Written in 2012

The Climatic Research Unit (CRU) was established in the School of Environmental Sciences (ENV) at the University of East Anglia (UEA) in Norwich in 1972. The contribution of the Founding Director, Professor Hubert H. Lamb, cannot be overstated. Hubert Lamb's determination and vision can only be appreciated in the context of the view, generally prevailing within the scientific establishment in the 1960s, that the climate for all practical purposes could be treated as constant on timescales that are of relevance to humanity and its social and economic systems. The weather changed from day-to-day, from week-to-week, and season-to-season. There was interannual variability, but over years to centuries (the perceived argument went) a constancy was reliably evident. It is now recognised that the climate is not constant, but changes on all timescales – years to millennia, as well as the climatic changes on longer (e.g. ice age) timescales that had become accepted in the late 19th century. Hubert Lamb, encouraged by the support of Keith Clayton and Brian Funnell, Deans of ENV around the time, made the brave decision in 1971 that his pioneering work on climatic change would be best conducted at a university.

Many climatologists would now say that CRU's work in these early years played a major part in navigating the study of climatic change out of an academic backwater and started to set the agenda for the major research effort that followed. The purpose of this brief history is to document some of these achievements by subject, in a loose chronological order. A list of all past and present CRU staff and students is given here.

Hubert Lamb retired as Director in 1978. He was succeeded by Tom Wigley (to 1993), Trevor Davies (1993-1998), Jean Palutikof and Phil Jones (jointly from 1998 to 2004) and Phil Jones (to the present). Each has brought their own specialities to bear in guiding CRU through what have mostly been good times as far as successful research is concerned, but occasionally through periods of fallow funding, and sometimes very difficult periods.

Since its inception in 1972 until 1994, the only scientist who had a guaranteed salary was the Director. Every other research scientist relied on 'soft money' - grants and contracts - to continue his or her work. The situation improved after 1994, and at present four senior staff are fully funded as members of ENV/UEA faculty, contributing to the teaching programme and to administration and leadership within the university, as well as pursuing their research. The fact that CRU has and has had a number of long-standing research staff is testimony to the quality and relevance of our work. Such longevity in a research centre, dependent principally on soft money, in the UK university system is probably unprecedented. The number of CRU research staff as of the end of July 2012 is 12 (including those fully funded by ENV/UEA).

The early years

The early priority of CRU was set against the backdrop of there having been little investigation before the 1960s of past climatic changes and variability, except by geologists and botanists, although there was an excess of theories. The objective of CRU, therefore, was "to establish the past record of climate over as much of the world as possible, as far back in time as was feasible, and in enough detail to recognise and establish the basic processes, interactions, and evolutions in the Earth's fluid envelopes and those involving the Earth's crust and its vegetation cover". The early efforts towards this objective were the interpretation of documentary historical records. This was painstaking and challenging work and progressed through the 1970s.

In 1979, CRU hosted a remarkable, international, interdisciplinary conference (Climate and History), a turning point for the future work on historical climatology and the influence of climate on human societies. This type of work still has an important place in CRU's research portfolio to the present day, although it has broadened to include the development and analysis of early instrumental records and the extension of important climate indicators and datasets as far back in time as possible. A second international conference again focussing on historical climate variations and their links with societal change, but with a view to future changes and interactions, was held in 1998. An almost complete list of CRU publications is given here, including the volumes resulting from these two conferences.

Instrumental climate data

The area of CRU's work that has probably had the largest international impact was started in 1978 and continues through to the present-day: the production of the world's land-based, gridded (currently using 5° by 5° latitude/longitude boxes) temperature data set. This involved many person-years of painstaking data collection, checking and homogenization. In 1986, this analysis was extended to the marine sector (in co-operation with the Hadley Centre, Met Office from 1989), and so represented the first-ever synthesis of land and marine temperature data - i.e., the first global temperature record, demonstrating unequivocally that the globe has warmed since 1850, with the warming now reaching about 0.8°C . Work continues year-on-year to update and enhance the record and the publication of the value for the past year is eagerly awaited around the world. The most recent update is the HadCRUT4 dataset (see Morice et al. 2012, which additionally includes the CRU land component, CRUTEM4, Jones et al. 2012).

