J. E. Campillo. M.D. pHD
Retired Professor. University of Extremadura. Spain.
Los datos utilizados proceden de The Earth System Research Laboratories (US).
Global confinement, which was established to control the COVID 19 epidemic, began in China in January 2020 and spread to other countries in the following months. This caused a drastic reduction in land, sea, and air transport and a halt to industrial activity that minimized the consumption of fossil fuels worldwide. During the month of April, with more than four billion people living under some degree of confinement, the greatest reduction in demand for fossil fuels occurred.
One of the consequences of this situation was the rapid decrease in air pollution in urban areas of the main cities in the world. For example, studies carried out on changes in air pollution in Spain showed that a reduction in NO2 concentrations in Barcelona and Madrid of 50 and 62%, respectively, was measured at the end of March (less than a month of confinement). Low air pollution around the world allowed Mount Everest to be seen with the naked eye from more than 200 kilometers away.
However, until now, there are no published data regarding the impact of such a reduction in fossil fuel consumption on atmospheric CO2 levels; one of the most significant gases regarding the greenhouse effect and global climate change. We have used in this study the data provided by public archives by The Mauna Loa CO2 monthly mean data. (Earth System Research Laboratories, U.S.). This center has been measuring atmospheric CO2 levels for decades at the summit of the Mauna Loa volcano in Hawaii. And the values it provides are considered one of the international standards for atmospheric CO2 levels.
Figure 1 shows the monthly mean values of atmospheric CO2 (ppm) measured during the months of January to July during the years 2018, 2019 and 2020. As has been observed for decades, atmospheric CO2 levels have been increasing steadily over time. In the years studied, these values range from 407.96 in January 2018 to 413.82 in July 2020. Given that the highest degree of confinement occurred in April, when more than four billion people were confined and fossil fuel consumption reached its lowest level, it is surprising the high value of atmospheric CO2 recorded in May 2020 (417.07), the highest since measurements began in the 1950s.
In each of the years studied, an increase in CO2 levels is observed from January to May, followed by a drop during June and July. This pattern is common to the three years studied. The average percentage increase in CO2 levels measured from January to May was similar for each year: CO2 levels rose from January to May by 0.80% in 2018, 0.92% in 2019 and 0.89 % in 2020. However, when considering the average percentage increase in CO2 between the different years, a slight reduction is observed in the increase in CO2 from 2019 to 2020 (0.61%) compared to the increase registered from 2018 to 2019 ( 0.74%).
These preliminary data show that the reduction of fossil fuel consumption worldwide during the confinement by COVID19 has had only a slight impact on atmospheric CO2 levels. The interpretation of these data is complex since many factors may be involved. CO2 is produced from various sources. Some are natural, such as the CO2 emission that any living being makes through respiration, others are geological, such as the degradation of calcareous rocks, and others are artificial (anthropogenic). In any case, the CO2 accumulates continuously, as has been observed since it is measured. Although confinement has slowed anthropogenic emissions, it may not have been sufficient to detect it in Mauna Loa, in the middle of the Pacific Ocean. Furthermore, the amount of atmospheric CO2 fluctuates depending on numerous factors, including meteorological factors, such as the effect of El Niño in the Pacific Ocean.
References
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Evans S. Daily global CO2 emissions https://www.carbonbrief.org/daily-global-co2-emissions-cut-to-2006-levels-during-height-of-coronavirus-crisiscut to 2006 levels’ during height of coronavirus crisis.
He G., Pan Y. and Tanaka T. The short-term impacts of COVID-19 lockdown on urban air pollution in China. Nat Sustain (2020). https://doi.org/10.1038/s41893-020-0581-y
Baldasano J.M. COVID-19 lockdown effects on air quality by NO2 in the cities of Barcelona and Madrid (Spain). https://www.researchgate.net/journal/0048-9697_Science_of_The_Total_Environment
F. Atmospheric Co2 levels rise sharply despite COVID-19 lockdowns. Atmospheric CO2 levels rise sharply despite Covid-19 lockdowns. https://www.theguardian.com/environment/2020/jun/04/
Tans P. Mauna Loa CO2 monthly mean data. Earth System Research Laboratories. (https://www.esrl.noaa.gov/ Global Monitoring Laboratory.
Campillo J.E. Homo climáticus. Editorial Crítica, 2018.
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