Impact of COVID ‐ 19 on fossil energies and its consequence in climate change , and nine other environmental indicators

Impact of COVID‐19 on fossil energies and its consequence in climate change, and nine other environmental indicators  A. Rashedi a,b,*, Taslima Khanam a, R. Saidur c,d a College of Engineering, IT & Environment, Charles Darwin University, Ellengowan Drive, Casuarina, Northern Territory 0810, Australia b Faculty of Business, Economics & Law, The University of Queensland, St Lucia Queensland 4067, Australia c Research Center for Nano‐Materials and Energy Technology (RCNMET), School of Science and Technology, Sunway University, Bandar Sunway, Petaling Jaya, 47500, Selangor Darul Ehsan, Malaysia d Department of Engineering, Lancaster University, Lancaster, LA1 4YW, UK  *Correspondence to: mabrur.rashedi@cdu.edu.au (A. Rashedi).

In order to answer these questions, the authors identify life cycle assessment (LCA) as the most promising methodological tool due to its capability to conduct the whole life cycle based analysis of all input-output flows starting from extraction of resources from nature to all interim life cycle phases to until the final end-of-life phase 8,10,11 . However, finding the comprehensive and real-time datasets of all anthropogenic activities that have or have not been slowed, halted or ceased due to COVID-19 situation is challenging as these represent an enormous data set and, even in an ideal situation, these involve tremendously large number of assumptions, simplifications and uncertainties 2,5,11 . The authors, therefore, rely on major linchpins of modern civilizations, viz., oil, gas and coal based fossil energies; nearreal time consumption data of which are available on monthly basis in various public domains 12-14 . More importantly, the fossil based energies shape almost every sector of modern life, living and society whether it is food production, clothing, accommodation, health, transportation, or any other industrial process or service. The current civilization is, therefore, befittingly called the 'age of oil' 15,16 . This study, accordingly, evaluates the changes in global environment based on sudden change in global consumption of fossil fuels owing to COVID-19 situation.
i) this is the first LCA based study that unravels the effects of COVID-19 on global environment. Accordingly, the study evaluates the changes in global environment by 10 LCA impact categories: a) global warming, b) stratospheric ozone depletion, c) ozone formation (human health), d) fine particulate matter formation, e) smog, f) ionizing radiation, g) human carcinogenic toxicity, h) human non-carcinogenic toxicity, i) water consumption, and, j) effect on human health -changes in none of these environmental impacts owing to COVID-19 situation has been studied so far from the LCA perspective; and, ii) this is the first study that highlights how much change each major fossil fuel carries to the global environment in 2020 by aforesaid 10 LCA impact indicators. pandemic situation.

Methodology
The LCA study has been performed following the guidelines of relevant international standards, as envisaged in ISO 14040 and ISO 14044 17,18 . Accordingly, the LCA study combines four major steps, as follows: i) goal and scope definition of the LCA study, ii) defining, arranging the life cycle inventory, iii) performing life cycle impact assessment (LCIA), and iv) interpretation of LCA results. Out of these four, the first three steps are described sequentially in this section while the last step is the focus of the "Results and discussion" section.

Goal and scope definition
The change in the consumption of widely used fossil fuels as a result of the COVID-19 pandemic situation forms the basis of the study. Consumption of three major fossil fuels, such as, petroleum, natural gas and coal, has been studied in this context. As a cradle to grave study, it models the entire life cycle processes of fossil fuels, including extraction from nature to entire production, refining, transportation, distribution to operational phase in different industry sectors to end-of-life emissions, as displayed in Figure 1. Out of the fossil fuels, consumption of petroleum based products except crude oil includes their production in field, production in renewable fuels and oxygenate plants, production in refineries and blenders, imports, net receipts, adjustments in inventory, minus exports, minus refinery and blender net inputs, minus stock change 12,13 . Likewise, for natural gas, the consumption data include the following: i) use in commercial sector together with use in commercial combined-heat-and power (CHP) and commercial electricity-only plant, ii) use in industrial sector (lease and plant fuel use, industrial CHP,   industrial electricity-only plants, consumption for non-combustion use and other industrial deliveries), iii) use in transportation sector (pipelines and distribution use, and vehicle fuel use), iv) use in electric power sector (electric utility and independent power producer use) and, v) use in residential sector 12,13 . Consecutively, the consumption of coal has been based on the data from: i) coke plants, ii) electric power, iii) residential, iv) commercial, and, v) industrial sector 12-14 . The EIA reports classify the petroleum and other liquids in seven subcategories -these include: hydrocarbon gas liquid, unfinished oil, motor gasoline, jet fuel, distillate fuel oil, residual fuel oil, and other oils. Details of the seven liquids and their components have been discussed in aforesaid EIA reports 12,13 . Consumption data of all major fossil fuels in the world in the year 2019 and 2020 have been highlighted in Table 1.