Besides the global temperature data set, there has been much CRU effort devoted to the compilation of a comprehensive, quality-controlled precipitation data base. This, together with CRU's high-resolution (0.5° by 0.5°) monthly datasets (for maximum and minimum temperature, precipitation, rainday counts, vapour pressure, cloudiness, wind speed and potential evapotranspiration) for all the world's inhabited land areas, has provided many researchers, in the UK and overseas, with their basic data for a whole range of studies. It is likely that CRU ranks only behind NCEP/NCARECMWF (ERA-40/ERA-Interim) and NCDC as the acknowledged data source by many climate scientists around the world.

Another research topic explored in the early days of CRU was the Southern Oscillation and its connections to the climate around the globe. This was amongst the first work to be undertaken on this phenomenon since its original identification by Sir Gilbert Walker in the 1920s, and presaged the later, enormous attention which would be paid to the El Niño Southern Oscillation (ENSO) phenomenon. Research here is still ongoing and has expanded to other major modes of atmospheric or ocean circulation variability (the Northern and Southern Annular Modes, North Atlantic Oscillation, North Pacific Oscillation, Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation). One of CRU's most cited papers (Jones et al. 1997) is on the North Atlantic Oscillation, and has been cited over 1000 times - much more than the global temperature papers. CRU's work in this area has extended many of the indices, assessed the changing influence of these phenomena on surface climate and evaluated how well the phenomena and their climate impacts are simulated by Global Climate Models.

Extending the instrumental record

The vast potential of tree rings to provide annually-resolved climate reconstructions over thousands of years has been exploited by the application of rigorous statistical methods to tree-ring data. In collaboration with a number of institutions throughout the world - in particular through a strong association with the Institute of Forest, Snow and Landscape Research in Birmensdorf, Switzerland - CRU is regarded as one of the world's foremost exponents of dendroclimatology, with particular emphasis on addressing standardization issues in tree-ring chronology construction. On longer time scales, the first rigorous quantification of past climate from the distributions and assemblages of beetle remains was made. Understanding the past has always been a primary aim of CRU, and until recently was mainly only of academic interest. Placing the instrumental period in a longer timescale context has provided renewed interest in proxy climate reconstruction. CRU was the first to develop a time series (based on tree-ring and other proxy climate data) of average Northern Hemisphere summer temperatures over the last 1000 years, which suggested that the recent decades were probably the warmest period in the record. Milder centuries were evident at the beginning of the millennium, with markedly cooler ones in the 17th and 19th centuries, but it is more likely than not that the average temperature for the period since 1975 is unprecedented during the past millennium.

Explaining the changes evident in the climate system

As it became clearer in the 1980s that the world was warming, a question that was asked with increasing frequency was how much, if any, of the warming was a consequence of human activity? CRU had made an important contribution to the posing of that question, so was in an excellent position to address it. The UK Government became a strong supporter of climate research in the mid-1980s, following a meeting between Prime Minister Mrs Thatcher and a small number of senior climate researchers, which included Tom Wigley, the CRU director at the time. This and other meetings eventually led to the setting up of the Hadley Centre for Climate Prediction and Research, within the Met Office. At the same time, other governments were also taking notice and wanted more information. As this need was not being met by existing international scientific bodies and institutions , the United Nations set up the Intergovernmental Panel on Climatic Change (IPCC), which undertook major assessments of climate science that were published in 1990, 1995, 2001 and 2007.  The first assessment was the basis for negotiating the United Nations Framework Convention on Climatic change (UNFCCC), and the IPCC has remained the most important source of scientific information for the Convention.  CRU staff have been heavily involved (probably more than anywhere else relative to the size of an institution - see IPCC AR4 Authors) in all four completed assessments as well as the fifth assessment that is currently in progress. The most recent IPCC assessment report (in 2007) concluded that "The warming of the climate system is unequivocal".

