinson pointed out.
“That’s what brought us together to have this summit.”
Venu Menon is an Indian Newslink reporter based in Wellington
