carbon

The Oman geoengineering scheme to save the planet

A story in the Arizona Daily Star, 4-14-17 (the great march for science issue) shows how some scientists create the most tenuous links between their research and climate change as a plea for funding.

This story is “Oman’s mountains may hold clues for reversing climate change.” (Link) The lede: “Deep in the jagged red mountains of Oman, geologists are searching for an efficient and cheap way to remove carbon dioxide from the air and oceans — and perhaps begin to reverse climate change. They are coring samples from one of the world’s only exposed sections of the Earth’s mantle to uncover how a spontaneous natural process millions of years ago transformed carbon dioxide into limestone and marble.”

The researchers are excited because the exposed mantle rock is mostly peridotite, a coarse-grained igneous rock made up of the minerals olivine and pyroxene, both magnesium silicates. “They hope to answer the question of how the rocks managed to capture so much carbon over the course of 90 million years — and to see if there’s a way to speed up the timetable.” A researcher goes on to say, ““Every single magnesium atom in these rocks has made friends with the carbon dioxide to form solid limestone, magnesium carbonate, plus quartz.”

A couple of nitpicks: Limestone is calcium carbonate, not magnesium carbonate (Calcium and magnesium together with carbonate form a rock called dolomite). Marble is a metamorphic rock which requires heat and/or pressure to form. That “spontaneous natural process” happened not only millions of years ago, but is a continuing natural process in the ocean when calcium ions derived from weathering of surface rocks combine with carbonate ions in the ocean. Basaltic ocean crustal rocks act as a buffer by continuously removing CO2 from the ocean by combining carbonate with calcium derived from surface weathering of rocks.

Their great scheme is this: “a drilling operation could cycle carbon-rich water into the newly formed seabed on oceanic ridges far below the surface. Just like in Oman’s mountains, the submerged rock would chemically absorb carbon from the water. The water could then be cycled back to the surface to absorb more carbon from the atmosphere, in a sort of conveyor belt.”

Perhaps the researchers made the climate change link to their research just to suck up grant money so they can continue studying. The geology is interesting, but their idea sounds like another crazy, expensive, and totally unnecessary geoengineering scheme. (See Wacky Geoengineering Schemes to Control Climate)

See also:

Evidence that CO2 emissions do not intensify the greenhouse effect

Deep Carbon Observatory, a journey to the center of the earth, almost

The Deep Carbon Observatory is “a broadly interdisciplinary, international effort to characterize Earth’s carbon—crust to core, at scales from nano to global.” This program was initiated two years ago and is run by the geophysical laboratory at the Carnegie Institution in Washington, D.C.

Areas of investigation:

The presence of microbial life in solid rock miles below the surface and its possible relationship to production of hydrocarbons.

Abiotic production of methane, natural gas. Russian scientists have long maintained that hydrocarbons are produced deep within the mantle by inorganic processes. If so, abiotic methane could greatly expand our supply of natural gas and petroleum.

The properties of carbon under high pressure and temperature.

What happened to the primordial carbon? “The nature and extent of carbon reservoirs and fluxes in Earth’s deep interior are not well known. The primitive chondritic meteorites that formed our planet average ~3.2% carbon, yet estimates of Earth’s total carbon inventory are much lower, ranging from 0.07 to 1.5 wt% (an uncertainty of more than 20-fold). Earth appears to be significantly depleted in highly volatile elements compared to chondrites, but we do not know for sure because large reservoirs of carbon may be hidden in the mantle and core.”

Diamonds, pure carbon, underwent a change about 3 billion years ago. Diamonds “provide age and chemical information for a span of more than 3.5 billion years and include clues to the evolution of the atmosphere, the growth of the continental crust, and the beginning of plate tectonics.”

This site seems worthy of checking from time to time. The News tab brings up press release of the research and links to scientific papers. The Science tab provides more detailed explanation of the areas of investigation.

Humans and the Carbon Cycle

Some people must think that humans are not part of nature according to two comments to my post: Carbon Dioxide and the Greenhouse Effect . The comments alleged: “Human carbon emissions are not a part of the natural carbon cycle.” and “We are now releasing huge amounts of fossil carbon too rapidly for natural processes to adjust.” Both claim that human carbon dioxide emissions upset “the balance of nature.” This belief reflects a misunderstanding of what “balance” really is. Nature is never really “in balance” or static, it is always seeking equilibrium between forces that upset the status quo.

This misunderstanding is reflected in one of the comments: “The natural carbon cycle involves the production/consumption of carbon. Humans do exhale – but energy production involves humans using historic carbon from earlier carbon cycles that are not contemporary. It isn’t part of a ‘natural’ carbon cycle.”

Tell me, how can nature distinguish between a carbon dioxide molecule produced by someone burning wood in a fireplace versus carbon dioxide resulting from burning wood in a forest fire? How can nature distinguish between a molecule of carbon dioxide produced by burning coal to generate electricity versus coal burning in a seam due to natural spontaneous combustion? Yes, that does happen. So much for “historic carbon.”

There are actually two carbon cycles. The geologic carbon cycle stores carbon in limestone, dolomite, petroleum, and coal deposits. Carbon dioxide from the atmosphere is used up during the weathering of silicate rocks, a process that speeds up with increasing temperature or increasing carbon dioxide, thereby forming a negative feedback or thermostat. It takes millions of years, usually, for this carbon to cycle back into the biosphere. Volcanoes recycle carbonate rocks and emit 200 million metric tons of carbon dioxide per year according to the U.S. Geological Survey. There are also carbon dioxide gas seeps. Carbon dioxide is also produced from metamorphism of carbonate rocks.

