System and method for assessing carbon neutralization capacity of urban green space based on whole life cycle

Abstract

The application discloses a city green land carbon neutralization capacity evaluation system and method based on a whole life cycle, relates to the technical field of carbon neutralization capacity evaluation, and comprises the following steps: acquiring city green land engineering design parameters, building material consumption, maintenance energy consumption and arbor tree species data, standardizing and processing, and determining a whole life cycle evaluation period and stage division; selecting a benchmark scheme, determining key influence factors, and constructing a single factor variant scheme family; calculating carbon emission and carbon absorption of each scheme year by year, accumulating to generate a whole life cycle cumulative carbon balance curve; obtaining marginal carbon loss and gain curves of each factor by difference at each time point and extracting time sequence characteristics; summarizing to form a marginal carbon loss and gain profile set; acquiring a scheme to be evaluated, calling the marginal carbon loss and gain curve corresponding to the changed factor, determining a carbon efficiency risk if any curve has continuous negative values and the continuous duration exceeds a tolerance threshold, otherwise determining carbon efficiency robustness, and outputting carbon neutralization capacity evaluation information.

Description

Technical Field

[0001] This invention relates to the field of carbon neutrality capacity assessment technology, specifically to a system and method for assessing the carbon neutrality capacity of urban green spaces based on their entire life cycle. Background Technology

[0002] As the primary natural carbon sink in urban ecosystems, urban green spaces play a crucial role in low-carbon city planning and design by assessing their life-cycle carbon neutrality capacity. Existing assessment methods typically collect basic data such as engineering design parameters and building material usage, calculate carbon emissions and vegetation carbon sequestration at each stage of construction and maintenance, and sum these to obtain the total net carbon balance over the entire life cycle. This summation is then used to determine whether the design scheme achieves carbon neutrality. During scheme comparison, the total indicators for each scheme are calculated separately, with the size of the net carbon sink or the achievement of carbon neutrality standards serving as the selection criterion.

[0003] However, such methods exhibit significant black-box characteristics during scheme comparison. When multiple design factors differ simultaneously, the evaluation results can only provide a comprehensive judgment of superiority or inferiority, failing to attribute differences in carbon neutrality capacity to specific design factors. This makes it difficult for designers to obtain targeted optimization directions. Existing evaluation logic uses the total net carbon balance at the end of the entire life cycle as the core criterion, ignoring the dynamic distribution of carbon balance over time and failing to reveal the potential phased carbon deficit risks during the construction, maintenance, or maturity phases. The assessment of scheme robustness is usually limited to observing whether the final conclusion reverses after changing the overall assumptions, lacking a process-level examination of the carbon efficiency performance of each design factor throughout the entire life cycle. This makes it difficult to effectively identify the implicit process carbon risks of some schemes, affecting the reliability of carbon neutrality potential predictions. Summary of the Invention

[0004] The purpose of this invention is to provide a system and method for assessing the carbon neutrality capacity of urban green spaces based on the entire life cycle, in order to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for assessing the carbon neutrality capacity of urban green spaces based on their entire life cycle, the method comprising: S100. Obtain design parameters, building material usage, maintenance energy consumption, and tree species data for urban green space projects, perform standardized processing, and determine the boundaries between the full life cycle evaluation period and stages. S200. Select a baseline scheme and determine several key influencing factors; for each key influencing factor, generate a variant scheme in which only the key influencing factor changes with respect to the baseline scheme, while the other key influencing factors remain unchanged, and construct a family of single-factor variant schemes. S300. For each single-factor variant scheme in the family of single-factor variant schemes, analyze the carbon emissions and carbon absorption at each time period throughout the entire life cycle, and sum them to generate the cumulative carbon budget curve for the entire life cycle of each single-factor variant scheme. S400. The cumulative carbon budget curves of each single-factor variant scheme are compared with the cumulative carbon budget curve of the baseline scheme at time points to obtain the marginal carbon gain / loss curves of each key influencing factor, and the time series features are extracted. S500: A marginal carbon profit and loss profile set is formed from the marginal carbon profit and loss curves of each key influencing factor; the scheme to be evaluated and its key influencing factor change information are obtained, and the marginal carbon profit and loss curves of the corresponding changed key influencing factors are retrieved. If the marginal carbon profit and loss curve of any changed key influencing factor shows a continuous negative value and the duration exceeds the tolerance threshold, the scheme to be evaluated is determined to have carbon efficiency risk; otherwise, it is determined to be a carbon efficiency robust scheme, and the carbon neutrality capacity assessment information containing the carbon efficiency robustness assessment results is output.

[0006] According to the above scheme, the design parameters include vegetation space configuration data and ground paving ratio data; The building material consumption includes the consumption of structural materials, paving materials, and auxiliary materials; The maintenance energy consumption includes energy consumption for irrigation operations, pruning operations, fertilization operations, and pest and disease control operations. The tree species data includes tree species type, growth curve parameters, and carbon storage model parameters; The standardization process involves unifying the design parameters, building material usage, maintenance energy consumption, and tree species data to the same time granularity and carbon emission accounting boundary. The determination of the full life cycle evaluation period and the boundaries of the stages include setting the evaluation start time and end time, and defining the time division points between the construction stage, the maintenance stage and the maturity stage.

[0007] According to the above scheme, step S200 includes: S210. Select a design scheme from industry-standard design criteria or typical engineering cases as a benchmark scheme, and extract the specific values ​​of all key influencing factors in the benchmark scheme; the key influencing factors are independent adjustable engineering parameters that affect the carbon emissions or carbon absorption of urban green spaces throughout their entire life cycle, including vegetation density parameters, ground paving ratio parameters, irrigation intensity parameters, fertilization intensity parameters, and pruning frequency parameters. S220. Among all the key influencing factors of the benchmark scheme, determine one key influencing factor to be changed; S230. Adjust the value of the key influencing factor to be changed along the specified direction by the specified step size, while keeping the values ​​of all other key influencing factors consistent with the baseline scheme, to generate a single-factor variant scheme. S240. Traverse all key influencing factors and take the generated set of single-factor variant schemes as a family of single-factor variant schemes.

