We Write Reports on CO2 Removal, But Fail to Remove Much

There has been a report issued on the state of carbon dioxide removal (https://ianmillerblog.wordpress.com/wp-content/uploads/2024/06/c57f5-the-state-of-carbon-dioxide-removal-2edition.pdf) that paints a rather gloomy picture. A large number of countries pledged in the Paris Agreement to reduce emissions of CO2. So far, what has actually happened is the total is increasing. This report has given up on the 1.5 degrees C temperature rise and focuses on the 2 degree rise. The Paris Agreement states that climate change mitigation must be done “in the context of sustainable development”. If we wish to reach the two degree goal, besides serious reduction in emissions we have to remove 260 billion tonne of CO2 from the atmosphere by 2050, and if the reduction in emissions target is not reached, whatever of the target was not reached by.

We are currently removing about 2 billion tonne per annum (t/a) of CO2 from the atmosphere, but most depend on land use change and forestry. Novel methods of removing CO2 from the atmosphere have accounted for approximately 1.3 million t/a of which approximately 0.6 million t/a involves geological storage of CO2. Most of that being fixed comes from specific projects  such as making bioenergy with carbon capture and storage, or by using biochar.

As to what is being done to remove it, there is a steady growth in publications about how to do it (19% /a). We are very good at sitting in an office and writing reports, and, additionally, requesting funds to write more reports. There are, apparently, a number of startups, however CO2 removal accounts for just 1.1% of investment in climate-tech startups. The good news is that the diversity of options appears to be growing. However, deployment is not. In terms of deployment, forestry accounts for almost all the carbon taken from the atmosphere. To summarize, there has been a lot of effort in research, some in demonstration, but very little in deployment, other than forest management. In principle, the carbon market should be playing a positive role here, but there is also a problem because somewhere along the line someone has to be paying real money and the political will to raise charges under current economic problems is a little thin.

A further problem lies in monitoring and verification. Different countries have different protocols. That has led to more reports trying to put numbers on the sum of the efforts. In my opinion, this is not money well-spent right now, and the most effort should go into developing and implementing the technologies we intend to use. There is only one useful monitor, and that is easy to do: monitor the CO2 levels in the atmosphere. We know what has to be done and we know we are nowhere even close to doing it. It is one of the curses of having gone down the track of using  “market forces” to achieve this result the efforts have to be measured in detail to get the accounting right and we spend more effort measuring our totally inadequate efforts than implementing more technology to remove CO2.

Going back to the report, the major conclusion is there is a serious gap between the amount of carbon dioxide removal required to meet the Paris temperature goal and the amount that nations are submitting in proposals. This is serious because nations are inevitably going to fail to meet such proposals and if the proposals are seriously inadequate anyway, all the hype from the politicians is a waste of breath. The report states that the gap can be closed by rapidly reducing emissions, scaling up methods to remove CO2 from the atmosphere, and “explicitly integrating sustainability considerations into carbon dioxide removal policy”. Even with massive reductions in emissions, right now we are removing about 2Gt/a, mainly through forestry. We should be removing about 5.4 Gt/a, and by 2050 we have to be removing 9.8 Gt/a, assuming we meet the target for reduction of emissions.

In my opinion, the only practical steps to reduce emissions is to deploy a large number of molten salt nuclear reactors to generate electricity. The reason for molten salt is to reduce the nasty wastes, and to remove the means of making more nuclear bombs.

Removing Greenhouse Gases

There are two issues with greenhouse warming that have to be addressed: the first one is to reduce the emission of more greenhouse gases, and the second is to reduce what we have already added to the atmosphere. There are a number of greenhouse gases, and some of the new ones are potentially very bad problems. One is sulphur hexafluoride, which is 23,500 times better at trapping heat than carbon dioxide, and it stays in the atmosphere for over 3,000 years. There are very few ways to get rid of SF6, as it hardly reacts with anything. It has been used in large electrical equipment as an insulator as a replacement for polychlorobiphenyls when these were considered to be environmentally unfriendly. PCBs are reasonably easily destroyed when the life of their equipment is over, and nobody knows what to do with sulphur hexafluoride. Very clever to replace one moderate hazard with one far worse in other respects.

However, that is a digression. It hardly matters what the other gases do if we cannot do something about carbon dioxide. We all know that we cannot eliminate totally the burning of carbon, and we seemingly cannot do much in the short term. But even if we stopped emitting  carbon dioxide into the atmosphere today, global temperatures would continue to rise for at least a century. It is like being in a bed when you are too hot. Stopping adding more blankets is not enough; you have to take some off. So how do we reduce the carbon dioxide from the atmosphere?

The first problem is to concentrate it in one place. That can be done by absorbing it with amines, and heating the amines to recover them. It is also possible to simply pass air through water under pressure, when the carbon dioxide with be preferentially absorbed. Ordinary water will not absorb much carbon dioxide, so that will require a lot of water. That does not get rid of the carbon dioxide, but it does make carbonic acid, which is a start. The idea then is the carbonic acid will react with certain rocks to make carbonates. That means we need a lot of rock.

One answer is the use of flood basalts, which are reasonably common, and provide large amounts. One example, noted in a Scientific Report (2024: 14:8116) considered the Paraná flood basalts, which cover an area of 1.2 million square km, involving Central and Southern Brazil, Paraguay and Uruguay. The basalt can be up to 1.75 km thick. That is a lot of rock. The rock comprises approximately 50% plagioclase and up to 25% clinopyroxene. These are important because the plagioclase contains 12 – 16% calcium oxide and the clinopyroxene contains about 22% calcium oxide and about 11% magnesium oxide. These absorb carbon dioxide to make lime and dolomite.