Details of the methodology have been presented in Supplementary Materials
(S1-S3). Additionally, relevant consumption data of fossil fuels have been highlighted in Supplementary Tables 1-6.

Life cycle inventory and life cycle assessment process
Each of the fossil fuels has been modelled either by defining new LCI process or using equivalent LCI process out of the existing LCI databases [19][20][21]  Environmental Impacts or briefly "TRACI" is another well-renowned method which is widely used in industrial ecology, environment and sustainability studies and has been developed by US Environmental Protection Agency 23 . The present study is based on the latest updates of these LCA methods. Accordingly, the mid-point impact 'smog' has been calculated by TRACI method while 'effect on human health', an end-point impact, has been quantified by ReCiPe end-point method.
Rest of the eight mid-point based impacts have been calculated by ReCiPe mid-point method. Overall LCA modelling has been conducted in licensed SimaPro LCA software platform version 9.0.0.41 24 .

Results and discussion
The Results and discussion covers three sections where Section 3.1 highlights the results of mid-point impact indicators; Section 3.2 focuses on the results of end-point impact indicator and Section 3.3 highlights total GHG emission worldwide in 2020 incorporating the GHG contribution by fossil fuels, as found in Section 3.1, together with the remaining GHG contribution by non-fossil sources without considering any change in this sub-compartment because of COVID-19 situation.

Global warming
Global warming impact has been calculated based on the global warming potential ( Out of the three major types of coal, anthracite carries the highest global warming impact, followed by bituminous and lignite coal, respectively. About 2.44 kg carbon dioxide equivalent (kg CO 2 eq) methane is emitted to the environment based on various life cycle processes of 1 kg lignite coal. This increases to about 2.98 and 3.57 kg CO 2 eq GHGs for bituminous and anthracite coals, respectively. Due to COVID-19 situation, worldwide consumption of coal will reduce by ~32.99% which will shrink the global warming impact by coal by ~7.71 billion metric ton CO 2 eq in 2020 (see Table 1). As like coal, global warming impact by natural gas will reduce by ~3.43% in 2020. In a quantitative scale, 1 cubic meter (m 3 ) natural gas carries much lower global warming impact of ~0.621 kg CO 2 eq. Out of this, emissions of methane, carbon dioxide and dinitrogen monoxide stand at approximately (approx.) 0.419, 0.2 and 0.00117 kg CO 2 eq, respectively. Other than coal and natural gas, use of all types of petroleum and other liquids will diminish in 2020 except 'other oils'. In total, reduced use of gasoline, jet fuel, distillate fuel oil and hydrocarbon gas liquid will slash the global warming impact by approx. 104, 46.3, 36.8 and 26.5 million metric ton CO 2 eq, respectively, in 2020. Consumption of hydrocarbon gas liquid only shrinks by ~1.68% in 2020 with respect to its base consumption level in 2019; this results in a lower decline of its GHG emission in comparison to other fossil fuels under study. By contrast, use of 'other oils' will increase by ~1.51% in 2020 which will intensify the global warming impact by ~3.72 million metric ton CO 2 eq. In turn, changes in global warming impact by jet fuel will not be significant although global aviation industry has been experiencing a major shift in COVID-19 situation. This can be attributed to two factors -i) jet fuel is consumed in a very low quantity in comparison to other fuels -497 billion litre (i.e., ~8.5% of total worldwide petroleum consumption) in 2019 versus 359 billion litre (i.e., ~6.67% of total worldwide petroleum consumption) in 2020; and ii) per kg global warming potential of jet fuel is ~1.67E+11 kg CO 2 eq which is much lower in comparison to all other fossil fuels except residual fuel oil and unfinished oil.

Stratospheric ozone depletion
As like global warming, a time horizon of 100 years has been considered for 21 ozone 2020. Contrarily, due to ~1.51% increase in consumption, 'other oils' will raise the same impact by ~1.96E+03 kg CFC-11 globally in the same time.

