What is it about?
The Valuing Nature Programme’s Peatland Tipping Points project is investigating how changes in climate and how we manage land might lead to abrupt changes, or “tipping points”, in the benefits that peatlands provide to UK society. We will identify early warning signs (such as changes in common insects) and provide evidence about the likely economic and social impacts of reaching tipping points. This information will be used to develop options for policy and practice that can help prevent tipping points being reached and facilitate restoration and sustainable management of peatlands across the UK.
Why is it important?
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.
We 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.