Toward integrated historical climate research: the example of Atmospheric Circulation Reconstructions over the Earth

Climate change has become a key environmental narrative of the 21st century. However, emphasis on the science of climate change has overshadowed studies focusing on human interpretations of climate history, of adaptation and resilience, and of explorations of the institutions and cultural coping strategies that may have helped people adapt to climate changes in the past. Moreover, although the idea of climate change has been subject to considerable scrutiny by the physical sciences, recent climate scholarship has highlighted the need for a re‐examination of the cultural and spatial dimensions of climate, with contributions from the humanities and social sciences. Establishing a multidisciplinary dialogue and approach to climate research past, present, and future has arguably never been more important. This article outlines developments in historical climatology research and considers examples of integrated multidisciplinary approaches to climate, climatic variability, and climate change research, conducted across the physical sciences, social sciences, humanities, and the arts. We highlight the international Atmospheric Circulation Reconstructions over the Earth (ACRE) initiative as one example of such an integrated approach. Initially, ACRE began as a response from climate science to the needs of the agricultural sector in Queensland, Australia for a longer, more spatially, and temporally‐complete database of the weather. ACRE has now evolved to embrace an international group of researchers working together across disciplines to integrate their efforts into a four‐dimensional (4D) dynamical global historical climate‐quality reanalysis (reconstruction). WIREs Clim Change 2016, 7:164–174. doi: 10.1002/wcc.379

disciplines to integrate their efforts into a four-dimensional (4D) dynamical global historical climate-quality reanalysis (reconstruction). ©