[0008] According to the above scheme, step S300 includes: S310. For each of the single-factor variant schemes, based on the standardized design parameters, building material usage, maintenance energy consumption, tree species data, and the stage division boundaries, the carbon emissions are calculated annually for each life cycle stage; the carbon emissions include the carbon emissions implied by building materials, construction carbon emissions, and maintenance energy consumption carbon emissions. S320. Based on the standardized design parameters and tree species data, calculate the carbon uptake annually; the carbon uptake includes the carbon sequestration by tree biomass and the change in soil carbon pool. S330. The difference between carbon absorption and carbon emissions in the same year is used to obtain the net carbon balance for that year. S340. Starting from the beginning of the life cycle assessment period, the net carbon balance is accumulated year by year to generate the life cycle cumulative carbon balance curve for this single-factor variant scheme.

[0009] According to the above scheme, step S400 includes: S410. Obtain the cumulative carbon budget curve of the benchmark scheme; S420. Align the life-cycle cumulative carbon balance curve of each of the single-factor variant schemes with the life-cycle cumulative carbon balance curve of the baseline scheme in the same time coordinate system, and perform difference calculations at each time point to obtain the marginal carbon gain / loss curve of the key influencing factor corresponding to the single-factor variant scheme. S430. Extract time-series features from each marginal carbon profit / loss curve. The time-series features include the carbon profit breakthrough point, the carbon loss reversal point, the negative value continuation interval, and the marginal profit / loss final value. The carbon profit breakthrough point is the starting time node when the marginal carbon profit / loss curve turns from negative to positive and remains positive. The carbon loss reversal point is the time node when the marginal carbon profit / loss curve turns from positive to negative. The negative value continuation interval is the continuous period when the marginal carbon profit / loss curve value is less than zero. The marginal profit / loss final value is the marginal carbon profit / loss value corresponding to the end of the life cycle evaluation period.

[0010] According to the above scheme, step S500 includes: S510. Summarize the marginal carbon profit and loss curves of all key influencing factors to form a marginal carbon profit and loss profile set. S520. Obtain the scheme to be evaluated, wherein the scheme to be evaluated is a green space engineering design scheme that is independent of the benchmark scheme and the single-factor variant scheme family; S530. Obtain the values ​​of each key impact factor in the scheme to be evaluated, and compare them one by one with the values ​​of the corresponding key impact factors in the benchmark scheme to determine the set of key impact factors that have changed. S540. From the marginal carbon profit and loss profile set, retrieve the marginal carbon profit and loss curve corresponding to each changing key influencing factor in the set of changing key influencing factors. S550. Check each of the retrieved marginal carbon profit and loss curves one by one. If any marginal carbon profit and loss curve has a continuous negative value and the duration of the continuous negative value exceeds the tolerance threshold, it is determined that the scheme to be evaluated has a carbon efficiency risk. If none of the retrieved marginal carbon profit and loss curves have a continuous negative value with a duration exceeding the tolerance threshold, it is determined that the scheme to be evaluated is a carbon efficiency robust scheme, and carbon neutrality assessment information including the carbon efficiency robustness assessment result is output.

[0011] The system is based on the whole life cycle assessment of urban green space carbon neutrality capacity. The system includes: data preprocessing module, scheme family generation module, carbon budget calculation module, marginal analysis module and robustness assessment module. The data preprocessing module is used to acquire design parameters, building material usage, maintenance energy consumption, and tree species data for urban green space projects, perform standardized processing, and determine the boundaries between the full life cycle evaluation period and stages. The scheme family generation module is used to select a baseline scheme, determine several key influencing factors, and generate variant schemes for each key influencing factor in which only that factor changes while the other factors remain unchanged, thus constructing a single-factor variant scheme family. The carbon balance calculation module is used to calculate the carbon emissions and carbon absorption over the entire life cycle for each scheme in the single-factor variant scheme family, corresponding to each life cycle stage, and to accumulate and generate a cumulative carbon balance curve. The marginal analysis module is used to calculate the difference between the cumulative carbon budget curves of each variant scheme and the cumulative carbon budget curve of the baseline scheme at each time point to obtain the marginal carbon gain / loss curves of each key influencing factor and extract time-series features. The robustness assessment module is used to form a marginal carbon profit and loss profile set from the marginal carbon profit and loss curves of each key influencing factor, obtain the change information of the scheme to be evaluated and its key influencing factors, and retrieve the marginal carbon profit and loss curves of the corresponding changing factors. Based on whether the duration of continuous negative values ​​exceeds the tolerance threshold, the module determines the carbon efficiency risk or robustness and outputs carbon neutrality capacity assessment information.

[0012] According to the above scheme, the scheme family generation module includes a baseline extraction unit and a variant generation unit; The benchmark extraction unit is used to select benchmark schemes from industry-standard design practices or typical engineering cases, and extract the specific values ​​of all key influencing factors in the benchmark schemes. The variant generation unit is used to adjust the values ​​of the selected key impact factors along a set direction and step size, while keeping the values ​​of the remaining key impact factors consistent with the baseline scheme, to generate a single-factor variant scheme, and to traverse all key impact factors to form a family of single-factor variant schemes.

[0013] According to the above scheme, the marginal analysis module includes a difference calculation unit and a feature extraction unit; The difference calculation unit is used to align the cumulative carbon budget curve of each single-factor variant scheme with the cumulative carbon budget curve of the baseline scheme in the same time coordinate system, and perform difference calculations at time points to obtain the marginal carbon gain / loss curve of the key influencing factor corresponding to the single-factor variant scheme. The feature extraction unit is used to extract time-series features from each marginal carbon profit and loss curve. The time-series features include the carbon profit breakthrough point, the carbon loss reversal point, the negative value continuation interval, and the final value of marginal profit and loss.

