The BOM Needs a ‘Please Explain’, Says Eminent Climatologist

Written by:
22 February 2021
The BOM Needs a ‘Please Explain’, Says Eminent Climatologist - Featured image

This review of Climate Change: The Facts 2020 is from Dr John Maunder, President of the Commission for Climatology of the World Meteorological Organization from 1989 to 1997, and author of Fifteen Shades of Climate. More information on Dr Maunder and his book is available at the end of the post.

Climate Change: The Facts 2020 is a guide to the latest international research and analysis on climate change science and policy.  Twenty experts in their field have written contributions on the key issues of scientific, political, and public debate about climate change. Contributors include Dr John Abbot, Dr Susan Crockford, Dr Bella d’Abrera, Scott Hargreaves, Professor Aynsley Kellow, Donna Laframboise, Professor Richard Lindzen, Dr Jennifer Marohasy, Jo Nova, Dr Peter Ridd, and Dr Roy Spencer.

Some of the issues addressed in chapters in Climate Change: The Facts 2020 include the extent and variability of sea level change, the historical record of temperature and ice coverage in the Antarctic, the impact of climate change on polar bear population, the ‘manipulation’ of temperature data by the Australian Bureau of Meteorology, whether the Australian bushfires of 2019-20 were in fact ‘unprecedented’, and the prevalence of ‘noble cause’ corruption in climate science.

Dr Jennifer Marohasy, the editor of Climate Change: The Facts 2020 and Senior Fellow at the IPA in commenting on the book said … “The contributors to Climate Change: The Facts 2020 don’t necessarily agree on the extent that recent global warming may be affected by human activity – but they all share the perspective that any such warming is subject to cycles, and is not unusual in its rate or magnitude, and is not catastrophic.”

She also comments that “If anything about the climate is unprecedented it is the notion that something as complex as climate science can be ‘settled’.  It is better to have questions that cannot be answered than answers that cannot be questioned…Far too frequently climate science has demonstrated noble cause corruption – where the ends justify the means.”

Climate Change: The Facts 2020 is the fourth edition in the IPA’s Climate Change: The Facts series, the previous edition being published in 2017. In that edition some of the interesting chapters were ocean acidification, the role of the moon in weather forecasting, taking Melbourne’s temperatures, the homogenisation of Rutherglen (the agricultural research station has one of the longest continuous temperature records in rural Victoria), carbon dioxide and plant growth, examining papal energy and climate ethics, and free speech and climate change.

The 2020 edition of the series is an excellent summary of our current knowledge of the climate system.  It includes very little about greenhouse gases, nuclear power, the sun, the Paris Accord and the politics of climate change, but other books, such as my (, cover many of those subjects. The focus on the polar regions (and in particular the Antarctic), polar bears, penguins, ice cores, monitoring sea ice with satellites, and the role of water vapour are very adequately covered. In addition, several parts of the book cover the difficult and often controversial aspects of the ‘homogenisation’ of surface temperatures with specific reference to Darwin and Rutherglen in Australia and Mawson in Antarctica.

In this regard, whenever data is observed the question needs to be asked: how good is the data, and how do the observations compare with what was observed in the past? These questions relate to almost all data, but it is especially pertinent when climate observations are considered. Most weather observations such as rainfall, maximum temperature, the hours of sunshine, and wind speed etc., are observed over long periods – in some cases such as Central England – two to three hundred years. In order to assess whether the climate is warming or cooling or becoming wetter or drier, it is necessary to “homogenise” the data so that what is observed today can be compared with what was observed in the past taking into account changes in the local environment such as urbanisation, the growth of trees, the changing landscape such as irrigation, changes in the location of where the observations are made, changes in observational authorities, and changes in the type of recording instruments used.

All of these factors are part of the climatological “know-how” of climatologists, but it is sometimes suggested that the observations are “adjusted” or in the words of some people “cooked”. While this may happen, and human judgements are made for some aspects of quality control, I believe that any adjustments of the data to fit a particular belief is not done (or should not be done) by any reputable climatologists. In particular, I would consider it irresponsible for climate data to be “adjusted” to so they become warmer or colder, or wetter or drier.  Internationally, the World Meteorological Organization (WMO) is the arbiter of the homogenisation of weather observations, and this is achieved by two of its Technical Commissions, the Commission for Instruments and Observations (CIMO), and the Commission for Climatology (CCl). CIMO is responsible for the design and quality control of most meteorological instruments, from mercury in glass thermometers to modern weather sensors. CCl is responsible for what happens to the weather/climate observations after they have been made.

The WMO Commission for Climatology (CCl) notes that climate data are the records of observed climate conditions taken at specific sites and times with particular instruments under a set of standard procedures. A climate dataset therefore contains climate information at the observation sites, as well as other non-climate-related factors such as the environment of the observation station, and information about the instruments and observation procedures (called Metadata). These factors can be associated with the changes that can affect the site, instruments or methods and procedures in the observations and data processing. Such changes can affect sheltering and exposure; mean calculations, observation hours and daylight-saving times, units of observed elements and data accuracy, urbanization and land-use changes, introduction of Automatic Weather Stations (AWS) or new types of instruments, quality control and data recovery procedures.