An experiment was carried out by bubbling water saturated with carbon dioxide through a column of such rock that had been pulverized. The calcium and magnesium started forming carbonates within 48 hrs, while the iron in the olivine took considerably longer. The pH of the water  increased and after 18 days a well-defined precipitate formed, and this was mainly a mix of calcite and aragonite, two forms of calcium carbonate.  The conclusion here was that carbon dioxide injected under pressure with water into the porous basalt will fix most of the carbon dioxide in a few days. There was another interesting fact: the presence of soluble magnesium inhibited the precipitation of calcite. This is of importance because aragonite is harder to precipitate as the acidity increases, and this is leading to a problem with shellfish. Because of the magnesium in seawater they cannot buy time by using calcite.

Rather than digging up flood basalts and crushing them, the slower option would be to inject the CO2 and water. There is plenty of area with the Paraná flood basalts.

Mission to Uranus

As many people know, Uranus is a planet that is tilted onto its side and that makes it very unusual. Why, and how did that happen? There is an incentive to send a mission o find out what we can, but that is extremely expensive, so if you do you want to find out as much as you can about the system. That includes looking at the moons, because their orbits follow the tilt. That tilt means the system has different overall illumination at different times in its orbit, and it so happens that in 2050 the orientation is favourable so that it and the plane of its moons are at right angles to the incoming sunlight, so in principle this should be of interest. 2050 may seem a long way away, but so is Uranus so NASA is at work designing a probe, and an article in Nature is advocating for ESA to become involved, partly to help with finance, and partly to help with design and build of some parts. One such part could be an entry probe.

Uranus is special because it is a planet we call an ice giant. The question then is how do such planets form. The standard theory is oligarchic collision. In this, they start with planetesimals, which are about the size of asteroids. Don’t ask how they formed because there is no answer. These then collide and form larger objects that collide and form Mars-sized objects, that go on to collide to form planets. I disagree with this for a number of reasons, the main ones being there is no way to form the planetesimals, when asteroids collide they form families of smaller asteroids rather than bigger objects, and lastly the giants could not form fast enough to collect the hydrogen and helium from the accretion disk, which for our system probably lasted no longer than a million years. The first such calculation had Neptune taking a billion years! The reason is that the further from the star and the bigger the object, the fewer collisions because matter is concentrated in lumps that become more spaced out as the bodies grow.

So how did it happen? In my ebook “Planetary Formation and Biogenesis” I argue they grew by monarchic accretion. For the giants, icy particles stuck together, and one grew bigger than the rest. The point of monarchic growth is that mathematics show that growth increases as the planet grows because the concentration of dust is constant but the gravitational cross-section of the planet increases as it gets bigger. When they get to roughly the size of Mars they start to accumulate an atmosphere from the gases in the accretion disk. This atmosphere causes an increase in the amount of solids falling onto the planet due to the increased cross-section, so growth speeds up. As the pressure rises, a further effect becomes possible in some temperature ranges. If the pressure gets to a point where a gas can form a liquid at that temperature, it rains out onto the planet from the accretion disk gases. Possible gases that can do this include CO2 and water, with water having the option of snowing at colder regions. Again growth is faster, because the planet is accreting material that was in the gaseous phase  in addition to the standard dust. As the planet grows, so does the atmosphere. When the planet gets to about ten Earth masses it starts to accrete hydrogen and helium from the disk. Neptune and Uranus have accreted a little over two Earth masses of hydrogen and helium which are retained in the giant atmospheres.

There are additional theories as to how Uranus formed, a favourite being it and Neptune formed near Saturn and migrated out by throwing planetesimals inwards. Accordingly, there is a strong reason for going there is to find evidence of what happened, but that makes it a complicated project. The flight time to Uranus will be about twelve to fifteen years, and it takes about ten years to design and build the mission, so it is time to get started. However, neither NASA nor ESA have yet committed. The difficulty in getting that far means that it is important to do as much as possible with the mission. To illustrate the problem, the entry probe needs to send information from as much depth as possible, but that means it has to withstand higher pressures, and that means more weight, and weight is a curse to space flight. If the probe could not get any information other than atmospheric composition, that would not tell us very much, although isotope ratios would be important to my theory because in addition to enhanced heavy C and N isotopes, I expect enhanced heavier argon isotopes.

In addition, I would hope for more information of the moons’ properties. If the moons migrated with the planet, they would have the same composition as Saturnian objects, although how they were not knocked off by the planetesimals is one of those problems left unexplained in that theory. My ebook gives a small number of predictions based on the proposed mechanism of formation where Uranus formed roughly where it is now, and the moons should have the predicted composition. Unfortunately, the moons are relatively small, which means no atmosphere, which may mean difficulty in arriving at useful compositional data when there is no landing vehicle.

Overall, some compromises are going to have to be made in designing the mission. The problem with compromises is when you do not know the answers it is hard to decide on which ones to let go. If you focus on proving a wrong theory, you may end up not getting any useful information. I know what I would like to see, but the reality is I won’t see any of it. It is extremely probable that with my age I will not see 2050, so I shall not know whether my predictions are rubbish or valid.