[0014] According to the above scheme, the robustness assessment module includes a change comparison unit and a risk assessment unit; The change comparison unit is used to obtain the values ​​of each key impact factor in the scheme to be evaluated, and compare them one by one with the values ​​of the corresponding key impact factors in the benchmark scheme to determine the set of key impact factors that have changed. The risk assessment unit is used to retrieve the marginal carbon profit and loss curve corresponding to each of the key influencing factors in the set of key influencing factors that have changed from the marginal carbon profit and loss profile. It checks one by one whether there are continuous negative values ​​and the duration exceeds the tolerance threshold. If so, the scheme under evaluation is determined to have carbon efficiency risk; otherwise, it is determined to be a carbon efficiency robust scheme.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention constructs a family of single-factor variant schemes and calculates the difference between the cumulative carbon budget curves of each variant scheme and the baseline scheme at each time point to generate the marginal carbon gain / loss curve of each key influencing factor, thereby realizing the factor-by-factor separation and quantification of the differences in carbon neutrality capabilities among the schemes. 2. This invention extracts time-series features from the marginal carbon gain-loss curve, distinguishes the merits of carbon neutrality achievement paths by the differences in time-series features, and prioritizes robust schemes that repay carbon debt earlier and have shorter carbon losses in the process. 3. By forming a marginal carbon gain-loss profile set and performing a factor-by-factor continuous negative value check on the marginal carbon gain-loss curves of each variable factor based on the tolerance threshold, this invention can effectively identify the hidden carbon risks that are masked in traditional total carbon assessment. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the steps of the present invention's method for assessing the carbon neutrality capacity of urban green spaces based on the entire life cycle; Figure 2 This is a schematic diagram of the structure of the urban green space carbon neutrality assessment system based on the whole life cycle of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example: Figures 1-2 As shown, this invention provides a technical solution: a method for assessing the carbon neutrality capacity of urban green spaces throughout their entire life cycle. This method includes: S100. Obtain design parameters, building material usage, maintenance energy consumption, and tree species data for urban green space projects, perform standardized processing, and determine the boundaries between the full life cycle evaluation period and stages. S200. Select a baseline scheme and determine several key influencing factors. For each key influencing factor, generate a variant scheme in which only that key influencing factor changes relative to the baseline scheme, while the other key influencing factors remain unchanged, and construct a family of single-factor variant schemes. S300. For each single-factor variant scheme in the family of single-factor variant schemes, analyze the carbon emissions and carbon absorption at each time period throughout the entire life cycle, and sum them to generate the cumulative carbon budget curve for the entire life cycle of each single-factor variant scheme. S400. The cumulative carbon budget curves of each single-factor variant scheme are compared with the cumulative carbon budget curve of the baseline scheme at time points to obtain the marginal carbon gain / loss curves of each key influencing factor, and the time series characteristics are extracted. S500: A marginal carbon profit and loss profile set is formed from the marginal carbon profit and loss curves of each key influencing factor; the scheme to be evaluated and its key influencing factor change information are obtained, and the marginal carbon profit and loss curves of the corresponding changed key influencing factors are retrieved. If the marginal carbon profit and loss curve of any changed key influencing factor shows a continuous negative value and the duration exceeds the tolerance threshold, the scheme to be evaluated is determined to have carbon efficiency risk; otherwise, it is determined to be a carbon efficiency robust scheme, and the carbon neutrality capacity assessment information containing the carbon efficiency robustness assessment results is output.

[0019] Specifically, the design parameters include vegetation space configuration data and ground paving ratio data; building material consumption includes structural material consumption, paving material consumption, and auxiliary material consumption; maintenance energy consumption includes irrigation operation energy consumption, pruning operation energy consumption, fertilization operation energy consumption, and pest and disease control operation energy consumption; tree species data includes tree species type, growth curve parameters, and carbon storage model parameters; standardization processing unifies the design parameters, building material consumption, maintenance energy consumption, and tree species data to the same time granularity and carbon emission accounting boundary; determining the full life cycle evaluation period and stage division boundaries includes setting the evaluation start time and end time, and defining the time division points between the construction stage, maintenance stage, and maturity stage.

[0020] Specifically, in this embodiment, the vegetation space configuration data for the urban green space project includes: a tree planting density of 80 trees per hectare, a tree planting area of ​​0.8 hectares; a shrub coverage area of ​​0.3 hectares; a lawn area of ​​1.2 hectares; a total green area of ​​2.3 hectares; ground paving ratio data: hard paving area accounts for 25% of the total project area; the total project area is the sum of the green area and the paved area, which is 3.07 hectares; structural material consumption is 500 cubic meters of concrete and 30 tons of steel bars; paving material consumption is 400 cubic meters of paving stone; and auxiliary material consumption is geotextile. 800 square meters; irrigation method is sprinkler irrigation, covering the entire green area of ​​2.3 hectares, with an irrigation quota of 0.6 cubic meters per square meter per year; pruning covers 1.1 hectares of trees and shrubs, with pruning frequency twice a year, and mechanical energy consumption per hectare per pruning session; fertilization covers 1.1 hectares of trees and shrubs, with fertilization frequency once a year, and fertilizer application rate of 300 kg of compound fertilizer per hectare; pest and disease control covers 1.1 hectares of trees and shrubs, with control frequency three times a year, and mechanical energy consumption per hectare per application session; tree species... The data includes tree species type, growth curve parameters, and carbon storage model parameters. The tree species type is deciduous broad-leaved trees. Among the growth curve parameters, the asymptotic tree height for the height growth model is 15 meters, the growth rate parameter is 0.08 per year, and the growth curve shape parameter is 1.5. The asymptotic diameter at breast height (DBH) for the diameter at breast height (DBH) growth model is 45 centimeters, and the growth rate parameter is 0.06 per year. Among the carbon storage model parameters, the trunk wood density is 0.52 grams per cubic centimeter, the biomass expansion coefficient is 1.8, and the carbon content is 0.48. The acquired data underwent standardization processing, including design parameters, building material usage, maintenance energy consumption, and the number of tree species. Based on a unified annual time granularity, the carbon emission accounting boundary uniformly adopts the system boundary from building material production to maintenance operations; the evaluation start time is set as the first day of the year in which the project begins construction, and the evaluation end time is set as the last day of the 40th year from the start of construction. The evaluation period is set with reference to the design service life of urban green space projects and the carbon sequestration stability cycle of trees; the construction phase is defined as year 0 to year 1, the maintenance phase as year 2 to year 10, and the maturity phase as year 11 to year 40. The phase division boundaries are determined with reference to the industry-standard cycle for the construction and operation of urban green space projects; this is only an example and is not a limitation.