The aim of climate data homogenization is to adjust climate records, if necessary, to remove non-climatic factors so that the temporal variations in the adjusted data reflect only the variations due to climate processes. WMO in collaboration with CCl developed a set of Guidelines on Climate Metadata and Homogenization on how to deal with homogeneity problems. Main steps in data homogenization include:

  1. Metadata analysis and quality control: Changes in the measurement as well as in quality control procedures can be detected.
  2. Building of a reference time series: Mostly a weighted average is calculated by using neighbouring stations.
  3. Breakpoint identification: It is searched for inhomogeneities in the difference between the weighted average and the candidate or in the candidate time-series itself.
  4. Data adjustment: It is decided which breakpoints are accepted as inhomogeneities. At the end the assessed discontinuities are adjusted and the data is corrected.
  5. For future projects and climate change studies it is important to document every step of the homogenization and data preservation.

Homogenisation is necessary because much has happened in the world between the French and industrial revolutions, two world wars, the rise and fall of communism, and the start of the internet age. Inevitably many changes have occurred in climate monitoring practices. As a consequence, the instruments used to measure temperature have changed, the screens to protect the sensors from the weather have changed and the surrounding of the stations has often been changed and stations have been moved in response. These non-climatic changes in temperature have to be removed as well as possible to make more accurate assessments of how much the climate has cooled or warmed.

For the land surface temperature measured at meteorological stations, homogenisation is normally performed using relative statistical homogenising methods. Here a station is compared to its neighbours. If the neighbour is sufficiently nearby, both stations should show about the same climatic changes. Strong jumps or gradual increases happening at only one of the stations indicate a non-climatic change. If there is a bias in the trend, statistical homogenisation can reduce it. How well trend biases can be removed depends on the density of the network. In industrialised countries a large part of the bias can be removed for the last century. In developing countries and in earlier times removing biases is more difficult and a large part may remain. Because many governments unfortunately limit the exchange of climate data, the global temperature collections can also remove only part of the trend biases.

In the case of Rutherglen which is discussed in Chapter 16, the author Jennifer Marohasy is rather critical of how the Australian Bureau of Meteorology (BOM) has homogenised the temperature data. She says the “the Bureau undertook some ‘remodelling’ of the data in 2018 that increased the overall rate of warming by 23% between Version 1 and Version 2 of the Australian Climate Observations Network – Surface Air Temperature (ACORN-SAT) database.”

She gives a reference (Trewin 2018) which shows that the Bureau claims that this remodelling of temperatures is justified for reasons:

  1. because of changes to the equipment used to record the temperatures; and
  2. because of the relocation of the weather stations.

As a long-time climatologist I find these reasons difficult to comprehend, and Marohasy says that this is not a logical explanation. On reading the further discussion in this chapter I must concur. However, because the Bureau’s data is and should be the “Official” record of past climates in Australia (at least those concerned with instrumental records), I recommend that in next series of Climate Change: The Facts it would be appropriate to ask the Bureau of Meteorology for a  “please explain”, and if appropriate  also  ask a former retired  climate data expert from the Bureau (such as William Kininmonth or Mary Voice)  to comment on the  “please explain”  so as to put the record straight as it is too important to be left the “too hard basket.“

In the introduction, Jennifer Marohasy says that any sceptic who raises the subject of the correctness of climate observations in polite society, however innocently, is likely to be branded a conspiracist as well as a science denier. This state of affairs is very well explained by Scott Hargreaves in Chapter 20 with reference to Dante’s great work about how we can find ourselves, most innocently, dragged down into hell.  Editor Marohasy suggests that Chapter 20 should be read first – which I would endorse – to serve as a warning to those of us who would seek the truth throughout the book.

The final chapter on “a descent into sceptics hell” written by Hargreaves is a somewhat disturbing read but is nevertheless well worth buying the book even for this chapter alone. It is not an easy read but those who have had a philosophical background will appreciate many of the concerns elaborated upon. Hargreaves uses the epic poem the Divina Commedia of Dante Alighieri (1265-1321 and describes nine circles of Dante’s circle of hell. They are limbo, the limits of reason, the IPCC, general circulation models, Climategate, peer-reviewed research, data homogenisation, raw temperature records, and finally ‘escaping hell’ to which Hargreaves says – presumably from climatological point of view – is “A sight more wonderful than anything…we could see the stars again”…. to which I can only add Amen.


The author of this review, Dr John Maunder, was President of the Commission for Climatology of the World Meteorological Organization from 1989 to 1997, and has over the last 70 years been involved in the “weather business” in various countries, including New Zealand, Australia, Canada, the USA, Ireland, Switzerland and England, through activities in national weather services, universities and international organizations.

He is the author of many works, and has most recently published Fifteen Shades of Climate: The Fall of The Weather Dice and The Butterfly Effect, which can be purchased at, here.

