Our meat-dependent world brings tears to Liz Bonnin’s eyes

As she carefully scales the heights of a tree in the Brazilian rainforest, animal biologist Liz Bonnin begins to express some worries. She and a nimble nature conservationist are approaching the nest of a Harpy Eagle, the largest bird of prey, with talons are the size of bear claws.

Losing its habitat to Brazil’s alarmingly rapid deforestation, driven by cattle farming, this animal is no less dangerous for being endangered.

But even when the chick's mother returns unexpectedly, Bonnin's guide, Professor Miranda, remains sanguine. "She'll vocalise a little bit if she's pissed off," he says.

So, it turns out, will Liz Bonnin. Her new documentary, Meat: A Threat to the Planet? (BBC One, Monday, 11.15pm), approaches its subject with a combination of scientific enquiry, field research and commentary tinged with distress or a bubbling sense of outrage. “It makes me petrified and angry,” Bonnin says at one point, folding stark facts about the meat industry’s effects on the environment into unabashed personal response.

'Germans think an Irish breakfast has too much meat'

---

A pasta dish Italians won’t argue with ... and there’s a love story attached

---

First Look: New wine bar is something completely different for Dublin

---

She counts out steakhouses and gathering methane levels in Texas cattle country with grim disappointment. She is disgusted to observe the telltale pink stain of pig manure contaminating farmland, lakes and rivers in North Carolina ("That would basically turn this into an open sewer," she says of the e.coli levels of one contaminated stream). She tears up while comparing razed Brazilian rainforest to the British countryside.

Where once science documentaries tended to eschew such personal expression, that colouring now seems like a necessary tool. Whether or not you think meat is murder, meat is certainly emotional: either your conscience snags on how it is produced, or you bristle at the suggestion you oughtn’t eat so much of it.

The facts Bonnin conveys would be sobering enough left unadorned: we consume 65 billion animals a year; those animals release more greenhouse gasses than all of our transport combined; and the farming undertaken to meet the planet’s soaring demand is hastening climate change, forcing animals and insects into extinction and radically reducing the planet’s biodiversity.

“Without all of this working,” says one admirably brusque entomologist, “we would be screwed as a species.”

But, given the combination of human obliviousness and stubbornness, facts may not be not enough in themselves. The programme is wise to include the remonstrations of one scientist, a Texan libertarian employed by the meat industry, because her don’t-tell-me-what-I-can’t-eat attitude is both so understandable and fundamentally childish. Wiser still is the inclusion of scenes from a thoroughly progressive farm, where even the humane killing of a chicken comes as a brutal shock.

Director Olly Bootle is happily alert to human idiosyncrasies, too, like the bluff entomologist who uses his own excrement to attract insect specimens. Bonnin, meanwhile, can display her own peculiarities. "I don't have this reaction with human babies," she says while cooing over a recently hatched African Penguin. "It's only animal chicks."

That seems harsh. Humans may be the root of all these problems, but until their appetites find an alternative, don’t give up on the species just yet.