Sep 15, 2022 · 53m · green-blueprint
Should we eat bugs, farmed fish, or soy?
Tamar Haspel · 22m spoken Michael Grunwald · 18m spoken Stephen Lacey · 1m spoken Lauren Passell · 45s spoken Brighton Stahl · 43s spoken Jacob Wagoner · 19s spoken
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gold bands on the timeline = statements, start to end. Hover to read, click to jump. CC turns on captions
In this listener mailbag episode of Climavores, hosts Tamar Haspel and Michael Grunwald evaluate diverse food and climate questions, analyzing topics such as insect protein, sustainable aquaculture, cattle methane mitigation, land-use efficiency, and practical dietary choices.
How this conversation actually went
Every chapter scored 0–10 on four independent dynamics. Hover any point for the reasoning behind the score. How this is scored →
The hosts as informed peer 4.8 Guest teaching 2.2 Guest disagreement 1.1 The hosts pushing back 1.6
speaking balance: gold is the hosts, purple is the guest (3 minute bins)
Sharpest disagreement ▶ 32:01 Debating carbon opportunity cost versus marginal pasture utility
Grunwald firmly insists that all grazing land carries a natural carbon opportunity cost, countering the framing that marginal land is free for grazing.
Hardest push from the hosts ▶ 29:26 Refusing simplistic land sparing assumptionsHaspel challenges the assumption that reducing livestock consumption automatically leads to rewilding, emphasizing the unanswered questions regarding landowner intent.
Biggest teaching moment ▶ 12:37 Explaining UC Davis seaweed trials and methane reduction dataGrunwald educates listeners on the specific chemistry, international trials, and 80 percent methane reduction data discovered during his reporting at UC Davis.
The host holds their own ▶ 47:15 Establishing the calories-per-acre frameworkHaspel demonstrates deep technical expertise by deploying her calories-per-acre metric, contrasting soy at six million calories per acre against alternative legumes.
the scores for every segment, with the reasoning behind each
| Chapter | Topic | The hosts as informed peer | Guest teaching | Guest disagreement | The hosts pushing back | Why |
|---|---|---|---|---|---|---|
| Stephen Lacey Introduces Climavores and Upcoming Live Show | 0 | 0 | 0 | 0 | Introductory monologue and promotional announcement by Stephen Lacey followed by banter between co-hosts Tamar Haspel and Michael Grunwald about listener mailbag questions and speech tics. | |
| Evaluating Insect Protein for Food and Animal Feed | 5 | 3 | 1 | 2 | Grunwald and Haspel analyze the potential of insect protein, agreeing that while feed/aquaculture is commercially promising, direct human consumption faces severe cultural disgust barriers in Western markets. | |
| Climate-Friendly and Affordable Eating Strategies for Students | 4 | 2 | 1 | 1 | Haspel outlines affordable, low-emission staple crops while warning against processed junk food like cup noodles; Grunwald adds baseline rules about eating less beef and wasting less food. | |
| Seaweed Feed Additives for Reducing Cattle Methane Emissions | 5 | 3 | 1 | 1 | Grunwald shares reporting from UC Davis on seaweed trial results showing an 80% methane reduction, while Haspel enthusiastically supports the initiative while tempering expectations around commercial scaling. | |
| Comparing Induction Cooktops, Gas Stoves, and Household Emissions | 5 | 2 | 1 | 2 | Grunwald and Haspel evaluate induction versus gas stoves, with Haspel calculating that yearly stove usage is only equivalent to driving 42 miles in an average car. | |
| Land-Based Aquaculture, Canned Fish, and Seafood Sustainability | 6 | 3 | 1 | 2 | Grunwald discusses the pros and technical hiccups of land-based salmon aquaculture like Atlantic Sapphire, while Haspel explains the key carbon and waste differences between flash-frozen, wild-caught, and canned seafood. | |
| Land Use Change, Agricultural Sparing, and Climate Models | 5 | 3 | 2 | 3 | Grunwald argues that reducing meat demand cuts deforestation globally, while Haspel pushes back by pointing out the practical ambiguities of land sparing and whether spared land actually gets rewilded. | |
| Marginal Pasture Land Versus Natural Carbon Opportunity Costs | 5 | 3 | 2 | 3 | Grunwald emphasizes the carbon opportunity cost of pasture land remaining nature, while Haspel defends the ecological role of grazing ruminants on marginal lands unsuitable for crops. | |
| Oyster Aquaculture and Ecological Benefits for Vegan Diets | 6 | 1 | 1 | 1 | Haspel explains why bivalves lack central nervous systems and actively improve coastal water quality by filtering up to 50 gallons of water daily, jokingly shutting down Grunwald's skepticism. | |
| Deconstructing Regenerative Agriculture and Soil Carbon Claims | 5 | 3 | 1 | 2 | Both hosts deconstruct regenerative agriculture, contrasting legally certified organic standards with ambiguous soil carbon sequestration claims that often suffer from lower yields and unproven scalability. | |
| The Environmental Efficiency and Caloric Yields of Soy | 6 | 2 | 1 | 1 | Grunwald and Haspel defend soy efficiency, with Haspel introducing her 'calories per acre' metric to prove soy yields six million calories per acre compared to only two million for other legumes. | |
| Fact-Checking Political Claims on Vegetables and Stroke Prevention | 5 | 1 | 1 | 1 | Grunwald brings up a political attack ad by Dr. Oz, prompting Haspel to explain the methodological limitations and surrogate endpoints in nutritional epidemiology regarding stroke prevention. |
Statements from this episode (24)
Grunwald: ADM is building the world's largest insect protein plant in Illinois
“In fact Archel Daniels Midland is right now, they're building the largest insect protein factory in the world in Decatur, Illinois, near its corn processing plant, and they're gonna feed the bugs, you know, essentially leftovers from the corn processing proces…”
Haspel: Edible insect protein for humans is a non-starter in the US
“Now, for humans, I'm gonna say in the United States, it is a non-starter. Americans will not eat insects.”
