GHG Estimation Methodologies

According to Jonas et al. (2019), GHG emissions are rarely measured directly. To assist countries in compiling comprehensive emission inventories and conducting quantitative uncertainty analyses under the United Nations Framework Convention on Climate Change (UNFCCC), the Intergovernmental Panel on Climate Change (IPCC) developed standardized methodologies to enable adequate accounting of national, natural, and human-induced GHG sources and sinks.

IPCC method (2006) is an internationally agreed methodologies intended for use by countries to estimate greenhouse gas inventories to report to the UNFCCC. It is the Panel recommendation for national GHG inventories.

IPCC (2006) provides detailed guidance on emission and removal categories, calculation formulae, data collection methods, default emission factors, and uncertainty management. It requires GHG emissions reporting from sectors and subsectors that takes place within a territory. It follows a PBA, assigning responsibility for emissions at the point where the emissions are produced (Lombardi et al, 2017). Despite recommended for National Inventories, IPCC methodology is also applied at city level.

The most common method to estimate GHG emissions is to combine information on the extent to which a human activity takes place (called activity data or AD) with coefficients which quantify the emissions or removals per unit activity. These are called emission factors (EF). The basic equation is therefore:

Math Formulae 1: GHG Emissions = Σ ADi × EFi for each activity i

GHG emission and removal estimates are divided into main sectors which are groupings of related processes, sources, and sinks, as presented at table 5.

Sectors Sub-Sectors 1-Energy 1.A. Fuel Combustion Activities

1.B. Fugitive emissions from fuels

1.C. Carbon Dioxide Transport and Storage.

2-IPPU⁴ 2.A. Mineral Industry

2.B. Chemical Industry 2.C. Metal Industry

2.D. Non-Energy Products from Fuels and Solvents Use 2.E. Electronics Industry

2.F. Product Uses as Substitutes for Ozone Depleting Substances 2.G. Other Product Manufacture and Use

3-AFOLU⁵ 3.A. Livestock

3.B. Land

3.C. Aggregate sources and non-CO2 emission sources on land.

4-Waste 4.A. Solid Waste Disposal

4.B. Biological Treatment of Solid Waste 4.C. Incineration and Open Burning of Waste 4.D. Wastewater Treatment and Discharge.

4.E. Other

Table 5: Main sectors and subsectors– IPCC Methodology Source: Elaborated by the author based on IPCC (2006).

Another methodology commonly used by cities to estimate GHG emissions is the Global Protocol for Community-Scale Greenhouse Gas Emission Inventories (GPC). It was developed by a partnership between the World Resources Institute (WRI), the Local Governments for Sustainability (ICLEI) and the Cities Climate Leadership Group (C40) in 2014 (WRI, 2014).

The GPC requires cities to measure and disclose a GHG inventory using both production and consumption activities within the city boundary. A geographic boundary that identifies the spatial dimension or physical perimeter of the inventory’s boundary

4 Industrial Processes and Product Use.

5 Agriculture, Forestry and Other Land Use

shall be defined. The GPC is designed to account for city GHG emissions within a single reporting year, covering a continuous period of 12 months. Ideally, it should align to either a calendar year or a financial year. GPC recommends that city GHG emissions be classified into six main sectors and sub-sectors presented at table 6.

Sectors Sub-Sectors

I-Stationary Energy I.1. Residential Buildings

I.2. Commercial and institutional buildings and facilities I.3. Manufacturing industries and construction.

I.4. Energy industries

I.5. Agriculture, forestry, and fishing activities I.6. Non-specified sources

I.7. Fugitive emissions from mining, processing, storage and transportation of coal

I.8. Fugitive emissions from oil and natural gas systems II-Transport II.1. On Road Transportation

II.2. Railways II.3. Water Transport II.4. Aviation

II.5. Off-Road Transportation III-Waste III.1. Solid waste disposal

III.2. Biological Treatment of Waste III.3. Incineration and open burning III.4. Wastewater treatment and discharge IV-IPPU IV.I. Industrial Processes

IV.II. Product Use

V-AFOLU V.I. Livestock

V.II. Land

V.III. Other Agriculture

VI-Other Scope 3 Any other emissions occurring outside the geographic boundary as a result of city activities

Table 6: Main sectors and subsectors– GPC Methodology Source: Elaborated by the author based on WRI (2014).

Activities taking place within a city can generate GHG emissions that occur inside the city boundary as well as outside the city boundary. To distinguish between these, the GPC groups emissions into three categories based on where they occur: scope 1, scope 2 or scope 3 emissions (WRI, 2014), as follows:

• Scope 1: GHG emissions from sources located within the city boundary.

• Scope 2: GHG emissions from using grid-supplied electricity, heat, steam and/or cooling within the city boundary.

• Scope 3: All other GHG emissions that occur outside the city boundary.

The GPC distinguishes between emissions that physically occur within the city (scope 1) from those that occur outside the city but are driven by activities taking place within the city’s boundaries (scope 3), and from those that occur from the use of electricity, steam, and/or heating/cooling supplied by grids which may or may not cross city boundaries (scope 2). Scope 1 emissions are the traditional emission accounted following PBA. It may also be termed “territorial” emissions because they are produced solely within the territory defined by the geographic boundary (WRI, 2014).

Providing scopes 2 and 3, GPC includes emission sources that are beyond the boundary of the city (e.g: electricity consumed from a grid; waste disposal out-boundary).

