Heat pumps are an efficient way of producing heat from electricity; they operate by capturing the latent heat in the air, ground or water and using it for heating.

Heat pumps are expected to play a significant role in decarbonising heat in Scotland; the Climate Change Committee has described them as a ‘low-regrets’ option, and they feature prominently in Scotland’s Draft Heat in Buildings Strategy.

However, heat pump efficiency can vary across the heating season and in different buildings, meaning the costs and impacts on wider energy systems depend on the context.

This desk-based review looks at evidence on how heat pumps currently, or are likely to, perform in practice in Scottish buildings. The research identifies best practice relevant to Scotland and gaps in the available evidence.

The scope of the research was for both domestic and non-domestic buildings. However, the majority of the relevant datasets relate to domestic settings.

Key findings

• Poor heat pump performance is most likely to arise due to poor design and specification. This means appropriate design and installation are the most important considerations to ensuring heat pumps perform well in Scotland.
• Heat pumps are a mature heating technology used in several European countries, including countries with colder winters than Scotland. The review found no evidence to suggest that heat pumps could not operate effectively or efficiently in Scotland. 
• The review suggests there is occupant satisfaction with heat pumps.
• There is evidence that heat pump performance could be maximised by building confidence in heat pump technology among consumers and the supply chain. 
• Where running costs were monitored, heat pumps were cheaper to run than previous electric, oil or LPG heating systems and are a key outcome for occupant satisfaction. 

The Scottish Government is committed to reducing greenhouse gas (GHG) emissions from agriculture as part of Scotland’s target to reach net-zero emissions by 2045. To meet this very challenging target, the sector and Government are likely to have to take steps to ensure uptake of all available emission-reduction technologies and practices by all farmers. Understanding behavioural change and attitudes will therefore be critical in order to develop policies and work with industry to deliver this goal.

This study explores the evidence for factors behind adoption of climate-friendly agricultural practices. It examines interventions across personal, institutional, farm-structural and socio-demographic factors to encourage practice change, and the key factors that influence successful adoption.

Key findings

Adoption factors:

• Most studies analyse the impact of more than one factor on adoption. This is in line with the wide understanding that behaviours are the outcome of interrelated and complementary influences.
• We found adoption was determined partly by earlier or concurrent choices.  
• The evidence demonstrates that farmers are influenced by their peers (usually sharing geography and farm type), indicating the need for interventions supporting collaborative networks. 
• Adoption factors are useful for explaining different behaviour and/or defining shared characteristics of farmers. This helps identify which practices might be more successfully adopted in a particular region by specific farm types, and thus assist with tailoring policy interventions.

Interventions:

• The more closely tailored an intervention is to the characteristics and needs of the target population, the more effective it seems to be.
• Compliance is positively related to the level of incentive payments. This suggests a focus solely on enhancing environmental outcomes may be less effective than coupling them with those interventions better tuned to economic considerations.
• Training and advice, supported within a collaborative framework, are effective on their own and even more so when used as additional incentives to assist other forms of interventions, in both the short and long term. They may be more effective when framed as industry-focused, rather than climate-focused.

This project set out to review the current state of knowledge on the potential for carbon sequestration in key Scottish upland open habitats. Upland soils play a vital role in regulating greenhouse gas (GHG) emissions in our environment. Scotland’s soils contain 2500-3500 Mt of carbon, much of which is located in upland soil environments. This is equivalent to more than 200 years of Scotland’s annual greenhouse gas emissions. The management of uplands and their soils will therefore be critical to achieving Scotland’s ambitious net-zero emissions target.

Despite the well-known potential of soils to store carbon, however, there is uncertainty as to the long-term stability of this carbon pool. Increasing temperatures, altered patterns of rainfall distribution, and changes in land use all influence this process and threaten to reduce soil carbon stocks.

This review identifies the key drivers of change and covers three upland habitats: upland dry heath, upland wet heath and upland grasslands, defined by vegetation communities. It assesses potential GHG fluxes and the impact on biodiversity within these habitats.

