The pandemic has shown us an unfortunate thing about climate change

0
3


The COVID-19 pandemic has so far confirmed two things that environmental activists have been saying for a long time. The first is that to significantly decrease the concentration of greenhouse gases in the atmosphere, as the international targets set to combat global warming would require, much more radical interventions are needed than those carried out so far on the push of conferences such as the Cop21 in Paris. The second is that individual efforts to reduce the impact of human activities on the atmosphere, however commendable, are of little use.

The effect of the pandemic on CO emissions2
Already in February, discussions had begun on the effect of restrictions on movement and production activities to contain coronavirus (SARS-CoV-2) infections on air pollution. It was seen first with Chinese factories, which stopped or slowed down production, then with private cars in Europe and the United States, which remained parked for weeks, and with flights canceled all over the world.

May 19 in the scientific journal Nature Climate Change the first study on the effects of the pandemic on carbon dioxide emissions (CO2), the main gas responsible for the greenhouse effect and climate warming. The study, carried out by 13 well-known environmental science experts from different parts of the world, estimates how much the amount of CO emissions has actually been reduced2 from the beginning of the year to the end of April: more than a billion tons compared to last year. In the period between January 1st and April 30th, April 7th was the day when less carbon dioxide was emitted than on the same day in 2019: the worldwide daily drop reached 17 percent. From late March to late April, the drop has always been more than 15 percent compared to last year.

The reductions obviously differ from country to country and sector to sector. At its peak, for example, the reduction in emissions from closures in China was greater than the peak of that due to closures in the United States. On average, in the moments of greatest closure, the individual countries achieved a reduction in their emissions of 26%.

As regards the various sectors that produce carbon dioxide emissions, a very high percentage decrease (minus 36 percent compared to 2019) has occurred in the surface transport sector: mainly relative in the use of cars, given that the transport of road freight continued. Civil aviation, on the other hand, produced 60 percent less emissions, having largely stopped: air flights, however, contribute only to a small fraction of the total emissions due to transport – only 9 percent in the case of the United States – therefore, this large percentage drop does not correspond to a truly significant decrease in total global emissions.

– Also read: Will the pandemic make us more sensitive to climate change?

Overall, the decrease in emissions has brought us back to global daily emission levels seen last time in 2006: the impact of the restrictions due to the pandemic on the production of emissions was therefore greater than that due to the economic crisis of 2008-2009.

According to experts, however, this effect is unlikely to continue in the coming months, on the contrary: government initiatives to revive the economy should lead to very strong growth in the production of emissions. The study published on Nature Climate Change forecasts that in 2020 global total emissions will be only 4-7 percent lower than those produced in 2019. Considering that in the past decades the global annual carbon dioxide emission has almost always increased (between 2008 and 2009 it decreased by 1.4 per cent) this decrease is not necessarily going to have a truly significant effect and to count for the long term in tackling climate change.

– Also read: Air pollution and coronavirus

What matters is the CO concentration2
Although the graphs and data on the drop in emissions in recent months are remarkable and impressive, in fact, it is important to remember that the main parameter to consider when talking about CO emissions2 and climate change is the concentration of this greenhouse gas in the atmosphere. It is since the beginning of the Industrial Revolution, in the eighteenth century, that human activities cause an increase in carbon dioxide in the atmosphere, in addition to that due to natural processes: a few months without cars, planes and coal-fired power plants cannot upset what made in more than two centuries.

It is easy to understand by looking at the so-called “Keeling curve”, a graph showing the trend of the CO concentration2 in the atmosphere from 1958 to today, according to measurements from the meteorological observatory of the Mauna Loa volcano, in Hawaii. In the graph you can see two lines. The one in red in the following image shows the level of carbon dioxide concentration in the atmosphere measured at the Mauna Loa observatory over time. It rises and falls according to the seasons, given that during the summer the plants of the northern hemisphere absorb more CO2 how much they manage to absorb the plants of the southern hemisphere (which are fewer) in winter. The black line, on the other hand, is the average trend, which flattens the growth and seasonal drops.

(NOAA)

Many asked the Mauna Loa observatory if the effect of the COVID-19 pandemic on emissions was seen in their measurements. The observatory explained:

For the drop in emissions to be visible it must be pronounced enough to distinguish itself from the natural variability of CO2 in the atmosphere caused by how plants and soil react to annual changes in temperature, humidity, etc. These variations are very wide and for now the “missing” emissions are not noticed. Here is an example: if the emissions were less than 25 percent, we would expect to see the monthly average of CO2 measured in March in Mauna Loa less than 0.2 parts per million, and again the same in April, etc. So in the comparison of the annual averages we would expect a visible difference after a series of months, each with 0.2 parts per million less.

The International Energy Agency expects emissions to drop by 8 percent this year. We therefore cannot see a global effect like this in a period of less than a year. The CO2 the atmosphere will continue to grow at more or less the same speed, which shows that aggressive investments in the field of alternative energy sources are needed to combat the emergency of global warming.

In short, the data on the concentration show no changes: the emissions should decrease much more than they have done so far so that the effect of their decrease was visible in the related graphs. On the contrary, in April 2020 the average concentration of carbon dioxide in the atmosphere was 416.21 parts per million, the highest ever recorded since 1958. Data on the concentration of CO2 that scientists obtained by studying the Antarctic ice – the only source we have to know what the Earth’s climate was like hundreds of thousands of years ago – they also say that for at least 800 thousand years there hasn’t been so much carbon dioxide in the atmosphere. Our species, Homo sapiens, has existed for about 300 thousand years.

According to a United Nations report released in November, to avoid the worst effects of climate change, carbon dioxide emissions should decrease by at least 7.6 percent annually for decades. So the “missing” emissions of this year will have no long-term effect if there are no similar declines in the coming years.

– Also read: The government changed the highway code to favor bikes

Individual choices matter little
The sectors in which the greatest drop in CO emissions was seen2 they are the ones we talk about when we talk about individual choices, to decrease the impact of human activities on the climate: transport by car and air flights. The fact that despite their great decrease, even at the time of maximum global restrictions, which occurred at the beginning of April, the world continued to produce more than 80 percent of its usual carbon dioxide emissions, clearly shows that to counteract the change one must not ask individuals to change their habits, but carry out more radical changes in the way energy is produced.

“Changing our behavior is not enough, now we see it,” he said Washington Post Corinne Le Quéré, first author of the study published on Nature Climate Change. Le Quéré explained that she would expect even greater reductions in the production of emissions, linked to the closure of the industries and the consequent lower production of electricity: instead, certain sectors continued to operate as usual and to consume energy «as if they had the pilot automatic », although many people worked from home. Emissions from industries decreased by 19 percent compared to 2019, those from the energy sector only by 7 percent.

Zeke Hausfather of the Breakthrough Institute, an American study center that deals with environmental issues, commented on the results of the study saying: “Unless structural changes arrive, we should expect emissions to return to pre-pandemic levels. I don’t think there is a positive side of COVID-19 with regards to the climate, unless we take advantage of the recovery of activities as an opportunity to build suitable infrastructures to support a clean energy future, as well as a moment to stimulate the economy. ”

– Also read: The INPS study on the true number of deaths from the epidemic





Source link
https://www.ilpost.it/2020/05/23/pandemia-effetto-emissioni-co2/

LEAVE A REPLY

Please enter your comment!
Please enter your name here