A drilling operation in the South Island's Mackenzie Country has successfully retrieved 17,000 years of climate data.
The drilling rig, on board a custom-built barge, extracted four continuous sediment cores up to 80m long from two sites beneath the floor of Lake Ohau.
It's material that has lain undisturbed for tens of thousands of years.
Webster Drilling project manager Tony Kingan has been operating specialist drilling equipment for 27 years, including stints in Antarctica.
He says conditions out on the lake have been challenging.
"It's certainly been difficult. There have been days we haven't worked because of the northwest wind," he says. "It can get pretty awful out in this part of the lake especially."
Despite a few weather delays, lead scientist Richard Levy from GNS Science says the project has been massively successful.
"It's gone incredibly well. The drill has reached the bottom of the sequence, 80m below the lake floor, and what that means is we've got a complete record of the climate variability for the last 17,000 years.
"Exactly what we wanted, we've been delivered."
Tony Kingan, project manager and Richard Levy, lead scientist on board the drilling rig on Lake Ohau (Newshub.)
The information collected in the sediment core samples will greatly enhance the current climate record which covers only the past 100 years.
"We see layers of sediment, layers of mud that accumulate each year," Dr Levy says. "So we've got an annual record or rainfall of climate change at a yearly resolution and we can count back in time just like you might count tree rings."
The sediment cores come to the surface in 3m lengths, with each year represented by a layer of mud approximately 5mm thick.
Gravel appears amongst the thin sediment layers at the base of the Lake Ohau core (GNS Science / Supplied)
The scientific team from GNS Science and Otago and Victoria Universities now have years of work ahead.
"This record is unprecedented," Dr Levy says. "We're going to pull it apart bit by bit, year by year.
"It's going to be a lot of work for us but it'll be awesome record for us to study."
The sediment will reveal annual rainfall, temperatures and flooding and drought events, essentially a weather map going back 17,000 years. But there's more in the mud than the secrets of the past climate.
"We can point quite precisely to when humans impacted the landscape around 1340AD," says Marcus Vandergoes, paleoecologist from GNS Science.
And with humans came destruction.
"There was a dramatic change to grassland and charcoal was present in these cores as well, as a result of burning."
The drilling rig sits on board a custom-built barge (Newshub.)
"We also can see the evidence of beech masting, so where the beech trees put out a huge amount of pollen every three years or so, we see that in the record as well," says Dr Vandergoes. "So that's the great thing about the detail of this record on a yearly cycle."
The frequency of past beech masts could force the Department of Conservation to rewrite its predictive tool and review its 1080 pest control response.
Liko Inkersell and her husband Simon manage the Lake Ohau Station and hope the drilling project will help predict long term weather patterns.
"If we can find out whether dry periods are going to last for one year, or if they're going to come in 10-year cycles, then we can plan for that a lot more in terms of our stocking rates and also the pasture that we're putting in," Ms Inkersell says.
"Weather is so crucial for us, especially in climates like this where we basically are at the whim of the weather. We don't have any irrigation on this farm so we are relying on rainfall and sunshine, so if we can predict when that's going to occur and when it's not, it will definitely help us plan more for the farming operation in terms of the future."
The aim is to find out how the westerly wind system and its associated rainfall responded to large scale climate change in the past.
The next step is decoding these messages from the past and their significance to the future.
Newshub.
