Abstract
This synthesis discusses the emissions of carbon dioxide from fossil-fuel combustion
and cement production. While much is known about these emissions, there is still much
that is unknown about the details surrounding these emissions. This synthesis explores
5 our knowledge of these emissions in terms of why there is concern about them; how
they are calculated; the major global efforts on inventorying them; their global, regional,
and national totals at different spatial and temporal scales; how they are distributed on
global grids (i.e. maps); how they are transported in models; and the uncertainties
associated with these different aspects of the emissions. The magnitude of emissions
10 from the combustion of fossil fuels has been almost continuously increasing with time
since fossil fuels were first used by humans. Despite events in some nations specifically
designed to reduce emissions, or which have had emissions reduction as a byproduct
of other events, global total emissions continue their general increase with time. Global
total fossil-fuel carbon dioxide emissions are known to within 10% uncertainty (95%
15 confidence interval). Uncertainty on individual national total fossil-fuel carbon dioxide
emissions range from a few percent to more than 50 %. The information discussed
in this manuscript synthesizes global, regional and national fossil-fuel carbon dioxide
emissions, their distributions, their transport, and the associated uncertainties.