Conference Agenda

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Session Overview
114R: The deep history of global land use change - needs and potentials for earth system modelling and understanding socio-ecological systems
Friday, 26/Apr/2019:
10:30am - 12:00pm

Session Chair: Marie-Jose Gaillard
Session Chair: Erle Ellis
Location: MB-101
Main Building, room 101, 1st floor, east wing, 80 (+14) seats
Session Topics:
What are the visions for the planetary land system?

Session Abstract

Land-use and related land-cover change transform environments in multiple interacting ways, including feedbacks with human social change and land use itself. Early changes in land-use are known to have altered global patterns of biodiversity and climate that have potent impacts on these into the present time. This session explores relationships between land-use change and the environment, in particular biodiversity and climate, based on long-term reconstructions from paleoecological and archaeological evidence that enable these complex processes to be understood and modelled over long time periods. Reconstructions of past land-use and anthropogenic land-cover change over past millennia also enable hypotheses on long-term processes, feedbacks and dynamics at global scale to be tested using Earth System Modelling and socio-ecological models. The PAGES LandCover6k working group is an example of recent efforts to achieve plausible quantitative reconstructions of past land use and land cover useful for Earth System Modelling, and that can also be used in other types of modelling. These reconstructions are based on pollen-inferred plant cover, and mapping and interpretation of archaeological data. Other initiatives have used alternative methods such as population-growth modelling based on databases of 14C dates from archaeological sites, and models of the relationship between population growth and land-use/deforestation. This session welcomes all contributions on sub-continental to global reconstructions of past long-term land-use change and/or applications of these reconstructions in hypothesis testing related to changes in biodiversity, climate and other global environmental change processes.

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Full talk
ID: 678 / 114R: 1
114R The deep history of global land use change – needs and potentials for earth system modelling and understanding of socio-ecological systems
Keywords: Holocene, land-use, land-cover, climate forcing, REVEALS

PAGES LandCover6k: Holocene land-use and land-cover reconstructions for climate modelling

Marie-Jose Gaillard1, Sandy Harrison2, Marco Madella3, Kathleen D. Morrison4, Nicola Whitehouse5, Oliver Boles4, Andria Dawson6, Esther Githumbi1, Emily Hammer4, Furong Li1, Eduardo Kasuo Tamanaha7

1Linnaeus University, Sweden; 2University of Reading; 3University Pompeu Fabra, Barcelona, Spain; 4University of Pennsylvania, Philadelphia, USA; 5University of Plymouth; 6Mount Royal University, Calgary, Canada; 7Mamirauá Institute for Sustainable Development, Tefé, Brazil

The PAGES LandCover6k working group (Gaillard et al. 2018) has the goal to achieve reconstructions of Holocene global land-use and land-cover (LULC) change over the Holocene for climate modelling. Biogeo-chemical and –physical feedbacks of vegetation change on climate in the past are studied using dynamic vegetation models (DVMs) coupled to climate models. Land-use is one of many climate forcings and includes biogeo-chemical and –physical effects from human-induced vegetation change. Because DVMs do not simulate land use, anthropogenic land-cover change (ALCC) scenarios are used in climate and carbon-cycle modelling. However, these scenarios are not consistent (Gaillard et al. 2010) and the impact of past LULC changes is still under debate. The LandCover6k LULC reconstructions are used to improve ALCCs and as benchmarking of model outputs. LandCover6k uses (i) the REVEALS model (Sugita et al. 2007) and the Modern Analogue Technique (Zanon et al. 2018) as two alternative methods to infer past plant cover from pollen records, and (ii) archaeological and historical records to map land-use types and associated quantitative attributes such as crop cultivation, grazing, irrigation, etc. in m2/m2 (Morrison et al. 2018). REVEALS land-cover reconstructions are available for the northern hemisphere (North of 40˚) and temperate China, and in progress for the southern hemisphere. Archaeologists established a LandCover6k global land-use categorization and designed a database to produce maps of past land-use categories and associated quantitative attributes. LandCover6k products are co-designed with climate and carbon-cycle modellers within the PMIP community in order to maximise their use in modelling experiments (Harrison et al., 2018).

Gaillard M.-J. et al. 2018, PAGES Magazine 26 (1); Gaillard M.-J. et al. 2010, Clim Past; Sugita 2007, The Holocene; Zanon M. et al. 2018, Frontiers in Plant Science; Morrison K. D. et al. 2018, PAGES Magazine 26 (1); Harrison et al. 2018, PAGES Magazine 26 (2).

