Regional spatial inventories (cadastres) of GHG emissions in the Energy sector: Accounting for uncertainty

An improvement of methods for the inventory of greenhouse gas (GHG) emissions is necessary to ensure effective control of commitments to emission reduction. The national inventory reports play an important role, but do not reflect specifics of regional processes of GHG emission and absorption for large-area countries. In this article, a GIS approach for the spatial inventory of GHG emissions in the energy sector, based on IPCC guidelines, official statistics on fuel consumption, and digital maps of the region under investigation, is presented. We include mathematical background for the spatial emission inventory of point, line and area sources, caused by fossil-fuel use for power and heat production, the residential sector, industrial and agricultural sectors, and transport. Methods for the spatial estimation of emissions from stationary and mobile sources, taking into account the specifics of fuel used and technological processes, are described. Using the developed GIS technology, the territorial distribution of GHG emissions, at the level of elementary grid cells 2 km?×?2 km for the territory of Western Ukraine, is obtained. Results of the spatial analysis are presented in the form of a geo-referenced database of emissions, and visualized as layers of digital maps. Uncertainty of inventory results is calculated using the Monte Carlo approach, and the sensitivity analysis results are described. The results achieved demonstrated that the relative uncertainties of emission estimates, for CO₂ and for total emissions (in CO₂ equivalent), depend largely on uncertainty in the statistical data and on uncertainty in fuels’ calorific values. The uncertainty of total emissions stays almost constant with the change of uncertainty of N₂O emission coefficients, and correlates strongly with an improvement in knowledge about CH₄ emission processes. The presented approach provides an opportunity to create a spatial cadastre of emissions, and to use this additional knowledge for the analysis and reduction of uncertainty. It enables us to identify territories with the highest emissions, and estimate an influence of uncertainty of the large emission sources on the uncertainty of total emissions. Ascribing emissions to the places where they actually occur helps to improve the inventory process and to reduce the overall uncertainty.     

The geography of global urban greenhouse gas emissions: an exploratory analysis

The purpose of this paper is to describe global urban greenhouse gas emissions by region and sector, examine the distribution of emissions through the urban-to-rural gradient, and identify covariates of emission levels for our baseline year, 2000. We use multiple existing spatial databases to identify urban extent, greenhouse gas emissions (CO₂, N₂O, CH₄ and SF₆) and covariates of emissions in a “top-down” analysis. The results indicate that urban activities are significant sources of total greenhouse gas emissions (36.8 and 48.6 % of total). The urban energy sector accounts for between 41.5 and 66.3 % of total energy emissions. Significant differences exist in the urban share of greenhouse gas emissions between developed and developing countries as well as among source sectors for geographic regions. The 50 largest urban emitting areas account for 38.8 % of all urban greenhouse gas emissions. We find that greenhouse gas emissions are significantly associated with population size, density, growth rates, and per capita income. Finally, comparison of our results to “bottom-up” estimates suggest that this research’s data and techniques are best used at the regional and global scales.     

Influence of soil C, N2O and fuel use on GHG mitigation with no-till adoption

Previous research has demonstrated that soil carbon sequestration through adoption of conservation tillage can be economically profitable depending on the value of a carbon offset in a greenhouse gas (GHG) emissions market. However adoption of conservation tillage also influences two other potentially important factors, changes in soil N₂O emissions and CO₂ emissions attributed to changes in fuel use. In this article we evaluate the supply of GHG offsets associated with conservation tillage adoption for corn-soy-hay and wheat-pasture systems of the central United States, taking into account not only the amount of carbon sequestration but also the changes in soil N₂O emission and CO₂ emissions from fuel use in tillage operations. The changes in N₂O emissions are derived from a meta-analysis of published studies, and changes in fuel use are based on USDA data. These are used to estimate changes in global warming potential (GWP) associated with adoption of no-till practices, and the changes in GWP are then used in an economic analysis of the potential supply of GHG offsets from the region. Simulation results demonstrate that taking N₂O emissions into account could result in substantial underestimation of the potential for GHG mitigation in the central U.S. wheat pasture systems, and large over-estimation in the corn-soy-hay systems. Fuel use also has quantitatively important effects, although generally smaller than N₂O. These findings suggest that it is important to incorporate these two effects in estimates of GHG offset potential from agricultural lands, as well as in the design of GHG offset contracts for more complete accounting of the effect that no-till adoption will have on greenhouse gas emissions.     

