David Wratt
David Stuart Wratt is a New Zealand climate scientist who specialises in meteorology and the science and impact of climate change. He is an adjunct research fellow at the New Zealand Climate Change Research Institute at Victoria University of Wellington, and has had many roles at the National Institute of Water and Atmospheric Research, including six years as chief scientist. His current position at NIWA is emeritus scientist. Wratt is a Companion of the Royal Society of New Zealand and was the chair of the society's New Zealand Climate Committee. He has had advisory roles for the New Zealand Government, including science advisor at the Ministry for the Environment, and is currently a member of the Science Board for the Ministry of Business, Innovation and Employment. He has had input into assessments by the Intergovernmental Panel on Climate Change, notably, contributing to its award of the 2007 Nobel Peace Prize through his contributions to the IPCC Fourth Assessment Report. Wratt has worked in the United States and Australia as well as New Zealand.
Education and early life
Wratt was raised on a farm in Motueka and realised at a young age that he was good at maths and science so went to the University of Canterbury where he graduated with a Bachelor of Science with first-class honours in physics, and stayed to complete a PhD in atmospheric science. The title of his doctoral thesis, supervised by Grahame Fraser and submitted in 1974, was Atmospheric physics: electron density variations in the mesosphere. He recalls that "by the time I'd followed this theme through a post-doc at the University of Illinois in the States, I was ready for a change and came back to New Zealand to work for the Meteorological Service at Kelburn in Wellington."Career
New Zealand Meteorological Service
Wratt was a research and consultant meteorologist with the New Zealand Meteorological Service, later becoming superintendent, Boundary Layer Meteorology Group with the organisation. When he began working at the Meteorological Service, Wratt had intended to train as a weather forecaster but instead did fieldwork to provide information to minimise problems of air quality from the big industries that were planned under a programme at the time in New Zealand called Think Big. The focus of this work was to build an understanding of pollutant emissions from factories and power stations and how they might impact local environments. He had a range of other roles in the Meteorological Service until 1992 when he and other climate researchers transferred to NIWA. At this point in his career, Wratt became more involved with the science of climate change.National Institute of Water and Atmospheric Research
In 2007 he became NIWA's general manager of climate change, noted by Wratt as a position established to coordinate research from "many disciplines – hazards, floods, aquaculture, water quality in rivers...... oversight of all these fields to understand what's driving change, what is vulnerable, and how to increase resilience." The aim was to work collaboratively with Crown Research Institutes and universities to develop of "tools and science-based policies for reducing greenhouse gas emissions and adapting to climate change." From November 2007 to September 2014, he was the chief scientist, climate, for NIWA and from September 2014 has been emeritus scientist, climate, for the organisation.When asked in 2007 what he thought was the most important "take-home message" about climate change, Wratt said:
“Climate has always changed. What's different now is that humans are causing some of the changes through burning fossil fuels. If we continue down this track, we're going to see major problems around the world. There's a strong scientific case for significantly reducing greenhouse gas emissions. We need a combination of reducing our emissions in New Zealand and being part of international negotiations to reduce emissions globally in order to forestall the worst effects.”
