The global production of cement has grown very rapidly in recent years, and after fossil fuels and land-use change, it is the third-largest source of anthropogenic emissions of carbon dioxide. The ...required data for estimating emissions from global cement production are poor, and it has been recognised that some global estimates are significantly inflated. Here we assemble a large variety of available datasets and prioritise official data and emission factors, including estimates submitted to the UNFCCC plus new estimates for China and India, to present a new analysis of global process emissions from cement production. We show that global process emissions in 2016 were 1.45±0.20 GtCO2, equivalent to about 4 % of emissions from fossil fuels. Cumulative emissions from 1928 to 2016 were 39.3±2.4 GtCO2, 66 % of which have occurred since 1990. Emissions in 2015 were 30 % lower than those recently reported by the Global Carbon Project. The data associated with this article can be found at10.5281/zenodo.831455.
Global production of cement has grown very rapidly in recent years, and, after fossil fuels and land-use change, it is the third-largest source of anthropogenic emissions of carbon dioxide. The ...availability of the required data for estimating emissions from global cement production is poor, and it has been recognised that some global estimates are significantly inflated. This article assembles a large variety of available datasets, prioritising official data and emission factors, including estimates submitted to the UN Framework Convention on Climate Change (UNFCCC), plus new estimates for China and India, to present a new analysis of global process emissions from cement production. Global process emissions in 2018 were 1.50±0.12 Gt CO2, equivalent to about 4 % of emissions from fossil fuels. Cumulative emissions from 1928 to 2018 were 38.3±2.4 Gt CO2, 71 % of which have occurred since 1990. The data associated with this article can be found at https://doi.org/10.5281/zenodo.831454 (Andrew, 2019).
Global production of cement has grown very rapidly in recent years, and after fossil fuels and land-use change, it is the third-largest source of anthropogenic emissions of carbon dioxide. The ...availability of the required data for estimating emissions from global cement production is poor, and it has been recognised that some global estimates are significantly inflated. Here we assemble a large variety of available datasets, prioritising official data and emission factors, including estimates submitted to the UNFCCC plus new estimates for China and India, to present a new analysis of global process emissions from cement production. We show that global process emissions in 2017 were 1.48±0.20 Gt CO2, equivalent to about 4 % of emissions from fossil fuels. Cumulative emissions from 1928 to 2017 were 36.9±2.3 Gt CO2, 70 % of which have occurred since 1990. Emissions in 2016 were 28 % lower than those recently reported by the Global Carbon Project. The data associated with this article can be found at https://doi.org/10.5281/zenodo.831454.
Since the first estimate of global CO2 emissions was
published in 1894, important progress has been made in the development of
estimation methods while the number of available datasets has grown. The
...existence of parallel efforts should lead to improved accuracy and
understanding of emissions estimates, but there remains significant
deviation between estimates and relatively poor understanding of the reasons
for this. Here I describe the most important global emissions datasets
available today and – by way of global, large-emitter, and case examples – quantitatively compare their estimates, exploring the reasons for
differences. In many cases differences in emissions come down to differences
in system boundaries: which emissions sources are included and which are
omitted. With minimal work in harmonising these system boundaries across
datasets, the range of estimates of global emissions drops to 5 %, and
further work on harmonisation would likely result in an even lower range,
without changing the data. Some potential errors were found, and some
discrepancies remain unexplained, but it is shown to be inappropriate to
conclude that uncertainty in emissions is high simply because estimates
exhibit a wide range. While “true” emissions cannot be known, by comparing
different datasets methodically, differences that result from system
boundaries and allocation approaches can be highlighted and set aside to
enable identification of true differences, and potential errors. This must
be an important way forward in improving global datasets of CO2
emissions. Data used to generate Figs. 3–18 are available at
https://doi.org/10.5281/zenodo.3687042 (Andrew, 2020).
Policy makers have called for a 'fair and ambitious' global climate agreement. Scientific constraints, such as the allowable carbon emissions to avoid exceeding a 2 °C global warming limit with 66% ...probability, can help define ambitious approaches to climate targets. However, fairly sharing the mitigation challenge to meet a global target involves human values rather than just scientific facts. We develop a framework based on cumulative emissions of carbon dioxide to compare the consistency of countries' current emission pledges to the ambition of keeping global temperatures below 2 °C, and, further, compare two alternative methods of sharing the remaining emission allowance. We focus on the recent pledges and other official statements of the EU, USA, and China. The EU and US pledges are close to a 2 °C level of ambition only if the remaining emission allowance is distributed based on current emission shares, which is unlikely to be viewed as 'fair and ambitious' by others who presently emit less. China's stated emissions target also differs from measures of global fairness, owing to emissions that continue to grow into the 2020s. We find that, combined, the EU, US, and Chinese pledges leave little room for other countries to emit CO2 if a 2 °C limit is the objective, essentially requiring all other countries to move towards per capita emissions 7 to 14 times lower than the EU, USA, or China by 2030. We argue that a fair and ambitious agreement for a 2 °C limit that would be globally inclusive and effective in the long term will require stronger mitigation than the goals currently proposed. Given such necessary and unprecedented mitigation and the current lack of availability of some key technologies, we suggest a new diplomatic effort directed at ensuring that the necessary technologies become available in the near future.
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