What is CO2 – friend or foe? Tom V. Segalstad Head of the Geological Museum, Natural History Museum, University of Oslo http://folk.uio.no/tomvs
Atmosphere gases The Earth's atmosphere contains on wet basis ~73.5 %nitrogen, ~22.5 %oxygen, ~2.7 % water, and ~1.25 %argonper weight. Among thetrace gasesare: CO2, neon, helium, methane, and others. The content of CO2 is ca.0.05 weight-%, compared with ca. 2.7 weight-% water.
What is CO2? Carbon dioxide CO2 is an colorless, odorless, non-toxic gas. CO2 occurs as a linear O=C=O molecule, where two oxygen atoms stick strongly together with one carbon atomwith double bonds. Hence CO2 is not very reactive. An analogy is how strongly two men (oxygens), each with their two arms, would like to stick to a beautiful woman (carbon).
Some daily life uses of CO2 • Fire extinguishers (replacement of oxygen) • Baking soda (expansion of non-toxic gas) • Soda ”pop” drinks, beer, champagne (effervescense; added or from fermentation) • Neutralizing agent for acid lakes (limestone) • Life jackets (gas expansion) • Cooling agent • Product of our breathing! CH2O + O2CO2 + H2O carbohydrate + oxygen CO2 + water
Plant photosynthesis consume CO2 Plants make carbohydrate by combining atmospheric CO2 with water, powered by light: CO2 + H2O+ energyCH2O + O2 CO2 + water+ energy carbohydrate + oxygen photosynthesis breathing, decay Increasing CO2, water and energy will make the chemical reaction go from left to right, making the plants produce more carbohydrates. We need for living carbohydrates made by plants. Hence CO2 is:THE GAS OF LIFE !
Consequence of photosynthesis The photosynthesis / breathing+decay reaction CO2 + H2O+ energyCH2O + O2 shows us that all CO2 accumulated by the plant, will be released again to the atmosphere when the plant material rot or is burned. Then tree planting will only temporarily remove CO2 from the atmosphere, unless the trees are somehow buried to prevent them from decay or being burned.
IPCC TAR 2001: CO2 in air (upper graph) and surface temperatures (lower graph) were constant for some 900 years, but have risen considerably the last 100 years. IPCC’s scenarios involve drastic rises in both air CO2 concentration and surface temperatures. These assertions have been strongly opposed by CO2 measurement critics and historical temperature facts: warm + cold missing. Medieval warm period missing called the ”Climate Optimum” The ”Little Ice Age” missing
Geological temp. evolution Figure from Bryant (1997) A geologist’s view of the evolution of the surface temperature of the Earth, based on geological data. We see the Pleistocene ice ages (middle right), the Medieval warm period (= the ”Climate optimum”), the Little Ice Age, and future projections!
Energy relations Some of the trace gasses in air can absorb heat, making the Earth habitable (~14°C vs. minus 18°C) by the “Greenhouse Effect”, 146 W/m² of cloud-free air, dominated by water vapor. Anthropogenic CO2 is less than ½ W/m²,judged from C isotopes (more later). Clouds are the real thermostat, with far more temperature regulating power than CO2.
Other energy relations All ice on Earth has a mass of 3.3 x 1022 g. Its latent heat of fusion is 9.3 x 1024 J. The Earth’s ocean has a mass of 1.4 x 1024 g. Assertions say that ”all ice on Earth will melt in a short time from anthropogenic CO2”. If melting energy hypothetically had been taken from the ocean, all its water would cool 2°C. Heat-absorbing part of the air has a mass of only 1.4 x 1022 g. Heating all of the atmosphere 2°C would require energy of 1.2 x 1022 J. This amount of energy is not enough to first heat the air over the poles to the melting point of ice (0°C) and next to overcome the latent heat of fusion for all ice on Earth. Thus ice and ocean participace as “thermostats”.
