Hoping That Sucking CO2 From the Air Will Fix the Climate? Good Luck (easac.eu)

From a study published on Thursday by scientists on the European Academies Science Advisory Council: Senior scientists from across Europe have evaluated the potential contribution of negative emission technologies (NETs) to allow humanity to meet the Paris Agreement's targets of avoiding dangerous climate change. They find that NETs have "limited realistic potential" to halt increases in the concentration of greenhouse gases in the atmosphere at the scale envisioned in the Intergovernmental Panel on Climate Change (IPCC) scenarios. This new report finds that none of the NETs has the potential to deliver carbon removals at the gigaton (Gt) scale and at the rate of deployment envisaged by the IPCC, including reforestation, afforestation, carbon-friendly agriculture, bioenergy with carbon capture and storage (BECCs), enhanced weathering, ocean fertilisation, or direct air capture and carbon storage (DACCs).

Comments

Complete BS

[dbialac]

Use salt-waterable plants to turn the Sahara desert green and you'll reach gigaton absorption. For perspective, the Sahara is about the size of the United States.

Re:Complete BS

[nealric]

Irrigating an area the size of the United States would be quite the project. Who is going to pay? And how are we going to coordinate a massive engineering project in a region with no stable government?

Re:Complete BS

[dbialac]

Anything we do is going to be quite an engineering project, and a number of those countries actually are quite stable. As for the "pay", part, grow the right plants and you can actually generate ethanol in a carbon-negative setup: http://energypost.eu/exclusive...

Re:Complete BS

[taiwanjohn]

Re-greening the desert is actually one of the most effective ways to sequester CO2, and it can be done with a lot less water than most of us would assume. Both Joel Salatin and Allan Savory have stated that large scale adoption of managed intensive rotational grazing (MIRG) could re-sequester all the CO2 we've added to the atmosphere since the industrial revolution within a couple of decades.

In a nutshell, well managed herbivores help keep the soil healthy, and actually increase the topsoil layer. More soil stores more carbon, as does healthier soil, so it's a double win. A triple win if you consider the healthier livestock -- grazing outdoors instead of crammed into factory feedlot "farms". More and healthier soil also retains more water, helping to alleviate the looming water crisis.

Re:Complete BS

[Anonymous Coward]

Wouldn't that destroy delicate desert habitat and extinct a variety of species?

Not sure if you have noticed... but the Sahara is a bit of a desert. The least number of lifeforms of any ecosystem. Biodensity and biodiversity is very low.

The worst danger is if the winds are no longer able to pick up sand from the Sahara (parts of it are high in nutrients from when the Sahara was a tropical paradise many millennia ago). The sands from the Sahara are currently responsible for feeding the rain forests in South America with certain nutrients. Cut off the sand and the rainforests quickly become weaker. The rainforests are currently ARE high in both biodensity and biodiversity.

Re: Complete BS

[Anonymous Coward]

I watched a documentary a few years back about a small village in Africa experiencing decades of drought. They were getting the people to plant various plants and use their limited water to water the plants. The people were completely against this idea for years but when the documentary was filmed they reluctantly went along with it.

I was absolutely amazed how fast the areas they planted stuff in the desert began to be green again. The scientists advising them said it should inevitably bring more rain (or at least, when it does rain the water will be absorbed into the vegetation areas and not lost) and, at the end of the documentary they had like a mini-lake forming in the middle of all the greenery they planted and all the villagers were super happy.

I don't know how long filming that took, maybe a year or up to four years, but I was amazed that something like that was even possible in the middle of the desert. They had beautiful vegetable gardens and a nice little lake forming. The final clip showed the villagers' kids splashing and playing in the water.

Re:Sucking CO2 from the air won't solve everything

[alvinrod]

I don't think the issue is removal, but sequestration. Eventually trees or other plants die and the carbon from the dead wood or plant matter must go somewhere. On a geologic time scale it becomes coal, oil, etc. but more immediately forest fires and the like will be returning a good chunk of it back to the atmosphere. Even if we could do something like ethanol in an efficient manner to where we could replace growing crops with drilling for oil, we're still just creating a carbon churn. The real task is finding something that's economically valuable to do with all of the carbon that's been pulled out of coal and oil deposits so that there's a real incentive for people to solve this problem. Telling them the world is going to end in 30, 100, 500 years unless we get our act together doesn't seem to work at all.

I think what we should be researching is how to fabricate carbon into building materials. We've already found that things like carbon fibers are incredibly useful in several domains, and carbon nanotubes have been shown to have orders of magnitude more tensile strength than other materials we're using now. Figuring out how to synthesize those things less expensively would provide economic incentive to capture carbon and a good long-term solution for sequestering it.

frustrating

[Goldsmith]

I'm pretty sure that blurb is not from the report. The conclusions of the report are

The EU should thus consider what possible policy options may be appropriate to climate policy. For instance, by considering:
- supporting initiatives such as "4 per mille" by incentivising agriculture to increase SOC;
- providing greater incentives to increase carbon stocks in forests (EASAC, 2017);
- reviewing and updating CCS development and demonstration programmes;
- conducting research on reducing energy and resource costs of DAC;
- maintaining a watching brief for other options to remove CO2 to compensate for sectors such as aviation where fossil fuels cannot easily be substituted; and
- addressing the weakness of market forces to fund deployment of CCS (and ultimately viable NETs) owing to the low carbon price and questions over the eligibility of NETs within the Emissions Trading Scheme.

There's a lot of text around those bullets, but it doesn't read as doom and gloom to me.

From the introduction

...humanity will require all possible tools to limit warming, and these technologies include those that can make some contributions to remove CO2 from the atmosphere even now, while research, development and demonstration may allow others to make a limited future contribution. We thus conclude it is appropriate to continue work to identify the best technologies and the conditions under which they can contribute to climate change mitigation, even though they should not be expected to play a major role in climate control at the present time.

Anyone who spends five minutes thinking about how carbon capture would work should understand that that's a pretty self evident statement.

Re:Sequestration

[Dr. Evil]

"Unless they are sequestered, for example, by being buried and converted into peat, or for that matter, coal.:"

The problem is if you look at the tree narrowly, then yes, it will rot and release all its CO2. If you look at the forest, fresh growth will replace the rotted tree and continue the cycle.

Old forests will very slowly sequester carbon in new topsoil, but will otherwise be mostly neutral.

New forests would be needed, and yes, sequestering new growth should help (soil impact aside).

The most secure way I can think to sequester carbon is to use it in our buildings, furniture and other products. They're sheltered and have an economic incentive to not rot. They'll evnetually be recycled, landfilled, or otherwise destroyed, but there will always be a certain tonnage of wood used in the homes and offices of living people.

Thick wooden floors, thick wooden roofs,... thick panels of wood on walls. Hardwood if you can.