LEAP 2018 includes the new Integrated Benefits Calculator (IBC).This extension to LEAP can be used to translate national-scale emissions scenarios into estimates of health (mortality), ecosystem (crop loss) and climate (temperature change) impacts. IBC is particularly useful for examining the multiple benefits of taking coordinated action on long-lived and short-lived climate pollutants (SLCPs) and local air pollutants.
LEAP 2018 includes an add-on module called the Integrated Benefits Calculator (IBC). IBC can be used to translate LEAP's existing emissions scenarios into estimates of air pollution-associated health (premature mortality), and ecosystem (crop yield loss) impacts, we well as climate (global temperature change) impacts. The tool is particularly useful for examining multiple benefits of taking action on long-lived and short-lived climate pollutants (SLCPs) and local air pollutants.
IBC uses parameterized results from the global atmospheric geochemistry model GEOS-Chem Adjoint, which are combined with emission estimates to calculate population-weighted concentrations of fine particulate matter (PM2.5) and ground-level ozone (O3). These concentrations are then used with standard concentration-response functions to estimate premature mortality associated with PM2.5 and ozone exposure and crop yield losses associated with ozone exposure. Results can be viewed by geographic source (in-country, natural background and rest of the world), by the contribution of emissions of different pollutants to the impact (e.g. the contribution of NOx, black carbon, organic carbon, etc.), by age group (for premature mortality) or by crop type (for crop losses, currently rice, wheat, maize and soy). Health impact functions are based on the standard dose-response functions used in the Global Burden of Disease Study (Burnett et al., 2014). GEOS-Chem Adjoint is a global 3-D chemical transport model for atmospheric composition driven by meteorological input from the Goddard Earth Observing System (GEOS) of NASA and is based on emissions inventories from the EDGAR database. The overall modeling pathway is illustrated below.
IBC runs are based on emissions inventories and projections developed in LEAP for a particular country or countries. Users are required to specify comprehensive emissions inventories and forward-looking scenarios for all major long- and short-lived climate pollutants (SLCPs), and local air pollutants including CO2, methane (CH4), black carbon, organic carbon, PM2.5, non-methane volatile organic compounds (NMVOCs), nitrogen oxides (NOx), sulfur dioxide (SO2) and ammonia (NH3). SEI has developed a comprehensive set of default emission factors for these pollutants, which users can opt to add in to their existing data sets. This can be useful if a country has, for example, already developed a LEAP data set for its analysis of its Nationally Determined Contributions (NDCs). Alternatively, SEI has developed a template LEAP structure for performing these types of analysis (included in LEAP as the "Asiana" data set). This focuses on sectors that are important in terms of generating emissions of important SLCPs (such as emissions from brick kilns, diesel vehicles, traditional cook stoves or agricultural practices such as residue burning and methane from manure). Users can also opt to merge their existing data sets with parts of the standard template structure, to create a data set that meets the needs of their particular country. A sample version of the "Asiana", data set illustrates how LEAP can be used to examine alternative policies and measures that can mitigate both short- and long-lived climate pollutants, and reduce the health and ecosystem impacts associated with air pollution.
The emissions scenarios generated in LEAP are combined with estimates of emissions of pollutants for the rest of the world for the period 2010-2050, taken from the ECLIPSE scenarios developed by the International Institute for Applied Systems Analysis (IIASA). Two scenarios are included. A baseline scenario that foresees only minor worldwide efforts to combat air pollution, and a maximal effort scenario that reflects full implementation of 16 measures including the banning of agricultural residue burning. LEAP users can conduct sensitivity analyses to see the effect of differing levels of effort in the rest of the world on the impacts experienced in their own country.
IBC is particularly notable because, for the first time, it makes a complex and highly computing-intensive modeling methodology accessible to planners in the developing world. By first parameterizing the calculations of GEOS-Chem Adjoint (which can take a few days to perform per country, even on super computers), the calculations in LEAP can then be run in just a few seconds. Moreover, LEAP is used for all data management and results visualization, making it readily usable by developing country planners. Previously, such analyses could only be done by highly experienced modelers working in large international institutions.
