News: 10 October 07
Studying climate history a weapon against global warming

Every day is a race against time for Dr Nancy Bertler – but rather than meeting the demands of an appointment-packed diary it’s saving the planet from the effects of climate change that keeps her running.

Originally from Germany, Dr Bertler has adopted New Zealand as her home and is applying her world leading expertise as a climatologist and glaciologist to finding out what vital information ice samples can reveal about the impact of global warming.

She is a member of New Zealand’s Joint Antarctic Research Institute, a collaboration between Victoria University and GNS Science which includes the state-of-the-art National Ice Core Research centre in Lower Hutt, housing laboratories, analytical equipment and refrigerated rooms for the long-term storage of hundreds of metres of ice cores from Antarctica? and New Zealand glaciers. The facility, which opened earlier this year, is a fusion of world leading technology, scientific leadership and Kiwi ingenuity.

"We have a huge sense of urgency in terms of what we need to do to curb climate change and how little time there is to do it," says Dr Bertler. "We have very senior international scientists, including our national icon Professor Peter Barrett, saying we only have about 10 years before it is too late to avoid serious consequences from climate change. It is easy to feel overwhelmed and to worry that we won't be able to mobilise people fast enough."

But feeling helpless is far from Dr Bertler’s mind most of the time, as she works to understand climate variability in the past few thousand years as a key to predicting the danger points and thresholds in the future.

Dr Bertler’s attention turned to New Zealand when she was researching climate patterns of the past while completing her Masters degree at the University of London. She heard about the multi-national Cape Roberts Project to unravel climate history by drilling into the sea floor in Antarctica, which is headed by Professor Barrett from Victoria University.

"It wasn’t an obvious fit because they were obtaining marine sediment cores that produce information about climate trends over millions of years. My idea was to add ice cores from low elevation, coastal sites which are particularly climate sensitive and tell you much more about abrupt and rapid change on the scale of decades. While scientists of these groups use different jargon and don’t normally collaborate too much, their knowledge is complementary and our efforts have been proven successful."

Within a year Dr Bertler was working with Professor Barrett and his team, enrolled in a PhD course at Victoria University and studying under experts at the University of Maine Climate Change Institute in the United States to learn more about interpreting climate trends from ice cores. The Foundation? for Research, Science and Technology saw the potential in Dr Bertler’s work and awarded her a three year Post Doctoral Fellowship, which was completed in June this year.

The Foundation invests NZ$6 million annually in the fellowships programme, which is designed to foster development of New Zealand’s emerging and future science leaders and build greater research knowledge and capability.

Dr Bertler is now receiving further support from the Foundation through its Bridge to Employment scheme.

Dr Bertler’s research to date has shown that samples taken from hundreds of metres below the surface in coastal areas of Antarctica can help scientists trace major climate shifts in the past that are not detectable in ice cores taken from the interior of Antarctica. The interior is more protected from storms and dramatic changes that circle the Antarctic and shape the world’s climate and ocean circulation.

Dr Bertler’s team, scientists from NIWA and international collaborators are studying the particles of dust and chemicals inside the ice cores to look back in time and learn more about what drives climate change. Dust caught in the ice is a measure of how vigorous past storms were while isotopic ratios frozen in snow crystals are used to reconstruct rapid temperature changes and the gas trapped in tiny bubbles provides a sample of an ancient atmosphere from thousands of years ago.

"We can see that there is a very stable relationship between these gases and temperature – as the concentration of gases increases so does the temperature and vice versa. In addition to the greenhouses gases we are emitting into the atmosphere there are also large natural sources in the oceans, for example, and in places such as the permafrosted tundra plains in Russia. We know from the ice cores that as global temperatures continue to rise they will trigger the release of these natural gases into the atmosphere, further accelerating human produced global warming.

"Our goal is to look at climate patterns in the past to try to put threshold points on some of these potential events and predict what will happen and when, in the near future."

She is sharing her findings with the international science community through her roles as a member of steering committees, such as the International Partnership in Ice Core Sciences (IPICS) and Antarctica in the Global Climate System (AGCS). She is also New Zealand’s representative on ITASE (International Trans Antarctic Scientific Expedition).

Dr Bertler says New Zealand’s capability in her field of research is highly regarded globally.

"The research team in New Zealand is small but highly specialised. Our ice core facility is also unique. It’s not the biggest – there are maybe 10 in the world and possibly three are larger than New Zealand’s – but it offers the most possibilities in terms of the breadth of analytical expertise."

In addition, she says the New Zealand ice core team has the advantage of working along side other world leading scientists from the multinational NZ-led ANDRILL programme which investigates marine sediment cores from Antarctica. "While the benefits of multidisciplinary integration are undeniable, few such partnerships exist."

Dr Bertler says there is a growing urgency among scientists to ensure their findings are rapidly fed into decision making that can mitigate the effects of climate change.

The Foundation for Research, Science and Technology is also a key investor in two research programmes led by GNS Science and Victoria University called Global Change Through Time and Antarctica-New Zealand Interglacial Extreme Climates respectively, both of which use the new ice core facility as part of investigations into the clues past climate change can offer into likely scenarios for the future.