Fifteen Shades of Climate Includes this Forward, by John Zillman AO FAA FTSE, Former Director (1978-2003) of the Australian Bureau of Meteorology and Former President (1995-2003) of the World Meteorological Organization

“There are probably few people in the world who have originated and accumulated as much detailed knowledge of as many different shades of climate as John Maunder. He is a font of wisdom on climate matters and I believe he has served the world extremely well over the past 50 years through the way he has shared that knowledge and wisdom with the global community.

I first met Dr Maunder, when he was Chief of the Agricultural Branch of the World Meteorological Organization (WMO), at the May 1975 WMO Congress in Geneva, and again through his contribution to the proceedings of the December 1975 Monash (Melbourne) Conference on climate change and variability. The WMO Congress commissioned one of the first high-level international expert assessments of climate change and Dr Maunder’s Monash Conference contribution was among the first on the international scene to preview the emerging political and economic dimensions of climate variability and change.

For the next 40 years, Dr Maunder was at the centre of the rapidly advancing international scene on climate data, research, applications and impact studies. This included academic appointments in New Zealand, Canada, the United States and Ireland. When the 1979 WMO Congress established the World Climate Programme (WCP) as an international interdisciplinary framework for understanding and managing climate variability and change, it assigned much of the responsibility for WCP implementation to the WMO Commission for Climatology of which John Maunder was a respected member and future leader.

Through the sixteen years of his Vice Presidency (1981-89) and Presidency (1989-96) of the WMO Commission for Climatology, Dr Maunder guided the international implementation of the ‘data’ and ‘applications’ components of the WCP. As a member of the WMO Executive Committee (now Council) through that period and President of WMO for Dr Maunder’s final two years as President of the Commission, I saw the benefit of his wise and balanced advice to all WMO Member countries across the full range of climate matters. And, as Director of the Australian Bureau of Meteorology at the time, I was particularly pleased when he crossed the Tasman and joined the Bureau as a resident climate expert in 1990-92.

Dr Maunder has always been ahead of the game on climate matters. Before the costs and benefits of the impacts of weather became an issue, he had written a book on ‘The Value of the Weather’. Before the rest of the world had worked out how to use weather and climate information to manage the risks and opportunities of weather and climate variability and extremes, he had captured the essence of the problem with a book on ‘The Uncertainty Business.’ And before the First Report of the Intergovernmental Panel on Climate Change (IPCC) and the 1990 Second World Climate Conference had set in train the negotiation of the United Nations Framework Convention on Climate Change (UNFCCC), he had produced a climate lexicon that became, for many years, the definitive international ‘Dictionary of Global Climate Change.’”

While Dr Maunder comes from a meteorological generation for whom the study of climate embraced much more than concern with greenhouse warming and before the venerable scientific field of climatology had been repackaged and narrowed to ‘climate science’, he also became deeply involved in the early study of human-induced climate change. His extensive background in traditional climatology and his participation in the 1985 Villach Conference on the climatic effects of increasing carbon dioxide made him a respected source of wise advice to WMO Member countries when concern with ‘greenhouse warming’ burst upon the world in the 1980s. No-one can keep up with it all but I know of few traditional climatologists who have kept such a careful watch on all aspects of the growing global concern with climate change over the 35 years since Villach. This book is the result and the repository of the accumulated Maunder wisdom of those years.

Dr Maunder sees himself as a ‘realist’ on human-induced climate change. He is troubled by the over-simplification of the climate story and sets out to foster a better public appreciation of the complexity of the climate system. But, while he goes to great lengths to present a wide range of perspectives, including many he disagrees with, he does not refrain from making clear his own views on greenhouse warming or on the many other contentious issues captured in the fifteen shades of climate covered in the fifteen chapters of this book. The issues covered, some quite succinctly but others in great detail, represent almost a complete climate lexicon in their own right and I would be surprised if any reader failed to find at least a few new and illuminating slants on some of the many fascinating different aspects of climate.

This is not a book for those looking for unambiguous scientific support for greenhouse action. But it is, in my view, among the best you could hope to find by way of highly readable and authoritative answers to many of the everyday puzzles of climate. And, for those who have come to the frontiers of climate science without a background in traditional climatology, it contains much distilled wisdom from a generation of progress in a field of study that was once described by the great mathematician John von Neumann, as the most difficult unsolved problem still to confront the scientific intellect of man(sic.

This book also provides a few sobering reminders that, despite the enormous progress of the past fifty years, the von Neumann characterisation may still be close to the mark. I have not always agreed with everything I have found in Dr Maunder’s writing but I have always regarded his books as the epitome of scientific honesty and practical wisdom on climate issues. This book brings it all together. Read any or all of its chapters and you will be wiser on the many fascinating twists of the climate story.”

Support the IPA

If you liked what you read, consider supporting the IPA. We are entirely funded by individual supporters like you. You can become an IPA member and/or make a tax-deductible donation.