In November 2021, the Global Carbon Project published its Global Carbon Budget 2021 which concluded:

  • The global average concentration of CO2 in the atmosphere increased from about 277 parts per million (ppm) in 1750 to 414 ppm in 2020 (up 49%)
  • In 2020, global CO2 emissions from fossil fuels were 34.8 GtCO2, a decrease of 5.4% from 36.7 GtCO2 in 2019.
  • For 2021, global CO2 emissions from fossil fuels are projected to grow 4.9% to 36.4 GtCO2, a level which is about 0.8% below the 2019 level. (The 2021 growth of 1.6 GtCO2 is similar to the growth observed in 2010 following the global financial crisis of 2008-2009: 1.7 GtCO2 or 5.5% above 2009 levels.)

Global fossil CO2 emissions in 2021 are set to rebound close to their pre-COVID levels after an unprecedented drop in 2020. Emissions from coal and gas use are set to grow more in 2021 than they fell in 2020, but emissions from oil use remain below 2019 levels.

The record decrease in 2020 emissions was 1.9 billion tonnes of CO2 (GtCO2) [-5.4%], from 36.7 GtCO2 in 2019 to 34.8 GtCO2 in 2020. Emissions are projected to grow 4.9% (4.1% to 5.7%) in 2021, to 36.4 GtCO2. Global emissions in 2021 remain about 0.8% below their level in 2019. The 2021 growth of 1.6 GtCO2 is similar to the growth observed in 2010 following the global financial crisis of 2008-2009 (1.7 GtCO2; 5.5% above 2009 levels).


Annual global CO2 emissions


Annual Global CO2 Emissions
(2011 - 2021)*

2021 Global Carbon Budget (November 2021)

1 Gigatonne (Gt) = 1 billion tonnes


Fuel* (Gt)

Land Use
Change (Gt)

Total* (Gt)
2021  36.4*    
2020 34.8 3.2 38.0
2019 36.7 3.8 40.5
2018 36.6 3.9 40.5
2017 35.9 3.7 39.6
2016 35.5 3.7 39.2
2015 35.5 4.8 40.3
2014 35.5 4.6 40.1
2013 35.3
4.3 39.6
2012 35.0 4.7 39.7
2011 34.5 4.8 39.3

Source data from Global Carbon Project 2021 (via ICOS):
data supplement + global data (.xlsx) + national emissions (.xlsx)

*NOTES: (1) Values for GtCO2 in the above table were calculated by CO2.Earth by multiplying carbon emissions in the linked Excel data file by 3.664, and by adding emissions from fossil fuels and land-use change to determine total emissions

(2) Fossil fuel emissions exclude sinks from cement carbonation

(3) Global fossil fuel emissions for 2021 are projected


Global carbon budget 2021

The data below summarize all human-caused sources of CO2 emissions and global sinks (where the CO2 goes).  Numbers present the yearly average for one decade (2011 to 2020).  Data were published November 5, 2021, in Global Carbon Budget 2021 by the Global Carbon Project.

Global CO2 emissions from human activity

Most human-caused emissions of CO2 into the atmosphere are from burning fossil fuels that had long been stored in the crust of the Earth.   A small part of the fossil fuel total is from new cement usage. 

image: fossil fuel emissions from stack


34.8 GtCO2/yr


Fossil fuel emissions

image: cleared patch of land 


4.1 GtCO2/yr


Emissions from land use change

(mostly deforestation)


Where the CO2 emissions go

From 2011 to 2020, about 55% of global emissions were absorbed by the terrestrial biosphere and oceans.  The remainder were added to the CO2 which is accumulating in the atmosphere.  This accumulation has been observed as continued increases in CO2 concentrations in the atmosphere.

image: blue sky with light clouds


18.6 GtCO2/yr


image: forest floor


11.2 GtCO2/yr

Vegetegation & Soils

(terrestrial biosphere)

image: ocean surface


10.2 GtCO2/yr


(terrestrial biosphere)


Balancing the Budget

The global carbon budget numbers above are the best available scientific determinations at the time they were reported.  Scientists also report an imbalance of 3% (-1.0 GtCO2/yr) between the estimates for global sources and sinks.  See the data description paper, Global Carbon Budget 2021, by Friedlingstein et al for information about the data reporting methods and uncertainties. 

image: fossil fuel emissions from stack


-1.0 GtCO2/yr


(all sinks vs. all sources)



About the Global Carbon Project

The Global Carbon Project and its partners provide annual scientific assessments of CO2 emissions from human activities and their redistribution in the atmosphere, ocean and terrestrial biosphere in a changing climate. The assessments support the understanding of the global carbon cycle, development of responses to the climate crisis and project climate changes ahead.

