WP1: How do climate change impacts and multiple policy objectives affect land use and GHG emissions?

This WP builds on existing national scale land use scenario modelling (Finch et al. 2023) before zooming in to investigate the potential contribution of our four focal landscapes to achieving national net zero for the UK land sector. Specifically, national models will be updated to include a wider range of land use and land management interventions, better data on soil carbon changes in grassland systems, and to incorporate the impact of climate change on crop and grass yields and bird populations. We will therefore address four key questions:

• How will future policy scenarios shape land use and management?

• How will climate change impact crop production and land use?

• How will GHG emissions be affected by changes in land management, land use, climate and food systems?

• Can land use be arranged to meet the multiple policy objectives?

We will conduct a literature review of published policies and policy recommendations to achieve targets such as tree planting, for either the UK or devolved nations, identifying the scale of different land use or management changes that are stated or implied. These findings will inform land use allocations in our land use scenario models.

We will model the effects of projected climate change on productivity of grass, wheat and barley, and identify where land use switches may be plausible, for example between cereals and grass. This will again inform land use allocations in the land use scenario models, as well as the productivity outcomes considered in trade-off assessments in WP3.

Building on the RothC model, which estimates the turnover of organic carbon in non-waterlogged soils, we will simulate changes in soil carbon and fluxes of methane and nitrous oxide resulting from the adoption of different grazing practices. We account for things like changes in climate, plant production, livestock activity and feed consumption to synthetically estimate the net GHG emission reduction potential.

Informed by the other components of this work package, we will compare land use scenarios that vary the relative contributions of different management interventions to achieve aggregate net zero land use at UK or devolved nation scales. Among the range of scenarios, we will compare those that achieve the same GHG reduction targets while also prioritising other objectives, such as maintaining food production or biodiversity recovery. Modelling will be conducted at the national scale to reflect national targets, and for each scenario we will also examine the land use change contribution implied for each of our focal landscapes. This will feed into trade-off modelling in WP3.