[0021] Specifically, step S200 includes: S210. Select a design scheme from industry-standard design or typical engineering cases as the benchmark scheme, and extract the specific values ​​of all key influencing factors in the benchmark scheme. Key influencing factors are independent adjustable engineering parameters that affect the carbon emissions or carbon absorption of urban green spaces throughout their entire life cycle. Independent adjustable engineering parameters include vegetation density parameters, ground paving ratio parameters, irrigation intensity parameters, fertilization intensity parameters, and pruning frequency parameters. S220. Among all the key impact factors of the baseline scheme, identify one key impact factor to be changed; S230. Adjust the values ​​of the key influencing factors to be changed along the specified direction by the specified step size, while keeping the values ​​of all other key influencing factors consistent with the baseline scheme, to generate a single-factor variant scheme. S240. Traverse all key influencing factors and take the generated set of single-factor variant schemes as a family of single-factor variant schemes.

[0022] Specifically, a design scheme is selected from the industry's general design standards as the benchmark scheme P0. The specific values ​​of all key influencing factors in the benchmark scheme are extracted: vegetation density parameter is 80 plants per hectare, ground paving ratio parameter is 25%, irrigation intensity parameter is 0.6 cubic meters per square meter per year, fertilizer intensity parameter is 300 kg per hectare per year, and pruning frequency parameter is twice per year. Among all the key influencing factors of the benchmark scheme, the key influencing factor to be changed is the vegetation density parameter. The value of the vegetation density parameter is adjusted in a positive direction with a specified step size, where the step size is 10% relative to the benchmark value, i.e., 8 plants per hectare. The step size is determined according to the industry's general settings for single-factor sensitivity analysis. After adjustment, the vegetation density parameter is 88 plants per hectare. At the same time, the ground paving ratio parameter remains at 25%, and the irrigation intensity parameter remains at 20%. The parameters are: 0.6 cubic meters per square meter, 300 kg / hectare fertilization intensity per year, and 2 times per year pruning frequency. This generates a single-factor variant scheme P1. All five key influencing factors are iterated over. The step size for each factor is set at approximately 10% of the baseline value, i.e., the step size for the ground paving ratio is 2.5 percentage points, adjusted to 22.5%. The step size for irrigation intensity is 0.06 cubic meters per square meter per year, adjusted to 0.66 cubic meters. The step size for fertilization intensity is 30 kg / hectare per year, adjusted to 330 kg / hectare. Pruning frequency is a discrete engineering parameter, with a step size of 1 time / year (the smallest adjustment unit in engineering practice), adjusted to 3 times per year. Five single-factor variant schemes, P1, P2, P3, P4, and P5, are generated. The set of these five single-factor variant schemes is considered a single-factor variant scheme family. This is only an example and is not a limitation.

[0023] Specifically, step S300 includes: S310. For each single-factor variant scheme, based on the standardized design parameters, building material usage, maintenance energy consumption, tree species data, and stage division boundaries, calculate the carbon emissions annually for each life cycle stage; the carbon emissions include the carbon emissions implicit in building materials, construction carbon emissions, and maintenance energy consumption carbon emissions. S320. Based on standardized design parameters and tree species data, carbon uptake is calculated annually; carbon uptake includes carbon sequestration by tree biomass and changes in soil carbon pool. S330. The difference between carbon absorption and carbon emissions in the same year is used to obtain the net carbon balance for that year. S340. Starting from the beginning of the life cycle assessment period, the net carbon balance is accumulated year by year to generate the life cycle cumulative carbon balance curve for this single-factor variant scheme.