Currently, LEAP-IBC works for a selected set of nations. It has so far been calibrated to work for 71 countries for PM2.5, and 20 countries for Ozone-related impacts. We plan to expand this coverage to about 150 countries in 2018 (as part of a forthcoming release of LEAP). A second version of the IBC tool is planned that can be applied at the city scale, and which will provide greater information on the impacts of indoor air pollution, including gender-based disaggregation of impacts.
IBC has been developed in a collaboration between SEI, the US-EPA, and researchers at the University of Colorado (Daven Henze). The work has been supported by UNEP and the Climate and Clean Air Coalition (CCAC).
Notes on using LEAP with IBC.
IBC can currently only be used with national-scale or multi-national scale LEAP areas. Its impact calculations assume that LEAP will be providing it with a comprehensive accounting for the emissions of all major long- and short-lived climate pollutants (SLCPs), and local air pollutants including CO2, methane (CH4), black carbon, organic carbon, PM2.5, non-methane volatile organic compounds (NMVOCs), nitrogen oxides (NOx), sulfur dioxide (SO2) and ammonia (NH3). Your LEAP model should cover all anthropogenic emissions including both energy sector and non-energy sector emissions. IBC itself will provide estimates of anthropogenic emissions from the rest of the world as well as natural background levels of pollutants.
To ensure that your emissions scenarios comprehensively cover all these pollutants, we recommend starting by constructing a data set based on the Asiana area distributed with LEAP. You can open this area and then use the Area: Revert to Version menu option to select a version of this data set containing emission factors and blank activity and energy intensity data. We recommend using this as a basis for any new model you wish to construct. Alternatively, you can opt to extend an existing LEAP data set to fully include all of the above pollutants. For example, you may already have a LEAP data set developed for national mitigation modeling (perhaps developed to contribute to your countries analysis of its Nationally Determined Contributions to the UNFCCC). You may wish to copy the default emission factors provided with Asiana into your existing data set, supplementing them where appropriate with better nationally-relevant data. In addition, you may wish to copy some of the default sectoral structures provided with Asiana into your existing data set so as to ensure your model has comprehensive national-scale coverage of all of the above pollutants. In particular, bear in mind that many existing LEAP models may not have coverage of non-energy sector emissions.
IBC has so far only been calibrated for a limited number of countries. At the time of its first release it was calibrated to work for 71 countries for PM2.5, and 20 countries for Ozone-related impacts. SEI plans to expand this coverage to about 150 countries in 2018 (as part of a forthcoming release of LEAP). For national-scale areas, you must select a country name in the Basic Parameters: Scope & Scale screen. That same screen will indicate if IBC currently supports that country. For multi-national (multi regional) LEAP areas, select a country for each of your regions in the General: Regions screen. That screen will indicate if IBC currently supports each country/region.
IBC has specific requirements for the time period over which LEAP scenarios may be run. To use IBC you must select a Base Year of 2010 and a First Scenario Year of 2011. In other words, IBC does not currently support multiple historical data years. The end year can be any year on or after 2020. You can edit these values in the Basic Parameters: Years screen.
IBC also requires certain specific Tree branches to exist under the Key Assumptions and Indicators high level branches. For example, under the Key Assumptions branch folders should exist labeled Demographics, Economics, Disease Rates, Crop Production, and Transport. Documentation for the data required in these various branches is under development. Indicators must be enabled (via the Basic Parameters: Scope screen) and under the Indicator branch, IBC will store all of its various calculated results for pollutant concentrations, (premature) deaths, crop loss, climate impacts and economic damages under a folder branch named Benefit Calculator Results. If these branches do not exist in your data set then IBC will fail to run. You can add those branches into your data set by copying and pasting from the Asiana data set, or by running a supporting VB script named "IBCCompatibleConversion.vbs" available in the LEAP program folder. Check here for information on how to run VB scripts.
