The European carbon balance. Part 1: fossil fuel emissions

Abstract

We analyzed the magnitude, the trends and the uncertainties of fossil-fuel CO₂ emissions in the European Union 25 member states (hereafter EU-25), based on emission inventories from energy-use statistics. The stability of emissions during the past decade at EU-25 scale masks decreasing trends in some regions, offset by increasing trends elsewhere. In the recent 4 years, the new Eastern EU-25 member states have experienced an increase in emissions, reversing after a decade-long decreasing trend. Mediterranean and Nordic countries have also experienced a strong acceleration in emissions. In Germany, France and United Kingdom, the stability of emissions is due to the decrease in the industry sector, offset by an increase in the transportation sector. When four different inventories models are compared, we show that the between-models uncertainty is as large as 19% of the mean for EU-25, and even bigger for individual countries. Accurate accounting for fossil CO₂ emissions depends on a clear understanding of system boundaries, i.e. emitting activities included in the accounting. We found that the largest source of errors between inventories is the use of distinct systems boundaries (e.g. counting or not bunker fuels, cement manufacturing, nonenergy products). Once these inconsistencies are corrected, the between-models uncertainty can be reduced down to 7% at EU-25 scale. The uncertainty of emissions at smaller spatial scales than the country scale was analyzed by comparing two emission maps based upon distinct economic and demographic activities. A number of spatial and temporal biases have been found among the two maps, indicating a significant increase in uncertainties when increasing the resolution at scales finer than ≈200 km. At 100 km resolution, for example, the uncertainty of regional emissions is estimated to be 60 g C m−2 yr−1, up to 50% of the mean. The uncertainty on regional fossil-fuel CO₂ fluxes to the atmosphere could be reduced by making accurate ¹⁴C measurements in atmospheric CO₂, and by combining them with transport models

A synthesis of carbon dioxide emissions from fossil-fuel combustion

“…Marland et al (1999) pursued a systematic comparison of the CDIAC and EDGAR data sets and Marland et al (2007) reported a systematic comparison of estimates from CDIAC, EIA, and UNFCCC for the three countries of North America. Macknick (2009) has recently attempted a systematic comparison of four emissions data sets, and Ciais et al (2010) have done a similar comparison for the countries of the European Union. A conclusion from these comparisons is that despite apparent similarity, there are differences in assumptions and boundary conditions that make it difficult to do quick quantitative comparisons.…”

“…Ciais et al (2010) compared two different emission maps over Europe. An increasing difference between the two products was obtained down to finer spatial and temporal scales, with root mean square error between the maps increasing to 40 g C m −2 d −1 at 50 km resolution, and being higher in winter than in summer.…”

“…In another data comparison exercise, four FFCO2 distributions [CDIAC, Marland et al (2006) Ciais et al (2010) for European countries. Gross comparison of country totals showed a range on the order of 19 % around their mean.…”

Analysis of the potential of near-ground measurements of CO<sub>2</sub> and CH<sub>4</sub> in London, UK, for the monitoring of city-scale emissions using an atmospheric transport model

“…These inventories are based upon activity data and corresponding emission factors and uncertainties can be substantial, particularly at the city scale. Ciais et al (2010a) showed uncertainties of 19 % of the mean emissions at country scale in the 25 EU member states and up to 60 % at scales less than 200 km. Currently there is no legal obligation for individual cities to report their emissions; however, as environmental awareness increases and actions are taken to reduce urban GHG emissions, monitoring of city emissions to evaluate the success of emissions reduction schemes becomes an important consideration.…”

A new evaluation of the uncertainty associated with CDIAC estimates of fossil fuel carbon dioxide emission

“…There have been many efforts to compare various FFCO 2 estimates (e.g. Marland et al, 2007;Macknick, 2009;Afsah and Aller, 2010;Ciais et al, 2010;Andres et al, 2012), but the task is not trivial. Francey et al (2013) suggest large underreporting, and hence uncertainty, in the global total of FFCO 2 emissions around years 1995Á2005 based on atmospheric measurements.…”