Tag Archives: future trends

Reducing CO2 Emissions to Reverse Global Warming

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Reducing CO2 Emissions to Reverse Global Warming

We know that Global Warming can be reduced during the years of the century ahead of us if we — our civilization — steadily reduces its emissions of carbon dioxide gas (CO2) into the atmosphere.

Given a specific rate for the reduction of anthropogenic (our CO2) emissions:

— how long will it take to return Earth’s average temperature to its unperturbed pre-industrial level?, and

— how much higher will Global Warming (Earth’s temperature) become before it begins to decrease?

Answering these questions is the subject of my recent study. This work is based on a Carbon Balance Model, which I described in an earlier report. [1]

That model has been further refined in order to address these questions, and the details of that refinement are described in a technical report. [2]

Prior to the buildup of anthropogenic CO2 emissions in the air, the fluxes of CO2 released by the respiration of Life-on-Earth; and the fluxes of CO2 absorbed from the air by photosynthesis, the surface waters of the oceans, and rock weathering chemical reactions; were in balance. That balance is known as the Carbon Cycle.

As the rate and buildup of anthropogenic emissions increased (after ~1750, but particularly from the mid-20th century), the Carbon Cycle was perturbed out of balance, and the magnitude of that imbalance is determined by the difference between two effects: Anthropogenic Sources, and Stimulated Sinks.

The Anthropogenic Sources are:

— the CO2 emissions by the human activities of fossil-fueled energy generation and industry, and

— the CO2 emissions from land use changes (deforestation and its attendant increase of wildfires).

The Stimulated Sinks are the additional absorption of CO2 by photosynthesis and the surface waters of the oceans, because of higher atmospheric concentrations of CO2. At a sufficiently high level of atmospheric CO2 concentration, both these sinks will saturate — stop absorbing CO2. What that “sufficiently high level” is remains uncertain.

The work summarized here includes more realistic (more complicated) models of these source and sink terms in the rate equation for the change of the Carbon Balance over time.

Now I am able to quantitatively link specific rates of the reduction of anthropogenic CO2 emissions, to consequent projected histories of the slowing and then reversal of Global Warming.

Such quantitative linkages have long been featured in the super-computer models of CO2 accumulation in the atmosphere, by the major Climate Science institutes; but now I have my own quantitative version of this correlation, which is analytical (expressed as math formulas, and enumerated with a hand calculator and basic home computer).

Anthropogenic CO2 emissions in year 2020 are 42.2GtCO2/y (42.2 giga-metric-tons of CO2 per year = 42.2*10^+12 kilograms/year). This magnitude of total anthropogenic emissions, E, is the addition of our fossil-fueled and land use emissions.

I considered three cases of the intentional steady reduction of annual human-caused CO2 emissions, which are defined to decrease exponentially. The characteristic decay time of each case is: 40 years (CASE 1, a 2.5% annual reduction), 100 years (CASE 2, a 1% annual reduction), and 200 years (CASE 3, a 0.5% annual reduction).

Emissions would be reduced to half their initial rate in 28 years for CASE 1; in 69 years for CASE 2; and in 139 years for CASE 3.

If each of these reduction plans were alternatively initiated in the year 2020, then:

CASE #1, ∆t=40y:

This trend reaches a peak of 449ppm and +1.32°C in year 2048 (in 28 years); it remains above 440ppm and +1.25°C over the years 2032 to 2064 (between 12 to 44 years from now); then descends to 350ppm and +0.56°C in year 2120 (in 100 years); and 300ppm and +0.18°C in year 2140 (in 120 years).

CASE #2, ∆t=100y:

This trend reaches a peak plateau of 485ppm and +1.6°C over the years 2078 to 2088 (between 58 and 68 years from now); it remains above 480ppm and +1.56°C during years 2066 to 2100 (between 46 and 80 years from now); it descends to 350ppm and +0.56°C in year 2202 (in 182 years); and 300ppm and +0.18°C in year 2225 (in 205 years).

CASE #3, ∆t=200y:

This trend reaches a peak plateau of 524ppm and +1.9°C over the years 2125 to 2135 (between 105 and 115 years from now); it remains above 500ppm and +1.72°C between years 2075 and 2190 (between 55 and 170 years from now); and descends down to 360ppm and +0.64°C in year 2300 (in 280 years).

