Scientists seek climate secrets buried in NZ peat bogs

Ancient conifers buried in the peat bogs of New Zealand could hold the key to a better understanding of changes in the Earth’s climate since the end of the last Ice Age.

However, scientists hoping to unlock the climate secrets held within the rings of these preserved kauri trees are in a race against time, as the timber is also highly prized by local furniture-makers and craftsmen. At the rate at which they’re being used today, the ancient trees could be gone within 10 years.

That’s why researchers from Exeter and Oxford universities are setting out to study the tree rings before their climate secrets are lost forever. Funded by a grant from the Natural Environment Research Council, they plan to carry out carbon dating and other analyses of the kauri tree rings. While the study will focus on the last 30,000 years, some trees actually date back 130,000 years.

The trees, which can measure up to four metres across and live for up to 2,000 years, store an immense amount of information about rapid and extreme climate change in the past. For instance, wide ring widths are associated with cool dry summer conditions. The scientists believe their findings will help us understand what future climate change might bring.

Tree rings are now known to be an excellent resource for extracting very precise and detailed data on atmospheric carbon from a particular time period. The researchers say this study could help plug a large gap in our knowledge of climate change by extending historical weather records that only date back to the mid-nineteenth century.

There is nowhere else in the world with such a rich resource of ancient wood that spans such a large period of time.

“This gives us a unique opportunity to increase our knowledge of the Earth’s climate and human responses to it at the end of the last Ice Age,” said Christopher Ramsey, a professor in the school of archaeology at the University of Oxford. “The radiocarbon measurements should give us important new data that will help us to understand interactions between the atmosphere and the oceans during this period when there was rapid and dynamic change. Equally exciting is the prospect it will give us of more precise dating of archaeological sites from this period — illuminating the only window we have onto how humans responded to these major changes in the environment.”

“We are facing a race against the clock to gather the information locked inside these preserved trees,” added lead researcher Chris Turney from the University of Exeter. “It is fantastic to have this funding so we are able to gather this information before it is lost forever. While it will be fascinating to find out more about the earth 30,000 years ago perhaps more importantly we will have a better appreciation of the challenges of future climate change.”