[0024] Specifically, taking the single-factor variant scheme P1 as an example, scheme P1 has a vegetation density of 88 plants per hectare, a planting area of ​​0.8 hectares, and a total of approximately 70 plants. Based on standardized data, carbon emissions are calculated annually. In this embodiment, the implicit carbon emissions from building materials are calculated using the carbon emission factor method, with the formula: E mat =ΣM i ×f i Among them, E mat M represents the total carbon emissions inherent in building materials. i f represents the amount of the i-th building material used; i Let E be the carbon emission factor for the i-th building material; the carbon emission factor for concrete is taken as 320 kg CO2 per cubic meter, the carbon emission factor for steel reinforcement is taken as 2.2 tons CO2 per ton, and the carbon emission factor for paving stone is taken as 180 kg CO2 per cubic meter; the carbon emission factors for building materials are obtained by querying public industry databases; E is obtained. mat =500×0.32+30×2.2+400×0.18=160+66+72=298 tons of CO2, included in the construction phase; construction carbon emissions are calculated based on the detailed energy consumption of construction machinery, including energy consumption for civil construction operations and greening and planting operations. Energy consumption for greening and planting operations is positively correlated with the total number of trees planted, as shown in the formula: E cons =V fuel ×f diesel Among them, E cons Carbon emissions from construction; V fuel This represents the total diesel fuel consumption for construction machinery; f diesel The carbon emission factor for diesel fuel is taken from the general value for diesel fuel emission factors in relevant national standards for greenhouse gas emission accounting. The carbon emission of the baseline scheme is 2.1 tons of CO2. Due to the increase in the number of trees in scheme P1, the energy consumption of planting operations is correspondingly increased, and the carbon emission of construction is approximately 2.3 tons of CO2, which is included in the construction phase. The carbon emission of maintenance energy consumption is calculated annually. In this example, the second year of the evaluation period, i.e., the first year of the maintenance phase, is taken as an example. The formula for irrigation carbon emission is: E irr =A irr ×Q×f pump Among them, E irr For irrigation carbon emissions; A irrThe irrigated area is taken as the total green area of ​​2.3 hectares, or 23,000 square meters; Q is the irrigation quota, taken as 0.6 cubic meters per square meter per year; f pump The carbon emission coefficient for sprinkler irrigation water lifting energy consumption was calculated using 0.25 kg CO2 per cubic meter, derived from the industry guidelines for carbon emission accounting of urban parks and green spaces, and determined in conjunction with the energy efficiency level of conventional sprinkler irrigation systems; E0 was obtained. irr =23000×0.6×0.25=3450 kg CO2, or 3.45 tons CO2; the formula for reducing carbon emissions is: E prun =A prun ×u prun ×n prun ×f elec Among them, E prun To reduce carbon emissions; A prun The area to be pruned is 1.1 hectares, including both trees and shrubs; prun The energy consumption for a single pruning operation is taken as 150 kWh per hectare; n prun For pruning frequency, twice a year is recommended; f elec For the carbon emission factor of electricity, 0.6 kg CO2 per kilowatt-hour was used, adopting the general value of the national regional power grid average carbon emission factor published by the Ministry of Ecology and Environment; E was obtained. prun =1.1 × 150 × 2 × 0.6 = 198 kg CO2, or 0.198 tons CO2; the formula for carbon emissions from fertilizer application is: E fert =A fert ×Q fert ×f fert Among them, E fert Carbon emissions from fertilization; A fert The fertilization area is taken as 1.1 hectares; Q fert For fertilizer application rate, use 300 kg of compound fertilizer per hectare; fert The comprehensive emission factor of compound fertilizer includes emissions from fertilizer production and direct emissions of nitrous oxide in the field, taking 3.0 kg CO2 equivalent per kg of compound fertilizer; E fert =1.1 × 300 × 3.0 = 990 kg CO2, or 0.99 tons CO2; the formula for carbon emissions from pest and disease control is: E pest =A pest ×u pest ×n pest ×f elec Among them, E pest Carbon emissions from pest and disease control; A pest The area to be treated is 1.1 hectares; pest The energy consumption for a single application of pesticides is taken as 80 kWh per hectare; n pest To determine the frequency of prevention and control, three times per year is recommended; elecAs the carbon emission factor for electricity, 0.6 kg CO2 per kilowatt-hour was used; E was obtained. pest =1.1 × 80 × 3 × 0.6 = 158.4 kg CO2, or 0.158 tons CO2; the total carbon emissions from maintenance energy consumption for the year are E total =E irr +E prun +E fert +E pest =3.45 + 0.198 + 0.99 + 0.158 = 4.796 tons of CO2; In Scheme P1, due to the increase in the number of trees from 64 to 70, the energy consumption per unit area for pruning and pest control increases sublinearly with the increase in the number of trees. Due to the influence of overlapping canopies and reuse of work paths, the increase in energy consumption is lower than the increase in the number of trees. The energy consumption per pruning and pest control operation is positively correlated with the number of trees. The energy consumption per hectare for pruning is adjusted from 150 kWh to 156 kWh, and the energy consumption per hectare for pest control is adjusted from 80 kWh to 83 kWh. The carbon emissions from pruning in Scheme P1 in this year are approximately 0.206 tons of CO2, the carbon emissions from pest control are approximately 0.164 tons of CO2, and the total carbon emissions from maintenance energy consumption are approximately 4.810 tons of CO2; Calculating carbon absorption year by year, in this embodiment, the formula for the aboveground biomass of a single tree is: B = a × D b Where B is the aboveground biomass of a single tree; D is the diameter at breast height (DBH); a and b are species-specific parameters, with a set to 0.15 and b to 2.3. The parameters of the allometric growth equation were obtained by fitting standard plot biomass survey data. The change of DBH D with tree age t was described using a Logistic growth model, with the formula: D = D max / [1+k×e (-r×t) Where D is the diameter at breast height (DBH) at tree age t; max The approximate diameter at breast height (DBH) is set to 45 cm; k is the integration constant, set to 8.5; r is the growth rate parameter, set to 0.06 per year. The growth model parameters correspond to the general growth patterns of common deciduous broad-leaved trees in cities and are obtained through fitting long-term plot observation data; t is the tree age; taking the 10th year as an example, the DBH is calculated as D = 45 / [1 + 8.5 × e] (-0.06×10) ]≈7.94 cm; aboveground biomass of a single plant B≈0.15×7.94 2.3 ≈17.64 kg; Total plant biomass formula: B total =B×(1+R); where B total The total biomass of a single plant is B; R is the root-to-shoot ratio, taken as 0.25; the total biomass of the plant is B. total =17.64 × 1.25 = 22.05 kg; The formula for carbon storage per plant is: C stock =B total ×CF; where C stock is the carbon storage per plant; CF is the carbon content, taken as 0.48; carbon storage per plant Cstock =22.05 × 0.48 ≈ 10.58 kg of carbon; the formula for CO2 absorption per plant is: C_CO2 = C stock ×(44 / 12); where C_CO2 is the CO2 absorption per tree; C_CO2=10.58×44 / 12≈38.80 kg CO2; the carbon sequestration of trees in the 10th year is calculated based on the increase in biomass that year; the aboveground biomass per tree in the current year increased by about 2.8 kg of dry matter compared to the previous year, and the formula for the increase in CO2 absorption per tree is: ΔC_CO2=ΔB above ×(1+R)×CF×(44 / 12); where, ΔB above The aboveground biomass increment per plant in the current year is represented by ΔB; R is the root-to-shoot ratio, taken as 0.25; CF is the carbon content, taken as 0.48; 44 / 12 is the carbon-to-CO2 conversion coefficient; the total biomass increment of the plant is ΔB. above ×(1+R)=2.8×1.25=3.5 kg dry matter; the increase in CO2 absorption per tree is 3.5×0.48×(44 / 12)≈6.16 kg CO2; the total carbon sequestration by trees is 70×6.16≈431.2 kg CO2, or 0.431 tons CO2; the change in soil carbon pool is calculated using the soil organic carbon accumulation rate method, the formula is: E soil =A green ×v soil Among them, E soil A represents the annual change in soil carbon pool. green The total green area is taken as 2.3 hectares; v soil The soil carbon sequestration rate was set at 0.5 tons of CO2 per hectare per year, referencing the industry average for the rate of organic carbon accumulation in urban green space soils, and determined through soil location monitoring data; E was obtained. soil =2.3×0.5=1.15 tons of CO2; the total carbon absorption for the year is 0.431+1.15=1.581 tons of CO2; the net carbon balance for the year is 1.581-4.810=-3.229 tons of CO2; starting from the evaluation start point, the net carbon balance is accumulated year by year to generate the life cycle cumulative carbon balance curve of the single-factor variant scheme P1, denoted as C1(t); the curve is in the negative range during the construction period and the early maintenance period; as tree growth accelerates and soil carbon sequestration continues, the curve gradually rises and crosses the zero line into the positive range in the 12th year; the carbon sink growth rate slows down in the later period but always remains positive, without turning from positive to negative; repeat the above steps to complete the cumulative curves of the baseline scheme P0 and variant schemes P2 to P5; this is only an example and is not a limitation.