Message to the Humans

The singular challenge for the progressive political and social elements of our civilization is to awaken the rest of the world — and particularly the “developed” and “developing” high-emissions nations — to a full commitment (demonstrated by action) to steadily and significantly reduce anthropogenic CO2 emissions for the rest of human history.

The sooner such reduction programs are initiated, and the greater the vigor with which they are implemented, the sooner we will begin slowing the advance of Global Warming and its continuing erosion of the habitability of Planet Earth, which humans have enjoyed for over 2 million years, and particularly since the end of the Ice Ages (~11,000 year ago).

With decades to a century of discipline applied to this purpose, we can even reverse Global Warming. The longer we wait to do this, the worse the consequences we will have to suffer through, and the longer it would take to extricate our species — and so many other wonderful forms of Life-on-Earth — from the Hell-on-Earth we are creating by our willful and destructive ignorance.

I can only imagine such major programs of CO2 emissions reductions being synonymous with the economic, political and social uplift of the vast majority of people, because Global Warming is directly caused by the unbounded economic, political and social exploitation of the many by the few.

The fact is that we all live on the same planet, and whatever happens to it — whether worsening conflagration and flooding in the now, or eventual cooling and restoration by human commitment — will affect everybody. There is no guaranteed escape.

The CO2 accumulation model that I have described here is just this old scientist’s way of saying: We can do so much better for ourselves, and our children deserve that we try.

NOTES

[1] A Carbon Balance Model of Atmospheric CO2
11 September 2020, [PDF file]
https://manuelgarciajr.files.wordpress.com/2020/09/a-carbon-balance-model-of-atmospheric-co2.pdf

[2] Trends for Reducing Global Warming
15 September 2020, [PDF file]
https://manuelgarciajr.files.wordpress.com/2020/09/trends-for-reducing-global-warming.pdf

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Possible Future Trends of CO2 Concentration and Global Temperature

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Oakland, California, 10:15 AM, 9 September 2020, “Burning Land Eclipse”

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Possible Future Trends of CO2 Concentration and Global Temperature

Carbon dioxide gas (CO2) has been accumulating in the atmosphere since the dawn of the Industrial Revolution (~1750), because increasingly voluminous fluxes of that gas have been exhausted from the lands and the oceans, and are beyond the capacity of natural CO2 sinks to absorb completely.

Prior to the Industrial Revolution, carbon would cycle through a variety of processes that sustained the continuation of life, death, evolution and rebirth, and that all meshed into one grand balance. That balance is called the Carbon Cycle.

The explosive growth of human activity, numbers, exosomatic power, economic wealth, military overkill, and hubristic political pretensions, all spring from the access to and profligate use of heat-energy liberated from fossil fuels. Carbon dioxide is the exhaust fume from our Promethean exertions for greater conquests — and wealth.

The carbon dioxide exhausted by our civilization’s generation of heat-energy, and from our massive exploitation of once virgin land areas, is an increasingly destabilizing perturbation of the Carbon Cycle. This perturbation is called Anthropogenic Emissions.

The imbalance of the Carbon Cycle reverberates through the natural world in many ways that are increasingly harmful and dangerous to Planet Earth’s habitability for ourselves and for many other animal and plant species. The central reality of this complex of growing threats to the viability of the Biosphere is called Global Warming.

Carbon dioxide gas traps heat radiated towards space, as infrared radiation from the surface of Planet Earth, reducing our planet’s ability to regulate its temperature by cooling to compensate for the influx of solar light that is absorbed by the lands and the oceans, and stored by them as heat.

Because of the existential implications of runaway global warming — as well as the intrinsic fascination to curious minds of such a richly complex and grand human-entwined natural phenomenon — scientists have been studying global warming, and its impact on the biosphere, which is called Climate Change.

While scientists of all kinds are excited to share their findings on climate change and impress their colleagues with their new insights, members of the public are singularly interested to know how climate change will affect their personal futures. Can science offer them clear and reliable answers to their questions — and fears — and provide practical remedies and technological inoculations to ward off the threats by climate change to our existing ways of life?

Science does what it can to offer practical insights and helpful recommendations, and humanity does what it usually does when faced with a collective existential crisis: it hides from the inconvenience of drastically changing its personal attitudes and societal structures, which is in fact the only way it would be able to navigate the majority of Earth’s people through the transition to a new social paradigm; a new, sustainable and harmonious relationship between human life and Planet Earth.

