Sunday, April 26, 2020

Is Atmospheric CO2 Declining from the Covid Economic Collapse?

I have had a number of people ask me:  with CO2 emissions collapsing from the economic downturn, are CO2 levels no longer going up or declining?   In fact, a brief search on the web reveals some headlines that seem to be suggesting this:


The bottom line of this blog is this:  CO2 levels are not falling, and it is difficult to see much impact on the rate of rise.  And it will be a good opportunity to talk about some aspects of the variation of CO2 in the atmosphere.

Let's start by looking at the concentrations of CO2 in the atmosphere as measured by NOAA at its Mauna Loa observatory on the Big Island (below).  This is an excellent place to measure CO2--away from any localized sources.  CO2 is relatively well mixed in the lower atmosphere (both spatially and in the vertical) so the measurements at this observatory are highly reflective of global variations over time.

You will note that CO2 has risen from around 317 parts per million (ppm) in 1960 to around 413 ppm today and the rate of increase is accelerating.  Mankind is not doing much to slow the increase, that is quite clear.  If you look closely, you will notice CO2 levels going up and down each year, like clockwork.
To get a view of this annual variability, here is a plot of the month values (red dash lines), with the black lines showing the impact of averaging designed to take out the seasonal variations (the plot goes through March).  CO2 levels tend to peak in mid-spring and the decline until they reach bottom in October.  Buy why?
It has to do with the cycle of plant growth in the northern hemisphere, where most of the planet's vegetated land area is found.   During the late spring and summer, plants grow and pull CO2 out of the atmosphere for their use in photosynthesis. But during the late autumn and winter, plants shut down, with many losing their leaves.  Their consumption of CO2 drops enormously, while CO2 is released as microbes feast on dead material, releasing CO2.  And, of course, we contribute to this increase with greater heating using fossil fuels.

But let's get back to the impact of mankind using less fossil fuels because of the coronavirus.  China put on the brakes in January and February, followed by Europe, the U.S. and most of the remainder of the world.  The numbers are still coming in, but the declines are substantial, with U.S. petroleum sales down by roughly 30% (see below).


To get a better idea of the recent changes in CO2, here are the weekly Mauna Loa CO2 numbers (green lines) for the past two years (below).   Monthly averages are shown by the red lines.   No obvious slowing of CO2 increases.  Note, there is often a flat period from February through March.

I downloaded the CO2 data and plotted it in all kinds of way, such as one year changes, one month and three month changes, and more.  Nothing suggested a major shift in the upward trends in CO2, so stories suggesting otherwise are not supported by observations.

 In some ways, the lack of  change in the upward trend in CO2 is not particularly surprising.    There is a lot of natural variability that obscures the signal.   CO2 emissions have only declined for a few months and China is already coming back online.  And there is still plenty of fossil fuels being used for heating, air conditioning, and basic transportation systems (including trucks and trains).    CO2 has a long lifetime in the atmosphere, so decreasing emissions would only slow the rise a bit, never causing a decline.

In short, with the world coming back online during the next few months, the long-term influence of this drop in emissions will be very small.  It is also provides notice that only really huge declines in CO2 emissions, far greater that what is occurring during this lockdown period, will be necessary to really move the needle on global warming.

A sobering thought.

23 comments:

  1. May be that's because human contribution to global warming is far smaller than what was originally believed? Food for thought.

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    1. There is nothing in Cliff's article that supports that conclusion. He points to plenty of human effects that contribute to rising Co2 in this article. Food for thought, indeed.

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    2. "In some ways, the lack of change in the upward trend in CO2 is not particularly surprising. There is a lot of natural variability that obscures the signal. CO2 emissions have only declined for a few months and China is already coming back online. And there is still plenty of fossil fuels being used for heating, air conditioning, and basic transportation systems (including trucks and trains)." The question of human caused climate change because of the emissions we have been putting into the atmosphere for decades isn't up for a debate. A few months of some slowing of emissions isn't going to have a huge impact on CO2 in the atmosphere because "CO2 has a long lifetime in the atmosphere, so decreasing emissions would only slow the rise a bit, never causing a decline." CO2 that we put out years ago is still in the atmosphere, which means the effects from that are ongoing, a few months of CO2 reduction will not change what has already been done. Anything we continue to add will only grow the heat capturing potential of our atmosphere. As stated by Cliff, we need major reductions for extended periods of time before we would start to see a difference, not just a few months of marginal reductions.

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    3. Food for thought? Maybe you are offering the same the same disinfectant food for thought that our glorious leader suggested we drink to combat COVID-19.

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    4. MAC: Perhaps you already drank the disinfectant and clouded your mind from thinking:


      https://edberry.com/blog/climate/climate-physics/human-co2-has-little-effect-on-the-carbon-cycle/

      Chuck Wiese
      Meteorologist

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  2. This is the source listed from the BBC article on the observation in mid-March that CO2 levels had decreased in NYC- https://atmoscomp.ldeo.columbia.edu/news/carbon-changes-nyc-during-covid-19-shutdown
    I'm curious what their data looks like for NYC and other metropolitan areas compared to Mauna Loa. I may have missed this but is there a reason to use Mauna Loa instead of places with high amounts of human-derived air pollution?
    Also, with the Mauna Loa data, how do the current CO2 levels look compare to what would have been predicted for April 2020 had covid not happened using some sort of predictive regression analysis? I think that's the comparison that is most interesting to look at, especially given that you note in the beginning that the amounts of CO2 in the atmosphere are accelerating.
    Thanks for the interesting post!

