Here's an interesting counterpoint in the Guardian to the "giving up meat will save the climate" argument. The problem with abandoning meat is that the resulting industrial farming puts too much pressure on the soil, and depletes already limited fertilizer resources.
In the UK topsoil depletion is so severe that in 2014 the trade magazine Farmers Weekly announced we may have only 100 harvests left. Letting arable land lie fallow and returning it to grazed pasture for a period – as farmers used to, before artificial fertilisers and mechanisation made continuous cropping possible – is the only way to reverse that process, halt erosion and rebuild soil, according to the UN Food and Agriculture Organisation. The grazing livestock not only provide farmers with an income, but the animals’ dung, urine and even the way they graze, accelerates soil restoration. The key is to be organic, and keep livestock numbers low to prevent over-grazing.
Conversely, pasture grazing is by nature not mass production, so the point of eating less meat is still valid, since moving solely towards pasture grazing would seem to reduce meat supplies. It would appear, that as in most things, the key is to achieve the right balance.