Climate change: evidence review in Agriculture, Forestry, Land Use, Waste

1 Introduction

1.1 Background

GHG mitigation is a central policy objective in Scotland. The Climate Change (Scotland) Act 2009 sets an interim 42% reduction target for 2020 and an 80% target for 2050 across all sectors of society (1990 baseline). Annual targets are also set by legislation, along with a report on policies and proposals for meeting the annual targets. Agriculture, land use and land use change and forestry (ALULULCF) and waste sectors have important roles to play in contributing to Scotland's emission reduction targets. Between 1990 and 2014 agriculture's emissions have reduced by 14%, waste emissions have reduced by 77% and carbon sequestration by the land use and land use change and forestry sector has increased by 3.9 Mt CO ₂e (carbon dioxide equivalent), based on solely territorial emissions (not taking account of the GHG impacts associated with the production of materials produced overseas). ^[1] However, further mitigation in these sectors will be required to achieve Scotland's 2050 emission reduction target.

Long-term sustainability requires finding a balance in our environmental, economic and social goals, taking into account the resources used in meeting these. This is complicated by potential and actual synergies or trade-offs between the sustainability goals and by the differences in how society and individuals value these goals. The final impacts on human well-being happen through a complex network of environmental, economic and social pathways.

As GHG mitigation has become one of the highest priority areas, it has become vital to understand the co-benefits and adverse impacts arising from such actions on our environment, economy and society ( IPCC 2014). Adopting a multi-objective perspective can help to identify areas where synergies make policies more robust and to mitigate the adverse impacts of policies which impose trade-offs.

Land use related activities can be particularly challenging because of multiple, often conflicting societal needs. A prime example is land use itself, as it provides food, fuels, area for human settlements and environmental benefits. Biological and chemical processes result in further need to consider trade-offs, for example reducing one particular form of reactive nitrogen (e.g. NH ₃) might cause an increase in other forms of reactive nitrogen pollution (e.g. NO _x or nitrogen leaching) (Sutton ed. 2011).

Integrated assessments require the consolidation of the various environmental and economic processes and a framework to evaluate the potential solutions against each other. For most such frameworks the ultimate end-point are the human welfare effects, which are quantified by translating the physical effects (e.g. NH ₃ pollution or human health effects) into monetary terms. Though difficult to obtain, such estimates already exist in relation to certain wider impacts and are important in impact assessment.

1.2 Research aims

As the Scottish Government further develops policies and proposals to increase GHG mitigation across society, a better understanding of the potential wider impacts of these is needed, along with developing an overview of potential co-benefits and adverse side effects of policy, and of how key synergies and trade-offs can be quantified. To support this work in the ALULUCF and waste sectors, Scottish Government identified the following research questions:

1. What is the evidence, both quantitative and qualitative, of potential wider impacts (co-benefits and adverse side effects) for Scotland arising from climate change mitigation actions which would be relevant to the Scottish context?
2. Based on a review and synthesis of quantitative evidence, which models and tools are assessed as the most robust to quantify and, where possible, monetise such wider impacts? What quantitative data would be required to apply these models to Scotland? What key assumptions are required?
3. Based on a review and synthesis of qualitative evidence, what are the key sources of robust evidence; and what is the balance of evidence, in terms of the direction (positive / negative) and potential magnitude, of those wider impacts relevant to Scotland?
4. From an equalities perspective, what evidence is there about the potential distribution of wider impacts relevant to Scotland across the population?
5. What are the most significant gaps in research and evidence about potential wider impacts which are relevant to Scotland?

The most important questions for the Scottish Government regarding the waste sector were slightly different from the other sectors; two aspects of the wider impacts of GHG mitigation in the waste sector were considered, as requested from the Scottish Government:

1. Employment benefits from diverting increased tonnages from landfill to recycling: an evidence review of the potential employment benefits (taking into account job displacement) from diverting tonnages from landfill to recycling. Is there any evidence for different sized benefits depending on the type of waste?
2. Evidence review of the potential magnitude of non-territorial emission savings as a result of meeting the Scottish Government's waste targets and a review of the potential approaches to assess the non-territorial emission savings.

This report considers the WIs of MOs in ALULUCF and waste sectors in Scotland. It provides an overview of the direction and magnitude of these impacts and considers appropriate models and tools for quantitative evaluation. A second objective is to summarise evidence on the monetary valuation of impacts in order to facilitate integrated assessment. The report also highlights further research needs in exploring the synergies and trade-offs arising from GHG mitigation in Scotland.

The report is structured as follows. Section 2 sets out the methodology, explaining how the MOs were selected and what wider impacts were considered. Section 3 summarises the key messages regarding the wider impacts, their modelling and valuation in the ALULUCF sectors - more details of these issues are provided in Appendix A1, Appendix A2 and Appendix A3. Section A1.1 describes the findings of the qualitative evidence review in the waste sector.