Biofuels and carbon management

Public policy supports biofuels for their benefits to agricultural economies, energy security and the environment. The environmental rationale is premised on greenhouse gas (GHG, “carbon”) emissions reduction, which is a matter of contention. This issue is challenging to resolve because of critical but difficult-to-verify assumptions in lifecycle analysis (LCA), limits of available data and disputes about system boundaries. Although LCA has been the presumptive basis of climate policy for fuels, careful consideration indicates that it is inappropriate for defining regulations. This paper proposes a method using annual basis carbon (ABC) accounting to track the stocks and flows of carbon and other relevant GHGs throughout fuel supply chains. Such an approach makes fuel and feedstock production facilities the focus of accounting while treating the CO₂ emissions from fuel end-use at face value regardless of the origin of the fuel carbon (bio- or fossil). Integrated into cap-and-trade policy and including provisions for mitigating indirect land-use change impacts, also evaluated on an annual basis, an ABC approach would provide a sound carbon management framework for the transportation fuels sector.     

Emissions of Nitrous Oxide and Methane from Conventional and Alternative Fuel Motor Vehicles

This paper provides estimates of emissions of two important but often not well-characterized greenhouse gas (GHG) emissions related to transportation energy use: methane (CH₄) and nitrous oxide (N₂O). The paper focuses on emissions of CH₄ and N₂O from motor vehicles because unlike emissions of CO₂, which are relatively easy to estimate, emissions of CH₄ and N₂O are a function of many complex aspects of combustion dynamics and of the type of emission control systems used. They therefore cannot be derived easily and instead must be determined through the use of published emission factors for each combination of fuel, end-use technology, combustion conditions, and emission control system. Furthermore, emissions of CH₄ and N₂O may be particularly important with regard to the relative CO₂-equivalent GHG emissions of the use of alternative transportation fuels, in comparison with the use of conventional fuels. By analyzing a database of emission estimates, we develop emission factors for N₂O and CH₄ from conventional vehicles, in order to supplement recent EPA and IPCC estimates, and we estimate relative emissions of N₂O and CH₄ from different alternative fuel passenger cars, light-duty trucks, and heavy-duty vehicles.     

Estimates of CO2 from wood fuel based on forest harvest data

Wood continues to be a major fuel source for vast numbers of the world's people. Even in the highly industrialized countries, use of wood and wood wastes as fuel produces a small (in comparison to fossil fuels) but non-negligible amount of CO₂. Although information on the worldwide harvest and use of wood is not as complete or as reliable as fossil fuel data, this paper uses what is available and develops annual estimates of CO₂ emissions for the period 1968–1983. Woods are separated into two types, coniferous and non-coniferous, and average content and carbon amounts are estimated for each type. Wood utilization is divided into several categories, e.g., fuelwood, lumber, poles, and use of wood wastes as fuels in the lumber and paper industries is included. Results are given for major world regions. In recent years the worldwide CO₂ emissions from wood used as fuels is estimated to be about one-tenth as much as CO₂ emissions from fossil fuels. This does not include fires in the forests, either associated with forest clearing or those from natural causes.     

Historical and future anthropogenic emission pathways derived from coupled climate�Ccarbon cycle simulations

Using a coupled climate?Ccarbon cycle model, fossil fuel carbon dioxide (CO₂) emissions are derived through a reverse approach of prescribing atmospheric CO₂ concentrations according to observations and future projections, respectively. In the second half of the twentieth century, the implied fossil fuel emissions, and also the carbon uptake by land and ocean, are within the range of observational estimates. Larger discrepancies exist in the earlier period (1860?C1960), with small fossil fuel emissions and uncertain emissions from anthropogenic land cover change. In the IPCC SRES A1B scenario, the simulated fossil fuel emissions more than double until 2050 (17 GtC/year) and then decrease to 12 GtC/year by 2100. In addition to A1B, an aggressive mitigation scenario was employed, developed within the European ENSEMBLES project, that peaks at 530 ppm CO₂(equiv) around 2050 and then decreases to approach 450 ppm during the twenty-second century. Consistent with the prescribed pathway of atmospheric CO₂ in E1, the implied fossil fuel emissions increase from currently 8 GtC/year to about 10 by 2015 and decrease thereafter. In the 2050s (2090s) the emissions decrease to 3.4 (0.5) GtC/year, respectively. As in previous studies, our model simulates a positive climate?Ccarbon cycle feedback which tends to reduce the implied emissions by roughly 1 GtC/year per degree global warming. Further, our results suggest that the 450 ppm stabilization scenario may not be sufficient to fulfill the European Union climate policy goal of limiting the global temperature increase to a maximum of 2°C compared to pre-industrial levels.     

