Man-made Emissions are the Primary Source of the Increase in Atmospheric CO2 Since the Industrial Revolution
Gregory Wrightstone
September 19, 2024
Presented to the CLINTEL Workshop on Recent Research Developments on Atmospheric Temperature, Carbon Dioxide, and Their Relationship,
Overwhelming evidence that the recent atmospheric CO2 increase is primarily from man’s emissions
Paleoclimate and Historical CO2 levels
• Ice core CO2 concentrations
• Plant stomata CO2 reconstructions over the Holocene
• Historical CO2 levels from direct measurements with chemical methods
Evidence of the human influence on recent CO2 increase
• The mass balance
• The 13C/12C ratio
• The 14C/12C ratio
• The oxygen use
• The ocean’s pH and pCO2
• The process characteristics
Discussion/Conclusions
Simplifying the Argument:
Will adding large amounts of CO2 to the atmosphere increase atmospheric CO2?
Creation of the bulk of the world’s coal reserves
lowered CO2 levels by nearly 4,000ppm
Why would the liberation of that same sequestered CO2 not have the ability to increase atmospheric levels by a mere 150 ppm?
No Dispute
Temperature has been driving CO2 levels for millions of years…
Until now.
An entirely new and unprecedented source of CO2 has upended this.
The past is NOT the key to the present due to new CO2 source.
Ice Core CO2 Measurement:
For details on paleoCO2 measurements using ice cores, please refer to recent publication by geologist and CO2 Coalition member
Renee Hannon
https://co2coalition.org/publications/measureme
nt-of-co2-concentrations-through-time/
Ice Core CO2 Measurement:
The gold standard for paleo-atmospheric global CO2 concentrations
• CO2 rarely exceeds 300 ppm in the past 800,000 years, much less than present day concentrations of 420 ppm.
• Strong confirmation that a new source of CO2 is present today and recently
• Allegations of “recent” high levels are based on flawed methodologies.
50% increase in current interglacial – Something is different…
That something is fossil fuel use
Why is this important??
High CO2 levels in the past are supportive of a primary role in recent increases
If recent levels are unprecedented over the last 800,000 years – that is strong evidence that human emissions are the primary source
Measurements using plant stomata and the chemical method are compromised due mainly to data acquired near large vegetative sources
and sinks near ground level
“I measured CO2 concentration on my porch every few hours for about a week. It got as low as 300 ppm at 3 pm in the afternoon after a day of photosynthesis by the trees and lawns of Princeton, and it got as high as 550 ppm at dawn after 10 hours of darkness with no photosynthesis but with continued respiration of living things.”
Dr. William Happer personal communication 9/18/24
The Carbon Dioxide Content of Field Air
Author(s): H. W. Chapman, L. S. Gleason and W. E. LoomisSource: Plant Physiology, Vol. 29, No. 6 (Nov., 1954), pp. 500-503Published
Plant Stomata CO2 have high Uncertainties
Stomata pore frequency shows inverse relationship with atmospheric CO2 concentrations
Short time intervals with high variability
• Uncertainty 10-50 ppm
348 or 310 ppm maximum during Early Holocene?
Normalized to ice core baseline
• Compares amplitudes and temporal synchroneity
• Variability from baseline consistent with seasonal amplitudes
Challenges
• Empirically derived calibration
• Northern Hemisphere dominant
• Species-specific responses
• Local and/or seasonal bias
Hannon, 2024
Chemical CO2 Measurements are Unreliable
Ernst Beck:
100,000 sample measurements based on wet chemical methods
• Poor sampling and calibration practices
Taken on land near large sources and sinks at near ground level
• Northern Hemisphere dominant
• Large variability between sites
• Variable wind speed and precipitation 1940 Peak Challenges
• Not seen in high resolution ice cores
• Not present in stomata CO2
• 70 ppm increase (decrease) physically impossible via vegetation and ocean releases (intake)
Six lines of evidence confirming that nature is a net sink, not a net source
• The mass balance
• The 13C/12C ratio
• The 14C/12C ratio
• The oxygen use
• The ocean’s pH and pCO2
• The process characteristics
The Mass Carbon Balance
Atmospheric CO2 increase: 218 PgC
Human fossil emissions: 405 PgC.
