Frequently Asked Questions

The following are frequently asked questions about the Carbon Transparency Initiative. This list will continue to be refined based on feedback received.

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    Which data are historical?

    The CTI relies on a number of trusted sources, including historical inventories that were used for calibrating the model. In some cases projections were based on a combination of analyses of trends of technologies, policies, and investments that affect the trajectory of a given sector, while in other cases the source data also included projections. The most recent year of historical data differs by metric depending on the data source. In the Tracking Dashboard, this is communicated graphically by solid lines (historical data) and dotted lines (projections). For CTI 2017, the most recent historical year is generally between 2014 and 2016.

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    What are the data sources?

    The CTI relies on a number of trusted sources for activity and intensity metrics. Leading sources include Bloomberg New Energy Finance’s New Energy Outlook for the Power sector, the International Council on Clean Transportation’s Global Transportation Roadmap Model for the Transport sector, and the International Energy Agency’s Energy Technology Perspectives for the Buildings and Industry sectors.

    A large number of additional sources were also incorporated into the models. For a full list of data sources, please consult Table 5 in the CTI Model Methodology Document.

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    What policy assumptions are in the Current Development Scenario, and are there alternative scenarios or the ability to create one’s own scenario?

    The Carbon Transparency Initiative presents a forward-looking Current Development Scenario (CDS) based on current policies, decarbonization trends, and energy-related investments. The CDS assumes continued effort in implementing policy and supporting and defending current policies and legislation. Included in ‘current policies’ are any policies in a sector that were promulgated in time to be incorporated into the data sources CTI relies on. Please consult the CTI Policies Document for more information.

    Five population and GDP scenarios are available for selection in the models, sourced from the Shared Socioeconomic Pathways (SSPs) developed for the climate change modeling community. The CDS is based on the ‘Middle of the Road’ SSP2, while users of the models may choose any of the five SSPs or specify their own GDP and population growth projections. This allows for a range of sensitivity analyses as these socioeconomic activity metrics drive changes through several sectors in the model.

    For population and GDP growth rates in the CDS, please consult Table 6 in the CTI Model Methodology Document. For a full list of the calculations sensitive to GDP or population growth assumptions, please consult Table 7 in the CTI Model Methodology Document. In addition, users can create their own scenarios by affecting policy levers or changing assumptions in the model.

    The regional emissions pathways in the Current Development Scenario are not consistent with limiting warming to 1.5°C or 2°C and they do not necessarily align with the Nationally Determined Contributions submitted to the Conference of the Parties in Paris in November 2015.

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    How can I access the models?

    Please contact us if you wish to access the models and/or create your own scenarios.

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    How do the CTI models compare with other models?

    The Carbon Transparency Initiative models are indicator-led forecasts of emissions pathways for Brazil, China, the European Union, India, Mexico, and the United States with a modeling horizon of 2030. There are many other models of emissions pathways which differ on methodology, data sources, Global Warming Potentials, coverage (by geography, by sector, and by the suite of greenhouse gases included), and the modeling horizon. Care must be taken to ensure that ‘apples to apples’ comparisons are being made when contrasting CTI’s outcome metrics to those of other modeling efforts.

    For comparisons of past projections with actual developments in renewable energy, coal consumption, and passenger vehicles, please consult our report ‘Faster and Cleaner: Decarbonization in the Power and Transport Sectors is Surpassing Predictions’.

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    What uncertainties are reflected in the models?

    While the Carbon Transparency Initiative models include five Shared Socioeconomic Pathways that a user may select, uncertainty about the future paths of GDP and population growth reflect only two potential sources of uncertainty. Uncertainty stemming from the methodology and other data sources (both in terms of projections and the revision of historical data) is endemic to all modeling exercises. The challenges of uncertainty are best dealt with by being transparent about the modeling choices made and by exploring the range of possible futures through scenario analysis. Emissions ranges published in the Regions dashboard only reflect the effect of changing between the 5 SSP scenarios; they do not constrain the full range of possible emissions pathways for a region and they should not be interpreted probabilistically (i.e. they are not confidence intervals or distributions of emissions pathways). Please consult the CTI Model Methodology Document for more information.

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    How frequently will the data be updated?

    Updates to the Carbon Transparency Initiative models are planned on a bi-annual basis with new releases in the second half of the calendar year. Data currently on the website are all from the first update to the models (CTI 2017), with the exception of the Tracking dashboard which compares this data to that in the first set of models (CTI 2015).

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    How do I cite use of the data?

    Website: Carbon Transparency Initiative. November 2016. ClimateWorks Foundation, San Francisco, CA. Accessed on (date). Available at climateworkstracker.org.

    Model Methodology: Monteith, S., Plechaty, D., Cronin, C. and Menon, S., “Carbon Transparency Initiative: Model methodology for all sectors.” November 2016. ClimateWorks Foundation, San Francisco, CA. Available at climateworkstracker.org.

    Brazil Model Methodology: Azevedo, T., Tsai, D., dos Santos Cremer, M., Costa Jr., C., Brandao Jr., A., Coluna, I., Albuquerque, I., Monteith, S., Plechaty, D., Cronin, C. and Menon, S., “Carbon Transparency Initiative: Brazil.” December 2017. System for Greenhouse Gas Emissions and Removals Estimates (SEEG) and ClimateWorks Foundation. Available at climateworkstracker.org.

    Brief (2015): Cronin, C., Menon, S., Monteith, S., Plechaty, D., Hagemann, M., Höhne, N., Sterl, S., van Breevoort, P., Wouters, K., Hare, B., Roming, N., and Sferra, F., “Faster and Cleaner: Decarbonization in the power and transport sectors is surpassing predictions.” December 2015. Available at climateworks.org.

