Gridded uncertainty in fossil fuel carbon dioxide emission maps, a CDIAC example

Robert J Andres,David M Higdon,Thomas A Boden

doi:10.5194/acp-16-14979-2016

Robert J Andres, David M Higdon + Show 1 more

Open Access

https://doi.org/10.5194/acp-16-14979-2016

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Abstract

Abstract. Due to a current lack of physical measurements at appropriate spatial and temporal scales, all current global maps and distributions of fossil fuel carbon dioxide (FFCO2) emissions use one or more proxies to distribute those emissions. These proxies and distribution schemes introduce additional uncertainty into these maps. This paper examines the uncertainty associated with the magnitude of gridded FFCO2 emissions. This uncertainty is gridded at the same spatial and temporal scales as the mass magnitude maps. This gridded uncertainty includes uncertainty contributions from the spatial, temporal, proxy, and magnitude components used to create the magnitude map of FFCO2 emissions. Throughout this process, when assumptions had to be made or expert judgment employed, the general tendency in most cases was toward overestimating or increasing the magnitude of uncertainty. The results of the uncertainty analysis reveal a range of 4–190 %, with an average of 120 % (2σ) for populated and FFCO2-emitting grid spaces over annual timescales. This paper also describes a methodological change specific to the creation of the Carbon Dioxide Information Analysis Center (CDIAC) FFCO2 emission maps: the change from a temporally fixed population proxy to a temporally varying population proxy.

Highlights

Prior to about the year 1980, the magnitude of fossil fuel carbon dioxide (FFCO2) emissions was the best-known component in the global carbon cycle (Andres et al, 2014)
While uncertainty for each of the major components of the global carbon cycle limits detailed understanding of these components, uncertainty in FFCO2 emissions impacts our knowledge of the terrestrial biosphere component because its global flux is often calculated as the residual of the other global carbon cycle fluxes
This paper aims to supplement the Carbon Dioxide Information Analysis Center (CDIAC) maps with similar spatial and temporal scale maps that represent the uncertainty in each map grid cell location

Summary

Introduction

Prior to about the year 1980, the magnitude of fossil fuel carbon dioxide (FFCO2) emissions was the best-known component in the global carbon cycle (Andres et al, 2014). Improvements in methodologies, instrumentation, and measurement platforms have improved estimates of the major components of the global carbon cycle (e.g., FFCO2, land use, atmospheric growth, oceanic uptake, and the terrestrial biosphere). This improvement has reached the point where uncertainty in FFCO2 emissions is an important quantity to characterize and understand. The magnitude and uncertainty in FFCO2 directly impact the best estimates of the global terrestrial biosphere fluxes. That analysis highlighted two features of the global FFCO2 flux uncer-

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