Full talk
ID: 371 / 114R: 2
114R The deep history of global land use change – needs and potentials for earth system modelling and understanding of socio-ecological systems
Keywords: agriculture, history, global environmental change, Anthropocene

The deeper roots of global change: land use changes from 10,000 BP to 1850 CE

Erle Ellis

University of Maryland, Baltimore County, United States of America

Archaeological evidence confirms that environmentally-transformative uses of land began with Late Pleistocene hunter-gatherers and accelerated with the domestication of plants and animals and the emergence of agricultural societies beginning more than 14,000 years ago. Yet global models and assessments generally represent the view that anthropogenic global environmental change is mostly recent. This presentation examines existing global reconstructions of land use history in the light of a new collaborative effort combining the contributions of 255 archaeologists in the first global assessment of archaeological knowledge on land use changes from 10,000 BP to 1850 CE at ten time points across 146 regions spanning all continents except Antarctica. While archaeological knowledge of land use was generally strongest between 4,000 BP and 1,000 BP, results indicate that hunter-gatherer societies were widespread across all continents by 10,000 BP and that intensive agriculture became common and widespread in most current agricultural regions much earlier than depicted in the most commonly used historical reconstructions of global land use history. Scientific understanding of anthropogenic global environmental changes past, present and future and their grounding in land system science will require the development of a more robust global archaeological evidence base developed both by expanding archaeological research to understudied areas and increased international collaboration in knowledge integration and open sharing of archaeological and paleoecological data in forms useful for global models and assessments.

Full talk
ID: 819 / 114R: 3
114R The deep history of global land use change – needs and potentials for earth system modelling and understanding of socio-ecological systems
Keywords: land use change; archaeology; radiocarbon dates; early farmers;

Mapping Land Use change during the Boreal and Atlantic phases in the NW Mediterranean region and Switzerland

Ferran Antolín, Héctor Martínez-Grau, Ana Jesus

Integrative Prehistory and Archaeological Science, Switzerland

The LandCover6K Working group for the European continent has been discussing in recent workshops how to best map land use in the past making the most of the available archaeological data. The underlying question to this work is whether prehistoric human impacts on land cover were sufficiently large to have had a major impact on regional climates. The project involves multiple challenges that are inherent to the nature of archaeological data. Unlike pollen data, which is usually extrapolated for unexplored areas following different parameters, the lack of archaeological information in one region cannot be filled based on actualistic assumptions and data available from other areas unless there are good reasons for it. This might result in an underrepresentation of human presence and anthropogenic land cover change.

Here we present a first test of the methodology proposed by the LandCover6k group for a specific region that is of interest for the AgriChange Project (funded by the Swiss National Science Foundation), dealing with agricultural and land-use change in the NW Mediterranean region and Switzerland. This region is of particular archaeological interest for the understanding of the beginnings of farming because it witnessed the arrival of at least two different farming traditions: the one coming along the Mediterranean coast, and the one that went along the Danube River. Taking into account the archaeobotanical evidence of farming and wild plant gathering practices, currently being gathered by the project, together with the available radiocarbon dates for specific time frames of interest (because they are moments of socioeconomic change) we will present an attempt to map land use change in this area.

Full talk
ID: 790 / 114R: 4
114R The deep history of global land use change – needs and potentials for earth system modelling and understanding of socio-ecological systems
Keywords: land-cover, sediment pollen, vegetation, land-use, REVEALS

Northern Hemisphere Holocene land-cover reconstructions from fossil pollen

Andria Elizabeth Dawson1, Xianyong Cao2, Michelle Chaput3, Emma Hopla4, Jed O. Kaplan5, Furong Li6, Mary Edwards4, Ralph Fyfe7, Konrad Gajewski3, Simon J. Goring8, Ulrike Herzschuh2, Florence Mazier9, Shinya Sugita10, Jack W. Williams8, Qinghai Xu11, Marie-Jose Gaillard6

1Mount Royal University, Canada; 2Polar Terrestrial Environmental Systems, Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association, Germany; 3University of Ottawa, Canada; 4University of Southampton, UK; 5University of Oxford, UK; 6Linnaeus University, Sweden; 7Plymouth University, UK; 8University of Wisconsin, Madison, USA; 9University of Toulouse II Jean Jaurès, France; 10University of Tallinn, Estonia; 11Hebei Normal University, China

Terrestrial ecosystems play an important role in Earth systems processes, yet we still do not fully understand the feedbacks between these ecosystems and Earth’s climate. These ecosystem processes operate at multiple timescales; fast processes occur at sub-annual timescales, and slow processes, driven by changes in forest composition and structure, occur over decadal and longer timescales. Slow processes are rarely directly observed from instrumental data, yet are critical to understanding the stability of the terrestrial biosphere over the coming decades. Networks of paleoecological data, particularly sedimentary pollen data, offer our strongest observational constraint on long-term vegetation dynamics and underlying processes and feedbacks.

We reconstruct maps of land-cover for the Holocene for the Northern Hemisphere. To do this, we use: (i) networks of fossil pollen records - the most reliable paleoecological proxy for land-cover; (ii) estimates of pollen productivity and fall speed, and (iii) a model of pollen-vegetation relationships, REVEALS (Sugita, 2007). For the Northern Hemisphere, we estimate the fraction of summergreen trees, evergreen trees, and open land.

