(Source, p. 16)
I only recently became aware how much worse red meat is than other meat for GHGs. The reason why this gets little attention is likely because it doesn't fit into the standard ideological division between meat-eaters and vegetarians. The reality for climate is that there's closer to three categories, not two: beef and sheep are worst, all other meats have half or much less than half the effect, and then vegetarian foods have less than half the effect of the other meats.
This is a simplification of course - here in the SF Bay Area, free-range cattle grazing provides an alternative land use to low-density sprawl in the hills, so I think that ranching has a positive climate impact. Still, the disparity speaks for itself.
The policy implications of this are less clear. Getting an adequate price on carbon equivalents could sort things out in theory, but we're still from that day. Letting people know for their personal choices can help, and institutional food providers like schools should keep it in mind as well.
UPDATE: this came with the carrots today - Climate impact of beef: an analysis considering multiple time scales and production methods without use of global warming potentials
Abstract: An analysis of the climate impact of various forms of beef production is carried out, with a particular eye to the comparison between systems relying primarily on grasses grown in pasture (‘grass-fed’ or ‘pastured’ beef) and systems involving substantial use of manufactured feed requiring significant external inputs in the form of synthetic fertilizer and mechanized agriculture (‘feedlot’ beef). The climate impact is evaluated without employing metrics such as CO2e or global warming potentials. The analysis evaluates the impact at all time scales out to 1000 years. It is concluded that certain forms of pastured beef production have substantially lower climate impact than feedlot systems. However, pastured systems that require significant synthetic fertilization, inputs from supplemental feed, or deforestation to create pasture, have substantially greater climate impact at all time scales than the feedlot and dairy-associated systems analyzed. Even the best pastured system analyzed has enough climate impact to justify efforts to limit future growth of beef production, which in any event would be necessary if climate and other ecological concerns were met by a transition to primarily pasture-based systems. Alternate mitigation options are discussed, but barring unforseen technological breakthroughs worldwide consumption at current North American per capita rates appears incompatible with a 2 °C warming target.
So there's the 1000 year viewpoint. See also this from the paper:
What kind of beef consumption and production scenarios are compatible with a 2 °C warming target? If consumption were to grow by a factor of three from its present 58 Mt yr−1 value, and the beef were produced by the midwest feedlot system, the equivalent cumulative carbon would be 504 Gt, which all by itself is enough to use up the remaining allocation of cumulative carbon corresponding to a probable warming below 2 °C.
That might put you off your feed.