Solar energy input NOAA’s measurements of the solar constant show that the Sun produced a forcing of 0.24 W/m² during the past sunspot cycle, while assertions said that greenhouse gases caused 0.25 W/m². Coffey et al. write: ”Global change models must discern between variations caused by anthropogenic and natural occurrences to provide a sound scientific basis for policy making on global change issues”. www.ngdc.noaa.gov/stp/SOLAR/solarda3.html
Carbon reservoirs on Earth The carbon in the Earth’s lithosphere and atmosphere has come from degassing of CO2 from the Earth’s mantle. The amount of CO2 in air is minute compared to the other reservoirs. Without sediments, the partial pressure of air CO2 alone would be 40-60 atmospheres. Figure from O’Nions (1984)
INORGANIC CARBON CYCLE This review is important; IPCC’s ocean is clean distilled water. CO2 enters the atmosphere from many sources to the left. Atmospheric CO2dissolves, hydrolyses and protolyses in the ocean. CO2may combine with calcium and precipitate as CaCO3 in limestone, sedimented on the sea floor together with shells from organisms. This is analogous to breathing CO2 into a test tube with Ca(OH)2; CaCO3 almost instantly precipitates.
CO2 equilibria air – ocean – CaCO3 CO2 (g) ↔ CO2 (aq) dissolution CO2 (aq) + H2O ↔ H2CO3 (aq) hydrolysis H2CO3 (aq)↔ H+ + HCO3- (aq) 1st protolysis HCO3- (aq) ↔ H+ + CO32- (aq) 2nd protolysis Ca2+ (aq) + CO32- (aq) ↔ CaCO3 (s) precipitation CO2 (g) + H2O + Ca2+ (aq) ↔ CaCO3 (s) + 2 H+net reaction Note that increase in CO2 (g) will force the reaction to the right. Equilibria are governed by the Law of Mass Action + Henry’s Law: The partial pressure of CO2 (g) in air is proportional to the concentration of CO2 (aq) dissolved in water. The proportionality constant is Henry’s Law Constant, KH; strongly dependent on temperature, less on pressure and salinity.
Henry’s Law in daily use Henry’s Law Constant is an equilibrium partition coefficient for CO2 (g) in air vs. CO2 (aq) in water: at 25°C KH ≈ 1 : 50 At lower temperature more gas dissolves in the water. We have all experienced this – cold soda or beer or champagne can contain more CO2; thus has more effervescense than hot drinks. The brewery sais that they add 3 liters of CO2 to 1 liter of water in the soda. But where did all the CO2 go?
Henry’s Law in daily use Henry’s Law Constant directs that CO2 (g) in air vs. CO2 (aq) in water at 25°C is distributed ≈ 1 : 50 ”atmosphere” This means that there will be about 50 times more CO2 dissolved in water than contained in the free air above. ”ocean” The soda bottle is a good analogue to nature: there is about 50 times more CO2 in the ocean than in the Earth’s atmosphere. Ocean water has 120mg HCO3- per liter; as much CO2 as in 180 liter of air.
The speed of Henry’s Law IPCC claims that the CO2 equilibration between air and water will take 50 - 200 years as ”a rough indication” (IPCC 1990; Table 1.1). ”atmosphere” Furthermore that most of the CO2 added to air will accumulate in the air, and very little be dissolved in water: ”ocean” Table from Segalstad (1998); after Rohde (1992). Experiments show this not to be the case. Do we all wait for 50 – 200 years for our soda or beer from the brewery?