THE CASE FOR INTEGRATED CLIMATE RESEARCH
D ebates over anthropogenic global warming, and the potentially 'looming and apocalyptic changes in future climate' 1 (p. 6), represent one of the dominant environmental narratives of the 21st century. However, this narrative has not widely incorporated research on the societal understanding of climatic variability and climate change, or the implications of such fluctuations and changes for human vulnerability and/ or resilience. Instead, it has tended to marginalize explorations of the institutions and cultural coping strategies that may have helped people adapt in the past. It has been argued that this may be a function of an overemphasis on climate science and modeling, and a lack of engagement with cultural climate history. 2 Determining both the likely future climates and how different communities might be affected by and respond to climate change, however, has become an issue of global and political importance. Establishing a multidisciplinary dialogue and approach to climate research past, present, and future, which can also feed into climate risk management, is therefore vital. 3 Developing a true capacity for multidisciplinary research, however, is extremely challenging, while sustaining such an endeavor is a significant task, logistically and financially. 4,5 The separation of the physical sciences as discrete from the social sciences, humanities, and arts, and emphasis on scientific evidence overlooks the cultural and social context of its production. Moreover, there are contrasting categories of research questions, different modes of academic debate, and different approaches to the presentation of research between disciplines. 4,5 In facilitating the development of multidisciplinary research in climatic variability and climate change, understanding these challenges is critical. Similar challenges stem from differences in ways of thinking and processing knowledge that underpin the language of, and research training in, different disciplines. 6 During the 1980s and 1990s, the primary focus of the climate science community was to develop model-based climate change scenarios extending out 50-100 years. 7 -9 More recently, major efforts have been made to seamlessly link the various models and research approaches used in forecasting to those investigating climate change 10 -with a more equal focus on disentangling climatic variability and climate change signals and drivers, improving seasonal forecasting, and the use of all of this material for climate services (see http://gfcs.wmo.int/). 11 The climate science community has also focused on the collection and refinement of observational evidence for climate change through historical global temperature records extending back to the mid-19th century. However, there is now a growing realization that improvements in the quantity, quality, and resolution of instrumental and documentary historical observations and proxy/palaeo climate data, and developments in both reconstruction methodologies and dynamical historical reanalyses, can provide new baselines of global weather and climate. The latter can be employed to test climate models for climate change detection, and provide an essential historical framework within which to develop an understanding of potential changes in weather and climate impacts, risks and extremes. However, embracing wider collaborations with, or inputs from, the social sciences, humanities, and the arts, seems to remain beyond the current thinking or capacity of the mainstream climate science community. 12 One area that has witnessed rapid growth over the last decade in particular is research focusing on the construction of regionally specific climatic histories and historical extreme weather events, and investigations of social responses to these events. These are central to understanding the nature of the changes that might take place in the future and their impacts. 3,13 This area of research is undergoing something of a re-emergence. There was of course much interest in this latter topic in the late nineteenth and early 20th century-for example in the work of Ellsworth Huntington, who was broadly concerned with the impacts of climate and climate changes over centuries and millennia on the development and location of civilisation and the influence of weather types on human efficiency. This 'simple determinism' faced considerable criticism, not least because of the way these arguments were interpreted and applied in racist dogmas in the early 20th century. 14 By the middle to latter parts of the 20th century, however, Hubert Lamb and Emmanuel Le Roy Ladurie played key roles in establishing more nuanced studies of historical climate-society relationships 15 using a mix of historical documentary and instrumental data and indices. 16,17 A new breed of scholars working at this interface, especially geographers and historians, have been at the forefront of a new form of historical climatology and climate history research, with its focus on both climate reconstruction and explorations of the societal impacts of, and responses to, past climate change at a range of scales (see, e.g., Refs 15,18-30 among many others). Such pioneering work is not only providing detailed regional climate histories but, perhaps most significantly, is offering important insights into how societies have coped with and have responded to climatic variability and anomalous weather events in the past. a The environmental history community is also now engaged in work that explores how society has conceptualized, apprehended and responded to climate changes in different contexts and at different points in time, a point acknowledged by Culver. 31 Moreover, there is an imperative to do so, given that it is 'increasingly acknowledged that the [climate change] agenda needs to include consideration of the strategies for human adjustment to future changes' and to address the factors that influence human perceptions and behavior all of which may contribute to relative vulnerability or resilience. 32 Yet such studies have often remained isolated from climate science endeavors and have been embedded within individual disciplines, leading to the problems of communication and integration listed above. New initiatives are seeking to address this problem. The emergence of the resilience paradigm, 33 e.g., has generated a new role for history in climate research. Driven by IHOPE (Integrated History and future of People on Earth), this approach develops Holling's theories 34 of ecological systems with multiple stable states into integrated social-environment systems. 35,36 Here, historical and archeological data provide the temporal dimension unveiling the processes that have governed system dynamics, in order to identify interventions toward sustainability. 37 -41 With a focus on agent-based models, this approach has been more closely aligned with policy-driving organizations such as the IPCC (Intergovernmental Panel on Climate Change) and Future Earth than historical climatology approaches. However, it has been criticized as downplaying the role of human agency in the past, and for failing to recognize that an individual's vulnerability is as much a function of their dynamic worldviews and beliefs as their assets and capabilities, to the extent that this cannot be replicated within a model. 42 -45 Although the current availability of digital climate data (particularly daily series, which enable extremes to be assessed) is often restricted to the second half of the 20th century over many parts of the world, there have emerged in recent years a number of integrated climate initiatives that build on historical climatology approaches. 46 The most recent include the University of Freiburg-led Tambora.org project, 47 which offers a collaborative research environment with access to large data collections on climatic parameters such as temperature, precipitation, storms, and floods with different regional and thematic foci derived from historical sources. Significantly, this provides 'a database for original text quotations together with bibliographic references and the extracted places, dates and searchable information on climate and environment' (https://www.tambora.org). A further example is the University of Bern-led Euro-Climhist database, 48 which represents a comprehensive tool for managing, analyzing, and displaying climatic (high-resolution) proxy evidence from 1.2 million natural and documentary archives, including data detailing the Late Maunder Minimum and its societal implications across Europe. These efforts highlight the need for the careful documentation of historical sources, rather than to just provide their interpretation as fact, made without sufficient consideration of the cultural and societal background shaping them.
There are also a number of very significant data rescue initiatives underway, recently discussed in the literature. 3,46,49 These include The Mediterranean Data Rescue (MEDARE) initiative-a cooperative effort aimed at enhancing surface climate data availability over the Greater Mediterranean Region. MEDARE's purpose is to 'develop, consolidate and improve surface climate data and metadata rescue activities across the [Greater Mediterranean Region] GMR.' The long-term goal is to work toward the development and provision of comprehensive highquality, high-resolution time series of instrumental climate data for the region 46 (p. 35). Another key example of an international consortium-led initiative with a major focus on data rescue is the Atmospheric Circulation Reconstructions over the Earth (ACRE). This initiative, with a strong multidisciplinary focus, melding together climate science with the social sciences, humanities, and the arts around global outputs from historical reanalyses based on archival records, is the focus of the next section.

