Ocean and coastal water temperatures warmest on record

photo: 123 RF

Ocean and coastal water temperatures are the highest they have been on record for more than 40 years.

The waters around New Zealand reached their highest average annual temperatures between 2022 and 2023, according to the latest data from Statistics New Zealand.

Statistics New Zealand says sea surface temperatures have risen by an average of 0.16 to 0.26°C per decade (equivalent to a rise of 0.63 to 1.05°C over the record period).

This is the temperature of the uppermost layer of the ocean. Statistics New Zealand says it is typically found at depths between 10 and 300 metres.

The Tasman Sea has been recorded as having the highest average rate of sea surface warming since 1982.

“Measuring sea surface temperatures gives us an idea of ​​how fast the uppermost productive layers of the ocean are warming,” said Stuart Jones, senior manager of environment and agricultural statistics at Statistics New Zealand.

Coastal areas have seen an average warming of 0.19 to 0.34°C per decade (equivalent to 0.74 to 1.35°C warming over the record period), with the highest average warming rates along the east coast of the South Island.

Statistics New Zealand says changes in sea surface temperature will affect marine processes, the environment, species and nature’s contributions to people.

This could include some species, including some sharks, dolphins and whales, which change position to maintain body temperature or risk not surviving if they can’t move.

It would also lead to changes in the growth and reproduction of fish such as snapper, and an increase in invasive species, the report said.

The data used come from the National Institute of Water and Atmospheric Research (NIWA), the National Oceanic and Atmospheric Administration (NOAA), and the National Aeronautics and Space Administration (NASA).