CO2 equilibria air - water IPCC tells us what will happen when the air CO2 has doubled. Is this possible by burning all available fossil carbon? O AIR WATER Imagine you hold up a Roman beam balance at the red circle, illustrating the action of the Henry’s Law balance. To double the air CO2 – how much CO2 must be added? + 1 kg + 50 kg = 51 kg total AIR WATER
CO2 equilibria air - water Let us enter actual data for the masses of CO2 in the atmosphere and the ocean; as carbon equivalents (GT C). O AIR WATER How much can the CO2 content increase in the atmosphere by burning all available fossil fuel, 7.000 GT C, under the condition of chemical equilibrium? + 137 GT + 6 863 GT = 7 000 GT AIR WATER = 20% increase Anthropogenic doubling is impossible
IPCC’s proof of anthropogenic global warming • Atmospheric CO2 increase ”closely parallels” accumulated emissions from the burning of fossil fuels. • CO2 in ice cores show that air CO2 has increased 21% from 280 til 353 ppm over the last 150 years. • Carbon isotope ratios of 13C/12C and 14C/12C have decreased in atmospheric CO2, they ”agree qualitatively” with expected additions of 12C from burning of fossil fuel (enriched in 12C). This implicate that CO2 has a long lifetime in the Earth’s atmosphere (”rough indication 50 – 200 years”).
IPCC’s proofs rejected In a number of publications our research group has rejected IPCC’s 3 proofs of anthropogenic warming.
Cumulative CO2 emissions Me! CO2 measurements near the top of the strongly CO2-emitting active volcano Mauna Loa in Hawaii have been taken as representative of the world’s air CO2 level. There is a 50% error vs. the expected CO2 level from burning fossil fuel. This enormous error of 3 – 4 GT C annually has been nicknamed ”The Missing Sink”, and disproves the IPCC.
Stable carbon isotopes 13C/12C isotope ratios are expressed as δ (delta) values defined as the standard-normalized difference from the standard, expressed as δ13C in per mil (‰). The reference standard used is PDB (Pee Dee Belemnite).
Proof from stable carbon isotopes Figure from Segalstad (1992 & 1996) Left: reservoirs found to be in carbon isotopic equilibrium. Burning of biospheric fossil fuel adds 12C (low δ13C)to the air. δ13Cof air in 1988 show ~4% anthropogenic CO2 in air (right scale shows % mixing). Not 21% as asserted by the IPCC, which would have given air δ13C ≈ -11.
Proof from isotopic mass balance Figure from Segalstad (1992) Using the radioactive decay equation for the lifetime of CO2 in air, we can calculate the masses of remaining CO2 from different reservoirs using isotopic mass balance; checking for match vs. air CO2 in December 1988: mass = 748 GT C; δ13C= -7.807 (Keeling et al. 1989).
Proof from isotopic mass balance Figure from Segalstad (1992) The calculations confirm that maximum 4% (14 GT C) of the air CO2 has anthropogenic origin; 96% is indistinguishable from non-fossil-fuel (natural marine and juvenile)sources. Air CO2 lifetime is ~5 years. ~134 GT C (18%) of air CO2 is exchanged each year, far more than the ~6 GT C annually released from fossil fuel burning.
Proof from isotopic mass balance Figure from Segalstad (1992) We also see why the IPCC’s ”rough indication” lifetime 50-200 years for atmospheric CO2 gives an atmosphere which is too light; only 50% of the atmospheric CO2 mass. This explains why the wrong IPCC model creates the artificial 50% error, nicknamed ”The Missing Sink”.
Conclusions • CO2 is the ”gas of life”, essential for life of organisms (photosynthesis). • CO2 is an integral part of an enormous natural cycle between the Earth’s interior – atmosphere – organisms – ocean – limestone. • The atmospheric CO2 is a small, short-lived, temporary stock of CO2. • The 50 times larger marine reservoir of CO2 is governing the atmospheric CO2 reservoir, not vice versa. • Carbon isotopes show that maximum 4% of air CO2 has anthropogenic origin; the rest is ”natural” CO2 from the ocean and the Earth’s interior. ~1/5 is exchanged each year, more than 20 times more than anthropogenic CO2. • Atmospheric CO2 absorbs minimal heat compared to the total ”greenhouse effect”; hence CO2 cannot affect the climate much. • Heat stored in the ocean, and the thermostat action from clouds, dominate the weather and climate on Earth. • Earlier warm periods were called ”climate optimums”. • Increase in air CO2 might be beneficial, not catastrophic, considering increasing plant growth and ability to feed more people on Earth.