This project uses UK peatlands as a case system in which to understand how the effects of climate change, combined with other drivers such as changes in land use and management, may trigger tipping points in the provision ecosystem services.
Peatlands cover over 400 million hectares of the Earth's surface and store between one-third and one-half of the world's soil carbon stock. However, climate change and changes in land use and management threaten to modify the structure and function of these systems, tipping them into new regimes that could trigger the collapse of many ecosystem services. If activated, some regime shifts have the potential to tip peatland systems into a state of perpetual carbon loss, creating a “positive feedback” to the climate system leading to further warming, which would exacerbate carbon loss from degraded systems (popularly called the global “compost bomb”). This threatens stocks of natural capital that have formed over millennia, undermining the resilience of peatland systems to climatic and other future changes (Fig. 1). Degraded organic-rich soils are already responsible for a quarter of CO2 emissions from the global land use sector and represent 75% of greenhouse gas emissions from agricultural land in the EU. Effective management of peatlands to protect stocks and avoid tipping points therefore has the potential to make a major contribution towards climate mitigation in Europe.
osely with stakeholders to identify options for policy and practice that can cost-effectively protect the natural environment and rural communities in these areas after the UK leaves the European Union.
Fig. 1: Conceptual framework showing how triggers can lead to tipping points in ecosystem state, which can in turn lead to tipping points for the provision of ecosystem services
We will study two types of peatland tipping points: i) tipping points between different peatland “steady states” or regimes (e.g. from blanket bog to dry heath or bare and eroding peat), triggered by changes in land use and management (e.g. drainage, grazing or burning regimes) in combination with climate change and other drivers; and ii) tipping points in the provision of ecosystem services arising from these regime shifts.
While large-scale external drivers such as climate change can push a system over a threshold to a different state or regime, vulnerability to these drivers and thus the fate of peatlands is in large part determined by how they are managed. Therefore, the fate of peatlands will most likely be decided by policy-makers and those who own and manage land. Some of these socio-economic and policy drivers may enable adaptive management in response to climate change (e.g. economic incentives for restoration management) while others may hasten progress towards tipping points in ecosystem stocks and services (e.g. market drivers that encourage intensification of land use and management). Changes in land use and management have already irreversibly turned a number of UK blanket peats from net carbon sinks to sources over short timescales, leading to the catastrophic collapse of the system through the loss of peat and its associated ecosystem services. However, little is known about how social drivers of change are likely to interact with climate change to increase or reduce the likelihood of tipping these systems into degraded states.
Aims and objectives
The aim of this project is to:
Understand how the combined effects of climate change and changes in UK blanket peatland use and management (and other drivers, such as atmospheric deposition) may trigger tipping points in the provision of ecosystem services
Assess the economic, social and cultural value of avoiding these tipping points versus reaching them
Use these insights to inform management and policy to enhance the resilience of natural systems to future abrupt changes.
We will consider provisioning (grazing), regulating (water quality and climate mitigation) and cultural services in terms of biodiversity, ‘places’ and key activities within them, following the UK NEAFO framework. We will focus on blanket bogs; they are the most extensive and well-understood peatland habitat and the UK’s single largest carbon stock.
Using blanket peatlands as a case system, the project asks three inter-connected sets of research questions:
Tipping point triggers: How might changes in climate, land use and management trigger regime shifts in blanket peatlands to degraded or alternative states? What biophysical and social factors influence whether these shifts then trigger tipping points in the provision of ecosystem services over space and time?
Tipping point values: What are the likely ecological, economic, social and cultural impacts of reaching tipping points in the provision of different ecosystem services in blanket peatlands?
Adaptive management: How might restoration move blanket peatlands from current degraded states to desirable new stable states that can prevent tipping points being reached and adaptively sustain the provision of ecosystem services from peatlands under future climate change?
The answers to these questions will be used to address three related policy objectives:
This project will take an interdisciplinary approach, integrating environmental, natural, and social science to understand the biophysical and socio-economic drivers that govern tipping points in ecosystem stocks and services, and evaluate policy responses that could sustain and enhance individual and shared values, and value to society from the management of these systems. The project will link a number of components (Figure 2):
Rapid reviews and meta-analysis of secondary data in WP1 will be used to develop dose- response functions (or “pressure-response functions”) that can inform how ecological and hydrological processes are treated in a model of peatland development – DigiBog (WP1);
DigiBog will be used to simulate the impact of predicted climate regimes and land use (arising from different policy scenarios) on peatland carbon balance and peatland hydrological regimes (WP2);
Metamodels from WP1 and outputs from DigiBog will be used to derive changes in biodiversity (by modelling a keystone cranefly species Tipula paludosa) and a range of ecosystem services under different climatic and policy scenarios (WP2);
This will enable monetary and non-monetary valuation of ecosystem services derived from DigiBog (WP3); and
Provide evidence that can inform adaptive policy and management (WP4)
We will focus on two study areas: the Flow Country in Scotland and the Dark Peak in England.
Figure 2: Project structure showing the methods that will produce outputs for each goal