Therefore, nature was more sink than source since 1960.
Declining 13C/12C ratios
Clear decreasing 13C/12C trend
• Strong seasonal variability in NH
• Organic decay/digestion produces lighter 13C/12C ratio.
• Burning of fossil fuels produces lighter 13C/12C ratio.
13C/12C ratio cannot distinguish between vegetation and fossil fuels.
• Need to look at other evidence such as 14C and O2.
13C/12C ratio from ice cores shown small variations of only +/-0.2 per mil.
Strong decrease of 13C/12C ratio excludes huge contribution of (deep) oceans to the CO2 increase in the atmosphere.
Declining 14C/12C ratio
Carbon isotope 14C created in atmosphere by impact of cosmic rays with short half life (5,730 years).
14C used for radiocarbon dating of organic material.
• Vegetation in equilibrium with 14C
• Fossil fuels have no measurable 14C Nuclear bomb testing nearly doubled atmospheric 14C content.
Strong depletion of 14C consistent with fossil fuels that have no 14C.
Declining oxygen concentrations
Oxygen levels have been decreasing as CO2 levels increase
Main reduction of oxygen is due to burning of fossil fuels
Burning methane yields heat plus:
CH4 + 2O2 = 2H2O + CO2
Declining oxygen concentrations
Declining oxygen clearly shows that plant CO2 uptake exceeds plant decay, thus the biosphere is a net absorber of CO2 and not the cause of the sharp 13C/12C decline since 1850.
South Pole
Declining oxygen concentrations
If the burning of fossil fuels can cause a decrease in atmospheric oxygen, why could it not also fuel atmospheric CO2?
South Pole
Ocean’s pH and CO2
The pCO2 of the ocean surface has increased in parallel with and slightly lower than the pCO2 of the atmosphere.
Ocean surface pH decreased ~0.1 pH since the start of industrial revolution.
Increasing pCO2 with decline in pH suggests oceans are a CO2 sink and not a source for modern CO2 increase.
Process Characteristics
Two main processes that influence CO2 levels in the atmosphere: human emissions and temperature.
Observed CO2 increase in the atmosphere follows human emissions at a near exact rate.
Temperature is not main cause of 130 ppmv CO2 increase over the last 170 years.
• Temperature influence on CO2 in the past is at maximum 16 ppmv/oC.
• Temperature influence is only 10% of measured CO2 increase.
Main cause of observed 130 ppmv
increase is the 210 ppmv one-way human addition.
Conclusions
Atmospheric CO2 concentration of 420 ppmv is significantly higher by ~100 ppmv than in the past 800,000 years.
Anthropogenic emissions of fossil CO2 are larger than the measured increase of CO2 in the atmosphere suggesting natural sinks.
• Nature is a net sink for CO2, and thus cannot be a net source.
Oceans are not a source for the modern increase of CO2 in the atmosphere.
• Strong decrease of the 13C/12C ratio in the atmosphere and ocean surface waters excludes huge contribution of oceans.
• Increasing inorganic carbon species content with decline in pH indicates oceans are a CO2 sink.
Vegetation is not a source for the modern increase of CO2 in the atmosphere.
• Strong decrease of the 13C/12C ratio cannot distinguish between vegetation and fossil fuels.
• Vegetation contains 14C and should not deplete 14C in the atmosphere.
• Vegetation releases O2 by photosynthesis or reverse during decay in exact ratio to each other.
Conclusions (con’t)
Burning of fossil fuels is the source for the modern increase of CO2 in the atmosphere.
• Strong decrease of the 13C/12C ratio associated with vegetation and fossil fuels.
• Strong depletion of 14C/12C ratio is consistent with fossil fuels that have no 14C.
• Burning of fossil fuels consumes O2 in the atmosphere although O2 decrease is less.
Two main processes influence CO2 levels in the atmosphere: human emissions and temperature.
• Temperature accounts for a maximum of 10% or only 13 ppmv of the current increase.
• The observed increase of CO2 in the atmosphere strictly follows human emissions at a near exact rate.
The main cause of the observed 130 ppmv increase is the 210 ppmv oneway human addition.