In the late 1980s, CRU started to explore the pattern correlation "fingerprint" method of detection, a technique to assess how the observed pattern of climatic change matches that which can be attributed to particular causes. This work culminated in 1995, when a team of researchers from American institutes and from CRU, using computer simulations of climatic change caused by increasing emissions of carbon dioxide - the most important anthropogenic greenhouse gas - and sulphate aerosols, was able to detect the effects of these climate forcing factors in the climate observations. This was a significant progression beyond the consensus view expressed by the IPCC in 1990, when it was considered that the effect of increased carbon dioxide concentrations could not yet be identified in the observed temperature record. This work played a critical role in the conclusion reached by the 1995 assessment of the IPCC that "the balance of evidence suggests that there has been a discernible human influence on global climate". Subsequent IPCC reports have strengthened these statements (in 2001: "there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities" and in 2007: "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations") and led most governments, industries, multi-national companies and the majority of the public to accept that the climate is warming, and humans are part of the cause.

Towards climate scenario development

CRU has also played a major role in efforts to predict future anthropogenic climatic change, and some of its consequences. In the late 1970s, rapid advances were being made elsewhere in atmospheric climate modelling (using Global Climate Models, GCMs), but it would be many years before these could be coupled to ocean GCMs. CRU pioneered simpler models (Energy Balance Models, EBMs) and, unlike the computer-intensive GCMs, they allowed the consideration of the consequences of a wider range of future emission scenarios and an assessment of the uncertainties due to parameters such as the climate sensitivity. Even though the GCMs have now improved in scope and speed, these simpler models are still valuable for interpolating between, or extrapolating beyond, the results of GCMs. CRU's work with these models led directly to the global-mean temperature projections given by the IPCC in 1990 and later assessments, and to corresponding projections of sea-level rise.

In 1992, CRU conducted a comprehensive integrated assessment of the climate projection problem, linking an EBM (now called MAGICC) and ice-melt models with models for translating greenhouse gas emissions to atmospheric concentrations and sulphur dioxide emissions that could be used to drive MAGICC. This work by CRU was the first attempt to consider the full spectrum of anthropogenic influences on climate in an internally consistent way. This methodology has improved, but the same basic approach is still valid and remains a vital tool used by the IPCC in the construction of future climate projections, as it is able to cover a much wider range of the uncertainties in greenhouse gas and aerosol scenarios than the more computationally expensive GCMs. The dramatic increases in computer power over the last 30 years have mainly been used to increase the spatial and vertical resolution of GCMs and to simulate many more aspects of the climate system (e.g., ENSO, extratropical cyclones, interactive atmospheric chemistry, interactive biosphere, runoff routing). Earth System Models or Global Environmental Models (as the more complex GCMs now tend to be called) require the largest and fastest computers in the world. These resources are best allocated to improving the comprehensiveness of the models, as opposed to running extensive scenario combinations for IPCC reports every few years. MAGICC and other similar developments around the world therefore continue to fill an important niche.

Regional climate scenario development and provision

CRU researchers have also pioneered several approaches to the construction of regional climatic change scenarios which have and continue to be used in climate impact assessments, environmental planning and climate policy debates. These approaches included some of the first analogue scenarios and the development of techniques for linking results from simple and complex climate models. In the 1990s, CRU incorporated model-based scenarios into integrated assessments of climatic change undertaken for the UK, European and US governments. This work has led to the creation of several scenario software applications which are widely used by the research communities. This scenario work has also been incorporated into IPCC reports.

Much climate scenario work is dependent on translating the broad-scale climate information produced by GCMs and their regional counterparts (RCMs) to a space- or time-scale which is of relevance for impact assessment (e.g., catchment or station scale and day-to-day weather). CRU pioneered some of the first work on this crucial issue of "downscaling", applying both statistical (using observed relationships between the different space- and time-scales) and dynamical (directly through RCMs) approaches, and was among the first to thoroughly compare the two approaches. Scenarios are becoming more and more detailed, and attempt to incorporate all aspects of uncertainty (emissions, model parameterization, etc.) including different modelling frameworks (also called structural uncertainty). The next-generation scenarios are moving towards probabilistic estimates of a range of future changes. The UK is leading the way in these endeavours, but more comprehensive education of the impacts community in the use and interpretation of probability-based information is required. CRU is taking the lead here with probability-based projections based on adapting weather generators to provide daily and hourly data within the latest set of UK national scenarios (UKCP09 http://ukclimateprojections.defra.gov.uk/), which were released in the summer of 2009. They have formed the basis of the first National UK Climatic Change Risk Assessment which was released in January 2012.  As these types of probabilistic scenarios are expensive to develop, it is likely that they will not be extensively updated for many years, with interim work assessing whether they are still compatible with newer GCM and RCM simulations.