The biologic carbon cycle is exchange of carbon dioxide between the atmosphere, biosphere, and ocean as shown in the graphic below. The biologic process involves photosynthesis, respiration, ocean absorption, and biological use of carbonates to form shells and other structures. Human emissions are part of these natural cycles.

 carbon-cycle-diagram

The relative amount of carbon in each “sink” is shown in the table below.

Carbon-sinks1

Notice that the amount of carbon stored as fossil fuel deposits is just one-tenth of that stored in the oceans, and the ocean store in continually in flux. The ocean is also the connection between the geologic carbon cycle and the biologic carbon cycle. As the amount of carbon dioxide in the atmosphere increases, ocean uptake also increases. The carbon dioxide is stored not only as dissolved gas, but also as carbonate ions which are sequestered by marine life and the production of limestone and dolomite deposits.

There is another complication. Some carbon is missing. When calculating the carbon flux, i.e., the emissions from known sources versus carbon sequestration by known sinks, there should be more carbon dioxide in the atmosphere than there is. So, either there is an unknown process taking up carbon dioxide or a known process is working faster than we thought (seeking equilibrium).

There is some observational evidence for that last process. We see that terrestrial plant life has increased its net primary productivity by growing more robustly and by making better use of nitrogen in the soil. (See here ) There are also new studies showing that small marine creatures, such as Thaliacea, are depositing more carbon into the geologic sink than previously realized.

Perhaps we still don’t know as much about the carbon cycle as we thought.

To put things in perspective, according to data from the Energy Information Administration, based on data derived from the IPCC, human carbon dioxide emissions represent about 3% of the total carbon dioxide flux, and 98.5% of that is reabsorbed in the biologic carbon cycle. (Source )

Slightly off subject but important: A new paper in Geophysical Research Abstracts (Vol. 13, EGU2011-4505-1, 2011) based on detailed spectrographic analysis of the atmosphere found that because the absorbance of water vapor overlaps the frequencies of long wave radiation that are absorbed by carbon dioxide and methane, the effective sensitivity of carbon dioxide and methane as greenhouse gases is only one-seven that claimed by the IPCC and used in climate models.

That makes our emissions from burning fossil fuels of even less concern.

Your Carbon Footprint Doesn’t Matter

We have all heard scary scenarios about global warming. We therefore propose to limit our carbon dioxide emissions, assuming that they are responsible for the warming. So, the central question is: How much carbon dioxide does it take to theoretically raise global temperatures by 1 degree C?

That number can be gleaned from global emissions reports and IPCC scenarios.

Based on data from the Carbon Dioxide Information Analysis Center (DOE) we see that it takes about 15,700 million metric tonnes (mmt) of CO2 to raise atmospheric concentration by 1 part per million by volume (ppmv).

In 2000, mean atmospheric CO2 concentration was 368 ppmv (NOAA global index).

The “let’s do nothing” scenario of the IPCC Fourth Assessment Report (2007) predicts CO2 concentration will rise to 836 ppmv by 2100– a 468 ppmv rise. In the same scenario, the IPCC predicts a temperature rise of 3.4 degrees C. Therefore, under that assumption, to get a 1 degree C temperature rise requires a 140 ppmv rise in atmospheric CO2 concentration (468/3.4 =140).

So, simple arithmetic shows that to get a 1 degree C temperature rise requires carbon dioxide emissions of 2,198,000 mmt. (15,700 mmt/ppmv x 140 ppmv/ C = 2,198,000 mmt of CO2 ). That’s 2 million million tonnes of CO2.

According to the EPA, total human CO2 emissions in the U.S., from all sources, including power plants, industry, automobiles etc. were 6,103 million metric tonnes in 2007. If we stopped all U.S. emissions it could theoretically prevent a temperature rise of 0.003 C. (6,103/2,000,000 = 0.003 C.)

You can do your part; just stop driving your car. The average family car puts out 5.5 tons of CO2 annually and is theoretically responsible for a temperature rise of 0.00000000000311ºC, three one-hundred-billionths of a degree. You can be so proud.

The calculation above ignores the fact that 98.5% of all carbon dioxide emissions are reabsorbed. http://www.eia.doe.gov/oiaf/1605/archive/gg04rpt/pdf/tbl3.pdf So that actual emissions would have to be 146 million million tonnes to get a 1 C temperature rise, i.e., if we stopped all U.S. emissions it would really prevent a temperature rise of just 0.00004 C. But it will take even more than that because the effect of CO2 concentration is logarithmic, not linear as assumed above.

Now do you see how stupid Cap & Trades schemes are? Why are we proposing to spend billions or even trillions of dollars on a temperature change we can’t even measure?

Bottom Line:

Human carbon dioxide emissions do not produce a significant change in temperature. We should not be wasting resources trying to control them. If you think differently, then provide some physical evidence to the contrary. IPCC climate models don’t count because they are just speculative computer games.

 

See similar calculations from Paul Knappenberger of CATO:

http://www.worldclimatereport.com/index.php/2009/04/30/what-you-cant-do-about-global-warming/