I think though all the standard llb modules (tort, equity, criminal, contract, eu, public and land) you’ll be doing that with everyone else.
So you could in fact do a standard llb and pick the optional climate modules (though maybe some are restricted or have caps). Then you’d be more flexible if you changed your mind by year 3 and wanted to focus on say family law.
Also, career wise, and longer term, I think a standard llb may raise less questions on a cv. It’s an interesting degree, I just think you could do those modules without committing yourself to the one path.
I imagine you could probably swap after a year to normal llb so check that anyway.
Good luck!