[0025] Specifically, step S400 includes: S410. Obtain the cumulative carbon budget curve for the baseline scheme; S420. Align the life-cycle cumulative carbon balance curve of each single-factor variant with the life-cycle cumulative carbon balance curve of the benchmark scheme on the same time coordinate system, and perform the difference calculation at each time point to obtain the marginal carbon gain / loss curve of the key influencing factor corresponding to the single-factor variant scheme. S430. Extract time-series features from each marginal carbon profit and loss curve. The time-series features include the carbon profit breakthrough point, the carbon loss reversal point, the negative value continuation interval, and the marginal profit and loss final value. The carbon profit breakthrough point is the starting time node when the marginal carbon profit and loss curve turns from negative to positive and remains positive. The carbon loss reversal point is the time node when the marginal carbon profit and loss curve turns from positive to negative. The negative value continuation interval is the continuous period when the value of the marginal carbon profit and loss curve is less than zero. The marginal profit and loss final value is the marginal carbon profit and loss value corresponding to the end of the life cycle evaluation period.

[0026] Specifically, the cumulative carbon balance curve C0(t) of the baseline scheme P0 is obtained; in this embodiment, the variant scheme P1 is used as an example, and the difference ΔC1(t) = C1(t) - C0(t) is calculated year by year to obtain the marginal carbon gain curve of the vegetation density parameter; in the 15th year, ΔC1(15) = 7.2 tons of CO2, which is the marginal gain; in the 2nd year, ΔC1(2) = -2.3 tons of CO2, which is the marginal loss; the time series characteristics are extracted from ΔC1(t), and the carbon profit breakthrough point is found to be the 8th year; since the marginal gain is always positive in the later period, there is no carbon loss reversal point; the negative value continues from the 1st to the 7th year of the evaluation period; the final value of the marginal gain is the positive value of 6.8 tons of CO2 in the 40th year; the marginal curves of other factors are generated in the same way; this is only an example and is not a limitation.

[0027] Specifically, step S500 includes: S510. Summarize the marginal carbon profit and loss curves of all key influencing factors to form a marginal carbon profit and loss profile set. S520. Obtain the scheme to be evaluated, which is a green space engineering design scheme that is independent of the benchmark scheme and the single-factor variant scheme family. S530. Obtain the values ​​of each key impact factor in the scheme to be evaluated, compare them one by one with the values ​​of the corresponding key impact factors in the benchmark scheme, and determine the set of key impact factors that have changed. S540. From the marginal carbon profit and loss profile set, retrieve the marginal carbon profit and loss curve corresponding to each changing key influencing factor in the set of changing key influencing factors. S550. Examine each of the retrieved marginal carbon profit and loss curves one by one. If any marginal carbon profit and loss curve shows a continuous negative value and the duration of the continuous negative value exceeds the tolerance threshold, the scheme to be evaluated is determined to have carbon efficiency risk. If none of the retrieved marginal carbon profit and loss curves show a continuous negative value with a duration exceeding the tolerance threshold, the scheme to be evaluated is determined to be a carbon efficiency robust scheme, and carbon neutrality capacity assessment information including the carbon efficiency robustness assessment results is output.

[0028] Specifically, five marginal curves are compiled to form a marginal carbon gain / loss profile set; the scheme to be evaluated is obtained, and the values ​​of each factor in the scheme to be evaluated include: vegetation density of 88 trees per hectare, ground paving ratio of 22.5%, irrigation intensity of 0.66 cubic meters per square meter per year, fertilizer intensity of 330 kg per hectare per year, and pruning frequency of 2 times per year; compared with the baseline scheme, vegetation density, paving ratio, irrigation intensity, and fertilizer intensity have changed, while pruning frequency has not changed; the marginal curves of the corresponding factors are retrieved from the profile set, and the variation range of each factor in the scheme to be evaluated corresponds one-to-one with the step size of the single-factor variant scheme; the four marginal curves are checked one by one; the tolerance threshold is preset according to the industry control requirements of the robustness evaluation of urban green space carbon neutrality capacity, and the value is adjusted in combination with the carbon risk control level of the project; in this embodiment, the tolerance threshold is 5 years; ΔC1(t) in the 1st to 7th The first year showed seven consecutive years of negative values, exceeding the threshold; ΔC2(t) was positive throughout the entire cycle with no negative value range, and did not exceed the threshold; ΔC3(t) was negative throughout the entire cycle from the second year, lasting for 39 years, far exceeding the threshold; ΔC4(t) was negative from the first year (the second year) of the maintenance stage, with the absolute value of the negative value accumulating and increasing year by year, remaining in a continuous negative state throughout the entire maintenance period and maturity period, lasting for 39 years, far exceeding the tolerance threshold; because ΔC1, ΔC3, and ΔC4 have consecutive negative values ​​exceeding the threshold, the scheme under evaluation is determined to have carbon efficiency risk; the output carbon neutrality assessment information is that the scheme has carbon efficiency risk, and the risk factors are vegetation density, irrigation intensity, and fertilization intensity; vegetation density causes a long carbon debt period in the early stage of establishment, and irrigation intensity and fertilization intensity generate continuous maintenance carbon deficit throughout the entire life cycle; this is only an example and is not a limitation.

[0029] This invention provides another technical solution: a system for assessing the carbon neutrality capacity of urban green spaces based on the entire life cycle. The system includes: a data preprocessing module, a scheme family generation module, a carbon budget calculation module, a marginal analysis module, and a robustness assessment module. The data preprocessing module is used to acquire design parameters, building material usage, maintenance energy consumption, and tree species data for urban green space projects, perform standardized processing, and determine the boundaries between the full life cycle evaluation period and stages. The scheme family generation module is used to select a baseline scheme, determine several key influencing factors, and generate variant schemes for each key influencing factor in which only that factor changes while the other factors remain unchanged, thus constructing a single-factor variant scheme family. The carbon balance calculation module is used to calculate the carbon emissions and carbon absorption over the entire life cycle for each scheme in the single-factor variant scheme family, corresponding to each life cycle stage, and to accumulate and generate a cumulative carbon balance curve. The marginal analysis module is used to calculate the difference between the cumulative carbon budget curves of each variant scheme and the cumulative carbon budget curve of the baseline scheme at each time point to obtain the marginal carbon gain / loss curves of each key influencing factor and extract time-series features. The robustness assessment module is used to form a marginal carbon profit and loss profile set from the marginal carbon profit and loss curves of each key influencing factor, obtain the change information of the scheme to be evaluated and its key influencing factors, and retrieve the marginal carbon profit and loss curves of the corresponding changing factors. Based on whether the duration of continuous negative values ​​exceeds the tolerance threshold, the module determines the carbon efficiency risk or robustness and outputs carbon neutrality capacity assessment information.

