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Here's the condensed blurb:

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**On methane & mammoths:** Pleistocene megaherbivores (mammoths, mastodons, giant sloths, etc.) collectively produced an estimated ~139 teragrams of methane per year before their extinction ~13,000 years ago — a figure similar in scale to what livestock produce globally today. So methane output alone isn't historically unprecedented; we've essentially swapped one giant methane-producing herd for another.

**Why that doesn't mean today's warming is "natural":** Methane is only part of the picture, and CO2 — not methane — is the dominant driver of global heating today. That CO2 comes overwhelmingly from burning fossil fuels: carbon locked away for millions of years, now released in one direction with no historical animal equivalent. Mammoths didn't run tractors, produce synthetic fertilizer, or clear forests for pasture — beef's footprint includes all of that on top of methane, which is why removing methane from the equation still leaves a real number behind.

**Why NZ beef is comparatively low once methane's removed:** NZ's pasture-based system is unusually efficient — high-productivity grazing land, minimal land-use-change penalty, well-managed pasture — landing among the lowest full beef footprints in the world (~22 kg CO2e/kg). Stripping out the ~49% methane share and adding refrigerated sea shipping to Canada brings it to roughly **12 kg CO2e/kg**.

**Your diet's estimated footprint (rough order-of-magnitude, not precise):**
- 175g NZ beef/day (methane removed, shipping added): ~774 kg CO2e/year
- 3 eggs/day (~150g): ~250 kg CO2e/year
- 100g wild-caught Great Lakes smelt-type fish/day: ~75 kg CO2e/year (wild small fish typically carry a low footprint — no feed inputs)

**Total: roughly 1,100 kg CO2e/year** for this specific combination — smaller than a full vegan diet's typical footprint (~1,500 kg CO2e/year), though that comparison isn't perfectly fair since your beef number has methane stripped out while the vegan figure hasn't been adjusted the same way.

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