Carbon dioxide removal requires more attention

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Tit is Earth it is remote, ancient and a site of constant change. This means that everything that happens on and below its surface is part of a cycle. For every change that uses things up, there must be another that provides those things anew. The basic elements of life, such as carbon and nitrogen, cycle endlessly in and out of living things, the oceans, the land and the atmosphere. Even the planet’s crust is recycled.

A new crust is created where tectonic plates move away from each other, usually in the middle of the ocean, and molten rocks rise from the mantle below to fill the gap. An old crust is destroyed where two plates are pushed together and one overlaps the other, sinking back into the mantle. But there are a few mistakes. The rocky peaks of the eastern Arabian Peninsula bear witness to one.

Most geologists looking at the Arabian Peninsula focus on the deep and wide sedimentary basin that underlies the Persian Gulf and its surrounding lands. Organic matter in the depths of this basin has been cooked by heat and pressure into large amounts of oil and gas which, after being filtered up, now sits in rocks near the surface. They are very profitable rocks to explore. Unfortunately their use, along with carbon-rich rocks elsewhere, has made the climate more stable. On November 30 the world’s governments will meet in Dubai, a city built on the wealth from these rocks, to further negotiate their response to that instability at the 28th Conference of the Parties (COP28) To the UN Framework Convention on Climate Change.

For those interested in tectonic glitches, however, it is the Hajar mountains to the east that matter. In the early stages of the collision between the Arabian plate and the Eurasian plate to the north a slab of ocean floor was caught between the two rotating landmasses in conditions that would normally see it pushed down to the mantle. On this occasion, however, the rocks did not go down, but up, raised like a tree on a carpenter’s plane. The ancient sea floor, mostly basalt, and some of the mantle on which it rested, an associated rock called peridotite, were eventually exposed to the open air. In time, the sea floor formed the mountains.

Like all mountains the Hajar range is being eaten away by erosion; it is another part of the great recycling. The erosion exposes new rock without stopping, and that rock takes carbon dioxide from the atmosphere through what is called “chemical weathering”. The alkaline minerals in the rocks react with water and groundwater made slightly acidic by dissolved carbon dioxide to produce carbonate minerals of the type that make up limestone. The peridotites in the Hajar are particularly susceptible to this weathering. Their dark stone is shot through with white veins of carbonate.

Chemical weathering is not the fastest of the natural processes that draw down carbon dioxide. Photosynthesis, carried out on land by plants and in the sea by algae and bacteria, operates on a much larger scale, removing more than 300 times more carbon dioxide from the atmosphere each year. But he does not stay away for a long time. The carbon is recycled into the sky by the plants themselves, the creatures that eat them and the soil in which they decompose over timescales from days to centuries. The geological carbon cycle is much slower. Carbonates in places like the Hajar are stable for hundreds of millions of years.

Until recently, adnocthe national oil company of the United Arab Emirates (uae). Now, however, he has turned his eyes to the peridotites of the Hajar, and to pumping carbon dioxide down. In the mountains above Fujairah, a city on the Gulf of Oman, adnoc and 44.01, an Omani startup, is working on a pilot plant where 44.01 injects carbon dioxide deep into the rock in a way that stimulates its mineralization into inert carbonate. Musabbeh Al Kaabi, head of “low carbon solutions” for adnocsees his company’s investments in this fast-track mining as part of a comprehensive decarbonisation strategy for the oil industry, one that aims to deliver its “critical commodity in the most sustainable way” .

The Fujairah tests are part of a planet-wide effort to undo another glitch in the world’s great cycles: mankind’s transfer of fossil fuel carbon from its quiet rest in the solid Earth to the rush of the atmosphere About 1trn tonnes of carbon dioxide has accumulated there as a result of human activity. The total is growing at just under 20bn tonnes per year.

