Source: Brian Wang
The Global Carbon Project reported that world CO2 emissions reached 37 billion tons per year in 2019. This was an increase from the 36.6 billion tons emission estimate for 2018. This was a 0.6% increase from 2018. There was 2.1 percent growth in 2018 and 1.5 percent growth in 2017.
The United States decreased emissions by 1.7% with reduced coal use and increased use of natural gas.
Net CO2 emissions from deforestation and other land-use change were 5.5±2.7 GtCO2 on average during 2009-2018, accounting for about 14% of all emissions from human activity (fossil fuel, industry, land-use change – aka less trees or more deserts).
Together, land-use change, fossil fuel and industry emissions, reached 42.1±2.8 GtCO2 in 2018. The 2019 projections is for a total CO2 emissions of 43.1 GtCO2 (39.9 to 46.2).
The cumulative carbon emissions are the sum of the total CO2 emitted during a given period of time. Total cumulative emissions from 1850 to 2019 were 1649 GtCO2 from fossil fuels and industry, and 751 GtCO2 from land use change. The total of 2,400±238 GtC of emissions was partitioned among the atmosphere 953±18 GtCO2, ocean 586±73 GtCO2, and the land 733±147 GtCO2.
Methane (CH4) is the second most important long-lived greenhouse gas and contributes about 17% of radiative forcing. Approximately 40% of methane is emitted into the atmosphere by natural sources (e.g., wetlands and termites), and about 60% comes from human activities like cattle breeding, rice agriculture, fossil fuel exploitation, landfills and biomass burning.
Atmospheric methane reached a new high of about 1869 parts per billion (ppb) in 2018 and is now 259% of the pre-industrial level.
Nitrous oxide (N2O) is emitted into the atmosphere from both natural (about 60%) and anthropogenic sources (approximately 40%), including oceans, soil, biomass burning, fertilizer use, and various industrial processes.
Nitrous oxide also plays an important role in the destruction of the stratospheric ozone layer which protects us from the harmful ultraviolet rays of the sun. It accounts for about 6% of radiative forcing by long-lived greenhouse gases.