If eating no meat at all is too hard, from a climate perspective eating no beef will have the biggest impact. Eating no ruminants to be specific, but hardly anyone is eating bison/sheep/goat on the regular.
Lamb is popular in the UK. Beef is actually behind chicken and pork already.
Is lamb a regular dish or more of a Christmas and special occasion dish? I’m not in the UK so I genuinely don’t know. Not sure that you can get lamb at a fast food joint like you can with beef burgers.
I’m in the US and can get lamb at fast food joints. Go to any Mediterranean shop for a gyro. Afaik it’s even more available in the UK since it’s primarily sold as people food, not dog food like the US market.
I went like 90% vegetarian and switched to the meat substitutes. If I can do it, anyone can. I’ve always had a meat-a-saurus diet until 2-3 years ago.
I’ve only met one person who couldn’t go veg, because they had allergies to everything: soy, legumes, nuts.
There’s been a lot of obsession with protein in popular culture when in reality unless you’re a bodybuilder you don’t need a ton and a veg diet will suffice. And there are tons of vegan athletes.
The point I was making is that there is one step even the laziest can take to have an impact: just stop eating beef. Going full veg is better of course.