Ozone formation (human health)
As like the above-mentioned ones, there will be drastic reduction in environmental impact by ozone formation (human health) impact category in 2020 due to COVID-19 situation.
Although no ozone is directly emitted to the atmosphere due to the life cycle processes of the fossil fuels under study, it is formed as a result of photochemical reaction of nitrogen oxides (NO x ) and non-methane volatile organic compounds (NMVOCs) and it carries intense potential to be a health hazard through infecting lungs, airways and respiratory systems; thereby causing significant respiratory issues to human being 22,29  kg NO x eq globally in 2020 due to COVID-19 situation. Majority of these reduction (~93.62%) in ozone formation (human health) occurs due to scaled-down consumption of coal in 2020.
Out of the three coals, anthracite carries the highest ozone formation (human health) impact of ~42.5% of the total, followed by bituminous and lignite coal with approx. 29.3% and 28.2% impact, respectively.

Fine particulate matter formation
Apart from tropospheric ozone formation, there are other impact contributors that lead to the pollution of atmospheric air. Fine particulate matters with a diameter of less than 2.5 micrometre (μm) or PM2.5 is a significant one in this context. PM2.5 represents a wide variety of organic and inorganic substances including primary and secondary aerosols.
Primary PM2.5 includes NO x , NH 3 , SO 2 which undergo several reactions in the atmosphere and transform into other secondary aerosols 29 . These particles lead to a wide range of respiratory symptoms followed by various health problems including increasing mortalities 22 . Due to the reduced use of fossil fuels, emission of fine particulate matters will reduce significantly in 2020, as highlighted in Figure 2

Ionizing radiation
As like most other impacts, there will be a remarkable change in ionizing radiation due to the reduced use of fossil fuels in 2020, as displayed in Figure 2 (f). The ionizing radiation potential of total 63 radionuclides that are released to air, freshwater (rivers and lakes) and marine environment have been studied in this context, for a time horizon of 100 years, to determine the total ionizing radiation of all fossil fuels 30  Other than these, the life cycle processes of per kg coal and per m 3 natural gas exude ~0.0092263 and ~0.0045 kBq Co-60 eq ionizing radiation impact, respectively. On the basis of total consumption, the topmost contributors in curtailment of ionizing radiation are coal and distillate fuel oil with ~2.37E+10 and ~2.72E+09 kBq Co-60 eq impact, respectively. This can be attributed to two factors -i) consumption of these fossil fuels diminishes remarkably in 2020 owing to COVID-19 situation, and, ii) unit process of these fuels carry high ionizing radiation potential.

Human carcinogenic and non-carcinogenic toxicity
As like most other environmental impacts, a significant reduction in both human carcinogenic toxicity and human non-carcinogenic toxicity is possible in 2020 due to the contributing fossil fuels in this impact reduction pathways are coal, natural gas and motor gasoline, sequentially, as shown in Figure 2 (g). In comparison to this, global human noncarcinogenic toxicity impact will remarkably reduce by about 1.84 billion metric ton 1,4-DCB based on this LCA study. Coal, motor gasoline and distillate fuel oil will be the leading contributors in these impact reduction pathways, as displayed in Figure 2 (h).

Water consumption
Lastly, diminishing consumption of fossil fuels induces an impressive reduction of ~24.8% in water consumption in 2020. Although a lot of life cycle processes of the fossil fuels necessitate large-scale water resources from various sources, about 90-95% of this water again returns back to nature by various pathways. Hence, consumptive water just includes 5-10% of industrial water use across various life cycle processes 32 . Based on this definition, jet fuel and coal deliver an intense reduction in water consumption of about 1.35E+10 and 2.83E+09 m 3 , respectively, in 2020. Other oil, by contrast, witnesses a 1.51% rise in consumption and associated rise in all environmental impacts including water consumption, as illustrated in Figure 2 (i). In addition, it appears from per unit based study that per litre motor gasoline exhibits the water consumption impact of ~3.38E-05 m 3 . All other fossil fuels issue higher impact than motor gasoline on per unit basis.

