Estimation of Gridded Atmospheric Oxygen Consumption from 1975 to 2018

Atmospheric Oxygen (O-2) is one of the dominating features that allow the earth to be a habitable planet with advanced civilization and diverse biology. However, since the late 1980s, observational data have indicated a steady decline in O(2)content on the scale of parts-per-million level. The current scientific consensus is that the decline is caused by the fossil-fuel combustion; however, few works have been done to quantitatively evaluate the response of O(2)cycle under the anthropogenic impact, at both the global and regional scales. This paper manages to quantify the land O(2)flux and makes the initial step to quantificationally describe the anthropogenic impacts on the global O(2)budget. Our estimation reveals that the global O(2)consumption has experienced an increase from 33.69 +/- 1.11 to 47.63 +/- 0.80 Gt (gigaton, 10(9)t) O(2)yr(-1)between 2000 and 2018, while the land production of O-2(totaling 11.34 +/- 13.48 Gt O(2)yr(-1)averaged over the same period) increased only slightly. In 2018, the combustion of fossil-fuel and industrial activities (38.45 +/- 0.61 Gt O(2)yr(-1)) contributed the most to consumption, followed by wildfires (4.97 +/- 0.48 Gt O(2)yr(-1)) as well as livestock and human respiration processes (2.48 +/- 0.16 and 1.73 +/- 0.13 Gt O(2)yr(-1), respectively). Burning of fossil-fuel that causes large O(2)fluxes occurs in East Asia, India, North America, and Europe, while wildfires that cause large fluxes in comparable magnitude are mainly distributed in central Africa.