For a sense of scale, compare that to other planetary currents. It is about 60 times faster than carbon dioxide is removed by the weathering of Earth’s rocks. It is about a tenth of the rate at which photosynthesis produces new biomass. It is amazing that an accidental industrial by-product should be remotely comparable in its carbon transfer to the process that powers all life on Earth.

Photo: The Economist

It may seem comfortable; great though the human current is, the biological one is much greater. Can’t it simply increase to accommodate human action? Oh, no. The biological carbon cycle is large, but it is also balanced; the rate at which the world’s biosphere photosynthesises is almost exactly the rate at which other life processes return carbon dioxide to the atmosphere. With carbon dioxide from fossil fuels added to the natural emissions, photosynthesis has tried hard to keep up, feeding back as much as it can. But he can’t do enough. It only includes about a third of the emissions from human industry and agriculture (see chart).

The accumulation of carbon dioxide in the atmosphere has increased the temperature of the planet by about 1.2°C (2.2°F). The temperature will continue to rise until the accumulation stops, that is to say until the annual addition drops to more or less zero. That is why the governments of the world agreed to work towards that at the Paris climate conference in 2015.

For the most part, that means cutting emissions of carbon dioxide and other greenhouse gases. But it is highly unlikely that some emissions – those from ocean transport, from some types of farming, from various industrial processes and others – will be completely eliminated anytime soon. So the Paris agreement specified that sustainability does not have to be a matter of no emissions at all; instead it could be achieved through “a balance between anthropogenic emissions…and removals”. Remaining, “difficult to reduce” greenhouse gas emissions were being balanced by removing carbon dioxide already in the atmosphere. The project in Fujairah aims to show one of the ways in which what has gone up can come down, and correct the way of the world.

This is the logic of “net zero”. Back in 2015 only one country had announced a net zero target for its economy: Bhutan. Now there are 101, and between them they account for just over 80% of global greenhouse gas emissions. The growing opposition to these net-zero targets on the political right says that many of the domestic policies associated with cutting emissions are too expensive, or irritating, or both. some Those who aim to keep global warming from the Industrial Revolution well below 2°C, according to the Paris agreement, know that these measures are not zero net to reach ambitious enough yet. As the “emissions gap” report put the one Environmental Program near to Dubai COP identify, none of the G20 countries are reducing emissions at a pace consistent with their net-zero target.

Business as usual

There are far fewer concerns about the widening mobility gap. Few of those with net zero commitments understand the importance of greenhouse gas removal to the idea; of those who do, few recognize the enormity of the challenge. Emissions cuts of 90% would still see enough gas entering the atmosphere for a balanced rate of movement to be a huge task.

Studies by the Intergovernmental Panel on Climate Change suggest that if the planet has a good chance of staying below 2°C warming it would make sense to plan to remove an extra 5bn tonnes of carbon dioxide from the atmosphere every year. According to a report published in 2023 by an international team of academics, if you do not count managed forests, which have little room for expansion, the amount of carbon dioxide removed in stable storage in 2020 2.3m tonnes, or about two thousand of that 2050 target. The pilot phase of the Fujairah plant runs at just 1,000 tonnes per annum.

New methods of sustainable removal need to be developed much faster than is happening. And they have to earn trust. At this time, many who are aware of the need for removal are still skeptical of the technology, especially since it is promoted by the oil industry. Mr Al Kaabi’s vision of a world free to produce and use oil “in the most sustainable way” does not sit well with those who believe it is necessary to stop burning all fossil fuel. The position of the cop28 it brings such questions to light.

One reason oil companies run is that they know how to move fluids in and out of the Earth’s crust. They also have a lot of money, and removing carbon dioxide at the moment looks very expensive. The obvious way to finance it effectively is through markets. But none of the carbon markets around today are up to the job. This means that the net-zero strategies adopted by most of the world rely not only on irresponsible technologies that can absorb carbon dioxide – out of the atmosphere and stored away, but has created a carbon economy that makes it valuable. Climate policy insists that people, their governments and their economies can and must be integrated into the great cycles of planetary renewal. But how is that to be done?

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