Atmospheric Carbon Dioxide: What Humans Have Added, Won't Just Go Away

Rising atmospheric carbon dioxide concentration — will it kill us all?

Even among the experts, opinions differ. The climate models, which attempt to predict the evolution of a chaotic atmospheric system, will likely always be controversial, but they indicate possible outcomes such as rises in sea level that would inundate the world's most heavily populated regions, a prediction that should give one pause for thought.

Plus, there are two other important and certain outcomes.

One is that as atmospheric carbon dioxide concentration rises it progressively impairs human mental function, as demonstrated by recent research by what one must assume are highly competent researchers at Harvard University and one of America's National Laboratories.

The other is that rising atmospheric concentration plays Hell with the biosphere, with effects that include mass species extinctions and, paradoxically, a huge increase in human population as carbon dioxide stimulates agricultural crop yields.

These facts seem now to have been generally accepted, even by major oil companies, with the result that the world is now headed for a broad-ranging set of government mandated actions to slow human-caused carbon dioxide emissions with the aim of achieving zero net emissions by 2050.

Problem is, we will still be left with a hugely elevated atmospheric carbon dioxide concentration, which will still be working its effects on the world, speeding the melting of glaciers, ice sheets and frozen soils, disrupting ecosystems and still, therefore, causing havoc.

How to respond?

One might simply hope that, in the course time, the atmospheric carbon dioxide concentration would gradually decline to where it was before the industrial revolution and the fossil fuel age. That, however, is a hope sadly to be disappointed. If there were any natural mechanism for lowering the atmospheric carbon dioxide concentration, the concentration prior to the industrial revolution would already have hit zero, all photosynthetic organisms would have died out, as would the entire animal world, dependent as it is, directly or indirectly, on photosynthetic organisms.

But, in fact, prior to the industrial revolution, atmospheric carbon dioxide concentrations were flat at around 270 part per million for hundreds of thousands of years. Yes, prior to the industrial revolution there would have been some sequestration of carbon dioxide, mainly by geological processes. But sequestration was evidently balanced by natural carbon dioxide emissions to the atmosphere resulting chiefly from volcanic eruptions. So if carbon dioxide concentrations are be reduced to something like the pre-industrial value it will be necessary for humanity to do something.

What to do?

The only answer, apparently, is CCS: carbon capture and storage.

How to capture and store carbon dioxide is a question subject to many lines of research and pilot-scale testing. Here I will consider only whether this approach to lowering atmospheric carbon dioxide concentration is economically viable:

First, how much carbon dioxide are we talking about?

Well here's the math:

The surface area of the world is ca 500 million square kilometers, or five trillion square meters.

The mass of the atmosphere is just over ten metric tons per square meter, or around 500 trillion metric tons in total. Of that, the amount of carbon dioxide that, since pre-industrial times, will have been added to the atmosphere by 2050 is:

500 trillion * (600 – 270)/1,000,000 * 1.84/1.24 = 2.45 trillion tons.

That's quite a lot, but there are methods known today for sequestering atmospheric carbon dioxide that are estimated to cost less than $100 per ton. Assuming that further research and development reduces that cost by something like a factor of ten, the cost of reducing atmospheric carbon dioxide concentration to the pre-industrial value will be around twenty-five trillion dollars, or about one quarter of the World's yearly GDP.

So, yes, adjusting the World's atmospheric carbon dioxide concentration back to normal, though costly, will be feasible, though depending on technical developments, it may take a few years.

RELATED:
CanSpeccy: 
Rising Atmospheric Carbon Dioxide Concentration, Part I: Carbon Dioxide Is Not a Greenhouse Gas

Global Warming: No Need to Panic Yet?

US Temperature anomaly 2004 to 2019. Source: U.S. Natioanal Oceanic

and Atmospheric Administration, National Temperature Index.