Results of end-point based environmental impact 'human health'
At

Global GHG emission reduction with respect to IPCC studies
As discussed in Section 3.1, reduced consumption of fossil fuels decreases the global warming impact immensely in 2020. Combining the contributions of all fossil fuels, the total global warming impact amounts to ~29.5 and ~21.5 billion metric ton CO 2 eq in 2019 and 2020, respectively -this results in total ~8 billion metric ton CO 2 eq GHG emission reduction in 2020. This is a remarkable decrease at a time when the total anthropogenic GHG emission has been in its maximum level since the record started and approximately reached ~59 billion metric ton CO 2 eq per year in 2019 combining the contribution from both fossil and non-fossil sources 33,34 . The GHG emission in 2019 was simultaneously about 13.5% higher than the GHG emission levels in 2010 (i.e., 52±5.2 billion metric ton CO 2 eq) which was the reference year of IPCC AR5 33 and was about 55.3% higher than the emission levels in 1990 (i.e., 38±3.8 billion metric ton CO 2 eq), the reference year of Kyoto protocol 34  Gross global GHG emission in 2020 Global GHG emission due to fossil fuels in 2019 Global GHG emission due to fossil fuels in 2020 (b) Figure 4: Changes in worldwide gross GHG emission due to reduced fossil fuel consumption as a result of COVID-19 situation -a) results in billion metric ton CO 2 eq; b) results in percentage Accordingly, the reduction of about 8 billion metric ton CO 2 eq or 27.2% reduction in GHG emission by fossil fuels scales down the total worldwide GHG emission from fossil and nonfossil sources to ~51 billion metric ton CO 2 eq in 2020, provided there is no change in GHG emission from non-fossil based sources or activities in this dynamic time. Additionally, this ~51 billion metric ton CO 2 eq GHG emission has not been witnessed by the current human civilization since 2010. This establishes the fact that COVID-19 unveils a significant change in global GHG emission and in associated global warming impact just based on quantifying the GHG reduction by the fossil fuels. Herein, the authors highlight three scenarios where the 'base case' scenario represents the GHG emission in 2020, as found in Section 3.1, and 'scenario I' and 'scenario II' model two additional scenarios whereby GHG emission by fossil fuels declines by further 15% and 30%, respectively, with respect to the 'base case' scenario. These 'scenario I' and 'scenario II' basically refer to the situation where COVID-19 pandemic further batters the world economy and reduces the anthropogenic activities globally. Accordingly, 'base case', 'scenario I' and 'scenario II' reduce the contribution of GHG emission by fossil fuels by approx. 27.14%, 38.06% and 48.99%, respectively, in 2020. Same GHG emissions, as in 'base case', 'scenario I' and 'scenario II' cases, ensure about 13.56%, 19.03% and 24.49% reduction in 2020 with respect to the total worldwide anthropogenic GHG emissions in 2019, as shown in Figure 4 (b). This is undoubtedly a remarkable change in GHG emission worldwide due to COVID-19 situation. However, this is not beyond expectation based on the fact that fossil fuels consistently carry a dominant share in total worldwide anthropogenic GHG emissions. For instance, these fuels contributed about 61.54% of total worldwide anthropogenic GHG emission in 2010 33,34 .

Conclusion
The study has conducted an evidence-based analysis of how COVID-19 initiated a drastic change in global environment at a particular time when the world has been grappling with series of compelling environmental issues. The dreadful coronavirus 2 (SARS-CoV-2) has threatened the current human civilization in one hand whereas the environmental restoration process is continuing on the other hand. In future, unfolding time, or once the pandemic ends, human being will be further able to decide whether some sort of partial lockdown or social restriction on a rolling basis in different corners of the world could play a key role in balancing the global ecosystem and environment. But as of now, this study carries testimonies of meaningful transitions in global environment in 2020 due to COVID-19, as such:  global warming impact reduces by ~27.14% with respect to the 2019 level with a corresponding reduction of ~8.0 billion metric ton CO 2 eq;  stratospheric ozone depletion impact reduces by ~28.14% with respect to the 2019 level with a corresponding reduction of ~3.68E+06 kg CFC11 eq;  ozone formation human health reduces by ~21.71% with respect to the 2019 level with a corresponding reduction of ~2.04E+10 kg NO x eq;  fine particulate matter formation reduces by ~28.86% with respect to the 2019 level with a corresponding reduction of ~2.4E+10 kg PM2.5 eq;  smog reduces by ~22.04% with respect to the 2019 level with a corresponding reduction of ~5.06E+11 kg O 3 eq;  ionizing radiation reduces by ~17.89% with respect to the 2019 level with a corresponding reduction of ~2.85E+10 kBq Co-60 eq;  human carcinogenic toxicity reduces by ~12.21% with respect to the 2019 level with a corresponding reduction of ~8.46E+09 kg 1,4-DCB;  human non-carcinogenic toxicity reduces by ~20.62% with respect to the 2019 level with a corresponding reduction of ~1.84E+12 kg 1,4-DCB;