{"id":11134,"date":"2020-06-10T12:32:14","date_gmt":"2020-06-10T10:32:14","guid":{"rendered":"https:\/\/nilu.gnist.dev\/?p=11134"},"modified":"2020-06-10T12:32:14","modified_gmt":"2020-06-10T10:32:14","slug":"covid-19-lockdown-effect-on-global-carbon-dioxide-levels-a-needle-in-a-haystack","status":"publish","type":"post","link":"https:\/\/nilu.gnist.dev\/en\/2020\/06\/covid-19-lockdown-effect-on-global-carbon-dioxide-levels-a-needle-in-a-haystack\/","title":{"rendered":"Covid-19 lockdown effect on global carbon dioxide levels: A needle in a haystack"},"content":{"rendered":"

\u201cThis is an estimate\u201d, says scientist Stephen Platt at NILU\u2019s Department of atmosphere and climate. \u201cThe question is whether or not we will be able precisely measure the drop in CO2<\/sub> emissions due to COVID-19?\u201d<\/p>\n

CO2<\/sub> as money in a bank account<\/h2>\n

When carbon dioxide (CO2<\/sub>) is emitted into the atmosphere it mixes with the rest of the air in a timespan of months to over a year. The atmosphere already contains a lot of CO2<\/sub>; plants need it to grow, and many different processes take up and release CO2<\/sub>, adding to the changes in time and space.<\/p>\n

To visualize this, let us relate all the CO2<\/sub> in the atmosphere to money in a bank account. We can equate CO2<\/sub> entering our atmosphere to earnings going into our account every year, and natural processes removing CO2<\/sub> to our yearly expenditure. We don\u2019t save the same amount every year because our income and expenditure vary \u2013 just like CO2<\/sub> emissions and CO2<\/sub> uptake vary in the real world. Overall, we have spent a little less each year than we have earned, and over time this has built up to a balance of 1 million Norwegian kroner.<\/p>\n

\u201cThat is as of today\u201d, Platt emphasizes. \u201cIf we look back to before anthropogenic emissions started, the balance was at 691.630 Norwegian kroner (NOK). So, for the last 200 years, we have increased the balance by up to 45%.\u201d<\/p>\n

According to NILU\u2019s measurements at the Zeppelin Observatory on Svalbard, a part of the integrated carbon observing system (ICOS)<\/a>, there has been a 0.7% yearly increase in CO2<\/sub> during the last 10 years.<\/p>\n

If we return to our bank account analogy, this means that we might have expected to save 5868 NOK (2.43 ppm CO2<\/sub>) this year. But now, the lockdown has impacted our net savings by about 4% in 2020. Compared to a typical year, we will save a little less \u2013 around 5634 NOK (2.18 ppm CO2<\/sub>).<\/p>\n

\u201cThe difference is about 234 Norwegian kroner \u2013 a negligible amount\u201d, says Platt.<\/p>\n

Covid-19 lockdown effect on CO2<\/sub> is very small<\/h2>\n
\"Figure<\/a>
Figure 1: Average yearly carbon dioxide at the Zeppelin Observatory since 1988 after changing units to give 1 million Norwegian kroner in 2019 on the left axis, and the original CO2 concentration in parts per million on the right axis. Click to enlarge. Source: NILU<\/figcaption><\/figure>\n

What Platt and his fellow climate scientists are able to say about the effect of the lockdown is that the effect on overall greenhouse emissions in 2020 is very small. Carbon dioxide (CO2<\/sub>) will not go down, but likely increase by a little bit less than normal. This is because the decrease in human emissions globally was at about 17% but entering June, we are coming out of the lockdown and returning to \u2018business as usual.\u2019<\/p>\n

Over the full year this will probably mean about 4-7% less human emissions than a typical year. Then the background variability in CO2<\/sub> due to normal year to year variation in all of the processes emitting and taking up CO2<\/sub>, i.e. changing land use, feedbacks and biological activity, is likely to hide this signal (see figure 1).<\/p>\n

\u201cNevertheless, as we are curious to see exactly how COVID-19 has impacted our account, we take a look at our budget for the year and see where we didn\u2019t quite manage to save\u201d, says Platt.<\/p>\n

He goes on to explain that in the real world there is no precise budget for CO2<\/sub>.<\/p>\n

\u201cWe don\u2019t know the exact expenditure or the exact earnings. The only number we can measure precisely is the total amount of money in the account. From this we can see that in some years we have a net saving of as little as 1431 NOK and in other years as much as 9085 NOK. This years\u2019 net savings fit well within this range, as seen in figure 2.\u201d<\/p>\n

\"Figure
Figure 2: Average yearly carbon dioxide at the Zeppelin Observatory since 2015 after changing units to give 1 million Norwegian kroner in 2019, and projections for the 2020 average. The upper-lower range is calculated from the average increase over the last 10 years. Including the variability in the time period yields a maximum of 9085 NOK per year and a minimum of 1431 NOK per year (normal range in light blue) and a typical 5868 NOK per year (dashed black line). If the COVID-19 lockdowns would perturb an average year increase by ~4 percent, the overall increase would be 5634 Kr (red line). Source: NILU<\/figcaption><\/figure>\n

Small needle, large haystack<\/h2>\n

Continuing the bank account analogy, this means that we can look at the total balance, but we still don\u2019t know whether we saved less than normal, because we still don\u2019t know our exact expenditure. There are variabilities within a year and between years.<\/p>\n

One such variability regarding CO2<\/sub> is it\u2019s strong seasonal cycle, because plants grow less in winter and thus take up less CO2<\/sub>. Since there is more land in the northern hemisphere, and hence more plants, CO2<\/sub> levels reach a maximum during winter\u00a0 in the northern hemisphere. Even shorter-term variability arises from weather patterns, which can bring air from polluted regions on one day and from clean regions on another.<\/p>\n

\u201cLooking at our savings, we tally them up at the end of each year to see how much we saved or lost\u201d, Platt says. \u201cThe same goes for CO2<\/sub>, we can\u2019t know in the middle of the year how our net result will be.\u201d<\/p>\n

A lot of people are working hard to find the small effect, but it will take a lot of effort to quantify all of the processes contributing to CO2<\/sub> emission and uptake in order to isolate the effect of the lockdown. One caveat is that we don\u2019t know what the future will bring. It is possible that further lockdowns will be introduced, which would of course increase the effect on emissions. To sum it up: Looking for the effect of COVID-19 is like looking for a (meaninglessly small) needle in a haystack.<\/p>\n

\u201dThe surprisingly small effect of the lockdowns on emissions, despite severe restrictions, for example in air travel, also highlight the challenges ahead in meeting the Paris Agreement goal of limiting global average warming to 2\u00b0C\u201d, Platt concludes.<\/p>\n","protected":false},"excerpt":{"rendered":"

\u201cThis is an estimate\u201d, says scientist Stephen Platt at NILU\u2019s Department of atmosphere and climate. \u201cThe question is whether or not we will be able precisely measure the drop in CO2 emissions due to COVID-19?\u201d CO2 as money in a bank account When carbon dioxide (CO2) is emitted into the atmosphere it mixes with the […]<\/p>\n","protected":false},"author":3,"featured_media":11117,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_searchwp_excluded":"","footnotes":""},"categories":[21],"tags":[],"class_list":["post-11134","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-newsarchive"],"acf":[],"_links":{"self":[{"href":"https:\/\/nilu.gnist.dev\/en\/wp-json\/wp\/v2\/posts\/11134","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nilu.gnist.dev\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nilu.gnist.dev\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nilu.gnist.dev\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/nilu.gnist.dev\/en\/wp-json\/wp\/v2\/comments?post=11134"}],"version-history":[{"count":5,"href":"https:\/\/nilu.gnist.dev\/en\/wp-json\/wp\/v2\/posts\/11134\/revisions"}],"predecessor-version":[{"id":11139,"href":"https:\/\/nilu.gnist.dev\/en\/wp-json\/wp\/v2\/posts\/11134\/revisions\/11139"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nilu.gnist.dev\/en\/wp-json\/wp\/v2\/media\/11117"}],"wp:attachment":[{"href":"https:\/\/nilu.gnist.dev\/en\/wp-json\/wp\/v2\/media?parent=11134"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nilu.gnist.dev\/en\/wp-json\/wp\/v2\/categories?post=11134"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nilu.gnist.dev\/en\/wp-json\/wp\/v2\/tags?post=11134"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}