Assessments and data from the GCP quantify the five major components of the global carbon budget: fossil CO2 emissions (including cement production); land-use change (mainly deforestation); ocean sinks, terrestrial sinks and atmospheric accumulation.  These assessments also provide the best-available quantification of the imbalance between global emissions from human sources and changes in the atmosphere, ocean, and terrestrial biosphere.





Quick Links


Global Carbon Project (Nov 2021) Global carbon budget 2021

Carbon Brief (Nov 2021) Global CO2 emissions have been flat for a decade, new data reveals

IEA (Mar 2021) Global energy review: CO2 emissions in 2020

Carbon Monitor Latest CO2 emissions variation (updated monthly)

Climate Action Tracker (Oct 2021) Press release: Progress lags to limit emissions to 1.5 C but rapid change is possible

Climate Action Tracker (Oct 2021) State of climate action 2021 (report)

CO2 in Context (2020) Foley: 3 most important climate graphs [web]

GCP  2015 global carbon budget highlights (compact)

CDIAC  Data for Global Carbon Project (all years) [2015 .xlxs]

CDIAC  DATA: Global CO2 emissions 1751-2011 [files] [more]

ESSD  Related articles & links

ESSD  Le Quéré et al. | Global Carbon Budget 2015 [.pdf]


ICOS web Links to all annual publications of the Global Carbon Project  


UNEP Emissions Gap Reports


"The Emissions Gap Report 2021 shows that new national climate pledges combined with other mitigation measures put the world on track for a global temperature rise of 2.7°C by the end of the century. That is well above the goals of the Paris climate agreement and would lead to catastrophic changes in the Earth’s climate. To keep global warming below 1.5°C this century, the aspirational goal of the Paris Agreement, the world needs to halve annual greenhouse gas emissions in the next eight years."  

--UNEP Emissions Gap Report 2021 (web: Oct 26 2021)


"Latest UNEP Emissions Gap Report finds new and updated Nationally Determined Contributions only take 7.5% off predicted 2030 emissions, while 55% is needed to meet the 1.5°C Paris goal."

--UNEP Press Release (web: Oct 26 2021)


UNEP web  2021 Emissions gap report

UNEP pdf  Download full report: 2021 Emissions gap report

UNEP web  Press Release (Oct 2021) Updated climate committments ahead of COP26 fall far short...


About UNEP

The UN Environmental Programme (UNEP) sets the environmental agenda for sustainable development within the United Nations system and serves as an authoritative advocate for the global environment.

UNEP works with 193 members states, representatives of civil society and other major groups and stakeholders. UNEP headquarters are in Nairobi, Kenya.

More about UNEP


Net Zero Tracker

The Net Zero Tracker (NZT) collects data on net zero targets and pledges by nations, states and regions, cities and companies. It reports on factors which indicate the integrity and seriousness of entities to cut net emissions to zero. The Net Zero Tracker is operated by the Energy & Climate Unit (UK) and partners. 

NZT web Home Page
ECIU web 2021 Scorecard (Net zero emissions race 2021) Scorecard


NZT web  interactive map Analysis by country (click a country on the map, then FIND OUT MORE)
NZT web  Canada - Analysis of pledges (example of one country)
NZT xlsx  Data by country
NZT web  G20 countries - Net zero stocktake

Companies  2000 largest publicly-traded companies

NZT web  Companies table
NZT xlsx  Companeis data 
NZT web  Walmart - Analysis of emissions target (example of one company)


UNEP pdf from Emissions Gap Report 2021 Zeroing in on net zero