Trends in global CO2 and total greenhouse gas emissions: 2017 report

Non-CO₂ greenhouse gas emissions the main cause of increase in global greenhouse gas emissions

The increase in greenhouse gas emissions, in 2016, was mainly due to the rise in non-CO₂ emission levels, such as methane and nitrous oxide, which was estimated at around 1%. With a share of about 28%, non-CO₂ emissions are a significant source of global greenhouse gas emissions. Of those, methane, which constitutes about two-thirds of these emissions, is by far the largest category. Its main sources are fossil-fuel production (25%), cattle (23%) and rice production (10%).

Global CO₂ emissions depend on changes in the global fuel mix

Global CO₂ emission levels remained essentially flat in 2015 and 2016. The recent slowdown in the growth in CO₂ has mainly been the result of lower coal consumption in China, from fuel switches to natural gas for power generation, notably in the United States, and increased renewable power generation.

Emissions in largest countries have stabilised or decreased, with India showing a major increase

The five largest emitting countries (China, United States, Russia, India and Japan) plus the European Union, together accounting for half of the global population, account for about 63% of total global greenhouse gas emissions. India’s greenhouse gas emissions in 2016 showed a significantly rising trend (+4.7%). Russia and the United States showed a decreasing trend (both -2.0%) as did Japan (-1.3%), whereas China, the European Union and the group of other G20 members stayed virtually at the same level as that of 2015.

Uncertainty in non-CO₂ greenhouse gas emissions much larger than for CO₂ emissions

A comparison between emissions of CH₄, N₂O and F-gases reported by EDGAR and those reported in national reports, in certain cases, showed substantial differences, due to different and more detailed data used by the countries to estimate these emissions. In most cases, however, these differences are within the often large uncertainties estimated for these emissions (30% to 50% for CH₄ and N₂O; 100% or more for F-gases).