aoner

Thank you for your thorough post.

There are alternative models, such as biocyclic veganic agriculture, or in the future, foods created through fermentation [1] (this almost require no arable land). I recommend checking them out if you are interested in cycles in nature. Using animal manure, opposed to "plant manure" from nitrogen fixing plants, it also has its downsides because of the high levels of ammonia it kills most of the soil creatures such as worms, and more tilling and maintenance is required (which releases more carbon).

Personally I don't think that using livestock is living with nature, but is its antithesis. Since the earth is (at this moment) bound by the amount of biomass available through photosynthesis there is a limited carrying capacity for biomass. What we have done specifically is reduced the biodiversity by using more and more land mass for livestock and its feed. Of all habitable land, 50% is used for agriculture and 77% of that is used for livestock (while only providing us 18% of calories and 37% of protein) [2]. This has drastically reduced the number of wild animals and biodiversity, which I consider "nature" [3].

Ultimately, using livestock kills living beings (primarily in nature) somewhere else. If you're goals are living closer to nature, and reducing your ecological footprint, and your definition of nature is: "the phenomena of the physical world collectively, including plants, animals, the landscape, and other features and products of the earth, as opposed to humans or human creations.", then living closer to nature would mean rewilding your land and perhaps be a steward of that land. It would be a great means of treating nature and life with more respect :).

[1]: https://www.theguardian.com/environment/2021/jun/21/microbes... [2]: https://ourworldindata.org/uploads/2019/11/Global-land-use-g... [3]: https://peakoilbarrel.com/wp-content/uploads/2017/11/Terrest...

Would be more than a plant based diet since there are more chains in between where plastic can accumulate (similar to heavy metals in fish)

There is a great mini documentary made that tries to answer this question https://m.youtube.com/watch?v=uD4izuDMUQA

I think you are underestimating the scale of our cattle. The majority of deforestation is due to cattle [1]. The world is basically dominated by us and our cattle [2] leading to massive losses in biodiversity [3].

If everyone in the world would eat the recommended USDA diet (mostly backed by industry and totally not healthy for you) we'd need another Canada to sustain us all [4]. By the way, most of the grasslands are man-made and we should try and reforest those areas to combat losses in biodiversity and climate collapse. Furthermore about a third of all fresh drinking water (not rainwater) is used for cattle [5].

[1]: https://rainforests.mongabay.com/0812.htm / https://scholar.google.nl/scholar?hl=en&as_sdt=0%2C5&q=defor...

[2]: http://peakoilbarrel.com/carrying-capacity-overshoot-and-spe...

[3]: https://www.ipbes.net/news/Media-Release-Global-Assessment

[4]: https://journals.plos.org/plosone/article?id=10.1371/journal...

[5]: http://www.takepart.com/article/2016/02/18/4-billion-people-...

I haven't dived into plant-based milks and health risks/benefits too much. What I can tell you is that Animal based Milk in general is not healthy, they are high in saturated fats, have a too high calcium and estrogen concentrations and increase the risk to prostate cancer[1], ovarian cancer [2], uteri cancer [2] and other health risks.

Do note that a lot of pro-milk studies are industry backed. The new Canadian food guide has discarded all industry backed studies and based on science created a new food guide [3]. This food guide removed the "recommended" glass of milk based on these studies with water.

[1]:https://link.springer.com/article/10.1023/A:1008823601897

[2]: https://www.ncbi.nlm.nih.gov/pubmed/16125328?dopt=Citation

[3]: https://www.treehugger.com/green-food/canadians-would-rather...

If plants suffer this is actually an argument FOR plant-based diets, since less plants/sentient beings suffer. Meat is a super in-efficient (land/water/energy consumption) way of turning plants, which are already food, into food.

I synthetic fuels are a temporary solution for cars. If you are changing car infrastructure, IMO it makes most sense to switch over to electricity (highest efficiency and you can use electrical car batteries to stabilize the grid).

Synthetic fuels will make most sense for aviation (higher energy density compared to hydrogen), (possibly) shipping and as a transitional fuel for transport to reduce our emissions.

Synthetic fuels could also be a solution for seasonal storage.

I think you're making an incorrect comparison. This is basically an energy storage system. What you could do is compare the EROI of the energy source that provided it (say wind-energy) and factor in the process efficiency and compare that with the extraction of a specific fossil fuel.

