To add to your third point, helps people understand, respect and build a relation with our planet.

Like the kids thinking food just appears in the store or blindly trusting the weather report instead of measuring it yourself. Understanding has been taken away from us so we are easier to exploit by capitalism.

It also helps the local fauna like bees, birds etc, which are usually destroyed by large agricultural farms.

It depends on how you measure efficiency. In terms of labor input, yes. In terms of food produced per area of land, smaller farms are actually far more efficient. So it’s not quite that simple.

Not sure if you watched the video but it goes into this topic a bit so if not it could be informative.

But yes home gardens have lots of benefits that go beyond carbon emissions. And since we have direct control of them, it may be easier to reduce those emissions than those from some distant farm.

In my city, personal/community gardens are a haven for bees and insects. However, there is a lot to be gained with scale if done responsibly.

Not that I know of. He’s summarizing and critiquing some research that was done recently. Here’s an article about the research but the video does raise some caveats so take it with a grain of salt: https://theconversation.com/urban-agriculture-isnt-as-climate-friendly-as-it-seems-but-these-best-practices-can-transform-gardens-and-city-farms-221537

I read the paper before seeing this video post. Maybe not what you’re looking for but here’s my TLDR takeaways from the publication:

• Infrastructure is the largest driver of carbon emissions at low-tech Urban Agriculture (UA) sites (63% of impacts)
  • A raised bed built and used for five years will have approximately four times the environmental impact per serving as a raised bed used for 20 years. The issue is, with frequent moving and development in urban environments, much of the infrastructure is gone or redone in a short timespan.
  • Climate-friendly sites in the sample cut their emissions by more than 52% by upcycling refuse from the urban environment for raised beds, structures and other infrastructure—twice as much savings as high-carbon sites
• Composing
  • Sites in the sample used 95% less synthetic nutrients than conventional farms
  • poorly managed composting can exacerbate GHGs. The carbon footprint of compost grows tenfold when methane-generating anaerobic conditions persist in compost piles.
  • We estimate that careful compost management could cut GHGs by 39.4% on sites that use small-scale composting.
• rainwater
  • In this study, more than 50 (of ~75) sites practiced rainwater recovery, but only four derived most of their irrigation this way
  • sites primarily used potable municipal water sources or groundwater wells, consistent with the underutilization of rainwater seen across past research
  • Irrigation from these sources emits GHGs from pumping, water treatment and distribution, and this rose to as high as 83% of total emissions on one UA site
• Non caloric benefits
  • UA practitioners overwhelmingly reported improved mental health, diets and social networks
  • Cost–benefit analysis of a collective garden in the UK estimated that social benefits, such as improved well-being and reduced hospital admissions, accounted for 99.4% of total economic value generated on-site
  • Because emissions allocation often follows economic value generation46, growing spaces that maximize social benefits can outcompete conventional agriculture when UA benefits are considered holistically.
  • Although UA may increase the carbon intensity of fruits and vegetables, these foods account for a small share of total dietary carbon impacts, which are driven mainly by meat and dairy. Studies have shown that UA practitioners often reduce their intake of animal products49. Future work should quantify this tradeoff between elevated carbon footprint in urban produce and shifting diets.