[0030] Specifically, the scheme family generation module includes a baseline extraction unit and a variant generation unit. The baseline extraction unit is used to select a baseline scheme from industry-standard design criteria or typical engineering cases and extract the specific values ​​of all key influencing factors in the baseline scheme. The variant generation unit is used to adjust the values ​​of the selected key influencing factors along a set direction with a set step size, while keeping the values ​​of the remaining key influencing factors consistent with the baseline scheme, generating a single-factor variant scheme, and traversing all key influencing factors to form a single-factor variant scheme family.

[0031] Specifically, the marginal analysis module includes a difference calculation unit and a feature extraction unit. The difference calculation unit is used to align the cumulative carbon balance curve of each single-factor variant with the cumulative carbon balance curve of the baseline scheme in the same time coordinate system, and perform difference calculations at time points to obtain the marginal carbon profit and loss curve of the key influencing factors corresponding to the single-factor variant scheme. The feature extraction unit is used to extract time-series features from each marginal carbon profit and loss curve, including the carbon profit breakthrough point, carbon loss reversal point, negative value persistence interval, and marginal profit and loss final value.

[0032] Specifically, the robustness assessment module includes a change comparison unit and a risk assessment unit. The change comparison unit is used to obtain the values ​​of each key influencing factor in the scheme to be evaluated and compare them one by one with the values ​​of the corresponding key influencing factors in the benchmark scheme to determine the set of key influencing factors that have changed. The risk assessment unit is used to retrieve the marginal carbon profit and loss curve corresponding to each key influencing factor in the set of key influencing factors that have changed from the marginal carbon profit and loss profile set, and check one by one whether there are continuous negative values ​​and the duration exceeds the tolerance threshold. If so, the scheme to be evaluated is determined to have carbon efficiency risk; otherwise, it is determined to be a carbon efficiency robust scheme.

[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for assessing the carbon neutrality capacity of urban green spaces based on their entire life cycle, characterized by: The method includes: S100. Obtain design parameters, building material usage, maintenance energy consumption, and tree species data for urban green space projects, perform standardized processing, and determine the boundaries between the full life cycle evaluation period and stages. S200. Select a baseline scheme and determine several key influencing factors; for each key influencing factor, generate a variant scheme in which only the key influencing factor changes with respect to the baseline scheme, while the other key influencing factors remain unchanged, and construct a family of single-factor variant schemes. S300. For each single-factor variant scheme in the family of single-factor variant schemes, analyze the carbon emissions and carbon absorption at each time period throughout the entire life cycle, and sum them to generate the cumulative carbon budget curve for the entire life cycle of each single-factor variant scheme. S400. The cumulative carbon budget curves of each single-factor variant scheme are compared with the cumulative carbon budget curve of the baseline scheme at time points to obtain the marginal carbon gain / loss curves of each key influencing factor, and the time series features are extracted. S500: A marginal carbon profit and loss profile set is formed from the marginal carbon profit and loss curves of each key influencing factor; the scheme to be evaluated and its key influencing factor change information are obtained, and the marginal carbon profit and loss curves of the corresponding changed key influencing factors are retrieved. If the marginal carbon profit and loss curve of any changed key influencing factor shows a continuous negative value and the duration exceeds the tolerance threshold, the scheme to be evaluated is determined to have carbon efficiency risk; otherwise, it is determined to be a carbon efficiency robust scheme, and the carbon neutrality capacity assessment information containing the carbon efficiency robustness assessment results is output.

2. The method for assessing the carbon neutrality capacity of urban green spaces based on the entire life cycle as described in claim 1, characterized in that: The design parameters include vegetation space configuration data and ground paving ratio data; The building material consumption includes the consumption of structural materials, paving materials, and auxiliary materials; The maintenance energy consumption includes energy consumption for irrigation operations, pruning operations, fertilization operations, and pest and disease control operations. The tree species data includes tree species type, growth curve parameters, and carbon storage model parameters; The standardization process involves unifying the design parameters, building material usage, maintenance energy consumption, and tree species data to the same time granularity and carbon emission accounting boundary. The determination of the full life cycle evaluation period and the boundaries of the stages include setting the evaluation start time and end time, and defining the time division points between the construction stage, the maintenance stage and the maturity stage.

3. The method for assessing the carbon neutrality capacity of urban green spaces based on the entire life cycle as described in claim 1, characterized in that: Step S200 includes: S210. Select a design scheme from industry-standard design criteria or typical engineering cases as a benchmark scheme, and extract the specific values ​​of all key influencing factors in the benchmark scheme; the key influencing factors are independent adjustable engineering parameters that affect the carbon emissions or carbon absorption of urban green spaces throughout their entire life cycle, including vegetation density parameters, ground paving ratio parameters, irrigation intensity parameters, fertilization intensity parameters, and pruning frequency parameters. S220. Among all the key influencing factors of the benchmark scheme, determine one key influencing factor to be changed; S230. Adjust the value of the key influencing factor to be changed along the specified direction by the specified step size, while keeping the values ​​of all other key influencing factors consistent with the baseline scheme, to generate a single-factor variant scheme. S240. Traverse all key influencing factors and take the generated set of single-factor variant schemes as a family of single-factor variant schemes.

4. The method for assessing the carbon neutrality capacity of urban green spaces based on the entire life cycle as described in claim 1, characterized in that: Step S300 includes: S310. For each of the single-factor variant schemes, based on the standardized design parameters, building material usage, maintenance energy consumption, tree species data, and the stage division boundaries, the carbon emissions are calculated annually for each life cycle stage; the carbon emissions include the carbon emissions implied by building materials, construction carbon emissions, and maintenance energy consumption carbon emissions. S320. Based on the standardized design parameters and tree species data, calculate the carbon uptake annually; the carbon uptake includes the carbon sequestration by tree biomass and the change in soil carbon pool. S330. The difference between carbon absorption and carbon emissions in the same year is used to obtain the net carbon balance for that year. S340. Starting from the beginning of the life cycle assessment period, the net carbon balance is accumulated year by year to generate the life cycle cumulative carbon balance curve for this single-factor variant scheme.