There's a great profile on Australia’s complex climate politics and rising fossil fuel exports made by carbonbrief: https://www.carbonbrief.org/the-carbon-brief-profile-austral... Highly recommended

Australia had the world’s 15th largest greenhouse gas emissions in 2015 and its citizens’ per-capita contribution is around three times the global average.

It is the world’s second largest coal exporter and recently became the top exporter of liquified natural gas (LNG). Its electricity system remains heavily reliant on coal, despite ramping up the use of gas and renewables, especially rooftop solar.

It is also highly vulnerable to the effects of climate change, including extreme heat, drought, bushfires and agricultural impacts.

Based on its current trajectory, Australia is off track on its international pledge to cut emissions 26-28% by 2030 compared to 2005 levels.

This is a super interesting in depth article on the current state of climate policy, energy systems etc in Australia: https://www.carbonbrief.org/the-carbon-brief-profile-austral...

I highly recommend carbonbrief in general

An important point that people are missing is that by capturing carbon directly from the air with electricity we can combine two very important energy systems: electrical and chemical. Going 100% renawable at an accelerated pace is within reach and if we could use all excess power due to intermittency to transform the carbon dioxide and synthesised hydrogen into hydrocarbons we can solve some other problems that are currently unsolvable before 2050 (jet fuels, chemical industry).

Also if we've improved this technology so that the costs are reduced (50$ per ton) we can do proper negative emissions in a scalable way without many downsides (can be used in non-arable land, no water consumption with low temperature direct air capture actually has water as a co-product which we can use for electrolysis). We could then sequester the carbon dioxide underground or even create carbonates out of them so we can store them safely in concrete or asphalt in the form of aggregates.

This is such a common misconception. US per capita emissions are around 15 tons and China is around 7 tons. And don't forget that there is a lot of creative accounting going on. All carbon emissions are "exported" by making china the factory of the world. Furthermore flying is not counted in US emissions... I don't think emissions are actually reducing in the US. And let's not forget about the shale "revolution". Oh also: the US has the highest historical emissions. There is an interesting interactive graph made by carbonbrief: https://mobile.twitter.com/carbonbrief/status/11207159885326...

Don't forget that there are also low temperature DAC routes that can use waste heat (climeworks, global thermostat, antecy, skytree). If you get the heat for free you only need energy for your fans. This drastically reduces the price. There are some good papers that do proper cost analysis on DAC. 100$ or lower is within range in a decade. I'm not in front of my computer now but if your interested I'll send the papers

Slightly off-topic: am I the only one noticing massive amounts of fake accounts that are into climate denying?

Check out carbon engineering[1]. They are using direct air capture and hydrogen to create synthetic fuels using a fischer-tropsch like process.

https://www.carbonengineering.com/

There is a company in the netherlands that uses excessive heat with a similar idea to create air conditioning (SoundEnergy BV[1]). Unfortunately I can't really find a good English article explaining the principle but it's like a sterling engine without moving parts and without pistons.

[1] https://www.soundenergy.nl

Afforestation is part of the solution but even if we would plant a lot of trees and not use them, this solution does not scale. Current most optimistic estimates think trees can sequester 600 GtCO2 by 2050 max while most estimated think this is around 100 GtCO2 or less. We'll probably need around 1000-1500 GtCO2 of negative emissions.

So yes we need to plant more trees, but we also need to pursue other negative emission technologies such as ocean fertilization/ocean liming, soil carbon sequestration, direct air capture and enhanced weathering.

I've definetly come across charm industrial :). What is your plan on the negative emissions part? Underground CCS or do you have utilization plans?

I've read a lot of papers about negative emissions. My main take-away was: 1. It will be necessary 2. We can solve part of the problem with cheaper/easier solutions like trees and ocean farming, but we will need more technological solutions.

I think BECSS are difficult since it's still uncertain how the actual net carbon negativity changes when we change land to grow 'BECSS' crops/grasses. Also BECCS cost a land and water, something which will be a luxury when we are going from 7.5 billion to 10 billion people in 2050. With DAC we can actually set an upper boundary of the total cost of the negative emissions, which will only go down due to technological improvements.