Climatic change mitigation and adaptation

Work on the development and application of regional climate change projections has become gradually more extensive to support the discussion of mitigation and adaptation options. This moved the agenda from the scientific determination of the global warming issue to how to respond to the problem. In the late 1990s, the UK Research Councils recognized the need for a centre to address these issues. CRU, ENV and other groups across the UK were successful with their bid, and the Tyndall Centre for Climatic Change Research was born in 2000. CRU and the Tyndall Centre work together on some projects, but their specific aims and agendas are different. The Tyndall Centre focuses on solutions to the problem of climatic change, while CRU continues to work on all aspects of climate science. The growing practical applicability of CRU work is nonetheless reflected in the increasing range of academic users, stakeholders, decision makers and professional bodies with which CRU is involved, as well as the range of impacts sectors covered. The latter include agriculture, water, health, energy and, most recently, the built environment. These aspects of CRU work in the UK are also facilitated by strong links with the UK Climate Impacts Programme (UKCIP), set up in 1997 and based at the University of Oxford.

In 1992, CRU established the Climate Impacts LINK Project and continued to play a key project role for the next 15 years. The purpose of the LINK Project was to disseminate the results of climate simulations and future climate projections from the Hadley Centre's computer models to research groups in the UK and overseas, who are concerned with attempting to assess the impacts of climatic change. The LINK project was instrumental in developing the capacity of the climate impacts community to make quantitative assessments of the possible impacts of climatic change throughout this period. This was done by raising awareness of the nature of the projections, the appropriate ways in which they should be applied, and constructing a set of standard climate data sets that could be used as input to the many impact assessments that have been undertaken. This helped to make the results of different impact assessments more comparable.  An early measure of the success of the LINK project in making consistent sets of past and future climate information available to non-climate experts, together with appropriate education and advice, was that the majority of studies up to about 2000 addressing impacts of climatic change around the world used data from Hadley Centre climate models. The LINK project became the mould for data dissemination from other climate modelling centres and it eventually led to the establishment by the IPCC of the Data Distribution Centre (DDC), now led by the British Atmospheric Data Centre (BADC).

Climate services and applications

A main thrust of the Unit's research programme since the early 1980s has, as outlined above, been global warming: the human contribution, the future climate response, and possible impacts of future climatic change, with an increasing emphasis on adaptation to these impacts. Most recently, CRU has been involved in European and Global activities relating to the development of climate services. Following recommendations from the third World Climate Conference (WCC-3) held in 2009, the World Meteorological Organization (WMO) will launch a Global Framework for Climate Services in late 2012. But this focus was not to the exclusion of other research, much of it of commercial relevance. A few examples follow.

From the late 1970s through to the collapse of oil prices in the late 1980s, CRU received a series of contracts from BP to provide data and advice concerning their exploration operations in the Arctic marginal seas. Working closely with BP's Cold Regions Group, CRU staff developed a set of detailed sea-ice atlases, covering estimates of data quality and climate variability as well as standard climatological means, and a series of reports on specific issues, such as navigation capabilities through the Canadian Archipelago. Assessment of the wind energy resource over the UK led to the development of predictive schemes to assess the potential power production at candidate wind turbine sites. Research on predicting canopy wetness as a vector for disease in cocoa plantations has been of special interest to Brazilian cocoa producers. Advice from CRU has been sought on far-future climate states in relation to the long-term safety of low- and intermediate-level radioactive waste storage sites. On shorter-term timescales, work on extreme events with implications for nuclear power station operation has been undertaken. Perhaps, not surprisingly, the insurance and re-insurance industries have been a regular sponsor of research with early studies evaluating the risk of hurricane landfall on the Gulf and Atlantic coasts of the US, the impacts of severe storms in Europe and the characteristic of the typhoon risk over Japan. Many other private, governmental and non-governmental bodies (ranging from the Central Electricity Generating Board and National Power to Friends of the Earth and Greenpeace) have turned to CRU for reliable scientific insight into climatic change, acid rain, wind energy, and surface ozone.