While I am grateful to all the professional climate scientists — and their related life scientists who study many aspects of this complex of geophysical processes and biological organisms and systems — for making known so much of the workings of the globally warming biosphere, I am nevertheless curious to gain a quantitative understanding of it all for myself. To that end, I have devised my own phenomenological thermodynamic “toy models” of global warming. The sequence of my reports charting the evolution of my quantitative understanding of global warming, are listed at [1].

My newest report describes a rate equation for the accumulation or loss of atmospheric CO2 over the course of future time. This equation is derived from considerations of recent data on the Carbon Cycle (from the Global Climate Project), along with some mathematical assumptions about the relationships used to quantify “carbon dioxide sweepers,” the processes that scavenge atmospheric CO2.

The results of this work are projections of possible future histories of the concentration of atmospheric carbon dioxide, as well as a projection of the most likely trend of rising average global temperature.

The complete report on the new work (of which this is just a brief summary) is available at [2].

As is true of all future-casts, we will just have to wait till then to see if they were accurate, assuming we don’t do anything beforehand — collectively — to avoid the worst possibilities.

Such is the dance with the chaos and nonlinearity of the approaching future.

From the general mathematical result of this model, three possible future trends of CO2 concentration history were calculated:

CASE #1, “business as usual,” anthropogenic emissions continue at today’s level indefinitely;

CASE #2, anthropogenic emissions are immediately reduced to the point of holding CO2 concentration constant at today’s level, indefinitely;

CASE #3, anthropogenic emissions are immediately reduced to a trickle, so as to reduce the excess of CO2 in the atmosphere as quickly as possible.

Also, the trend of rising global temperature that accompanies CASE #1 was calculated.

CASE #1 is a pure growth trend, from 407.4ppm to 851.8ppm over the course of about 3,000 years (ppm = parts per million of concentration in the atmosphere).

CASE #2 requires that the anthropogenic emission rate be ~50% of the current rate (or 21GtCO2/y instead of 41GtCO2/y; for the units GtCO2/y defined as giga-metric-tonnes of CO2 emission per year).

This reduced rate of anthropogenic emission would just keep the CO2 concentration at 407.4ppm (from the beginning of 2019) into the near distant future (~1,600 years, and beyond), during which time the excess heat-energy presently in the biosphere would continue to degrade our weather, climate, environments, biodiversity, and planetary habitability.

CASE #3 would clear away the current excess of CO2 in the atmosphere, and then continue to reduce the atmospheric CO2 concentration to a very low level over the course of about 700 years. This would require that anthropogenic emissions be immediately reduced to about one-fifth (1/5) of their current levels, and maintained at or below that level indefinitely.

The implication is clear: if we wish to reduce the amount of CO2 in the atmosphere we have to reduce our anthropogenic emissions well below 50% of what they are today, maintain that discipline indefinitely, and wait centuries to millennia to achieve a significant reduction.

The global temperature excursion (above the average global temperature of the pre-industrial world) that accompanies CASE #1 rises steadily, though at a diminishing rate, from +1°C in 2019, to nearly +2.6°C in 2300 (~300 years). Along the way it passes +1.5°C in year 2065 (in ~40 years), and it passes +2°C in year 2120 (in ~100 years).

Global temperature would rise higher and sooner if the absorption rates of CO2 by photosynthesis and the oceans did not continue increasing — as they do today — in proportion to the increases in the atmospheric concentration of CO2. At present, increased CO2 concentration stimulates increased CO2 absorption. The model here assumes this is always true, but in reality this “sink growth” effect may saturate (be limited) at some higher level of CO2 concentration. Whether any such saturation limit on the absorption (sink) rate exists or not, is unknown.

If the +1.5°C and +2°C temperature rise milestones are truly to be avoided then it is imperative that anthropogenic emissions be drastically reduced immediately. As yet there is no sign that such reductions will occur.

The physics and mathematics of all this are fascinating, but the implications for civilization and life-on-Earth are stark.

NOTES

[1] One Year of Global Warming Reports by MG,Jr.
15 July 2020
https://manuelgarciajr.com/2020/07/15/one-year-of-global-warming-reports-by-mgjr/
Updated to 7 September 2020

[2] A Rate Equation for Accumulation or Loss of Atmospheric CO2
5 September 2020 (revised 9 September 2020)
[take a copy]
Rate Equation for Atmospheric CO2 (revised)

or view directly:

Click to access rate-equation-for-atmospheric-co2-revised.pdf

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