What I do agree on is that we need to stop using fossil fuels where possible. I don't think every sector will be ready in time (airplanes and boats for example). However we can make synthetic fuels using direct air capture which are almost carbon neutral (look at the super work David Keith is doing with Carbon Engineering: http://carbonengineering.com/ )

If you are interested in negative emissions this is the best review paper I've come across so far that covers all various negative emission technologies, from trees and oceans to bio-energy with carbon capture storage (BECSS) and direct air capture (DAC). Highly recommended.

Modern heat pumps are still highly efficient at 40F (4C) the coefficient of performance is 4+ at this temperature. We switched from an hybrid set to a full-electric setup (also PV and solar thermal) and are super happy with (live in Amsterdam, so regularly goes below 40F/4C). There's probably something wrong with your neighbors setup.

I'd say practical limits of current models are probably around -20C (-4F)

If you're interested here is an example datasheet[1] of an air to water heat pump (2018) (using Celsius here):

Mitsubishi PUHZ-SHW112YAA Guaranteed operating range (outdoor): Heating: -28 to +21 Domestic hot water: -28 to +35

On page 108 you can find the actual co-efficient of performance (COP) for different outside temperatures and inside water heating temperatures. As an example: at -10 and an water temperature for heating at 25 you still get a COP of 3+. That means that 100% electricity moves 300% of heat into your house.

[1]: https://www.mitsubishi-les.info/database/servicemanual/files...

We ditched our gas and have an air to water heat pump, costed around €6000 ex subsidies (I live in Amsterdam so not the coldest weather, we also have solar thermal and PV).

However air to water heat pumps are also applicable in cold climates. If you're interested here is an example datasheet[1] of an air to water heat pump (2018) (using Celsius here):

Mitsubishi PUHZ-SHW112YAA Guaranteed operating range (outdoor): Heating: -28 to +21 Domestic hot water: -28 to +35

On page 108 you can find the actual co-efficient of performance (COP) for different outside temperatures and inside water heating temperatures. As an example: at -10 and an water temperature for heating at 25 you still get a COP of 3+. That means that 100% electricity moves 300% of heat into your house.

[1]: https://www.mitsubishi-les.info/database/servicemanual/files...

Air to water heat pumps are also used in harser climates. If you're interested here is an example datasheet of an air to water heat pump (2018) (using Celsius here):

PUHZ-SHW112YAA Guaranteed operating range (outdoor): Heating: -28 to +21 Domestic hot water: -28 to +35

On page 108 you can find the actual co-efficient of performance (COP) for different outside temperatures and inside water heating temperatures. As an example: at -10 and an water temperature for heating at 25 you still get a COP of 3+ (which are the average low temperatures in Maine). That means that 100% electricity moves 300% of heat into your house.

Direct Air Capture (capturing CO2 right from the air and utilising it in the form of synthetic fuels, building materials, polymers and more)

Just use an air to water heat pump. We've got one installed in the netherlands, costs was about €6k (ex subsidies) and we're disconnected from the gas supply. The newest generations can go up to -25 degrees celcius (look up Mitsubishi zubadan for example)

I recently looked into the literature and I think the evidence is ambiguous [1] If you've found some clear evidence supporting your case, could you point me in the right direction?

[1]https://www.researchgate.net/profile/Shourong_Shi/publicatio...

Or make direct fuels out of it :P /s (that would not work, otherwise you've created a perpetuum mobile). Would be interesting if you could use your car's surface as a kind of anode.

I'm also not sure how much of a big win the drones are. Proper forest management is probably way more important. So protecting against illegal logging and making sure that whenever trees are almost dying to take them out so that they don't rot and replant a new one.

Curious, how does desert flooding fit into this? It's basically energy creation using hydro or am I missing the point here?

Edit: Never mind, missed the YC dessert flooding article:

>> This system of oases would be used to grow phytoplankton. With additional desalinated water, it could irrigate the surrounding area to propagate vegetation as well as provide fresh water to nearby communities. These oases would operate similarly to the ocean phytoplankton cultivation concept but executed in a relatively controlled and, thereby, safer environment than in the ocean. Unlike BECCS, the oases would absorb CO2 via phytoplankton growth - phytoplankton produce biomass faster than agriculture, reducing the necessary surface area by almost 4x - which would be periodically harvested to extend the length of sequestration and set up downstream use as fertilizer or other higher value products. This would be the largest infrastructure project undertaken, making its scale the main challenge.