Climate Change in New Zealand - Science of Climate Change in New Zealand - Instrumental Records and Effects - Carbon Dioxide

Carbon Dioxide

New Zealand has a long-term record of atmospheric carbon dioxide similar to the Keeling Curve. In 1970, Charles Keeling asked David Lowe, a physics graduate from Victoria University of Wellington to establish continuous atmospheric measurements at a New Zealand site. The south-facing Baring Head, on the eastern entrance to Wellington Harbour, was chosen as being representative of the atmosphere of the southern hemisphere. Lowe initially built an automatic air-sampling machine using parts from a used telephone exchange.

Modelled wind directions indicated that air flows were originating from 55 degrees south. The Baring Head data shows about the same overall rate of increase in CO₂ as the measurements from the Mauna Loa Observatory, but with a smaller seasonal variation. The Baring Head CO₂ concentrations have increased by 50 parts per million between first records in the early 1970s and 2005. The rate of increase in 2005 was 2.5 parts per million per year. The Baring Head record is the longest continuous record of atmospheric CO₂ in the Southern Hemisphere and it featured in the IPCC Fourth Assessment Report: Climate Change 2007 in conjunction with the better-known Mauna Loa record.

The National Institute of Water and Atmospheric Research has also recorded atmospheric concentrations of methane (from 1989) and nitrous oxide (from 1997) at Baring Head.