It found very limited information regarding impacts on soil carbon stocks or GHG emissions; studies giving a full balance sheet of ecosystem stocks and flows of carbon in response to environmental or management change were particularly scarce.

Key findings include:

• Scotland’s soils contain around 2,500-3,500 Mt of soil organic carbon. The various mineral, organo-mineral and organic soils found under moorland, montane, and rough grassland contain around 45% of total Scottish soil organic carbon stock.
• Soil organic carbon accounts for 90% of the carbon stocks in these habitats. Therefore, studies which only consider changes in carbon held within the vegetation severely under-estimate changes in total carbon stocks.
• GHG emissions in open upland habitats in Scotland occur as a result of emissions of carbon dioxide, methane and nitrous oxide. 
• There is some evidence from Scotland that Molinia grasslands contain large carbon stocks within the vegetation, which are reduced by grazing.
• When upland soils are left bare after excessive grazing or burning, there is a significant increase in the risk of soil carbon loss due to erosion.
• The impacts of future climate change on carbon stocks are complex and are likely to depend on current and future management, soil type and vegetation communities. They have not been well researched in the Scottish context: this is a substantial gap in knowledge.
• The review found an important knowledge gap on the interactions of drivers on GHG emissions, carbon stocks and biodiversity.

Drought, as a significant risk to Scottish forests, is likely to be exacerbated by the changing climate. This report summarises the current state of research, describes ongoing projects and identifies knowledge gaps and potential research directions. Considerations around the policy and practice implications are made, taking into account the available information.

Key findings

• There is high confidence that especially in east, central, and south Scotland the direct effects of severe droughts are likely to be felt primarily in forest productivity and carbon sequestration. 
• Tree species are known to differ in their vulnerability to drought impacts. The productivity of Scots pine, Douglas fir, and Sitka spruce can be heavily impacted by severe droughts. Trials of different species provenances have shown that there can be as large a variation in drought susceptibility between provenances as between species.
• Drought effects are the result of the complex interplay between climate extremes, many different components of forest ecosystems and other biotic and abiotic disturbances. All these elements will be affected by climate change in ways that cannot be confidently projected, which makes predicting the interactions between them even more difficult.
• There is medium confidence that applying dendrochronology (the study of annual growth increments, or tree rings) alongside remote sensing and drought indices could help understanding of the risk of large-scale drought impacts.

The Scottish Government is investing significant resources into expanding Scotland’s woodland cover to increase carbon sequestration and mitigate climate change. Wild animals are rarely considered in carbon storage policy. However, there is growing evidence that Scotland’s wild deer population could hinder targets for woodland creation. High pressure from deer can also harm the health of pre-existing woodland and therefore reduce the ability of Scotland’s woodlands to store carbon and off-set greenhouse gas (GHG) emissions.

The latest figures show Scotland’s wild deer population to be approaching 1 million individual animals. The need to control wild deer has led deer management to become Scotland’s largest terrestrial wildlife management challenge.

This short review explores the current state of knowledge on wild deer populations and how they effect carbon sequestration in Scottish woodlands. It gives an overview of the key factors and identifies areas where there is an absence of evidence.

Findings

• The impacts of deer fall into two categories:
  • Direct – such as removing vegetation, preventing natural regeneration, and increasing mortality of mature trees.
  • Indirect – promoting the dominance of less palatable species and reducing the quality of the plant litter that in turn can affect the nutrient balance.
• Analysis of the evidence indicates that the primary mechanisms by which deer interfere with carbon cycling in woodlands are largely identified. However, we found limited data that quantify the size of these effects. Therefore, more research is needed to establish the scale of the threat to carbon sequestration in woodlands.
• A larger body of evidence exists to demonstrate the effects deer have on above-ground carbon storage. Conversely, there were limited data on the less direct, but potentially significant, effect deer have on below-ground carbon stores.
• Although more data are needed to determine the significance of deer browsing in relation to meeting carbon sequestration goals in woodlands, reducing deer impact to a level where woodlands can naturally regenerate would likely increase woodland productivity and carbon storage.
• For Scotland’s natural landscape and woodlands to recover, deer densities need to be reduced and maintained around a <5 deer/km² In some cases, deer fences may need to be erected temporarily to protect certain areas. Although, they are a costly solution.

