“Consensus” climate science has for decades assumed that the vast majority of the increase in atmospheric concentration of carbon dioxide (from about 280 parts per million by volume [ppmv] before the Industrial Revolution to about 400 today) has come from burning fossil fuels for energy. On that assumption, “consensus” scientists have alleged that human activity has driven all or most global warming over that time.
Most criticism of that thinking has focused on “climate sensitivity”—how much warming comes from added atmospheric CO2, with “skeptics” opting for “climate sensitivity” in the range of 0.5–2.0 deg. C while “alarmists” opt for 1.5–4.5 or even higher. More recent studies increasingly lean toward the lower range as they note that observed warming has been considerably less than predicted.
But what if far less of the increase in CO2 has come from human activity? If that’s so, then human contribution to global warming would be far less, too—regardless what “climate sensitivity” turns out to be.
And what if CO2 added to the atmosphere remains there not for hundreds of years but for only a few? That, too, would reduce human contribution to global warming.
That’s the implication of a new paper in Global and Planetary Change by Hermann Harde, “Scrutinizing the carbon cycle and CO2 residence time in the atmosphere,” which concludes that human activity has contributed only about 4% of total atmospheric CO2 and 15% of the ~120 ppmv increase in CO2 concentration since the Industrial Revolution, and that CO2 added to the atmosphere stays there for only about 4 years.
Here’s the abstract:
Climate scientists presume that the carbon cycle has come out of balance due to the increasing anthropogenic emissions from fossil fuel combustion and land use change. This is made responsible for the rapidly increasing atmospheric CO2 concentrations over recent years, and it is estimated that the removal of the additional emissions from the atmosphere will take a few hundred thousand years. Since this goes along with an increasing greenhouse effect and a further global warming, a better understanding of the carbon cycle is of great importance for all future climate change predictions. We have critically scrutinized this cycle and present an alternative concept, for which the uptake of CO2 by natural sinks scales proportional with the CO2 concentration. In addition, we consider temperature dependent natural emission and absorption rates, by which the paleoclimatic CO2 variations and the actual CO2 growth rate can well be explained. The anthropogenic contribution to the actual CO2 concentration is found to be 4.3%, its fraction to the CO2 increase over the Industrial Era is 15% and the average residence time 4 years.
Dr. Kenneth Talbot says
Very interesting!
Josh says
The biggest problem with ruining the earth besides the trash we create is the agricultural industry. Up to 91% of the Amazon is destroyed to make fields for grazing cattle. This is unsustainable. The waste and destruction of nature are going to result in further damage. Research this and see how we are doing irreversible damage to this planet we were entrusted to be stewards of.
E. Calvin Beisner says
One thing is certain: Your 91% claim is not merely false but a vast exaggeration absolutely lacking in all empirical evidence. According to Brazil’s Instituto Nacional de Pesquisas Espaciais (INPE, or National Institute of Space Research) (see https://en.wikipedia.org/wiki/Deforestation_of_the_Amazon_rainforest), 81.2% of the Amazon rainforest that was standing in 1970 is still standing, and the depletion rate is slowing. From 1978-1987 it averaged about 0.5% per year; in 1988 it was about 0.4%, likewise in 1990. But it was about 0.2% per year in 2010; 0.1% in 2011; 0.1% in 2012; 0.2% in 2013; 0.1% in 2014; and 0.2% in 2015. Whether one considers this rate good or bad is a distinct question from what the rate is–and certainly these data refute your claim that up to 91% of the Amazon is destroyed. Historical perspective is also helpful. Deforestation is highest during early stages of economic development but declines afterward as a higher percentage of the population leaves farming (highly land intensive) for urban industrial and commercial life; meanwhile, higher agricultural earnings (driven by rising non-farm population) lead to greater mechanization and greater use of fertilizers, pesticides, and insecticides, and to greater use of high-yield crop varieties, which all lead to higher yield per acre and hence lower demand for agricultural acreage. The result is that deforestation rates decline, level off, and then reverse, with forest cover expanding, as it has done in all developed countries of the world. The one thing that might reverse that trend is the demand to substitute biofuels–primarily ethanol, but also palm oil and others–for fossil fuels, a demand that threatens to send agricultural acreage back upward. Feeding the human population is no great challenge with current technologies; turning its food into vehicle fuel is disaster in the making.
Robbo Holleran says
Very good response. Deforestation worldwide is slowing dramatically and Brazil is one example. I am a professional forester in Vermont, and am partial to trees. Beisner spells out Vermont’s history well: nearly 100% forest in 1761, cleared to about 25% forest about 1860 (.75% annually for 100 years!) and naturally reforested as agriculture moved west to about 78% forested today. That percent has been fairly stable for 25 years.
Miner49er says
The entire CAGW hypotheses is apocryphal and unproven. It is the worst sort of scientism. Political leaders who impose or accept taxes or regulations on fossil fuels will be seen as fools.
Climate change is a false premise for regulating or taxing carbon dioxide emissions. Nature converts CO2 to calcite (limestone). Climate change may or may not be occurring, but is is surely NOT caused by human fossil fuels use. Changes in temperature cause changes in ambient CO2, with an estimated 800 year time lag.
Fossil fuels emit only 3% of total CO2 emissions. 95% comes from rotting vegetation. All the ambient CO2 in the atmosphere is promptly converted in the oceans to calcite (limestone) and other carbonates, mostly through biological paths. CO2 + CaO => CaCO3 (exothermic). The conversion rate increases with increasing CO2 partial pressure. A dynamic equilibrium-seeking mechanism.
99.84% of all carbon on earth is already sequestered as sediments in the lithosphere. The lithosphere is a massive hungry carbon sink that converts ambient CO2 to carbonate almost as soon as it is emitted. All living or dead organic matter (plants, animals, microbes etc. amount to only 0.00033% of the total carbon mass on earth. Ambient CO2 is only 0.00255%.
Full implementation of the Paris Treaty is now estimated to cost $50 trillion to $100 trillion by 2030–$6,667-$13,333 per human being. Nearly two-thirds of humanity’s cumulative savings over history. And will not affect climate at all.