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    1. As Cliff said, Mauna Loa is used precisely avoid local effects, where the data would have a poor signal to noise ratio. Mauna Loa is a good overall measure of average CO2 in the entire atmosphere.

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  3. A recent NASA Earth Observatory page had a satellite-sensed map of the aerosol decline over India during this spring, compared to the previous four.
    It's here: https://earthobservatory.nasa.gov/images/146596/airborne-particle-levels-plummet-in-northern-india

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  4. Cliff,

    It is a sobering thought indeed! We'll keep learning I suppose. Thanks for sharing your findings.

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  5. The level of CO2 is bound to increase no matter what. Volcanoes produce CO2 as well, not a lot but they do. The only way for CO2 to decline is when vegetation increases.

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  6. And here I thought the BBC was one of the last credible news sources, but I guess that's not so.

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  7. Obvious. The largest sink of CO2 is the oceans of the world that cover 2/3 or the planet. The oceans will continue to be the what drives CO2. As we have seen in the last two months. Most people are gullible and lead by fear. I was at a grocery store yesterday with a line 30 people deep and the entrance protected by a police officer.

    The virus risk simply doesn't warrant that behavior, but most people are ruled by emotion and not reason. So we will continue this charade a bit longer until more people start to look at the data, and conclude that the lockdown no longer makes sense.

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    1. There's a good article in Science (2019) summarizing research RE the role of oceans as a CO2 sink. The research confirms that the sink is still functioning (ie saturation level has not been reached), though ocean capacity varies; read about the lowered capacity in the North Atlantic,thus far offset by an increased capacity in the South Atlantic. But CO2 does cause acidification: "Our data has shown that this acidification reaches deep into the ocean's interior, extending in part to depths of more than 3000 m....Documenting the chemical changes imparted on the ocean as a result of human activity is crucial, not least to understand the impact of these changes on marine life." (Quote from Gruber, one of the authors.)

      Though there's always an element of fear when it omes to the not-perfectly-known, I think it is more accurate to suggest that in novel situations most are simply being humble about what they/we don't know yet. I am heartened by the research being conducted now, both about climate change and about the coronavirus.

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  8. Yes, I noticed on the graph that the eruption of Kilauea in May 2018 didn't seem to create a change in the seeming regularity of the graphs, especially because of its proximity to the Mauna Loa Observatory. Checking out NOAA's Mauna Loa Observatory website is fascinating. How about this...tax breaks for house plants. We should be able to claim them as dependents!

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  9. There's a huge difference between measuring CO2 in a city where day to day traffic, factories, power plants, etc. produce localized CO2 and measuring it at a stable location like a laboratory on an island in the ocean.

    The BBC is not lying when they say the CO2 emissions in NYC are down, but a few weeks of lower emissions have no effect on the CO2 in the atmosphere where it has slow seasonal variation and even slower annual variation.

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  10. What about the particulate matter? That's the stuff that aggravates all sorts of breathing problems, is it not? Tire dust has to be down, because there aren't many cars on the road. Aren't there all sorts of pollutants besides carbon dioxide, that are produced by the burning of petrol? From the website of The Union of Concerned Scientists:
    https://www.ucsusa.org/resources/cars-trucks-buses-and-air-pollution
    Particulate matter
    VOC's
    Nox
    Sulfur dioxide
    All very different than carbon dioxide, i believe.
    It would seem that these pollutants might be less now that people aren't driving cars or flying in airplanes.

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    1. On my pollution monitor in Seattle, the particulate matter pollution has been WAY DOWN so I think at the very least there are some healthier lungs in cities as a result of this.

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  11. " It is also provides notice that only really huge declines in CO2 emissions, far greater that what is occurring during this lockdown period, will be necessary to really move the needle on global warming."

    In other words, forget about it! It's better to develop technology to deal with global warming than to have all of us go back in time (technologically) and live in caves.

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  12. What is clear is air in most big cities right now- can we talk about that? I think that's the "miracle" everyone is so excited about. People not driving does make a difference. Any oceans are a lot more active without all the boating traffic- even here in The Sound. I'd like to think that Cliff is making a clear distinction about long term upward trajectories, vs. the immediate relief of cutting emissions right now. Best of all- oil prices have crashed, making it clear that we really don't need to guzzle so much to begin with. :-)

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  13. If the CO2 measured at the top of Mauna Loa did start to rapidly drop, it would call in to question every climate model ever used by the IPCC. Even in the most optimistic scenarios, temperatures continue to rise and CO2 continues to increase for decades after a change is made, before leveling off. Somewhat analogous to "flattening the curve" in a pandemic--it doesn't immediately happen when a change is made.

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  14. Here in Salem OR Area people are driving like it's normal traffic. Where are they all going with everything under lock and key?

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    1. According to State of Oregon: Between 70,000 and 80,000 vehicles traveled Interstate 5 southbound at the Interstate Bridge on any given weekday in March 2019. Since the governor's executive order, that number has dropped to the 40,000 range. Traffic accidents in Region 1 have dropped by 75%.

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