ACRE and Historical Reanalysis
The international ACRE initiative (http://www.metacre.org) 50 undertakes and facilitates historical global surface terrestrial and marine weather data recovery, imaging, and digitization. Under ACRE's international umbrella, there are various regional data foci and collection partners, each taking responsibility for finding, digitizing, and making accessible historical weather data from their region (see Figure 1). All of these data are fed into several existing international repositories, including the International Comprehensive Ocean Atmosphere Data Set (ICOADS), International Surface Temperature Initiative (ISTI), Global Precipitation Climatology Centre (GPCC), and the International Surface Pressure Databank (ISPD). ACRE works with the above repositories to provide the best quality and quantity of surface weather observations for assimilation into all reanalyses, b especially the ACRE-facilitated 20th Century Reanalysis Project (20CR; http://www.esrl. noaa.gov/psd/data/20thC_Rean/). 51 The current version extends from 1850 to near-present, with various experiments ('scout runs') looking to push 20CR back into the early 19th century.
The 20CR is an ongoing international project led by the National Oceanic and Atmospheric Administration (NOAA) and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado. It generates 4 dimensional (4D) global reanalysis datasets for climate applications extending back to the 19th century using an Ensemble Kalman Filter and only surface synoptic pressure observations. 51 Monthly sea-ice boundary conditions from the COBE-SST2 dataset plus new pentad Simple Ocean Data Assimilation with sparse input (SODAsi.2) sea surface temperature fields 52 provide boundary conditions for the latest release, 20CRv2c. Dynamical downscaling by the Met Office regional climate modeling system-Providing REgional Climates for Impacts Studies (PRECIS; http://www.metoffice.gov.uk/precis)-is being used to

Multidisciplinary Background
Over the past 5 years, ACRE has been working with climate-linked projects and networks led by colleagues in the UK social sciences, humanities, and arts communities, funded by bodies such as the Arts and Humanities Research Council (AHRC) and the Joint Information Systems Committee (JISC; Figure 1). ACRE is also part of the Indian Ocean World Centre (IOWC) initiative based at McGill University in Canada (http://indianoceanworldcentre.com/), and is contributing, along with the University of Sussex, to their focus on The Indian Ocean World: The Making of the First Global Economy in the Context of Human-Environment Interaction (http://indianoceanworldcentre.com/Team_7). The challenge now, is to engage with the wider international social sciences, humanities, and arts communities. Already, ACRE's data collecting activities embrace many of the archives of the old European empires, an invaluable source for the Global South (the nations of Africa, Central, and Latin America, and most of Asia) where data can be sparse and difficult to locate. In support of this, the initiative is working to develop a formal collaboration with the International Council on Archives (http://www.ica.org/3/homepage/home.html).
These collaborations (Figure 2), have led ACRE, and its wider community, to begin to go further, and to look at integrating historical 20CR reanalysis output with broader social, historical, cultural, environmental research from the social sciences, humanities, and arts communities. Here, we briefly review the nature of some of these collaborations.

Citizen Science and Maritime Logbooks
One of the largest and yet underused sources of historical meteorological and environmental data are archive collections of ships logbooks. These logs contain detailed weather observations-air and sea temperatures, air pressure, wind, and clouds, etc.-and qualitative descriptions of sea-ice. There are millions of handwritten pages, and ACRE and its partners have been working to mine them-photographing hundreds of thousands of pages from UK and US ship voyages dating back into the late 18th to early 19th century. Rescuing the observations is an enormous task, requiring the reading of millions of handwritten entries, and the transcription of weather and ice records within the entries. This work builds on previous projects such as the EU funded Climatological Database for the World's Oceans (CLIWOC) project, and on pioneering work on the potential and reliability of ships logbooks as a historical source. 53 Through a combination of serendipity and necessity, ACRE has been integral to the development of 'citizen science' data rescue projects, such as Old Weather (http://old.oldweather.org/), Old Weather 2 (http://www.oldweather.org/) (initially funded by JISC, Figure 2.) and Weather Detective (http://www. weatherdetective.net.au/) (funded by the Australian Broadcasting Commission as the winner of their 2014 National Science Week Citizen Science project). By providing scanned ship logbook weather observations via dedicated web sites, these projects enable volunteers to contribute to the data rescue and digitization task. So far, around 20,000 volunteers have read well over 1 million pages of paper records and contributed millions of recovered weather observations to international climate datasets-such as the ICOADS, ISTI, GPCC, and the ISPD. This initiative improves the quality and quantity of material in such repositories, increasing the pool of global historical surface weather observations assimilated by all reanalyses, especially 20CR.

