Why COVID-19 hasn’t slowed Australia’s rising CO2 emissions

Carbon dioxide levels in Australia rose even as COVID-19 forced global emissions down.

Why COVID-19 hasn’t slowed Australia’s rising CO2 emissions

COVID-19 has curtailed the activities of millions of people across the world and with it, greenhouse gas emissions. As climate scientists at the Cape Grim Baseline Air Pollution Station, we are routinely asked: does this mean carbon dioxide concentrations in the atmosphere have fallen?

The answer, disappointingly, is no. Throughout the pandemic, atmospheric carbon dioxide (CO2) levels continued to rise.

In fact, our measurements show more CO2 accumulated in the atmosphere between January and July 2020 than during the same period in 2017 or 2018.

Emissions from last summer’s bushfires may have contributed to this. But there are several other reasons why COVID-19 has not brought CO2 concentrations down at Cape Grim – let’s take a look at them.

Measuring the cleanest air in the world

Cape Grim is on the northwest tip of Tasmania. Scientists at the station, run by the CSIRO and Bureau of Meteorology, have monitored and studied the global atmosphere for the past 44 years.

The air we monitor is the cleanest in the world when it blows from the southwest, off the Southern Ocean. Measurements taken during these conditions are known as ‘baseline concentrations’, and represent the underlying level of carbon dioxide in the Southern Hemisphere’s atmosphere.

The Cape Grim station The Cape Grim station measures the cleanest air in the world. Bureau of Meteorology


Read more: Forty years of measuring the world's cleanest air reveals human fingerprints on the atmosphere


A drop in the CO2 ocean

Emissions reductions due to COVID-19 started in China in January, and peaked globally in April. Our measurements show atmospheric CO2 levels rose during that period. In January 2020, baseline CO2 was 408.3 parts per million (ppm) at Cape Grim. By July that had risen to 410 ppm.

Since the station first began measurements in 1976, carbon dioxide levels in the atmosphere have increased by 25 per cent, as shown in the graph below. The slowdown in the rate of carbon emissions during the pandemic is a mere tug against this overall upward trend.

The CO2 increase is due to the burning of fossil fuels for energy, and land use change such as deforestation, which leaves fewer trees to absorb CO2 from the air and changes the uptake and release of carbon in the soils.

Baseline CO2 record from Cape Grim. Baseline CO2 record from Cape Grim. Author provided

Atmospheric transport

Large air circulation patterns in the atmosphere spread gases such as CO2 around the world, but this process takes time.

Most emissions reduction due to COVID-19 occurred in the Northern Hemisphere, because that’s where most of the world’s population lives. Direct measurements of CO2 in cities where strict lockdown measures were imposed show emissions reductions of up to 75 per cent. This would have reduced atmospheric CO2 concentrations locally.

But it will take many months for this change to manifest in the Southern Hemisphere atmosphere – and by the time it does, the effect will be significantly diluted.

Natural ups and downs

Emissions reductions during COVID-19 are a tiny component of a very large carbon cycle. This cycle is so dynamic that even when the emissions slowdown is reflected in atmospheric CO2 levels, the reduction will be well within the cycle’s natural ebb and flow.

Here’s why. Global carbon emissions have grown by about 1 per cent a year over the past decade. This has triggered growth in atmospheric CO2 levels of between 2 and 3 ppm per year in that time, as shown in the graph below. In fact, since our measurements began, CO2 has accumulated more rapidly in the atmosphere with every passing decade, as emissions have grown.

Annual growth in CO2 at Cape Grim since 1976. Red horizontal bars show the average growth rate in ppm/year each decade. Annual growth in CO2 at Cape Grim since 1976. Red horizontal bars show the average growth rate in ppm/year each decade. Author provided

But although CO2 emissions have grown consistently, the resulting rate of accumulation in the atmosphere varies considerably each year. This is because roughly half of human emissions are mopped up by ecosystems and the oceans, and these processes change from year to year.