Conclusions

This evidence review suggests the mechanisms by which deer impact carbon cycling have been investigated and mostly identified. However, very limited evidence was identified that examined the size and significance of these effects. Without these quantitative data, it is difficult to create an informed mitigation strategy. Hence, further research is needed in Scotland to fully understand this complex relationship.

Given that the actions taken to mitigate the climate emergency are time sensitive, action may have to proceed using the limited data currently available. Scholars and practitioners largely agree that reducing deer numbers in woodlands to a threshold believed to allow natural regeneration of the full assemblage of woodland plant species would be beneficial for plant productivity and therefore carbon storage. Thus, reducing deer numbers to a sustainable threshold could counter many of the adverse effects presented in this report. In addition, reducing deer numbers will be essential in protecting the woodlands that will help Scotland reach its goals of net zero by 2045.

Scotland is a global pioneer of peatland restoration which is widely seen as having a significant role in addressing the global climate emergency.

Peatlands cover nearly a quarter of Scotland and contain over half of the total Scottish soil carbon. However, a high proportion of Scottish peatlands has been altered to such an extent that it is now degraded, causing substantial greenhouse gas (GHG) emissions. Consequently, the Scottish Government has established ambitious peatland restoration targets; a large funding programme – Peatland Action – has been in place since 2012, complementing work by other delivery partners such as Scottish Water and Forestry and Land Scotland.

While there is evident potential for peatland restoration to provide climate and wider ecosystem benefits, much less is known about the broader perceptions of peatlands, and the values attached to their restoration.

This report examines current experiences of peatland restoration, as well as the anticipated outcomes and factors influencing engagement with restoration. We also consider the opportunities and challenges for upscaling restoration efforts going forward. This information can help guide the administration of public support for peatland restoration as it evolves and increases in prominence.

Findings

• Land managers are motivated to restore peatland by the multiple benefits that it generates.

Some of the most frequently observed benefits are: changes to the hydrology, prevention of further peat erosion (and retention of existing carbon stores) and habitat and landscape improvement. This, in turn, can result in: flood risk reduction, lower water treatment costs, and improved ability of local communities to engage with peatlands.

• Early engagement with landowners and communities facilitates participation in restoration, as does funding of up-front costs.

Organising talks, walks and early consultation events helps to explain benefits, raise awareness and address negative perceptions. Conducting feasibility studies and embedding Peatland Action (PA) officers in local organisations also facilitates participation.   

• The main barriers to engagement relate to the wider impacts on how land is managed and a lack of knowledge or understanding. We also found evidence of ‘cultural’ clashes.

Concerns were expressed regarding the impact of restoration on farming activities and eligibility for agricultural payments or governmental tax breaks. Lack of knowledge or understanding was mentioned in relation to the support available and the application and funding process, and to the benefits of peatland restoration. Peatland restoration is seen by some as undermining cultural and historical values.

• Challenges during restoration activities are closely tied to environmental challenges, as well as problems of communication and coordination.  

Environmental challenges can result in general logistical problems during restoration. Communication issues among different actors can also lead to problems during restoration.    

Conclusions

• Improved communication might encourage uptake by a more diverse range of land managers. This includes clearer information on what support is available in terms of preparing applications, carrying out restoration and managing the projects.
• There are clear benefits in facilitating connections across stakeholders. This can be done by embedding PA officers (or other knowledge brokers / facilitators) in organisations and also by promoting partnership working.
• Funding of up-front restoration costs is effective. There may be value in supporting maintenance /management costs and cross-overs with farm payments. All these aspects were considered very important to encourage other land owners to engage in peatland restoration.
• Training and resources are important to ensure works are carried out to satisfactory standards even in the most challenging locations.
• Pooling or shared hire systems of specialist equipment might improve physical provision and alleviate concerns from a number of potential participants.

Peatland restoration has a significant role in tackling the global climate emergency and helping Scotland meet its ambitious climate change targets. Globally, peatlands are the largest natural terrestrial carbon store, containing about 25% of global soil carbon. However, they have been damaged by overexploitation. The Scottish Government has committed to restoring 250,000 hectares of peatland in Scotland by 2030. About a quarter of Scotland’s area is covered in peat, storing over 3 billion tonnes of carbon.

Peat also provides a range of other co-benefits. Changing some current uses of peatland, particularly for agriculture, may lead to significant savings in greenhouse gas (GHG) emissions and offer some of the highest per hectare emissions savings.

This report assesses the current evidence for the potential for emissions savings from re-wetting peatland currently used for agriculture in Scotland and explores alternative uses that might provide an economic return.

Key findings

• The quality and coverage of spatial data on peatland in Scotland is mixed. In the last 40 years, a variety of different datasets have been gathered at different times on Scotland’s soils, land use and land cover.
• The definition of what constitutes drainage is critical to the outcome of mapping exercises with currently available data products; no mapping has specifically targeted this question.
• Emissions resulting from land use on peatlands have only recently been included in the Provisional UK greenhouse gas emissions national statistics.
• Peatland with the poorest agricultural production capability presents the greatest opportunity for emission reductions.
• While cropland on peat has a very high emission factor per unit area, it only covers a small area of Scotland.

The report identifies specific locations across Scotland where there may be GHG emission reduction opportunities, largely on low-grade agricultural land (very often upland heath vegetation on peat). Holdings for this type of land often cover large areas; because of this the potential exists to achieve significant emission reductions through engagement with a small number of key land managers.

The Paris Agreement aims to keep global mean temperatures to within 2^o C Celsius of pre-industrial levels, with an aspirational aim of remaining within 1.5^o C. To achieve this, global carbon emissions (principally CO₂) have to at least halve every decade over the next century. In line with the agreement, Scotland has committed to achieving net-zero emissions by 2045. We therefore require accurate and frequently updated knowledge of human-driven emissions. Robust monitoring is essential if we are to verify progress.

At present, greenhouse gas (GHG) emissions for Scotland are published annually, approximately 18 months after the period to which they relate. The current approach combines annual production and usage statistics with estimates of how much carbon is emitted per unit measure of production and usage. An alternative approach is to look to the atmosphere. This study examines how satellite observations of the atmosphere could be used to build on existing modelling efforts and report GHG emissions well in advance of the present estimates.

In this report, we describe the software we have developed to download and interpret publicly available satellite observations of tropospheric NO_2, as a proxy for fossil fuel emissions of CO₂ (ffCO₂). The observations cover three spatial areas: onshore Scotland; the Scottish zone of the UK continental shelf; and the subset of the Scottish zone corresponding to the location of oil and gas platforms.

We used data from two satellite instruments: the Ozone Monitoring Instrument (OMI) and the TROPOspheric Monitoring Instrument (TROPOMI).

In the longer-term, the data collected can be used to improve emission estimates of ffCO₂ over Scotland in the context of its commitment to achieving net-zero emissions by 2045.

In 2019, the Scottish Government set ambitious targets to deliver net-zero greenhouse gas (GHG) emissions by 2045. In 2018, agriculture was responsible for 18% of Scotland’s total GHG emissions. More than half of this was attributed to methane (56%) with most methane arising from enteric fermentation (produced during digestion of feed by cattle and sheep). The Government’s net-zero target, therefore, creates strong demand for methane-mitigation technologies.

We explored  the potential of two close-to-market feed additive products designed to reduce enteric methane emissions. We made a formal assessment of published scientific literature and consulted with product manufacturers and industry specialists to understand product efficacy, current and likely future regulatory status and the challenges of practical implementation on Scottish farms. This summary paper captures the initial findings. Detailed results are currently protected by commercial confidentiality.