Carbon capture can be part of the climate solution


Imagine a group of campers carelessly polluting the forest, leaving beer cans, plastic wrap, and propane tanks strewn about the understory. An ecologist arrives at their campsite and explains how they are harming the forest ecosystem. Campers decide to stop polluting, but never clean up the mess. This is analogous to a climate strategy without removing carbon.

At its root, the climate crisis is a chemical imbalance. Global warming is just one of its side effects. To restore the ecological conditions in which we have evolved, we must restore the balance of carbon fluxes between our atmosphere, hydrosphere, biosphere and lithosphere. This not only means stopping carbon emissions, but also sending the carbon back to where it came from.

Since 1750, an estimated 26 to 46 percent of cumulative historical emissions have been released from the biosphere through deforestation and other forms of habitat destruction. Fortunately, ecosystems have a myriad of ways to reverse this process. Even at the mouth of a chimney, the most advanced technology for cleaning up the densest plume of coal pales in comparison to a tropical forest, itself pale in comparison to a mangrove. It is true that nothing sequesters carbon faster than nature.

But the world’s ecosystems have a carbon cap, or carrying capacity. Even if we somehow returned all converted land to its pre-industrial state, models estimate that we could only sequester about 41% of cumulative historical emissions – in other words, about as much. of carbon that the biosphere originally contained.

In fact, at least half of the carbon we release into the atmosphere comes from the lithosphere, burning fossil fuels in the earth’s crust. There is no natural process to reverse this on the scale and speed needed.

Despite this reality, many major climate advocates argue that carbon capture is not necessary. They point out – and rightly so – that if we decarbonize quickly, the planet could return to halfway to pre-industrial carbon dioxide levels by the turn of the century.

But again, climate change is just a consequence of the global chemistry experiment we’re conducting. If we leave all that carbon in the atmosphere, the levels will be possibly decrease once we stop broadcasting. This is because most of it will dissolve in the ocean, setting off a chain reaction with carbon compounds that acidify the seawater. Removal of carbon from the atmosphere reverses this process. Even if we were to reach pre-industrial temperatures in the 2100s by reducing emissions alone, we will have done nothing to combat ocean acidification. Is it a victory to reach a planet where there are vast expanses of ocean without oysters to filter water, without corals to house fish, without pteropods to support food webs?

Worse yet, without burying the carbon, the effects of temperature change will be catastrophic both at sea and on land. We will almost certainly cross the two-degree threshold, virtually dooming the corals to extinction, liquidating the Arctic sea ice, sinking hundreds of cities from Bangkok to Miami and killing millions in heat waves. To survive, we need to stabilize our climate – and quickly.

While leading biogeochemists have long advocated carbon capture technology, its most visible proponent is the fossil fuel industry. Its lobbyists use it to sell carbon credits to big polluters and empty promises to world leaders. His interest in technology is not driven by an obligation to humanity or the planet, but rather by a strategy to silence critics and stay in business, whether that means emitting less or more. Today, most of the small amount of carbon captured by industry is not stored, but rather used in enhanced oil recovery to lubricate geological cracks and accelerate carbon extraction. Needless to say, this makes the problem worse.

There are only a few forms of carbon capture technology that produce net negative emissions. First, some catalyze natural processes, such as increased weathering of rocks and iron fertilization of the oceans. However, the sequestration potential of these approaches is generally considered modest – and with a high risk of negative ecological side effects.

Then there is bioenergetic carbon capture and storage, or BECCS. BECCS augments the theoretically neutral process of biofuel growth and combustion by capturing carbon in the stack, storing it underground to push emissions into the red. This method could potentially sequester a lot of carbon, but at a high cost in soil. While we would not have to expand cropland if we drastically reduced agricultural land use by raising fewer animals, using the land to grow biofuels would sacrifice its higher potential for carbon sequestration through rewilding. .

This leaves Direct Air Capture (DAC) perhaps the most technologically difficult of all. DAC typically involves a system of huge fans sucking air through a chemical sponge that filters about a thousand molecules of air for every four of carbon dioxide. These are then liquefied in solvents and pumped underground.

The drawbacks associated with direct air capture are small compared to other forms of geoengineering and related to the risks we already take when mining fossil fuels, including seismic destabilization and leaking wells. ‘injection. However, DAC consumes a lot of water, and although we can develop passive systems using wind, absorbent solvents, or electrodialysis, current direct air capture technology requires large amounts of energy and n is negative in emissions only if it is powered by renewable energies.

Herein lies the most important caveat: carbon capture is not an excuse to aggressively reduce emissions. This will only help if we also quickly eliminate the fossil fuel industry.

Unfortunately, he is the one who gets all the funding. Fossil fuel companies are raking in public investments and tax breaks to research and develop carbon capture, while showing dismal results. Despite decades of R&D, billions in carbon capture subsidies and proposals for an additional $ 100 billion, ExxonMobil said it captured less than 1% of its emissions in 2019.

The charitable interpretation is that the engineering of carbon capture is a unique challenge. A less gullible explanation is that fossil fuel companies simply have no incentive to develop carbon capture technology. Funding does not depend on progress, and scaling is not worth the capital of thousands of engineers and millions of construction workers. Either way, research and development of carbon capture technology can only be successful if we decouple it from the fossil fuel industry and build it within the public sector, away from the tyranny of the fringes. beneficiary.

Despite such a poor investment, the net carbon capture technology does exist. In August 2021, a prototype called Orca went online, making it the largest direct air capture facility in the world. While its developer, Climeworks, is a net neutral company at best – it sells carbon offsets to make a profit – Orca is net-negative, running on geothermal power and pulling a relatively impressive four thousand tons of CO2 per year. At this rate, we would need more than eight million of them operating for fifty years to capture all the fossil carbon we have burned (and it would take longer for the atmosphere to stabilize).

The good news is that the facilities aren’t that big – the size of a sea container, of which we have around 43 million – and like solar and wind power, we can expect this technology to become more efficient. over time. Plus, if you are considering where to install them, we already have millions of complete drilling rigs with tubing connected to oil fields or porous shale strata. Finally, it’s not all or nothing. Every atom counts.

Carbon capture is not the easy road to net zero that oil lobbyists want to sell us. True net zero is around 280 ppm CO2. We should think of carbon capture more like putting imperceptibly diffused toothpaste back into countless millions of leaking tubes – essentially reverse-engineered fossil fuel, our most disastrous geoengineering experiment ever. It’s a moon stroke, but it’s not rocket science. And while there is a complex engineering case for carbon capture, the ecological case is simple: we need to re-bury the carbon to reverse ocean acidification.

Carbon capture is a challenge that we cannot afford to shy away from, regardless of the market purposes for which the technology has been developed so far. Today, it serves as a justification for prolonging our dependence on fossil fuels and enriching those who have benefited from its extraction. Tomorrow, this may be the only way to address the crime against nature that precedes and precipitates climate change – the distortion of planetary chemistry.


About Lucille Thompson

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