Archives par mot-clé : Covid-19

Carbon dioxide levels continue at record levels, despite COVID-19 lockdown

by WMO, Nov 23, 20°20


 

 

2020 Trends

The Global Carbon Project estimated that during the most intense period of the shutdown, daily CO2 emissions may have been reduced by up to 17% globally due to the confinement of the population. As the duration and severity of confinement measures remain unclear, the prediction of the total annual emission reduction over 2020 is very uncertain.

 

Why lockdown had little to no effect on global temperatures

by A.N. Archer & J.Weber, Oct 22, 2020 in Phys.Org


Countries across the world took unprecedented action in the first few months of 2020 to control the spread of COVID-19. At its peak, one-third of the world’s population was in lockdown. Around the world, car travel fell by 50%, the number of flights plummeted by 75% and industrial activity fell by around 35%.

With so many cars parked, airplanes grounded and factories closed, global carbon dioxide (CO₂) emissions fell by around 17% compared with the same period in 2019. But greenhouse gases such as CO₂ weren’t the only emissions to fall, and not all pollution heats the planet. Some of the industrial activities that shut down—particularly heavy industry, including steel and cement making—also produced aerosols, which are that linger in the atmosphere for weeks and reflect heat from the Sun.

Previous studies have suggested that if a lot of these industrial processes were to suddenly shut down, it would lead to short-term warming because the atmosphere would lose the reflective effect of aerosols. But as the lockdown cleared skies, temperatures didn’t rocket.

In new research, we show that lockdown had a negligible effect on global temperatures. So what really happened?

COVID-19 Global Economic Downturn not Affecting CO2 Rise: May 2020 Update

by Roy Spencer, June 5, 2020 in GlobalWarming


The Mauna Loa atmospheric CO2 concentration data continue to show no reduction in the rate of rise due to the recent global economic slowdown. This demonstrates how difficult it is to reduce global CO2 emissions without causing a major disruption to the global economy and exacerbation of poverty.

After removal of the strong seasonal cycle in Mauna Loa CO2 data, and a first order estimate of the CO2 influence of El Nino and La Nina activity (ENSO), the May 2020 update shows no indication of a reduction in the rate of rise in the last few months, when the reduction in economic activity should have shown up.

I had previously explained why the slowdown would likely not be large enough to affect measured atmospheric CO2 levels compared to natural variations in global sources and sinks of CO2. I calculated that the Energy Information Administration-estimated 11% reductions in CO2 emissions during 2020 would have to be four times larger to stop the rise of atmospheric CO2 over 2019 values (assuming no substantial natural variations in CO2 sources and sinks).

See also

Global Economic Downturn Not Affecting CO2 Rise: May 2020

Quarantines, Lockdowns Had No Impact On Global CO2 Levels

by Climate at a Glance, June 1, 2020 in ClimateChangeDispatch


The COVID-19, aka Coronavirus pandemic, is causing a worldwide shutdown in economic activity as businesses close, airlines cancel flights, energy production is reduced, and people shelter in their homes and drive less.

Climate activists expected this economic downtown to translate to less energy usage, and therefore less CO2 emissions globally.

While that has indeed happened, with China seeing a 40% emissions drop, and an expected 11% reduction in energy-related CO2 emissions in the U.S. this year, it didn’t translate into the proof they were seeking.

What scientists are looking for is any evidence of a decline in global atmospheric CO2 concentrations that would be strong enough to attribute to the economic downturn.

University of Alabama climate scientist Dr. Roy Spencer used a simple method1 for removing the large seasonal CO2 cycle2, due to plant photosynthesis increases/decreases with seasons, from the Mauna Loa CO2 data, and well as the average effects from El Nino and La Nina events, which change the rate of ocean outgassing of CO2.

The result: no obvious downtown in global CO2 levels has been observed3,4.

As can be seen in Figure 1, the latest CO2 data show no downtrend, but instead just a ripple, that is not unlike other ripples in the graph when there was no crisis and resulting economic downturn.

Figure 1: Using a simple method1 for removing the large seasonal cycle from the Mauna Loa CO2 data, and well as the average effects from El Nino and La Nina events, no obvious downtown in global CO2 levels has been observed4. Analysis by Dr. Roy Spencer.

 

The Global CO2 lockdown problem

by Sherrington G., May 22, 2020 in WUWT


The global problem.

In response to the threat of a global viral epidemic, countries announced lockdowns at various times near 25th March 2020. https://en.wikipedia.org/wiki/COVID-19_pandemic_lockdowns

This caused a reduction of industrial activity and hence a lower rate of emission of anthropogenic carbon dioxide to the atmosphere. An example of reduction from aircraft is given at https://en.wikipedia.org/wiki/Impact_of_the_COVID-19_pandemic_on_aviation

Numerous sources asked if the reduction in CO2 emission could be detected in analysis of air for CO2 content, which had been done for decades. Early questions and speculative answers came from many sources including –

https://www.esrl.noaa.gov/gmd/ccgg/covid2.html

https://www.aljazeera.com/news/2020/03/coronavirus-lockdown-leads-improved-air-quality-200322094404592.html

By late May 2020, the emerging consensus was that the reduction would be too small to show at the main measuring stations such as Mauna Loa, Hawaii.

Why the Current Economic Slowdown Won’t Show Up in the Atmospheric CO2 Record

by Rotter, from Spencer, May 15, 2020 in WUWT


May 15th, 2020 by Roy W. Spencer, Ph. D.

[UPDATE: MISSING IMAGES INSERTED]

Summary: Atmospheric levels of carbon dioxide (CO2) continue to increase with no sign of the global economic slowdown in response to the spread of COVID-19. This is because the estimated reductions in CO2 emissions (around -11% globally during 2020) is too small a reduction to be noticed against a background of large natural variability. The reduction in economic activity would have to be 4 times larger than 11% to halt the rise in atmospheric CO2.

Changes in the atmospheric reservoir of CO2 occur when there is an imbalance between surface sources and sinks of CO2. While the global land and ocean areas emit approximately 30 times as much CO2 into the atmosphere as humans produce from burning of fossil fuels, they also absorb about an equal amount of CO2. This is the global carbon cycle, driven mostly by biological activity.

Fig. 2. Monthly CO2 data since 2015 from Mauna Loa, HI after the average seasonal cycle is statistically removed.

ADDENDUM: How much of a decrease in CO2 emissions would be required to stop the atmospheric rise in CO2?

 

Continuer la lecture de Why the Current Economic Slowdown Won’t Show Up in the Atmospheric CO2 Record