To determine the differences between these pollen-based reconstructions and more commonly used land-use models, we compare the fraction of open land with estimates of open land from the anthropogenic land-cover change (ALCC) model KK10 (Kaplan et al., 2009). Identifying cause to these differences provides an opportunity for improvement in ALCCs used to inform both global earth system and dynamic vegetation models.

This work results in improved understanding of the history of Holocene land-use change over a large spatial extent and slow ecosystem processes, the biogeochemical and physical forcings from past anthropogenic land-cover change on climate, and the long-term carbon dioxide budget. It is a contribution to PAGES LandCover6k.

Full talk
ID: 286 / 114R: 5
114R The deep history of global land use change – needs and potentials for earth system modelling and understanding of socio-ecological systems
Keywords: land use, history, paleo-ecology, archaeology, modelling

A global historical land use reconstruction database for earth system modelling; state-of-art and remaining challenges

Kees Klein Goldewijk

PBL Netherlands Environmental Assessment Agency, Netherlands, The

Earth System Models (ESMs) are used to investigate the coupled behavior of the land-atmosphere system, and the transient response of the climate system to different forcings, both in the past and in the future. The treatment of ALCC in ESMs currently is not satisfactory and this hampers our ability to understand past trajectories and the reliability of future projections (Gaillard et al., 2010). The two major scenarios of past ALCC, the HYDE database (Klein Goldewijk et al., 2017; Klein Goldewijk et al., 2011) and the KK10 database (Kaplan et al., 2011) differ substantially from one another and it is therefore imperative to produce more robust and reliable descriptions of past ALCC at the global spatial scale (Gaillard et al., 2017).

The current HYDE 3.2 database (Klein Goldewijk et al. 2017) is an internally consistent combination of historical population and land use estimates for 10,000 BC – 2015 CE. The various incarnations of HYDE are widely used by the climate-modelling community, and HYDE forms the basis for prescribed land-use for last millennium, historic and future simulations currently being carried out within the Coupled Modelling Intercomparison Project (CMIP6; Eyring et al. (2016)) as a basis for the next assessment by the Intergovernmental Panel on Climate Change. HYDE inputs are particularly important for the last millennium and historic simulations, which are used for detection/attribution of climate change (Bindoff et al., 2013).

However, recent contributions from the paleo-ecology and archaeology communities reveal that HYDE does not agree well in variious areas, regions or time slices, so the major challenge ahead is how to incorporate knowledge from those diffrent disciplines.

Flash talk
ID: 691 / 114R: 6
114R The deep history of global land use change – needs and potentials for earth system modelling and understanding of socio-ecological systems
Keywords: relative pollen productivity, ERV model, REVEALS model, land-use, LandCover6k

Quantitative pollen-based reconstruction of Holocene plant-cover in temperate China: insights on climate- and human-induced land-cover change

Furong Li1, Marie-José Gaillard1, Shinya Sugita2

1Linnaeus University, Sweden; 2University of Tallinn, Estonia,

Quantification of the effects of human-induced vegetation-cover change on past (present and future) climate is still a subject of debate. Our understanding of these effects greatly depends on the availability of empirical reconstructions of past anthropogenic vegetation cover. Until recently quantitative reconstructions of plant cover based on pollen data was a challenge due to the non-linear relationship between pollen percentages and vegetation abundances. The REVEALS model (Sugita, 2007) corrects biases due to intertaxonomic differences in pollen productivity, dispersal and deposition, and between-site differences in size and type of accumulation basin (lake or bog). The model estimates regional vegetation cover using pollen records from one large lakes or multiple small sites (lakes and bogs). The spatial scale of REVEALS reconstructions is ca. 104 km2,which is a relevant spatial scale for climate modelling. Relative pollen productivity (RPP) of plant taxa is a key parameter required for the application of the REVEALS model. RPP estimates are available from earlier studies for plant taxa characteristic of steppes and meadows of northern China, and forests of temperate NW China. We estimated RPPs for plant taxa of traditional agricultural landscapes in the Shandong province, central-eastern China (Li et al., 2017). We then assessed all available RPPs and combined them into a synthesized data set (Li et al., 2018). We used this RPP dataset with pollen records from lakes and bogs to produce REVEALS-based reconstructions of Holocene regional vegetation-cover change in temperate China. Finally, we compared land-cover change to existing data on past climate and human history to identify major periods of human-induced land-cover change and their spatial extent over time. This study is a contribution to PAGES LandCover6k.

References: Sugita S., 2007. The Holocene; Li F. et al., 2017. Veg. Hist. Archaeobot; Li F. et al., 2018. Front. Plant Sci.