Documentary Reconstructions of Extreme Weather Events in the UK, Past, Present, and Future
There is rising concern over the impacts of 'extreme' weather events such as droughts, floods, storms and unusually high or low temperatures. While social and economic systems have generally evolved to accommodate some deviations from 'normal' weather conditions, extremes can overwhelm them. Such events, therefore, can have significant impact. 54 The reconstruction of regionally specific historical extreme weather events, and investigations of the social responses to these events, are of crucial significance to assess how different communities in different contexts might be affected by, and respond to, future events and to understand the nature of the events that might take place in the future. Such studies could provide a guide to where the critical human sensitivities to future events may lie. One such study

The Snows of Yesteryear/'Eira Ddoe'
In a related project, The Snows of Yesteryear/'Eira Ddoe' (http://eira.llgc.org.uk/), funded by the AHRC's Landscape and Environment Programme, a research team based at the National Library of Wales and the University of Wales examined archival sources from the early modern period for descriptions of extreme weather events. Information came from diaries, letters, and ballads. The team also engaged the community to understand how extreme weather is processed as memory. The project team discussed these representations of climate data as a series of keywords with climate scientists, and began a narrative about using archives from the preinstrument period for the end result of the researcha source for understanding historic weather events. These data were also the basis-in an allegorical sense-for a performance by Eddie Ladd, Dawns Ysbrydion/Ghost Dance, subsequently commissioned by the National Theatre of Wales. This showed the importance of understanding community  vulnerability and resilience to extreme weather, historically and in contemporary society. The project also was a good example of the ways that digital humanities and information management in the humanities have much to add to the study of climate change, especially in the requirements for an underlying digital infrastructure to support this collaborative work, integrating research questions with content, tools, methods, and community involvement where appropriate.

The Chinese Maritime Customs project
The value of interactions between disciplinary initiatives can be seen in the relationship between the History of the Chinese Maritime Customs Service (CMCS) project (http://www.bristol.ac.uk/history/ customs/), and ACRE ( Figure 2 55 to try to secure access to this, and to provide details of the history of the CMCS meteorological system, its development, standards and equipment. 56

FACILITATING ACCESS
Support for a baseline of high-resolution, highquality digital images of archival records containing weather, climate, environmental, cultural, and societal information to support integrated historical climate research is essential. In order to facilitate access to such material, there is a need for a generic digital research infrastructure that can support the management of data gathered remotely, especially historic weather primary source materials including logbooks and other weather diaries; provide a transcription platform where necessary, provide open access to the primary sources and the data they contain, and provide the ability to integrate reanalyses products. There should be a means to oversee transcription, data management support, and support for use of reanalyses tools, especially access to the complex range of multidisciplinary information required to work with these data. With ACRE, it would allow future use and re-use by processing tools for reanalysis that do not yet exist. Given that these data and reanalyses outputs must ultimately be multilingual, and multi-disciplinary, this is an enormous task. Nonetheless, what is required is an archive that can be accessed by anyone undertaking digitization of archival records that relate to historic weather and the reanalyses generated from them (the current efforts in climate are still very climate science focused http://www.idare-portal.org/). There are relevant international standards, developed by organizations including the Digital Curation Coalition (http:// www.dcc.ac.uk). Integration of existing data archives, through the use of linked data approaches, may be suitable. Critically, the technical solutions require sustained support and intervention.