Haspel: The most climate-friendly foods are also the cheapest
“And there's actually really good news here, and that is that the foods that are the most climate-friendly Also happened to be the cheapest, and we are talking staple crops here”
Grunwald: UC Davis trials showed seaweed additive cuts steer methane by 80%
“When I was out there, they were finding 80% less methane emissions from these particular steers that did have a little bit of seaweed in the diet.”
Grunwald: 3-NOP feed additive is approved in some countries, cutting emissions 30%
“There's a chemical additive called Threenop that is now actually approved for use in some countries, and that one's looking pretty good. Only gets 30% less emissions.”
Grunwald: Symbrosia raised $7M to grow seaweed feed, backed by Danone
“They, but they got seven million dollars to grow seaweed in Hawaii, and in fact Danone was one of their big investors, and I think that's really exciting.”
Haspel: Induction cooktops are roughly 20% more energy efficient than coil stoves
“And induction versus standard issue electric with the coil, induction is better. It's more efficient, and I've seen numbers, Varying but in the 20% range, and it depends on what you're replacing, of course.”
Haspel: Annual household gas stove emissions equal driving 42 miles
“If you look at the amount of greenhouse gases from your stove, and you compare it to driving your car, your yearly stove use is going to be about the equivalent of driving 42 miles in an average car.”
Grunwald: Any carbon advantage of gas stoves over electric will disappear quickly
“And even if it's true that right now, if you look at the national grid, the gas stoves are slightly, slightly better. As the grid gets greener, which is happening every day that's not going to be true for very long.”
Grunwald: Ocean wild fish catches cannot expand beyond current levels
“There's no way we're gonna get more fish from the ocean than we're getting now. You know, at best, we can sustain it.”
Haspel: Diesel drives wild catch emissions, while feed drives aquaculture emissions
“For wild-caught fish, the biggest contributor to climate is the diesel that you burn on the boat. In aquaculture, the biggest contributor to climate is the feed”
Haspel: Canned tuna greenhouse emissions are comparable to chicken
“Tuna, a couple people have analyzed this, and it's in the same sort of greenhouse gas range as chicken.”
Haspel: Grazing utilizes land largely unsuitable for other purposes
“And the thing about grazing is that it actually, it does make use of land that is not so great for other things.”
Grunwald: Global farmland equals the area of Asia plus the Americas
“Right now, it's like, you know, Asia plus the Americas is used for agriculture”
Grunwald: There is always a carbon opportunity cost to using land
“There is always a carbon opportunity cost to using land.”
Grunwald: 40% of global grazing land was originally forest
“You know, 40% of grazing land on the planet was originally forest, and so there's clearly a major carbon opportunity cost”
Haspel: Oyster aquaculture is net positive for marine ecosystems
“Unlike almost everything we grow, oysters can be a positive out in the ecosystem. In fact, here on Cape Cod, where we have nutrient loading problems in our estuaries oyster farming is a codified part Of the solution.”
Grunwald: Scientific evidence for soil carbon sequestration in agriculture is thin
“There's this intense focus that this is going to solve our carbon problem, By just storing a lot more carbon in soils, and the evidence for that is really thin right now.”
Grunwald: No-till farming leads to increased weeds and smaller crop yields
“When you do things like, you know, not tilling the soil you're gonna have more weeds and smaller yields, and we are obsessed with yields because we need to grow more food on less land.”
Haspel: Corn and soy dominate due to crop efficiency, not subsidies
“There's a reason that soy and corn came to dominate the landscape, and it's not because of subsidies. It's because corn is the most efficient cereal grass, and soy is the most efficient leg.”
Grunwald: Palm oil is the most efficient vegetable oil crop
“Palm oil, which everybody hates, is the most efficient vegetable oil.”
Haspel: Soy Yields Six Million Calories Per Acre, Tripling Other Legumes
“So soy, here in the United States, we can grow about six million calories per acre, and that's less than half of what corn can do, because protein has a lot of plant overhead, so any protein-rich plant is going to generate fewer calories per acre than a crop t…”