Once your LEAP area has been properly set up to work with IBC, you can view many additional types of results in LEAP including premature mortality (deaths), crop losses, and temperature change. Results can be viewed by geographic source (in-country, natural background and rest of the world), by the contribution of emissions of different pollutants to the impact (e.g. the contribution of NOx, black carbon, organic carbon, etc.), by age group (for premature mortality) or by crop type (for losses of rice, wheat, maize and soy). Below is an example of the type of result that can be generated.
Notes on some key uncertainties and limitations when using IBC within LEAP.
GEOS-Chem Adjoint coefficients for PM2.5: The GEOS-Chem Adjoint coefficients quantify the sensitivity of PM2.5 concentrations in the target country to NOx, SO2, NH3, BC and OC emissions in grid squares across the world. These sensitivities are calculated for a base set of emissions, for the year 2010. The coefficients are applied in IBC to look at changes in PM2.5 concentrations in the target country that result from changes in emissions in the target country, and across the world. They are linear coefficients, which means that a change in emissions results in a linear increase/decrease in PM2.5 concentrations in the target country. The methodology therefore does not account for non-linear changes in target PM2.5 concentrations resulting from non-linear chemical reactions in the atmosphere, e.g. combination between NOx, SO2 and NH3 to form secondary inorganic aerosol.
GEOS-Chem Adjoint coefficients for Ozone: The GEOS-Chem Adjoint coefficients quantify the sensitivity of ozone concentrations in the target country to NOx, VOC, CO and CH4 emissions in grid squares across the world. These sensitivities are calculated for a base set of emissions, for the year 2010. The coefficients are applied in IBC to look at changes in ozone concentrations in the target country that result from changes in emissions in the target country, and across the world. They are linear coefficients, which means that a change in emissions results in a linear increase/decrease in ozone concentrations in the target country. Ozone formation depends on the relative emissions of VOC and NOx, with ozone increasing due with increasing NOx emissions in VOC-limited regimes, and with increasing VOC emissions in NOx-limited regimes. Hence changes in the relative emissions of NOx and VOCs will result in non-linear changes in ozone concentrations. This interaction is not taken into account in the application of the ozone coefficients in IBC.
Health impact assessment methodology: The health impact assessment estimate premature mortality associated with PM2.5 and ozone exposures, using concentration-response functions that have been used by the Global Burden of Disease project. These concentration-response functions are based on health effects research that has been carried out in North America and Europe. It is assumed that the same relationships apply in other regions of the world, including those where PM2.5 and ozone concentrations are much higher, and where the composition of PM2.5 may differ.
Crop impact assessment methodology: Agricultural crop yield loss is estimated using concentration-response functions that quantify the relationship between wheat, maize, rice or soy yield and ozone exposure. These functions are based on experiments carried out in North America, that assessed this relationship for ozone exposure between 20 and 90 ppb. The relationship between yield loss and ozone exposures above 90 ppb is uncertain. To avoid unrealistic estimates of ozone-induced yield loss, for ozone concentrations above 90 ppb, there is assumed to be no increase in yield loss. This means that for mitigation scenarios to show a benefit for ozone crop yield loss, ozone concentrations must be reduced to below 90 ppb, e.g. a reduction from 110 ppb to 100 ppb in ozone exposure does not result in an estimated reduction in yield loss.
Other: Significant but hard to quantity uncertainties exist in the activity levels, energy intensities and emission factors used in any LEAP area. Currently LEAP's calculations are deterministic and do not reflect any uncertainty in these values. However, you can use LEAP to perform sensitivity analyses or even connect it with tools such as Oracle Crystal Ball that allow uncertainties to be explored using techniques such as Monte Carlo analysis. Bear in mind also that all future values are inherently uncertain since they depend on policy choices that may or may not be made.
SEI is currently developing a new online technology database that will contain performance data, costs and emission factors suitable for use in LEAP-IBC. In the meantime, here are set of default emission factors stored in Excel worksheets that can be used when developing LEAP-IBC data sets. These factors have been compiled by Harry Vallack at SEI's York Center. Please contact Harry for further information.