As the world continues the fight against the COVID-19 pandemic, we are starting to observe first potential effects on the climate system. The CO2 levels have currently paused the seasonal increase, likely due to the slowdown of the industry in China and the rest of the countries that are dealing with the outbreak of the new Coronavirus.
Last Autumn, we wrote about the new record high CO2 levels, that were recorded in 2019. Carbon dioxide (CO2) is a well-known greenhouse gas, along with Methane (CH4), which also a very potent greenhouse gas. Greenhouse gasses trap the heat from the Sun in the Earth’s atmosphere, increasing global temperatures as the trapped heat builds. Scientists say that the last time the Earth experienced a comparable concentration of carbon dioxide was 3 to 5 million years ago based on ice core data. Back then, the temperature was 2-3C warmer and sea level was 10-20 meters higher than now.
Global CO2 levels are being monitored at several stations around the world, and also by satellites. The most commonly used is the data from the Mauna Loa observatory. CO2 levels are increasing steadily, but they have a seasonal cycle. We know from the data that CO2 does not increase with each and every day, but we actually have a regular decrease every year. Below we have a graphic with data for the past few years, where we can see the seasonal curve more closely. Why do the CO2 values drop every year and then rise again? The reason is quite simple. In late spring and summer, land and ocean vegetation (plant life) is abundant and consumes CO2 in the process of photosynthesis. In autumn and winter, the plants die off, and especially on land, the vegetation decays and releases some of the CO2 back into the atmosphere. Since most of the landmass and vegetation is in the Northern hemisphere, it has the strongest impact on the seasonal cycle.
The biggest seasonal increase of CO2 usually happens during the cold months of the Northern Hemisphere, due to the reasons we mentioned above. This year, we are noticing an interesting development, as the CO2 levels are currently increasing at a much slower rate than expected. Looking at the last 12 months of CO2 data from Mauna Loa observatory, we can see the CO2 rise last year and this season, which shows slower growth than expected.
Looking at the past 6 months, we can see that the slowdown in the CO2 increase is a more recent development, more specifically in the past two months.
Zooming in even further into the last month and the last week, it is getting obvious that the CO2 levels are increasing at a much slower rate than expected. It looks almost like the CO2 levels have stopped increasing for the time being.
We made a graphic from NASA GEOS-5 model analysis data, which shows the global CO2 atmospheric mass, in ppm (parts per million). We can see that current CO2 concentrations are higher over the Northern Hemisphere, as the Earth’s northern half is still in the cold season, with higher CO2 emissions from industry and fossil fuel burning for heating. What this graphic also shows, is that CO2 is circling the globe, so any reduced emissions take some time to infiltrate into the global circulation, to be detected at the station on Mauna Loa.
Where are the main sources of CO2? We made a map that shows the human sources of CO2 from fossil fuel burning, food production, and industry. As expected, we see the Eurasian sector and North America lighting up. Transportation also leaves a signature, so we can also see the global transportation leaving a signature.
So why are we currently seeing a reduction in CO2 increase? As the entire world probably knows by now, we are dealing with a global pandemic crisis. The novel Coronavirus is spreading across the world, causing the COVID-19 disease. Most cases are so far in the Northern Hemisphere. One of the most common countermeasures to limit the spreading of the virus, is quarantine, self-isolation and/or a complete country lockdown. That has an impact on the industry and transport, which are two major sources of CO2. The reduction of CO2 increase does coincide with the spreading of the COVID-19 across the world.
— Kris Karnauskas (@OceansClimateCU) March 14, 2020
It would not be the first time that a global crisis has temporarily halted the CO2 increase, as reported from the Global Carbon Project.
Global Fossil CO2 emissions could decline in the range of 0.2 to 1.2% this year due to Covid-19, based on current predictions on economic growth.
— GlobalCarbonProject (@gcarbonproject) March 17, 2020
One of the largest CO2 “hotspots” in the Northern Hemisphere, is China. It was the first country to fight against the new Coronavirus. They had strict quarantine and have temporarily closed down large industrial areas. The graphic below from CarbonBrief, shows the coal consumption in China, before and after the Chinese new year. This year, coal consumption did not sharply increase after the Chinese new year, as the country was battling the virus outbreak. This is why the CO2 and NO2 emissions in China were greatly reduced, likely also impacting the global values to a certain degree.
We will keep you updated on any important further development. While you wait for more updates, don’t miss our articles on the reduction of Nitrogen Dioxide pollution due to the battle against the spreading of COVID-19: