NetZero’s Mycological Snake Oil

** UPDATE May 2021: BuzzFeed News story from Zahra Hirji: The Mushroom Scammer **
Zahra Hirji has fully reported this story, including many more details than were originally apparent. Please read the article above for the full picture of history and consequences.

Early this year, I started seeing a lot of folks sharing a Kickstarter campaign from a company called NetZero. This company was fundraising for a new product in which mycorrhizal fungi play a central role –  ’a mycelial orb’ advertised as an easy way to combat climate change.

At the risk of giving their campaign more exposure, here’s the link:
https://www.kickstarter.com/projects/netzero/netzero-capture-your-carbon-footprint-in-your-lawn/posts

Despite my reluctance to tangle with social-media-incubated (read: hyped) crowdfunding campaigns, I was troubled by this one in particular for a number of reasons, but especially that mycorrhizal fungi are the core of this product – I teach, talk, and think about the ecology of this group of organisms almost every day; so I felt the need to make my concerns more public.

The campaign has now already closed. My efforts to raise the alarm went unheeded by Kickstarter (even though they “escalated” my Trust and Safety Violation report to their team). The money has now been transferred to the product creators, and their backers no longer have the option to withdraw their money or be refunded (this is baked into the structure of the Kickstarter platform). The campaign has far exceeded its original goal of $10,000, and raised nearly $160,000. The project has been profiled in various online interviews and articles, including some more notable outlets, including Forbes and Fast Company.

Update: When we raised our deep concerns about Joseph Kelly and the NetZero Project to the author of the original Forbes article, he almost immediately realized that he had unwittingly given support to this sales pitch. He eventually took down the first article and has posted this follow-up:
NetZero Retraction

This project and the people behind it – in particular the CEO, Joseph Kelly – need to be really critically examined.

I’m going to lay out my issues with this campaign step-by-step, starting from practical immediate concerns, followed by more subjective/broader critique.

The basic premise:

Netzero is marketing a "mycelium orb" (presumably a bath-bomb style ball of spores embedded in some matrix) that will be sent to purchasers. Customers are then supposed to dissolve the orb in water and pour the resulting slurry onto their lawns with the idea of stimulating their lawn to draw in and lock up a significant amount of carbon dioxide in roots, thus hiding it underground.

This is one way of achieving carbon ‘sequestration’ – pulling atmospheric carbon into forms that are ‘locked up’, and thus not contributing to greenhouse warming. 

The basic mechanism behind this idea has real scientific basis – the vast majority of plants on earth form mutualistic relationships with various groups of fungi. These relationships are collectively called mycorrhizae.

Note: Not every species of plant does this, and most groups of fungi *don’t* form this kind of relationship.

These relationships are a mutualistic symbiosis: Plants create sugar by photosynthesis (fungi can’t do this), and some of that sugar is moved into roots which are in close physical contact with a fungal partner. The large surface area and enzymes of the fungal vegetative ‘body’ (called a mycelium) allow for very efficient uptake of water and soil nutrients, some of which are ‘traded’ with the plant host in exchange for sugar. 

Since plants make their tissues out of CO2, they are temporary carbon ‘sinks’ – places where carbon comes out of the air and is ‘locked up’ for some amount of time.

Generally speaking, plants that have mycorrhizal relationships are usually bigger, more robust, healthier, and have more biomass (both aboveground and below). This means they act as a ‘sink’ to lock up/sequester more carbon dioxide.

So far, so good.

But the makers of this product appear to have taken this starting point and overstated their ability to leverage it.

The issues:
Let’s assume for the moment that lawns can be stimulated to sequester substantially more carbon following a one-time application of a slurry of fungal spores, as the company advertises:

Note: The last sentence here is scientifically indefensible except for extremely non-standard values of ‘forever’.

The following claim is the crux of the company’s pitch:

“According to Kelly’s calculations, NetZero’s mycelial orb treatments can roughly double the amount of atmospheric carbon captured by America’s lawns (whose average size is 10,871 square feet), boosting the sequestration capacity to roughly 1.3 gigatons. The difference represents around 13% of the world’s global emissions of CO2 related to changes in land use each year.”

If this calculation holds up, it would seem worth pursuing: A cheap, low-tech, easily-implemented technique that boosts the carbon-sink capacity of ubiquitous American lawns, thus, perhaps a feasible way to take a non-trivial bite out of atmospheric CO2

Although representatives of NetZero are quick to state that their methodology and “mycelium technology” is backed by an extensive body of literature, a cursory view into the literature on the topic indicates that turfgrass-centered carbon sinks, although in some ways promising, are – at minimum – a complicated topic.

For example, although Selhorst and Rattan (2013) note significant potential of turfgrass to sequester carbon in soil on 100-200 year time scales (after which, on average, carbon dioxide emissions from such lawns actually exceed lifetime sequestration – an issue that NetZero does not mention), this near-term capacity is diminished by cultural practices around lawn management: 

"The use of extensive mowing and chemical applications to ensure proper health and aesthetic beauty of lawns is responsible for emitting a significant amount of C into the atmosphere. Even under optimal conditions, the high C emissions produced by these maintenance practices can greatly reduce their potential to mitigate global climate change. Over time, the C emitted to the atmosphere through maintenance practices can not only equal but in some cases exceed the amount of C sequestered, shifting home lawns from sinks to sources of atmospheric C."

Source: Selhorst, Adam & Rattan Lal. 2013. Net Carbon Sequestration Potential and Emissions in Home Lawn Turfgrasses of the United States. Environmental Management 51:198–208

To summarize: If implemented poorly, incentivizing tended lawn could actually increase inputs of C to the atmosphere.

As far as original research, NetZero makes multiple references to data emerging from a green roof pilot project in Chicago, as well as gas station roofs associated with Shell Oil. It has so far not been possible to find data from either of these claimed projects. However, NetZero haven’t been transparent about providing the data or results from this project. However, they do claim to have such evidence, and that it has been “vetted” or “validated” by third-party companies.

My request for the evidence directly from founder Joseph Kelly was met with animosity and I was referred back to VERRA.
I requested comment or clarification from both of these companies to determine what “green-lighting a scientific note” means, and what vetting their “mycelium technology protocol” entailed.

VERRA wrote back to confirm that they did NOT vet this product.

There are glaring factual inaccuracies in NetZero’s written explanations of the product (scattered in descriptions and comments across the Campaign’s multiple pages). Some of the more egregious cases are highlighted below.

In response to a backer’s concern about the potential for introducing invasive species by watering the lawn with inoculum of unknown provenance, the Campaign replied:

To begin with, I can’t find any evidence of mycologists on staff at NetZero. Secondly, the term “universally genomic” is unmitigated nonsense.

A slightly different version of this assertion appears on one of the pages associated with the Sacred Rivers Climate Project – a related initiative also started by founder Joseph Kelly:

This framing is less nonsensical, but that just makes it easier to declare categorically false.

Mycelium refers to the vegetative structure or ‘body’ of some (not all) kinds of fungi. Even two adjacent mycelia of the same species are likely to have different genomes; much less “all mycelium sharing the same genome globally”. This is equivalent to declaring that all plants are the same species, which is to say – absurd.

These kinds of clues suggest that there is no mycologist (or even biologist of any kind) behind the scenes at this operation – and that the team’s understanding of the mycological fundamentals of their product are very thin indeed.

Without some specific accounting of the “dozens of endo and ecto-mycorrhizal species”  that are used to make the company’s mycelium orbs, concern about introduction of invasive species remain valid. Some of the most invasive fungi globally are ectomycorrhizal taxa (e.g. Amanita muscaria and Amanita phalloides) introduced by anthropogenic movement of plant hosts between continents. It would be reassuring if the NetZero project team could assert specifically how they plan to avoid introducing non-native and potentially invasive ECM propagules in their products.

It is also worth noting that it is not clear how the self-described skeleton crew at NetZero plans to generate large volumes of spore inoculum for commercial-scale production. By definition, endo- and ecto-mycorrhizal species require a plant host to survive – making large-scale propagation difficult.

Combative dialogue in response to Backer questioning:

There are also red flags in the tone of dialogue in response to critical questioning on the NetZero Kickstarter campaign page. The NetZero response even included a demand that the questioner plant forty trees in reciprocity! Perhaps as penance for their impudence?

Note: The recurring theme of ignorance about basic fungal biology is again apparent here: “Mycelium spores” is a bit of an oxymoron (those are two fundamentally different structures), but more importantly, fungal spores most definitely *do* degrade. Not all spores have the same long-term persistence in soil banks, and some degrade in short order as they are exposed to UV light.

And then, incredibly, went on to double down with new lows of petulance:

This is a strident and defensive posture to take in response to a fairly innocuous request – not what one would expect from a team fully confident in the theoretical foundation and experimental evidence supporting the efficacy of their product.

Bigger issues:
Deflection from the need for larger systemic change is perhaps the biggest danger posed by these kind of ‘solutions’. Although in theory it is possible that the lawns might be leveraged as sites of increased carbon sequestration (practical implementation problems aside), the deficit compared to all global sources of carbon emissions is still staggering. Seemingly-easy “solutions” would seem to risk blunting or distracting from the urgency of large-scale action. In such cases, “democratizing” the solution comes with a shift-of-focus towards individuals rather than corporations and economic systems as the appropriate scale for making progress on what are undoubtedly serious civilization-scale challenges.

In the worst-case scenario, these products might actually stimulate greater individual-level consumption and thus larger carbon footprints because they have the effect of ‘absolving’ guilt or anxiety – after all, if you have every confidence that the invisible results of a one-time application of a spore-laden bath bomb on your front lawn is sequestering 1 gigaton of carbon annually for a decade, why not treat yourself to an extra plane flight?

“An entrepreneur in Atlanta, Joseph Kelly, has successfully demonstrated to large corporate clients and carbon registries that underground mycelial networks can naturally sequester enormous amounts of carbon dioxide without altering the commercial or leisure activities that are taking place aboveground in any way.”
Source: Forbes Article

The takeaway:
The combination of abundant factual inaccuracies, outright dishonesty, lack of data transparency, and strangely combative tone in response to critical questioning suggest to me that this product and its creator deserve a critical review before they are widely backed or supported, or their products implemented.

Please pass the word around in the mycology community so that backers of the project have the opportunity to look more carefully at these claims and avoid being taken in by Joseph Kelly.

Christian Schwarz
Research Associate, Norris Center of Natural History and Santa Barbara Botanic Garden,
Lecturer on Natural History of Fungi at UC Santa Cruz; author of Mushrooms of the Redwood Coast

Supporting signatures:
Dr. Thomas Volk, Mycologist, Professor of Biology at UW La Crosse
Dr. Jerry Cooper, Mycologist, LandCare Research, New Zealand
Dr. Barbara Thiers, Vice President, New York Botanical Garden; President Elect, American Society of Plant Taxonomists (ASPT)
Dr. Gordon Walker, Board Member, Sonoma County Mycological Association
Dr. Roo Vandegrift, Mycologist, expert on Xylariaceae 
Dr. Greg Mueller, Chief Scientist of Plant Science and Conservation, Chicago Botanic Garden, Chair of IUCN Fungal Specialist Group
Matthias Salomon, PhD candidate, Soil Ecology, University of Adelaide, Australia