5. The method for assessing the carbon neutrality capacity of urban green spaces based on the entire life cycle as described in claim 1, characterized in that: Step S400 includes: S410. Obtain the cumulative carbon budget curve of the benchmark scheme; S420. Align the life-cycle cumulative carbon balance curve of each of the single-factor variant schemes with the life-cycle cumulative carbon balance curve of the baseline scheme in the same time coordinate system, and perform difference calculations at each time point to obtain the marginal carbon gain / loss curve of the key influencing factor corresponding to the single-factor variant scheme. S430. Extract time-series features from each marginal carbon profit / loss curve. The time-series features include the carbon profit breakthrough point, the carbon loss reversal point, the negative value continuation interval, and the marginal profit / loss final value. The carbon profit breakthrough point is the starting time node when the marginal carbon profit / loss curve turns from negative to positive and remains positive. The carbon loss reversal point is the time node when the marginal carbon profit / loss curve turns from positive to negative. The negative value continuation interval is the continuous period when the value of the marginal carbon profit / loss curve is less than zero. The marginal profit / loss final value is the marginal carbon profit / loss value corresponding to the end of the life cycle evaluation period.

6. The method for assessing the carbon neutrality capacity of urban green spaces based on the entire life cycle as described in claim 1, characterized in that: Step S500 includes: S510. Summarize the marginal carbon profit and loss curves of all key influencing factors to form a marginal carbon profit and loss profile set. S520. Obtain the scheme to be evaluated, wherein the scheme to be evaluated is a green space engineering design scheme that is independent of the benchmark scheme and the single-factor variant scheme family; S530. Obtain the values ​​of each key impact factor in the scheme to be evaluated, and compare them one by one with the values ​​of the corresponding key impact factors in the benchmark scheme to determine the set of key impact factors that have changed. S540. From the marginal carbon profit and loss profile set, retrieve the marginal carbon profit and loss curve corresponding to each changing key influencing factor in the set of changing key influencing factors. S550. Check each of the retrieved marginal carbon profit and loss curves one by one. If any marginal carbon profit and loss curve has a continuous negative value and the duration of the continuous negative value exceeds the tolerance threshold, it is determined that the scheme to be evaluated has a carbon efficiency risk. If none of the retrieved marginal carbon profit and loss curves have a continuous negative value with a duration exceeding the tolerance threshold, it is determined that the scheme to be evaluated is a carbon efficiency robust scheme, and carbon neutrality assessment information including the carbon efficiency robustness assessment result is output.

7. A system for assessing the carbon neutrality capacity of urban green spaces based on their entire life cycle, characterized by: The system includes: a data preprocessing module, a scheme family generation module, a carbon budget calculation module, a marginal analysis module, and a robustness assessment module; The data preprocessing module is used to acquire design parameters, building material usage, maintenance energy consumption, and tree species data for urban green space projects, perform standardized processing, and determine the boundaries between the full life cycle evaluation period and the stages. The scheme family generation module is used to select a baseline scheme, determine several key influencing factors, and generate variant schemes for each key influencing factor in which only that factor changes while the other factors remain unchanged, thus constructing a single-factor variant scheme family. The carbon balance calculation module is used to calculate the carbon emissions and carbon absorption over the entire life cycle for each scheme in the single-factor variant scheme family, corresponding to each life cycle stage, and accumulate them to generate a cumulative carbon balance curve. The marginal analysis module is used to calculate the difference between the cumulative carbon budget curves of each variant scheme and the cumulative carbon budget curve of the baseline scheme at time points to obtain the marginal carbon gain / loss curves of each key influencing factor and extract time-series features. The robustness assessment module is used to form a marginal carbon profit and loss profile set from the marginal carbon profit and loss curves of each key influencing factor, obtain the change information of the scheme to be evaluated and its key influencing factors, retrieve the marginal carbon profit and loss curves of the corresponding changing factors, determine the carbon efficiency risk or robustness based on whether the duration of continuous negative values ​​exceeds the tolerance threshold, and output carbon neutrality capacity assessment information.

8. The urban green space carbon neutrality assessment system based on the entire life cycle as described in claim 7, characterized in that: The scheme family generation module includes a baseline extraction unit and a variant generation unit; The benchmark extraction unit is used to select benchmark schemes from industry-standard design or typical engineering cases and extract the specific values ​​of all key influencing factors in the benchmark schemes. The variant generation unit is used to adjust the value of the selected key influence factor along a set direction by a set step size, while keeping the values ​​of the remaining key influence factors consistent with the baseline scheme, to generate a single-factor variant scheme, and to traverse all key influence factors to form the single-factor variant scheme family.

9. The urban green space carbon neutrality assessment system based on the entire life cycle as described in claim 7, characterized in that: The marginal analysis module includes a difference calculation unit and a feature extraction unit; The difference calculation unit is used to align the cumulative carbon budget curve of each single-factor variant scheme with the cumulative carbon budget curve of the baseline scheme in the same time coordinate system, and perform difference calculations at time points to obtain the marginal carbon gain / loss curve of the key influencing factor corresponding to the single-factor variant scheme. The feature extraction unit is used to extract time-series features from each marginal carbon profit and loss curve. The time-series features include the carbon profit breakthrough point, the carbon loss reversal point, the negative value continuation interval, and the final value of marginal profit and loss.

10. The urban green space carbon neutrality assessment system based on the entire life cycle as described in claim 7, characterized in that: The robustness assessment module includes a change comparison unit and a risk assessment unit; The change comparison unit is used to obtain the values ​​of each key impact factor in the scheme to be evaluated, and compare them one by one with the values ​​of the corresponding key impact factors in the benchmark scheme to determine the set of key impact factors that have changed. The risk assessment unit is used to retrieve the marginal carbon profit and loss curve corresponding to each changing key influencing factor in the set of changing key influencing factors from the marginal carbon profit and loss profile set, and check one by one whether there are continuous negative values ​​and the duration exceeds the tolerance threshold. If there are, it is determined that the scheme to be evaluated has carbon efficiency risk; otherwise, it is determined to be a carbon efficiency robust scheme.

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