For example, in southeast Australia, last summer’s extensive and prolonged bushfires emitted unusually large amounts of CO2, as well as changing the capacity of ecosystems to absorb it. And during strong El Niño events, reduced rainfall in some regions limits the productivity of grasslands and forests, so they take up less CO2.

The graph below visualises this variability. It shows the baseline CO2 concentrations for each year, relative to 1 January. Note how the baseline level changes through a natural seasonal cycle, how that change varies from year to year and how much CO2 has been added to the atmosphere by the end of the year.

Daily baseline values for CO2 for each year from 1977 relative to 1 January for that year Daily baseline values for CO2 for each year from 1977 relative to 1 January for that year. Author provided

The growth rate has been as much as 3 ppm per year. The black line represents 2020 and lines for the preceding five years are coloured. All show recent annual growth rates of about 2–3 ppm/year – a variability in the range of about 1 ppm/year.


Read more: Coronavirus is a 'sliding doors' moment. What we do now could change Earth's trajectory


Research in May estimated that due to the COVID-19 lockdowns, global annual average emissions for 2020 would be between 4.2 per cent and 7.5 per cent lower than for 2019.

Let’s simplistically assume CO2 concentration growth reduces by the same amount. There would be 0.08–0.23 ppm less CO2 in the atmosphere by the end of 2020 than if no pandemic occurred. This variation is well within the natural 1 ppm/year annual variability in CO2 growth.

CO2 is released in industrial emissions CO2 levels in the atmosphere are increasing due to fossil fuel burning and land use change. Shutterstock

The road ahead

It’s clear COVID-19 has not solved the climate change problem. But this fact helps us understand the magnitude of change required if we’re to stabilise the global climate system.

The central aim of the Paris climate agreement is to limit global warming to well below 2’C, and pursue efforts to keep it below 1.5’C. To achieve this, global CO2 emissions must decline by 3 per cent and 7 per cent each year, respectively, until 2030, according to the United Nations Emissions Gap Report.

Thanks to COVID-19, we may achieve this reduction in 2020. But to lock in year-on-year emissions reductions that will be reflected in the atmosphere, we must act now to make deep, significant and permanent changes to global energy and economic systems.


The lead author, Zoe Loh, discusses the CO2 record from Cape Grim in Fight for Planet A, showing now on the ABC.


Read more: Why there's more greenhouse gas in the atmosphere than you may have realised The Conversation


Zoe Loh, Senior Research Scientist, CSIRO; Helen Cleugh, Senior research scientist, CSIRO Climate Science Centre, CSIRO; Paul Krummel, Research Group Leader, CSIRO, and Ray Langenfelds, Scientist at CSIRO Atmospheric Research, CSIRO

This article is republished from The Conversation under a Creative Commons licence. Read the original article.