Tracing anthropogenic carbon dioxide and methane emissions to fossil fuel and cement producers, 1854–2010

This paper presents a quantitative analysis of the historic fossil fuel and cement production records of the 50 leading investor-owned, 31 state-owned, and 9 nation-state producers of oil, natural gas, coal, and cement from as early as 1854 to 2010. This analysis traces emissions totaling 914 GtCO₂e—63 % of cumulative worldwide emissions of industrial CO₂ and methane between 1751 and 2010—to the 90 “carbon major” entities based on the carbon content of marketed hydrocarbon fuels (subtracting for non-energy uses), process CO₂ from cement manufacture, CO₂ from flaring, venting, and own fuel use, and fugitive or vented methane. Cumulatively, emissions of 315 GtCO₂e have been traced to investor-owned entities, 288 GtCO₂e to state-owned enterprises, and 312 GtCO₂e to nation-states. Of these emissions, half has been emitted since 1986. The carbon major entities possess fossil fuel reserves that will, if produced and emitted, intensify anthropogenic climate change. The purpose of the analysis is to understand the historic emissions as a factual matter, and to invite consideration of their possible relevance to public policy.     

Estimates of UK CO2 emissions from aviation using air traffic data

The allocation of CO₂ emissions to specific sources is a major policy issue for international aviation, especially for determining allocations for emissions trading schemes. This paper addresses the problem by recommending a possible methodology to allocate emissions to specific sources using detailed air traffic data. The basis for the calculations is an air traffic sample for one full-day of traffic from the UK. In order to analyse aircraft fuel burn use and hence CO₂ emissions, the Reorganized Air Traffic Control Mathematical Simulator (RAMS Plus) and the Advanced Emission Model (AEM III) are used. The results from these detailed simulations are compared with two of the most widely-used aviation CO₂ emission estimates to have been made for the UK: the SERAS study and NETCEN estimate. Their estimates for the year 2000 are 26.1 and 31.4 Mt, respectively. In addition, the most recent NETCEN estimate for the year 2003 is 34.1 Mt of CO₂. Our estimate of total aviation CO₂ emissions, using detailed simulations and real air traffic data, is 34.7 Mt for the year 2004. In addition, emission estimates are compared with two global aviation emission inventories: AERO2K and SAGE. Contributions of the highest-emitting flights and aircraft types are identified. International departures dominate; 6% of flights account for 50% of total emissions. The largest aircraft emit the most per flight-km, although not per passenger-km. Different methodologies and their implications are also discussed.     

Competitiveness of terrestrial greenhouse gas offsets: are they a bridge to the future?

Activities to reduce net greenhouse gas emissions by biological soil or forest carbon sequestration predominantly utilize currently known, readily implementable technologies. Many other greenhouse gas emission reduction options require future technological development or must wait for turnover of capital stock. Carbon sequestration options in soils and forests, while ready to go now, generally have a finite life, allowing use until other strategies are developed. This paper reports on an investigation of the competitiveness of biological carbon sequestration from a dynamic and multiple strategy viewpoint. Key factors affecting the competitiveness of terrestrial mitigation options are land availability and cost effectiveness relative to other options including CO₂ capture and storage, energy efficiency improvements, fuel switching, and non-CO₂ greenhouse gas emission reductions. The analysis results show that, at lower CO₂ prices and in the near term, soil carbon and other agricultural/forestry options can be important bridges to the future, initially providing a substantial portion of attainable reductions in net greenhouse gas emissions, but with a limited role in later years. At higher CO₂ prices, afforestation and biofuels are more dominant among terrestrial options to offset greenhouse gas emissions. But in the longer run, allowing for capital stock turnover, options to reduce greenhouse gas emissions from the energy system and biofuels provide an increasing share of potential reductions in total US greenhouse gas emissions.     

Spatial GHG inventory at the regional level: accounting for uncertainty

Methodology and geo-information technology for spatial analysis of processes of greenhouse gas (GHG) emissions from mobile and stationary sources of the energy sector at the level of elementary plots are developed. The methodology, which takes into account the territorial specificity of point, line, and area sources of emissions, is based on official statistical data surveys. The spatial distribution of emissions and their structure for the main sectors of the energy sector in the territory of the Lviv region of Ukraine are analyzed. The relative uncertainties of emission estimates obtained are calculated using knowledge of the spatial location of emission sources and following the Tier 1 and Tier 2 approaches of IPCC methodologies. The sensitivity of total relative uncertainty to change of uncertainties in input data uncertainties is studied for the biggest emission point sources. A few scenarios of passing to the alternative energy generation are considered and respective structural changes in the structure of greenhouse gas emissions are analyzed. An influence of these structural changes on the total uncertainty of greenhouse gas inventory results is studied.     

Agricultural production and greenhouse gas emissions from world regions—The major trends over 40 years

Since 1970, global agricultural production has more than doubled with agriculture and land-use change now responsible for ∼1/4 of greenhouse gas emissions from human activities. Yet, while greenhouse gas (GHG) emissions per unit of agricultural product have been reduced at a global level, trends in world regions have been quantified less thoroughly. The KPI (Kaya-Porter Identity) is a novel framework for analysing trends in agricultural production and land-use change and related GHG emissions. We apply this to assess trends and differences in nine world regions over the period 1970–2007. We use a deconstructed analysis of emissions from the mix of multiple sources, and show how each is changing in terms of absolute emissions on a per area and per produced unit basis, and how the change of emissions from each source contributes to the change in total emissions over time. The doubling of global agricultural production has mainly been delivered by developing and transitional countries, and this has been mirrored by increased GHG emissions. The decoupling of emissions from production shows vast regional differences. Our estimates show that emissions per unit crop (as kg CO₂-equivalents per Giga Joule crop product), in Oceania, have been reduced by 94% from 1093 to 69; in Central & South America by 57% from 849 to 362; in sub-Saharan Africa by 27% from 421 to 309, and in Europe by 56% from 86 to 38. Emissions per unit livestock (as kg CO₂-eq. GJ⁻¹ livestock product) have reduced; in sub-Saharan Africa by 24% from 6001 to 4580; in Central & South America by 61% from 3742 to 1448; in Central & Eastern Asia by 82% from 3,205 to 591, and; in North America by 28% from 878 to 632. In general, intensive and industrialised systems show the lowest emissions per unit of agricultural production.     

Estimating greenhouse gas emissions from cattle raising in Brazil

The study estimated, for the first time, the greenhouse gas emissions associated with cattle raising in Brazil, focusing on the period from 2003 to 2008 and the three principal sources: 1) portion of deforestation resulting in pasture establishment and subsequent burning of felled vegetation; 2) pasture burning; and 3) bovine enteric fermentation. Deforestation for pasture establishment was only considered for the Amazon and Cerrado. Emissions from pasture burning and enteric fermentation were accounted for the entire country. The consolidated emissions estimate lies between approximately 813 Mt CO₂eq in 2008 (smallest value) and approximately 1,090 Mt CO₂eq in 2003 (greatest value). The total emissions associated with Amazon cattle ranching ranged from 499 to 775 Mt CO₂eq, that of the Cerrado from 229 to 231 Mt CO₂eq, and that of the rest of the country between 84 and 87 Mt CO₂eq. The full set of emissions originating from cattle raising is responsible for approximately half of all Brazilian emissions (estimated to be approximately 1,055 Mt CO₂eq in 2005), even without considering cattle related sources not explicitly estimated in this study, such as energy use for transport and refrigeration along the beef and derivatives supply chain. The potential for reduction of greenhouse gas emissions offered by the Brazilian cattle industry is very high and might constitute Brazil’s most important opportunity for emissions mitigation. The study offers a series of policy recommendations for mitigation that can be implemented by public and private administrators at a low cost relative to other greenhouse gas reduction options.     

Optimal production resource reallocation for CO2 emissions reduction in manufacturing sectors

To mitigate the effects of climate change, countries worldwide are advancing technologies to reduce greenhouse gas emissions. This paper proposes and measures optimal production resource reallocation using data envelopment analysis. This research attempts to clarify the effect of optimal production resource reallocation on CO₂ emissions reduction, focusing on regional and industrial characteristics. We use finance, energy, and CO₂ emissions data from 13 industrial sectors in 39 countries from 1995 to 2009. The resulting emissions reduction potential is 2.54 Gt-CO₂ in the year 2009, with former communist countries having the largest potential to reduce CO₂ emissions in the manufacturing sectors. In particular, basic material industry including chemical and steel sectors has a lot of potential to reduce CO₂ emissions.     