Advisory roles
On 20 May 2015, Wratt was appointed as departmental science advisor to the Ministry for the Environment. In announcing the appointment, Nick Smith, the Minister for the Environment, clarified that Wratt's role was to provide advice directly to the Secretary for the Environment, so that high-quality science was used by the Ministry, and to support "cross-government science policy and research initiatives such as the National Science Challenges." Wratt also became a member of The Science Board, a statutory body associated with the Ministry of Business, Innovation & Employment which makes investment decisions for the Endeavour Fund and National Science Challenges. In 2015 he became chair of the Independent Science Panel for the MBIE-funded Deep South National Science Challenge, which has the mission of enabling New Zealanders to adapt, manage risk and thrive in a changing climate. He also became the deputy chair of the Science Advisory Panel for Our Land and Water, which had the aim of enhancing "the production and productivity of the primary sector while maintaining and improving our land and water quality for current and future users."The Royal Society of New Zealand
He is a Companion of the Royal Society of New Zealand and from April to May 2015 served on an expert advice panel established by the society to "provide a clear summary of the scientific evidence and projections of climate change and to identify key risks these changes pose to New Zealand, including as a result of wider societal changes and environmental pressures."The Intergovernmental Panel on Climate Change (IPCC)
Wratt has been involved with the IPCC since 1990 and was a coordinating lead author of the "Australia and New Zealand" chapter of the IPCC Third Assessment Report. He has served on the panel's 30-strong Bureau, and from 2002 to 2015 was a vice-chair of Working Group 1, which is concerned with the science of past, present, and future climate change and assesses the physical science of climate change.Academic positions
Controversies
In 2003, Chris de Freitas, then of Auckland University, questioned anthropogenic global warming, and the way statistics about this were received and interpreted. He claimed that carbon dioxide emissions were reducing and therefore were not necessarily the source of recent increases in global temperature. Wratt, along with Dave Lowe and Brett Mullin responded to de Freitas with data that showed the rise in worldwide temperatures was real and this could be largely attributed to human activity. In 2006, de Freitas again challenged the way statistics on climate change were being interpreted and continued to hold that research was suggesting that extreme climate events may become less frequent and severe, and in 2013 claimed that the "global warming issue is as emotionally charged as it is misunderstood" and the models that were being used to make global-warming predictions were not distinguishing between anthropogenic and natural causes. When de Freitas, Dedekind and Brill in 2015 published a paper that questioned the reliability of previous analyses of regional long-term data used to detect trends in global climate change, focussing particularly on New Zealand, Wratt, along with other scientists Mullan, Jim Salinger and James Renwick published Comment on A Reanalysis of Long-Term Surface Air Temperature Trends in New Zealand . In this paper they identified what they considered were "methodological flaws" in the document by de Freitas and listed several lines of evidence pointing to an increase of 0.7 to 1.0 °C per century for New Zealand temperatures. Wratt and his colleagues argued that the increase of temperatures of New Zealand land surfaces for the period 1909-2009 claimed by de Freitas et al. were too low. They disagreed with de Freitas et al.'s claim that processes used previously for analysing data from the "seven-station series" were incorrect. They concluded "there is no reason to reject the previous estimates of around 0.9 °C warming per century".On July 5, 2010, The New Zealand Climate Science Education Trust, associated with the New Zealand Climate Science Coalition, unsuccessfully sought a judicial review of climate data published by National Institute of Water and Atmospheric Research claiming that the organisation had employed the wrong methodology to adjust historic temperature readings based on this data. The case was dismissed, with the judgement concluding that the "plaintiff does not succeed on any of its challenges to the three decisions of NIWA in the issue. In the New Zealand Herald, Wratt said that the judgement was clear and that "while it is important for scientists to have an open mind, the research and data from around the world showed the big picture, which is that the climate has warmed and this is very likely due to increases in greenhouse gases."
Selected research
The influence of mountains on weather
Early in his career with NIWA, Wratt had a lead role in a programme called The Southern Alps Experiments. The findings of this programme, that explored how the Alps influence New Zealand's weather and the climate were later published in a journal article co-authored by Wratt. The study used rain gauge and radar observations to show how precipation varied across the Alps during a northwesterly storm in 1994 and concluded that this information was critical to accurate forecasting of floods. Wratt later recalled that for their fieldwork, they used the "Australian CSIRO's instrumented plane – a Fokker Friendship – to measure droplet size and winds." Wratt was involved in further research in the Southern Alps in 2000 that confirmed the importance of hydrologists and weather forecasters understanding how New Zealand's mountains influence weather and so improve predictive modelling of rainfall and river flows.Wratt took part in a study in 1999 that looked at diurnal wind variation on the side of mountain ranges in New Zealand and Japan and how it affected surrounding areas such as the Canterbury Plains and the Kanto Plain. The study showed the importance of understanding how diurnal surface heating affected the behaviour of the winds in the lee convergence zone, a region or line downwind of a mountain where winds interact and result in distinctive weather conditions.