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    COMMENTS

    To make a comment, please register or login
    45er
    20th Aug 2020
    5:07pm
    Simple over the past 50 years the world's population has doubled. Over that period CO2 has increased by less than 50%. Using the fact that people use energy creating CO2 emissions as well as breathing out CO2. Using the principle of scientific facts picked at random to support an argument, we should to reduce emissions to the level of 50 years ago, we should then reduce the population by 50% as it is obviously one of the main causal factors. In reality there is no simple solution but a mixture of many factors developed over long periods in a gradually changing world.
    Veritas
    20th Aug 2020
    5:08pm
    The first instances of COVID infections were met with a sluggish response by many governments including Boris Johnson, Jair Bolsonaro, and Donald Trump. The rise in constituents dying forced their hand to act. The same urgency and global sharing of information and resources should be applied to reducing CO2 emissions as the economic impact, should no action be undertaken, will make coronavirus look like an insignificant curtain-raiser.
    Oxleigh
    21st Aug 2020
    12:17am
    Anybody with eyes and a nose and a few years under their belt will know that the air is cleaner and sweeter than it was about 40 years ago.
    Living in a previous heavy industrial area I can attest that is a fact, I can see for many more kilometres and I can breath much better without the smell and fumes of industry.
    Cars are much more cleaner than before even with more diesels around.
    Since Corona there has been a great reduction in flights and car usage and some industry shut downs as well.
    Look out your windows and into the sky, I bet you can say you have never seen it so clear.
    I also find that the older I get the more normal the weather is as well. We have always had cycles of good and not so good, look at all the reports from the past.
    Trust your eyes, nose and lungs and think for your self, numbers can and are manipulated to suit certain agendas, just ask Greta.
    The fact that when our coal exports are burned in China and other countries the numbers of pollution are added to Australia's log of pollution, that is they way these nerds say that Australia has the highest results for pollution than any other country.
    Its just to make us feel guilty and so the researchers can reap rewards for research on pollution and global warming.
    The same with sea level rises, ask Bob Brown about the sea level rise in Hobart, what a joke he was.
    Knight Templar
    21st Aug 2020
    10:39am
    CO2 is demonized as air pollution. CO2 in the air is the global food supply. Our meat, our vegetables, milk, and wine depend on it. We should be very glad that the earth is greening as a result of increased CO2 in the air. Instead, climate alarmists want to reduce it. Plants use the energy of sunlight to transform CO2 and water into their food. The earth is better for it.
    ChannelingOrwell
    21st Aug 2020
    11:29am
    Right on Knight Templar!
    I don't accept politicised "science" either.
    Notice how alarmists totally ignore the obvious benefits of increased atmospheric CO2 and accentuate the few, if any, negatives.
    This is a dead giveaway of an underlying political agenda at work.
    ChannelingOrwell
    21st Aug 2020
    11:15am
    "our measurements show more CO2 accumulated in the atmosphere between January and July 2020 than during the same period in 2017 or 2018"

    Exactly the same result has occurred with NORTHERN HEMISPHERE Moana Loa, Hawaii CO2 measurements.
    i.e. A 17% reduction in global CO2 emissions since Feb 2020 has had NO DISCERNIBLE EFFECT on the steady NATURAL rise in CO2 levels, which have been rising steadily as the world warms after the end of the Little Ice Age about 1600.

    The reasons for this are simple.

    Firstly, human CO2 emissions are about 3% of emissions from Mother Nature. i.e. TINY!

    By far the biggest contributors to atmospheric CO2 levels are temperature dependent processes such as outgassing from warming oceans and rotting vegetation.

    This proves that ANY reduction of RE|LATIVELY TINY human CO2 emissions is futile!


    “roughly half of human emissions are mopped up by ecosystems and the oceans”

    This is FALSE. Mother Nature cannot distinguish between naturally emitted CO2 and that emitted by human activity. All it sees is an ocean of atmospheric CO2 with a SLIGHT 3% increase due to humanity.
    This extra 3% has been easily mopped up by nature as evidenced by the greening of the planet.

    What the alarmists are, in effect, saying is that there is a little daemon picking out half of human emissions and leaving the rest in the atmosphere!! Believe it or not …

    Atmospheric scientist, professor Salby, who has a myriad of peer-reviewed and heavily cited articles in climate science, as well as being an author of the 1996 book “Fundamentals of Atmospheric Physics”, has confirmed all this.

    As a result of his failure to toe the line on climate change junk science he has been ceaselessly persecuted.
    He was banned from lecturing on climate & his research papers were confiscated by Macquarie university.
    WHAT ARE THEY AFRAID OF?? THE TRUTH?
    Knight Templar
    21st Aug 2020
    3:11pm
    Well pointed out Channeling Orwell. Climate modeling and forecasting are even less reliable than early modeling for COVID-19. Garbage in, garbage out!

    It was estimated that upwards of 30-40 million people worldwide would die from CV despite lockdowns, masking and social distancing. To date, an estimated 700,000 people worldwide have died.

    Tragic as that may be, it should be noted that on average 60 million people die annually from all conditions.


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