Greenhouse gas emissions

The following figure taken from [L52] shows how global greenhouse gas emissions have developed in the period 1970 to 2010. Emissions of methane, N₂O and other greenhouse gases are converted to CO₂ equivalents, i.e. converted to the amount of CO₂ having the same effect as the gas in question. The term "CO₂ FOLU" means emissions of CO₂ from forestry and other land use. Emissions of CO₂ from agriculture (use of agricultural machinery, etc.) are accounted for in other sectors. The emissions in 2010 were, as the figure shows, a total of 49 gigatonnes of CO₂ equivalents. An IPCC report from 2019 [L122] shows that emissions have increased to a total of 55.3 gigatons in 2018.

The emissions lead to an increased concentration of greenhouse gases in the atmosphere. How the atmospheric concentration has evolved can be seen in the pages Carbon dioxide and Methane.

Emissions are distributed across different economic sectors. The figure below (also taken from [L52]) shows how the emissions were distributed in 2010. Here, emissions from all greenhouse gases are converted to CO₂ equivalents and added together. This total is then distributed across the various sectors:

What constitutes the different sectors is further defined in [L53] (A.II.9.1 page 1302). Below is a brief overview of the sectors. I have also included some information from chapters 7 to 11 (in [L53]) which deal with each individual sector. All percentages given here are the percentage of total emissions in 2010, which was 49 gigatonnes of CO₂ equivalents (1 gigatonne = 1 000 000 000 tonnes)

Energy In 2010, energy production was the sector in the economy that emitted the largest share of greenhouse gases (about 35% of total emissions). In the figure above, these emissions are divided into electricity and heat production used by other sectors (25%), and other energy (9.6%).

Transport In 2010, 14% of total emissions were from transport. The dominant part of this, 10%, was road transport. 1.5% came from aviation and 1.3% from shipping. The rest 1.2%, was divided between railways, pipelines, etc.

Buildings In 2010, 6.4% of total emissions were from direct emissions from buildings. In addition, buildings used a significant part of the energy production from the Energy sector (corresponding to 12% of total emissions).

Industry In 2010, 21% of total emissions were related to direct emissions from industry. In addition, industry used energy production from the Energy sector corresponding to 11% of total emissions. In total this amounted to 32%, of which iron and steel production as well as cement production and other non-metallurgical production accounted for almost half of these emissions (14% of total emissions).

AFOLU This abbreviation stands for Agriculture, Forestry and Other Land Use. There is great uncertainty associated with this sector. Agriculture includes plant production, which constitutes a natural cycle of CO₂ production by respiration and plant decay, and binding of CO₂ when the plants grow. This process is excluded from the accounts for the agricultural sector. Direct emissions from the AFOLU sector account for 24% of total emissions in 2010. Indirect emissions through the use of energy amount to about 1%. These 25% were divided into the following subgroups: about 11% of total emissions were related to forestry and land use changes, emissions of CH₄ from "burping cows" (enteric fermentation) accounted for about 4.3%, the rest, about. 9.7% were from log burning, fertilisation, etc.

The US Environmental Protection Agency (EPA) also has an overview of emissions by the economy sector. This overview includes emissions by type of greenhouse gas and land area (China, USA, EU, etc.) [L1]

Latest update: 2021-07-13