Uncertainties and limitations of IBC module

The document details limitations in the IBC module's use of linear GEOS-Chem Adjoint coefficients for PM2.5 and ozone, which fail to account for non-linear atmospheric chemical reactions. It also notes that health and crop impact assessments rely on concentration-response functions derived from North American and European data, which may not be universally applicable or accurate at very high ozone concentrations.

• The IBC module uses linear GEOS-Chem Adjoint coefficients based on 2010 emissions to estimate PM2.5 and ozone concentrations. Because these are linear, the methodology fails to account for non-linear chemical reactions in the atmosphere, such as the interaction between NOx, SO2, and NH3 that forms secondary inorganic aerosols, or the VOC-limited and NOx-limited regimes that govern ozone formation.
• Health impact assessments for premature mortality from PM2.5 and ozone use concentration-response functions from the Global Burden of Disease project. These functions are based on research from Europe and North America and are assumed to apply globally, despite potential differences in PM2.5 composition and higher concentrations in other regions.
• Crop yield loss estimates for wheat, maize, rice, and soy are based on North American experiments for ozone exposure between 20 and 90 ppb. Because the relationship above 90 ppb is uncertain, the module assumes no further increase in yield loss beyond this threshold, meaning mitigation benefits are only estimated when concentrations are reduced to below 90 ppb.
• LEAP calculations are currently deterministic and do not inherently reflect uncertainties in activity levels, energy intensities, or emission factors, although users can employ sensitivity analyses or external tools like Oracle Crystal Ball for Monte Carlo analysis.

APA

Stockholm Environment Institute (n.d.). Uncertainties and limitations of IBC module. https://leap.sei.org/Help24/IBC/Uncertainties_and_Limitations_in_Using_IBC.htm

Chicago

Stockholm Environment Institute. Uncertainties and limitations of IBC module. n.d. https://leap.sei.org/Help24/IBC/Uncertainties_and_Limitations_in_Using_IBC.htm.

Wikipedia

{{cite report |author=Stockholm Environment Institute |title=Uncertainties and limitations of IBC module |url=https://leap.sei.org/Help24/IBC/Uncertainties_and_Limitations_in_Using_IBC.htm |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{stockholmenvironmentinstitutenduncertainties, author = {{Stockholm Environment Institute}}, title = {{Uncertainties and limitations of IBC module}}, institution = {Stockholm Environment Institute}, url = {https://leap.sei.org/Help24/IBC/Uncertainties_and_Limitations_in_Using_IBC.htm}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }