“Up until now, we’ve lacked information on the climate change impact on subantarctic islands,” Drew Bingham, DOC Principal Science Advisor says.

“We knew we had to take a deeper look and identify actions needed to ensure the survival of the taonga species that depend on the islands for their survival.”

The study focuses on 11,300-ha Campbell Island, 740km south of Dunedin. Its terrain is steep, rugged and covered in extensive peat. The highest point is 569m.

“Meteorological observations were made over 83 years, which was an excellent base to start with, and gave us confidence in identifying past trends,” Drew says.

“The pattern we’ve observed is a general increase across all climate indicators related to warmer conditions. This is expected to continue into the future.

“Increases in temperatures, rainfall and wind are projected for Campbell Island. Winter rainfall is expected to be particularly heavy, with a warmer atmosphere storing more water vapour and increasing the severity and intensity of downpours.”

Drew says these climate projections have implications for conservation management on Campbell and other subantarctic islands.

“Extensive rainfall events and slips will potentially have the biggest impact on nesting birds. We’d also like to find out more about how sea level rise and storm surges will affect sea lions.

“Increasing the resilience of the subantarctic islands and keeping them pest-free becomes even more important in the face of climate change, especially given the wealth of biodiversity on many of the islands.

“The project to remove pests from Campbell island’s neighbour, Maukahuka/Auckland Island, is a great example, and will boost the climate change resilience of Auckland Island and by extension, the surrounding Southern Ocean.”

Data from the study shows the following trends and records for Campbell Island’s climate:

An increase in the average daily temperature over the past 83 years.
A decrease in the number of cold days over the past 83 years.
An increase in annual rainfall since 1970 (an additional annual rainfall of 79mm per decade).
The three warmest years and four wettest years on record were after 2011.
Drew says further research is still needed to assess the impact of the projected weather on Campbell Island’s species in more detail.

“This climate report is a good start as we look at ways to help our taonga species on the subantarctic islands adapt to climate change.”