Returning to the beginning, Hubert Lamb's work during the early 1970s on historic North Sea storm surges contributed in no small part to the implementation of plans for a flood barrier on the River Thames, drawn up after the disastrous East Coast floods of 1953. The number of times the Thames Barrier has been closed since its completion - increasingly so in recent years because, as Lamb predicted, sea level has risen - testifies to the value of this research. Hubert Lamb's other ground-breaking research (much of it summarised in the two volumes of his landmark book Climate: Present, Past and Future, which appeared during the 1970s) is still widely cited in science articles today.

Climatic Research Unit email controversy

This history would not be complete without mention of the events that took place in November 2009. CRU had a server that backed up files from researchers' PCs, including many emails and documents and some data. During 2009 this back-up server was hacked into and some or all of its contents copied. A small part of this hacked material was released and rapidly generated intense discussion, criticism and furore across many blogs and the mainstream media worldwide (further material, probably from the original hacking, was released two years later but received much less interest and no further controversy). The 2009 release occurred in the run up to the Copenhagen Conference of the Parties to the UNFCCC, and some commentators argued that it was a deliberate attempt to unsettle these negotiations.

The main criticisms were directed at the quality of our science (particularly our work on the instrumental temperature record and proxy/tree-ring-based reconstructions of past temperatures), our approach to the peer-review of science, our contributions to the IPCC assessments, and our sharing of data and information (including via the UK's recently introduced Freedom of Information legislation).

UEA was quick to set up two independent inquiries and related investigations were initiated by the House of Commons Select Committee on Science and Technology and other bodies in the USA. The main outcome of these inquiries was that CRU's scientific work, peer-review and IPCC work was beyond reproach:

  • "the scientific reputation of Professor Jones and CRU remains intact" (House of Commons Science and Technology Committee)
  • "we saw no evidence of any deliberate scientific malpractice in any of the work of the Climatic Research Unit" (Lord Oxburgh Science Assessment Panel)
  • "their rigour and honesty as scientists are not in doubt" (Sir Muir Russell Independent Climatic change Emails Review)

They did find that CRU could have been more open when dealing with some requests for data and some Freedom of Information requests. CRU already made much of our data holdings freely available. In the first two months after the hacked email controversy began, we released most of the underlying station temperature data used in the construction of the global temperature record jointly with the Met Office Hadley Centre. We then jointly continued our efforts to obtain permission from the originating National Meteorological Services to release the remainder, and in July 2011 almost all the station data (the only exceptions were a few stations in Poland) were made available. The station data for the new CRUTEM4 dataset were made available when the paper was published in spring 2012, and the paper provided numerous links to websites and reports to document the sources of the station temperature data that we used.

One of the reviews (by Sir Muir-Russell) made many recommendations, one of which was:

"We note that much of the challenge to CRU's work has not always followed the conventional scientific method of checking and seeking to falsify conclusions or offering alternative hypotheses for peer review and publication. We believe this is necessary if science is to move on, and we hope that all those involved on all sides of the climate science debate will adopt this approach."

Thus, like much of our earlier work from 1972 onwards, CRU is again at the forefront of climate science: however this time we are learning how to deal with a large and vocal web community, and communicating the importance of peer review and of following the norms of scientific publication has presented an extra challenge.

CRU today

Today (July 2012), CRU is still dependent upon research grant income to maintain the size and breadth of our research and student communities. The European Commission of the European Union (EU) provides the largest fraction of our research income under the Environment and Climatic change Programme. Since the mid-1990s, CRU has co-ordinated 7 EU research projects and been a partner on 23 others within the 4th, 5th, 6th and 7th Framework Programmes. Although EU funding is very important, we also endeavour to maintain the diverse pattern of funding reflected by the research described in this "history of CRU" and in the list of Acknowledgements below.

