Vegetarianism to reduce carbon emissions

I first came across this concept in the Geographical magazine a couple of years ago in an article on cattle and green house gases.
It is undoubtedly true that meat production, and particularly beef, is resource hungry,and that the growth in demand for beef has contributed to deforestation in Central and South America. There are also health issues associated with excess red meat consumption. And there are big issues regarding the standard of husbandry associated with meat production (industrial farming of pigs and chickens in particular), and big sustainability issues around fish stocks.
However, it's important to remember that much of the pasture used to rear livestock is not particularly well suited for crop production, either because of the soil or climate and therefore they would be limitations on increasing in arable farming. In addition there are a whole set of issues around freedom and culture that need to be considered.
On a personal level I've been vegetarian for short periods of time,a month or two when travelling in India and Nepal, but I very much enjoy meat and fish and would find it difficult to make the switch permanently. However, I can see the logic of reducing in meat consumption and could buy accept the idea of "Meat-free Mondays" or similar.
But before heading down this route there's alot of stuff we can do in areas such as reducing food waste that could have a significant impact in this area.