The University of Auckland's climate scientist Dr Kevin Trenberth says it is "not surprising" that 2023 was the hottest year on record.
According to a BBC analysis, last year was the warmest on record, driven by anthropogenic in climate change and enhanced by the El Niño event.
Every month for the past seven years, Dr Kevin Trenberth and other researchers from around the world analysed data taken from 4000 argo floats - instruments used to measure ocean temperatures and salinity levels.
Each year has been hotter than the prior year in the ocean in the last decade, according to Dr Trenberth.
The ocean's role in crucial in regulating the climate as it acts as a carbon sink, absorbing huge amounts of CO2 and heat from the sun.
Dr Trenberth said a warm ocean leads to severe weather events, such as, more intense cyclones and heavier rains and devestating flooding.
"Right now, we're in the midst of a strong El Niño event, which means a warming of the tropical Pacific from the dateline across to the Americas," he said.
"That influences the patterns of weather that influences the storm tracks - it influences the jet streams in both hemispheres where the main cyclones and anti-cyclones tend to go."
Changes to the ocean temperatures also threatens marine life.
"As the ocean warms, it warms from the top down," Dr Trenberth said.
"Warm water on top of cold water is a stable configuration and that means there's less penetration of oxygen into the ocean and also carbon dioxide. So the ocean doesn't take up quite as much carbon dioxide which otherwise helps to bury and take out of the atmosphere.
"This has implications for all the animal life throughout the ocean and animal life that depends on the ocean like penguins, otters and seals...all around the world. So this has consequences."
Switching to greener energy sources
Dr Trenberth said the that the results highlight the need to promptly cease burning fossil fuels and to make the switch to renewable sources such as wind, solar and hydropower.
He said he is not satisfied with how global leaders are currently addressing the climate crisis, saying the issue was realised "years ago".
"We recognise that there were more stronger storms associated with global warming. There has been some progress in a number of countries like the United States and Europe who have cut emissions, somewhat.
"But other countries like China and India are still increasing emissions.
"From the New Zealand standpoint, we need to recognise that climate change is happening," Dr Trenberth said.
"We need to prepare for the consequences and so this relates especially in coastal regions, to the rising sea levels and also the stronger rain. So water management and drainage systems are key."
"It's pleasing to see that Australia has gone ahead a lot in terms of rooftop solar - New Zealand could do a lot more in that regard.... a lot of countries could do a lot more."