It opens the possibility of accounting and reporting emissions from consumption of goods and services within an area regardless of they have happened (Dahal & Niemelä, 2017;

Lombardi et al., 2017). Therefore, GPC offers the possibility to combine PBA and CBA.

Cities can expand this possibility reporting other scope 3 emissions.

IPCC and GPC methodologies (IPCC, 2006; WRI, 2014) follow the same accounting and reporting principles as follows:

• Transparency: The inventory should present clear documentation about activity data, emission sources, emission factors, and accounting methodologies. The information should be sufficient to allow individuals outside of the inventory process to use the same source data (WRI, 2014).

• Completeness: All required emissions sources within the inventory boundary shall be estimated. Any exclusion of emission sources shall be justified and clearly explained.

• Consistency: Approach, emissions sources, approach, boundary, and methodology shall be consistent over time, enabling meaningful documentation of emission changes over time, trend analysis, and comparisons. Any deviation shall be disclosed and justified.

• Accuracy: The inventory shall not systematically overstate or understate actual GHG emissions. This means making all endeavors to remove bias from the inventory estimates.

There is only one principle of each methodology that is not expressly provided for in another. IPCC establish the principle of comparability that says that the GHG inventory shall be reported in a way that allows it to be compared with GHG inventories of other territories. And GPC provides the principle of relevance, which says that the reported GHG emissions shall appropriately reflect emissions occurring because of activities and consumption patterns of the city.

There are other recently developed methodologies, such as PAS 2070:2013 (PAS 2070) (Andrade et al., 2018). PAS 2070 specifies requirements for the assessment of the GHG emissions of a city using two distinct methodologies: (I) a direct plus supply chain (PAS 2070-DPSC) methodology and (II) a CBA methodology (PAS 2070-CB).

PAS 2070-DPSC includes PBA emissions plus emissions associated with the largest supply chains serving the cities, including water supply, food and drink, and construction materials, specifically cement and steel. PAS 2070-CB captures lifecycle GHG emissions for all goods and services consumed by the city. The PAS 2070-CB methodology sets out an approach to calculate the GHG emissions linked to global and national supply chains with the use of environmentally extended input output (EEIO) matrices. Table 7 shows characteristics of carbon accounting methodologies.

Characteristics Carbon Accounting Methodologies

IPCC GPC PAS 2070-DPSC PAS 2070-CB

Carbon Accounting Approach

PBA PBA PBA + largest supply

chains

CBA Sectors Energy (including

Transportation), Waste, IPPU and AFOLU

Stationary Energy;

Transportation;

Waste; IPPU;

AFOLU and Other emissions out- boundary

Stationary Energy;

Transportation; Waste;

IPPU; AFOLU and Goods and Services

Food and Drink;

Utility Services;

Household;

Transport Services;

Private Services;

Other Good and Services

Table 7: Characteristics of carbon accounting methodologies Source: Developed by the author

Emission data are fundamental for guiding climate change mitigation research and actions. Despite these accounting and reporting principles, uncertainties of GHG inventories are high. Although several papers provide methods to improve the comprehensiveness and accuracy of carbon accounting in cities, there are still uncertainties in these inventories. Furthermore, little effort has been made to identify and classify the gaps in a comprehensive manner based on the existing inventories and plans.

This fact influences not just the comparability of cities GHG reports. It can also impact the understanding of city emissions and may limit public policies to combat climate change (Harris et al., 2012).

Mi et al. (2019) argue that efforts are needed to reduce those uncertainties. Li et al. (2017b) mentioned problems in the Chinese cities inventories as incompleteness due

to data unavailability, reporting problems and inconsistencies between the framework and the contents of the inventories. Andrade et al. (2018) also mention important sources of uncertainties associated to the Madrid's GHG emissions inventory as lack of disaggregated and high-quality data at a local scale. The lack of consistent and comparable GHG emissions data at the city level is highlighted as one of the four remaining gaps in the urban climate actions research area highlighted by Mi et al. (2019).

The only study found that explores the quality of GHG disclosures by cities is Mia et al. (2019). This paper highlights that prior studies predominantly focused on corporate- level GHG disclosure and that there has been limited research, exploring cities’ GHG disclosure. The manuscript analyzes GHG disclosure of 42 cities published on Carbon Disclosure Project (CDP) platform through the expectation gap framework.

Mia et al. (2019) uses the following characteristics to assess the quality of CDP cities disclosure data: completeness, consistency, timeliness, accuracy, reliability and comparability. Therefore, parameters used are very aligned with principles suggested by GPC Methodology (WRI, 2014). This paper is focused on reports of cities from C-40 international network (that comprises only Mega Cities) and just discusses data provided by CDP. Details of cities GHG reports documents are not analyzed.

Authors highlighted that there is a lack of empirical research investigating disclosures at the regional or community level, mainly with a detailed examination of emissions information that is already disclosed by cities. Kennedy et al. (2012) also found that Berlin, Boston, Greater Toronto, London, New York City and Seattle are not counting all emission sources and despite progress. Further improvements in city GHG inventorying procedures are needed.

No paper was found in the international databases discussing the quality of GHG reports from Latin America cities what brings the questions: how GHG reports are being developed in Latin America? Which carbon accounting approaches methodologies have been used? Do they also present gaps?