Unleakable carbon†

Unleakable carbon, or the uncombusted methane and carbon dioxide associated with fossil fuel systems, constitutes a potentially large and heretofore unrecognized factor in determining use of Earth’s remaining fossil fuel reserves. Advances in extraction technology have encouraged a shift to natural gas, but the advantage of fuel switching depends strongly on mitigating current levels of unleakable carbon, which can be substantial enough to offset any climate benefit relative to oil or coal. To illustrate the potential warming effect of methane emissions associated with utilizable portions of our remaining natural gas reserves, we use recent data published in peer-reviewed journals to roughly estimate the impact of these emissions. We demonstrate that unless unleakable carbon is curtailed, up to 59–81% of our global natural gas reserves must remain underground if we hope to limit warming to 2°C from 2010 to 2050. Successful climate change mitigation depends on improved quantification of current levels of unleakable carbon and a determination of acceptable levels of these emissions within the context of international climate change agreements.

Policy relevance

It is imperative that companies, investors, and world leaders considering capital expenditures and policies towards continued investment in natural gas fuels do so with a complete understanding of how dependent the ultimate climate benefits are upon increased regulation of unleakable carbon, the uncombusted carbon-based gases associated with fossil fuel systems, otherwise referred to as ‘fugitive’, ‘leaked’, ‘vented’, ‘flared’, or ‘unintended’ emissions. Continued focus on combustion emissions alone, or unburnable carbon, undermines the importance of assessing the full climate impacts of fossil fuels, leading many stakeholders to support near-term mitigation strategies that rely on fuel switching from coal and oil to cleaner burning natural gas. The current lack of transparent accounting of unleakable carbon represents a significant gap in the understanding of what portions of the Earth’s remaining global fossil fuel reserves can be utilized while still limiting global warming to 2°C. Successful climate change mitigation requires that stakeholders confront the issue of both unburnable and unleakable carbon when considering continued investment in and potential expansion of natural gas systems as part of a climate change solution.     

Substitution of Natural Gas for Coal: Climatic Effects of Utility Sector Emissions

Substitution of natural gas for coal is one means of reducing carbon dioxide (CO₂) emissions. However, natural gas and coal use also results in emissions of other radiatively active substances including methane (CH₄), sulfur dioxide (SO₂), a sulfate aerosolprecursor, and black carbon (BC) particles. Will switching from coal to gas reduce the net impact of fossil fuel use on global climate? Using the electric utility sector as an example, changes in emissions of CO₂, CH₄,SO₂ and BC resulting from the replacement of coal by natural gas are evaluated, and their modeled net effect on global mean-annual temperature calculated. Coal-to-gas substitution initially produces higher temperatures relative to continued coal use. This warming is due to reduced SO₂ emissionsand possible increases in CH₄ emissions, and can last from 1 to 30years, depending on the sulfur controls assumed. This is followed by a net decrease in temperature relative to continued coal use, resulting from lower emissions of CO₂ and BC. The length of this period and the extent of the warming or cooling expected from coal-to-gas substitution is found to depend on key uncertainties and characteristics of the substitutions, especially those related to: (1) SO₂ emissions and consequentsulphate aerosol forcing; and (2) the relative efficiencies of the power plantsinvolved in the switch.     

Oceanic transport and storage of carbon emissions

Using a global carbon cycle model (GLOCO) that considers seven terrestrial biomes, surface and deep ocean layers based on the HILDA model and a single mixed atmosphere, we analyzed the response of atmospheric CO₂ concentration and oceanic DIC and DOC depth profiles to additions of carbon to the atmosphere and ocean. The rate of transport of carbon to the deepest oceanic layers is rather insensitive to the atmosphereic-ocean surface gas exchange coefficient over a wide range, hence discrepancies between researchers on the precise global average value of this coefficient do not significantly affect predictions of atmospheric response to anthropogenic inputs. Upwelling velocity, on the other hand, amplifies oceanic response by increasing primary production in the upper ocean layers, resulting in a larger flux into DOC and sediments and increased carbon storage; experiments to reduce the uncertainty in this parameter would be valuable.The location of the carbon addition, whether it is released in the atmosphere or in the middle of the oceanic thermocline, has a significant impact on the maximum atmospheric CO₂ concentration (pCO₂) subsequently reached, suggesting that oceanic burial of a significant fraction of carbon emissions (e.g. via clathrate hydrides) may be an important management option for limiting pCO₂ buildup. Our analysis indicates that the effectiveness of ocean burial decreases asymptotically below about 1000 m depth. With a constant emissions scenario (at 1990 levels), pCO₂ at year 2100 is reduced from 501 ppmv considering all emissions go to the atmosphere, to 422 ppmv with ocean burial at a depth of 1000 m of 50% of the fossil fuel emissions. An alternative scenario looks at stabilizing pCO₂ at 450 ppmv; with no ocean burial of fossil fuel emissions, the rate of emissions has to be cut drastically after the year 2010, whereas oceanic burial of 2 GtC/yr allows for a smoother transition to alternative energy sources.     