    Brief (2017): Cronin, C., Menon, S., Monteith, S., Plechaty, D., Sterl, S., Hagemann, M., Fekete, H., Höhne, N., Cantzler, J., Ancygier, A., Beer, M., Hare, B., Wouters, K., Deng, Y., Blok, K., “Faster and Cleaner 2: Kick-starting global decarbonization.” April 2017. Available at climateworks.org.

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    Are oil prices considered in the model?

    As the CTI is an activity and intensity-indicator led model, the future path of oil prices is not an explicit policy lever; assumptions about oil prices are embedded in data sources and projections in the sectors.

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    What assumptions are made regarding non-CO2 emissions?

    The radiative forcing from greenhouse gases other than carbon dioxide is modeled and reported in tons of carbon dioxide equivalent using the 100-year Global Warming Potentials from the Intergovernmental Panel on Climate Change’s Fourth Assessment Report. These gases include methane, nitrous oxide and hydrofluorocarbons. Non-CO2 emissions are released by almost every sector; the CTI 2017 model update focused in part on providing a more comprehensive representation of non-CO2 emissions by gas from a wider variety of sources.

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    Why are Aviation & Marine Sector emissions treated separately from Transport Sector emissions?

    Aviation & Marine emissions are presented separately from terrestrial Transport emissions in order to aid inter-model comparison as not all models attempt to calculate emissions from aviation and marine transport.

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    How does the Current Development Scenario compare to the Nationally Determined Contributions (NDCs) or 2°C/1.5°C scenarios?

    The regional emissions pathways in the Current Development Scenario are not consistent with limiting warming to 1.5°C or 2°C and they do not necessarily align with the Nationally Determined Contributions (NDCs) submitted to the Conference of the Parties in Paris in November 2015. While the models assume that promulgated policies are implemented they do not immediately assume that all stated targets or pledges are met, and the CDS does not ‘backcast’ from a specific temperature goal. That being said, it is possible to change the model assumptions in order to simulate the effects of an NDC or to reach an emissions rate for a region in 2030 that is in line with limiting warming to a certain threshold if one makes assumptions about national effort-sharing and the rate of emissions reductions post-2030.

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    How is the ClimateWorks Foundation using the CTI model?

    ClimateWorks Foundation is using the CTI model to understand the materiality of greenhouse gas emissions and inform philanthropic investments. All our work is grounded in science, and the CTI is one component in a broader toolkit meant to provide context to and inform, not define, strategies.

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    What differences are there between the model developed for Brazil and the original five models?

    In 2015, ClimateWorks published Carbon Transparency Initiative models for China, the EU, India, Mexico and the US, with harmonized methodologies and data sources. Since then, ClimateWorks has partnered with SEEG, a consortium of Brazilian NGOs, to a) produce a model of Brazil’s greenhouse gas emissions that is based off of the CTI methodology and b) to update the methodology for the Land Use sectors (Forestry, Agriculture and Waste). This work culminated in 2017 with a new model for Brazil and updated models for the original five regions.

    The Brazil model differs from the other models in that it was produced by in-country experts and relies on national inventories and datasets whenever possible. Because of differences in the availability or the structure of the data, there are many instances in which the methodology of the Brazil model deviates from the other models, even when the same metrics are reported. For more information on the specifics of the Brazil model methodology, please visit the SEEG website.

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    How should I cite usage of the CTI Brazil model?

    Azevedo, T., Tsai, D., dos Santos Cremer, M., Costa Jr., C., Brandao Jr., A., Coluna, I., Albuquerque, I., Monteith, S., Plechaty, D., Cronin, C. and Menon, S., “Carbon Transparency Initiative: Brazil.” December 2017. System for Greenhouse Gas Emissions and Removals Estimates (SEEG) and ClimateWorks Foundation. Available at climateworkstracker.org.

Suggested Citations

Website: Carbon Transparency Initiative. November 2016. ClimateWorks Foundation, San Francisco, CA. Accessed on (date). Available at climateworkstracker.org.

Model Methodology: Monteith, S., Plechaty, D., Cronin, C. and Menon, S., “Carbon Transparency Initiative: Model methodology for all sectors.” November 2016. ClimateWorks Foundation, San Francisco, CA. Available at climateworkstracker.org.

Brazil Model Methodology: Azevedo, T., Tsai, D., dos Santos Cremer, M., Costa Jr., C., Brandao Jr., A., Coluna, I., Albuquerque, I., Monteith, S., Plechaty, D., Cronin, C. and Menon, S., “Carbon Transparency Initiative: Brazil.” December 2017. System for Greenhouse Gas Emissions and Removals Estimates (SEEG) and ClimateWorks Foundation. Available at climateworkstracker.org.

Brief (2015): Cronin, C., Menon, S., Monteith, S., Plechaty, D., Hagemann, M., Höhne, N., Sterl, S., van Breevoort, P., Wouters, K., Hare, B., Roming, N., and Sferra, F., “Faster and Cleaner: Decarbonization in the power and transport sectors is surpassing predictions.” December 2015. Available at climateworks.org.

Brief (2017): Cronin, C., Menon, S., Monteith, S., Plechaty, D., Sterl, S., Hagemann, M., Fekete, H., Höhne, N., Cantzler, J., Ancygier, A., Beer, M., Hare, B., Wouters, K., Deng, Y., Blok, K., “Faster and Cleaner 2: Kick-starting global decarbonization.” April 2017. Available at climateworks.org.