This description provides an overview of the total CO2 emissions in 2019, which was 36.2 billion metric tons. This figure represents an increase from the previous year and is indicative of the growing need to reduce emissions in order to mitigate the effects of climate change.
Greenhouse gas emissions from human activities intensify the greenhouse effect which contributes to climate change. Carbon dioxide from burning fossil fuels is the main cause of climate change. The largest annual emissions are from China followed by the United States, which has higher emissions per capita. The main producers fueling the emissions globally are large oil and gas companies. Emissions from human activities have increased atmospheric carbon dioxide by about 50% over pre-industrial levels. The growing levels of emissions have varied, but have been consistent among all greenhouse gases. Over 60 billion tons were emitted in 2025, higher than any year before. Total cumulative emissions from 1870 to 2022 were 703 GtC, of which 484±20 GtC from fossil fuels and industry, and 219±60 GtC from land use change. Land-use change, such as deforestation, caused about 31% of cumulative emissions over 1870–2022, coal 32%, oil 24%, and gas 10%.