Educational Structures and Digital Resources
It is equally important to advertise the 'endeavors and successes in data recovery.' 57 For example, ACRE must look to develop the tools and structures that will allow it to engage with a wider audience, especially in the educational sphere, through the provision of a new dynamical global 4D historical database of the weather vastly enhanced via integration with layers of multidisciplinary content. Reaching out in this manner is important for many reasons: First, in many developed countries there is a marked decline in the number of secondary school students pursuing maths and science subjects. 58,59 In the United States, e.g., from the mid-1970s to the early-2000s, there has been no substantive change in the proportion of high school graduates who go on to complete or enroll in a STEM field of study. 60 Second, associated with the decline in students pursuing science at secondary and tertiary level are concerns about shortages of teachers, especially in primary schools, with science and mathematics qualifications (http://www.cpre.org/images/stories/ cpre_pdfs/math%20science%20shortage%20paper% 20march%202009%20final.pdf and https://royalsociety.org/~/media/education/policy/vision/reports/ev-7-vision-research-report-20140624.pdf). Third, the past decade has seen a rise in skepticism about the reality of human-induced climate change. The US National Research Council 61 (p. 35) reports a 'deliberate and organized effort to misdirect the public discussion and distort the public's understanding of  62 The challenge now is to produce an international resource for students and the public, presenting weather/climate, climatic variability, and climate change in its fuller context. Such a digital resource could be as large as funding permits and would bring to the global audience the vast resources of ACRE and its wider community extending into the social sciences, humanities, and the arts. Users would be able to access historic dynamical 4D global reanalysis fields and the weather data and other relevant information used to generate them. Such material would be embellished by access to layers of social, historical, cultural, and environmental information provided by the social sciences, humanities, and the arts. With such a resource, it would be possible to track local weather historically over centuries, either from direct observations, or historical reanalyses and/or their downscaled products. There would also be the potential to link climatic and environmental changes with key historic events.
This digital resource would be managed and maintained by a well-coordinated multidisciplinary team, including professional science communicators, web experts, and researchers. However, in order to support the veracity and sustainability of such efforts, there would need to be new educational structures. It would require the development of a truly multi/cross-disciplinary curriculum at secondary to tertiary education levels which would expose students and researchers to a wider range of integrated science, social sciences, humanities, and arts subjects and studies. In a very broad sense, some fledgling elements of such engagements are seen in the UK RCUK School-University Partnerships Initiative (http:// www.rcuk.ac.uk/pe/PartnershipsInitiative/) where the University of East Anglia's component notes that 'We will also show that sciences, arts and humanities subjects do not exist in isolation, and that much can be gained by working together in a cross-disciplinary way to investigate and solve problems.'

CONCLUSION
This article has argued the need for climate research to incorporate investigations of societal understanding of climate variability and change, and implications for human vulnerability and resilience. It has outlined new research in historical climatology and climate history research, which explores the societal impacts of, and responses to, past climate change, but argues that this research needs closer links to climate science. The article demonstrates that the capacity for genuine integrated historical climate research, incorporating scientific, social scientific, and arts and humanities perspectives, is already in place. This alignment would have the propensity to produce new and enhanced products and perspectives which would be invaluable for policymakers involved in adaptation and management decisions across various scales. Such potential is embodied in an enhanced international ACRE initiative integrated within historical climate research activities.
The next step for ACRE will be to build on the multidisciplinary interactions noted in this article and to demonstrate the effectiveness of this collaborative platform. Numerous historical events, however, could provide a timely forum for the implementation of multidisciplinary collaborations. These include the eruptions of Tambora in 1815, and the subsequent 'year without a summer' in 1816, and of Krakatoa in 1883. Work by ACRE is starting to reveal important insights into the implications of different estimates of volcanic aerosols. c ACRE has also started to reconstruct and model the temperature and pressure data recorded through Shackleton's Imperial Trans-Antarctic Expedition (1914)(1915)(1916)(1917) and the loss of the Endurance in October 1915. d There is also significant scope to extend ACRE's activities to highresolution downscaled 20CR output via the Met Office PRECIS team, with foci on key episodes in British climate history, such as the autumn 1894 floods and the following winter 1894-1895 freeze. e There is also potential to link into other major climate research projects, such as the Oxford University led Managing the Risks, Impacts and Uncertainties of drought and water Scarcity (MaRUIS) project (http://www.mariusdroughtproject.org/), in which at least one member of the 20CR ensemble output will be downscaled to provide a high-resolution baseline of UK droughts from 1850 to 2014. Details of all of the publications that have referred to or used ACRE-facilitated 20CR output and products can be found at http://www.esrl.noaa.gov/psd/data/ 20thC_Rean/pubs/ With the right level of support and, critically, ongoing multidisciplinary collaboration, some examples of which have been considered in this article, such initiatives are certainly within reach. These activities are imperative if progress is to be made in our understanding of past, present, and potential future climate changes and their socioeconomic and cultural implications for our future.