The temperature anomaly is the difference between the temperature at a particular time relative to the long-term mean temperature. So currently, and for the last fifteen years, the average temperature recorded across the continental United States has shown essentially zero deviation from the long-term mean temperature. Which is not to say, however, that rising atmospheric carbon dioxide is a good thing. On the contrary, as comments linked below indicate, it is potentially a very bad thing.

Related: 
Zero Hedge: Creator Of Global-Warming's Infamous "Hockey Stick" Chart Loses 'Climate-Science' Lawsuit
CanSpeccy: Rising Atmospheric Carbon Dioxide Concentration, Part I: Carbon Dioxide Is Not a Greenhouse Gas
CanSpeccy: Rising Atmospheric Carbon Dioxide Concentration, Part II: Ecosystem Disruption
CanSpeccy: Rising Atmospheric Carbon Dioxide Concentration, Part III: Induced Stupidity and the Decline of the West
CanSpeccy: Rising Atmospheric Carbon Dioxide Concentration, Part IV: Reversing the Trend

Rising Atmospheric Carbon Dioxide Concentration, Part II: Ecosystem Disruption

Some global warming "skeptics" dismiss the climatic effect of carbon dioxide by claiming that the gas exists in the atmosphere in such a negligible quantity that even several times that negligible quantity is still negligible. In terms of climate, this may even be true, but the atmospheric concentration of carbon dioxide has a massive effect on the biosphere. Each year, worldwide plant dry biomass production totals around 170 billion tons, of which about half, or 85 billion tons, comprises carbon. All of that carbon is derived from atmospheric carbon dioxide at a rate that is closely dependent on the concentration of carbon dioxide in the atmosphere.

The reason for the dependence of photosynthetic production on the atmospheric carbon dioxide concentration is that plants extract carbon dioxide from the atmosphere by diffusion. Assimilating atmospheric carbon dioxide by diffusion entails a challenge because, if there is a path for the carbon dioxide to diffuse from the atmosphere to the plant cell, there must also be a path for water vapor to diffuse from the plant cell to the atmosphere. This means that plants exchange water, which is usually in limiting supply, for carbon. Moreover, the rate of exchange depends directly on the concentration gradients of the two gases between plant cell and atmosphere. Therefore, if the atmospheric carbon dioxide concentration rises, the amount of carbon fixed by plants in exchange for the water available to them also rises. (When available water has been exhausted, plants close down the path for gaseous diffusion between photosynthetic tissue and atmosphere and both photosynthetic production and water loss ceases.)

Australia's outback greening up: a response to rising carbon 
dioxide concentration.

Thus, an increase in atmospheric carbon dioxide concentration makes possible something like a proportional increase in plant biomass production. This effect has already been observed in the case of some crop species, and in both tropical and boreal forests. We know, for certain, therefore, that rising atmospheric carbon dioxide concentration is raising the carrying capacity of the planet for mankind and other animals by increasing yields of crops and the productivity of natural ecosystems.

Rising atmospheric carbon dioxide concentration is also changing the structure of ecosystems, because it has been shown that some plants respond more vigorously to rising carbon dioxide concentration than others. Particularly responsive are woody species of arid habitats such as the Australian outback, the Sahel to the immediate south of the Sahara Desert, and the South American Savanna. This means that rising carbon dioxide concentration is changing the species composition of plant communities and thereby changing the composition of the animal communities that depend on the plants for food and shelter. The extent and significance of these changes has thus far, received barely any attention, but they will become increasingly obvious as the atmospheric carbon dioxide concentration continues its accelerating rise.

Related: 

CanSpeccy: Rising Atmospheric Carbon Dioxide Concentration, Part IV: Reversing the Trend

CanSpeccy: Rising Atmospheric Carbon Dioxide Concentration, Part III: Induced Stupidity and the Decline of the West

CanSpeccy: Rising Atmospheric Carbon Dioxide Concentration, Part I: Carbon Dioxide Is Not a Greenhouse Gas