Carbon dioxide capture and storage: a status report

Abstract

Fossil fuel combustion is the largest source of anthropogenic greenhouse gas (GHG) emissions. As a result of combustion, essentially all of the fuel carbon is emitted to the atmosphere as carbon dioxide (CO₂), along with small amounts of methane and, in some cases, nitrous oxide. It has been axiomatic that reducing anthropogenic GHG emissions requires reducing fossil-fuel use. However, that relationship may no longer be as highly coupled in the future. There is an emerging understanding that CO₂ capture and storage (CCS) technology offers a way of using fossil fuels while reducing CO₂ emissions by 85% or more. While CCS is not the ‘silver bullet’ that in and of itself will solve the climate change problem, it is a powerful addition to the portfolio of technologies that will be needed to address climate change. The goal of this Commentary is to describe CCS technology in simple terms: how it might be used, how it might fit into longer term mitigation strategies, and finally, the policy issues that its emergence creates. All of these topics are discussed in much greater detail in the recently published Intergovernmental Panel on Climate Change (IPCC) Special Report on Carbon Dioxide Capture and Storage (SRCCS) (IPCC, 2005).     

Contributions of individual countries?? emissions to climate change and their uncertainty

We have compiled historical greenhouse gas emissions and their uncertainties on country and sector level and assessed their contribution to cumulative emissions and to global average temperature increase in the past and for a the future emission scenario. We find that uncertainty in historical contribution estimates differs between countries due to different shares of greenhouse gases and time development of emissions. Although historical emissions in the distant past are very uncertain, their influence on countries?? or sectors?? contributions to temperature increase is relatively small in most cases, because these results are dominated by recent (high) emissions. For relative contributions to cumulative emissions and temperature rise, the uncertainty introduced by unknown historical emissions is larger than the uncertainty introduced by the use of different climate models. The choice of different parameters in the calculation of relative contributions is most relevant for countries that are different from the world average in greenhouse gas mix and timing of emissions. The choice of the indicator (cumulative GWP weighted emissions or temperature increase) is very important for a few countries (altering contributions up to a factor of 2) and could be considered small for most countries (in the order of 10%). The choice of the year, from which to start accounting for emissions (e.g. 1750 or 1990), is important for many countries, up to a factor of 2.2 and on average of around 1.3. Including or excluding land-use change and forestry or non-CO₂ gases changes relative contributions dramatically for a third of the countries (by a factor of 5 to a factor of 90). Industrialised countries started to increase CO₂ emissions from energy use much earlier. Developing countries?? emissions from land-use change and forestry as well as of CH₄ and N₂O were substantial before their emissions from energy use.     

Probability distributions for carbon emissions and atmospheric response

Probability distributions for carbon burning, atmospheric CO₂, and global average temperature are produced by time series calibration of models of utility optimization and carbon and heat balance using log-linear production functions. Population growth is used to calibrate a logistically evolving index of development that influences production efficiency. Energy production efficiency also includes a coefficient that decreases linearly with decreasing carbon intensity of energy production. This carbon intensity is a piecewise linear function of fossil carbon depletion. That function is calibrated against historical data and extrapolated by sampling a set of hypotheses about the impact on the carbon intensity of energy production of depleting fluid fossil fuel resources and increasing cumulative carbon emissions. Atmospheric carbon balance is determined by a first order differential equation with carbon use rates and cumulative carbon use as drivers. Atmospheric CO₂ is a driver in a similar heat balance. Periodic corrections are included where required to make residuals between data and model results indistinguishable from independently and identically distributed normal distributions according to statistical tests on finite Fourier power spectrum amplitudes and nearest neighbor correlations. Asymptotic approach to a sustainable non-fossil energy production is followed for a global disaggregation into a tropical/developing and temperate/more-developed region. The increase in the uncertainty of global average temperature increases nearly quadratically with the increase in the temperature from the present through the next two centuries.