Since its inception in 1972,  65 students have been awarded PhD degrees. Today, CRU has a postgraduate research student community of 5 PhD students (July 2012). CRU also runs a NERC-recognized Master of Science degree programme on Climatic change. About 10 years ago, this degree attracted between 6 and 10 students per year, but the last few academic years have seen an upsurge to between 15 and 20 students per year. Altogether, almost 200 students have completed their MSc degrees. This is a strong endorsement of the growing importance of the subject and of our reputation.

A number of CRU staff have been awarded medals, certificates or fellowships from the Royal Meteorological Society, the European Geosciences Union, the American Meteorological Society, the American Geophysical Union and the Leverhulme Trust. Over the last 35 years also, several staff have been on the editorial boards of a number of major climatic journals (International Journal of Climatology, Climatic ChangeWeatherAtmospheric Science LettersJournal of ClimateThe HoloceneBoreasClimate ResearchTheoretical and Applied Climatology).

A research unit this size doesn't run itself. The directors and research staff over the years have been supported by a number of administrative, secretarial and other support staff, although this number has fallen in the last decade due to changes in working practices, organization and information technology. CRU has made extensive use of information technology, whether pushing the limits of university computer processing and data storage, or establishing a website soon after the birth of the world-wide-web that grew into one of the most popular sources of climate research and data.


This list is not fully exhaustive, but we would like to acknowledge the support of the following funders (in alphabetical order):

British Council, British Petroleum, Broom's Barn Sugar Beet Research Centre, Central Electricity Generating Board, Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Climate and Development Knowledge Network (CDKN), Commercial Union, Commission of European Communities (CEC, often referred to now as EU), Council for the Central Laboratory of the Research Councils (CCLRC), Department of Energy, Department of the Environment (DoE, 1970-1997), Department of the Environment, Transport and the Regions (DETR, 1997-2001), Department of the Environment, Food and Rural Affairs (DEFRA, 2001-present), Department of Energy and Climatic Change (DECC), Department of Health, Department of Trade and Industry (DTI), Earth and Life Sciences Alliance, Eastern Electricity, Engineering and Physical Sciences Research Council (EPSRC), Environment Agency, Forestry Commission, Greater London Authority, Greenpeace International, International Institute of Environmental Development (IIED), Irish Electricity Supply Board, KFA Germany, Joint Information Systems Committee (JISC), Leverhulme Trust, Ministry of Agriculture, Fisheries and Food (MAFF), National Assembly for Wales, National Power, National Rivers Authority, Natural Environmental Research Council (NERC), Norwich Union, Nuclear Installations Inspectorate, Overseas Development Administration (ODA), Reinsurance Underwriters and Syndicates, Royal Society, Scientific Consultants, Science and Engineering Research Council (SERC), Scottish and Northern Ireland Forum for Environmental Research, Shell, SQW Consulting, Stockholm Environment Agency, Sultanate of Oman, Tate and Lyle, Tyndall Centre, UK Met. Office, UK Nirex Ltd., UK Water Industry Research (UKWIR), United Nations Environment Plan (UNEP), United States Department of Energy, United States Environmental Protection Agency, Wolfson Foundation and the World Wildlife Fund for Nature (WWF).


Jones, P.D., Jónsson, T. and Wheeler, D., 1997:  Extension to the North Atlantic Oscillation using early instrumental pressure observations from Gibraltar and SW Iceland.  International Journal of Climatology 17, 1433-1450.

Jones, P.D., Lister, D.H., Osborn, T.J., Harpham, C., Salmon, M., Morice, C.P. 2012: Hemispheric and large-scale land surface air temperature variations: An extensive revision and an update to 2010. J. Geophys. Res. 117, D05127, doi:10.1029/2011JD017139.

Morice, C.P., Kennedy, J.J., Rayner, N.A. and Jones, P.D., 2012: Quantifying uncertainties in global and regional temperature change using an ensemble of observational estimates: the HadCRUT4 dataset. Journal of Geophysical Research, 117, D08101, doi:10.1029/2011JD017187.