New paper finds only ~3.75% of atmospheric CO2 is man-made from burning of fossil fuels – Published in Atmospheric Chemistry and Physics

New paper finds only ~3.75% of atmospheric CO2 is man-made from burning of fossil fuels

A paper published today in Atmospheric Chemistry and Physics finds that only about 3.75% [15 ppm] of the CO2 in the lower atmosphere is man-made from the burning of fossil fuels, and thus, the vast remainder of the 400 ppm atmospheric CO2 is from land-use changes and natural sources such as ocean outgassing and plant respiration.

According to the authors,

We find that the average gradients of fossil fuel CO2 in the lower 1200 meters of the atmosphere are close to 15 ppm at a 12 km × 12 km horizontal resolution.
The findings are in stark contrast to alarmist claims that essentially all of the alleged 130 ppm increase in CO2 since pre-industrial times is of man-made origin from the burning of fossil fuels, finding instead that only 15 ppm or ~11.5% of the increase is of fossil fuel origin. The findings cast additional doubt upon the IPCC carbon-cycle Bern Model, previously falsified by the atomic bomb tests.

Furthermore, if use of fossil-fuels has contributed such a small part of total atmospheric CO2 levels, restricting use of fossil fuels will have little effect upon CO2 levels.

Full paper open access:

Atmos. Chem. Phys., 14, 7273-7290, 2014

Simulating the integrated summertime Δ14CO2 signature from anthropogenic emissions over Western Europe

D. Bozhinova1, M. K. van der Molen1, I. R. van der Velde1, M. C. Krol1,2, S. van der Laan3, H. A. J. Meijer3, and W. Peters1
1Meteorology and Air Quality Group, Wageningen University, the Netherlands2Institute for Marine and Atmospheric Research Utrecht, Utrecht, the Netherlands3Centre for Isotope Research, University of Groningen, Groningen, the Netherlands

Abstract. Radiocarbon dioxide (14CO2, reported in Δ14CO2) can be used to determine the fossil fuel CO2 addition to the atmosphere, since fossil fuel CO2 no longer contains any 14C. After the release of CO2 at the source, atmospheric transport causes dilution of strong local signals into the background and detectable gradients of Δ14CO2 only remain in areas with high fossil fuel emissions. This fossil fuel signal can moreover be partially masked by the enriching effect that anthropogenic emissions of 14CO2 from the nuclear industry have on the atmospheric Δ14CO2 signature. In this paper, we investigate the regional gradients in 14CO2 over the European continent and quantify the effect of the emissions from nuclear industry. We simulate the emissions and transport of fossil fuel CO2and nuclear 14CO2 for Western Europe using the Weather Research and Forecast model (WRF-Chem) for a period covering 6 summer months in 2008. We evaluate the expected CO2 gradients and the resulting Δ14CO2 in simulated integrated air samples over this period, as well as in simulated plant samples.We find that the average gradients of fossil fuel CO2 in the lower 1200 m of the atmosphere are close to 15 ppm at a 12 km × 12 km horizontal resolution. The nuclear influence on Δ14CO2 signatures varies considerably over the domain and for large areas in France and the UK it can range from 20 to more than 500% of the influence of fossil fuel emissions. Our simulations suggest that the resulting gradients in Δ14CO2 are well captured in plant samples, but due to their time-varying uptake of CO2, their signature can be different with over 3‰ from the atmospheric samples in some regions. We conclude that the framework presented will be well-suited for the interpretation of actual air and plant 14CO2 samples.

Excerpts from the conclusions:

In this work, we demonstrated the ability of our modeling
framework to simulate the atmospheric transport of CO2
and consequently the atmospheric 114CO2 signature in integrated
air and plant samples in Western Europe. Based on
our results we reach the following conclusions.

1. Simulated spatial gradients of 114CO2 are of measurable
size and the 6-month average CO2ff [CO2 from the burning of
fossil fuels] concentrations in the lower 1 km of the atmosphere
across Western Europe are between 1 to 18 ppm.

2. Enrichment by 14CO2 from nuclear sources can partly
mask the Suess effect close to nuclear emissions, particularly
in large parts of UK and northwestern France.
This is consistent with previous studies (Graven and
Gruber, 2011) and we show that in these regions the
strength of the nuclear influence can exceed the influence
from fossil fuel emissions.

3. The simulated plant 114CO2 signatures show spatial
gradients consistent with the simulated atmospheric
gradients. Plant growth variability induces differences
between the simulated plant and the daytime atmospheric
mean for the period of growth, of a magnitude
that is mostly within the measurement precision of
±2 ‰, but can be up to ±7‰ in some areas.

4. Integrated 114CO2 samples from areas outside the immediate
enrichment area of nuclear emission sources
are not sensitive to occasional advection of enriched air
due to their long absorption period. However, to properly
account for the nuclear enrichment term on smaller
time scales, improvements in temporal profiles of nuclear
emissions are needed.

5. New 114CO2 sampling strategies should take advantage
of different sampling methods, as their combined
use will provide a more comprehensive picture of the
atmospheric 114CO2 temporal and spatial distribution.