linguistic:paraphrasing, structural:expansion
Livestock issues

A senior UN official, Henning Steinfeld, said that "Livestock are one of the most significant contributors to today's most serious environmental problems". Livestock production occupies 70% of all land used for agriculture, or 30% of the land surface of the planet. It is one of the largest sources of greenhouse gases, responsible for 18% of the world's greenhouse gas emissions as measured in CO equivalents. By comparison, all transportation emits 13.5% of the CO. It produces 65% of human-related nitrous oxide (which has 296 times the global warming potential of CO) and 37% of all human-induced methane (which is 23 times as warming as CO.) It also generates 64% of the ammonia emission. Livestock expansion is cited as a key factor driving deforestation; in the Amazon basin 70% of previously forested area is now occupied by pastures and the remainder used for feed crops. Through deforestation and land degradation, livestock is also driving reductions in biodiversity. A well documented phenomenon is woody plant encroachment, caused by overgrazing in rangelands. Furthermore, the United Nations Environment Programme (UNEP) states that " methane emissions from global livestock are projected to increase by 60 per cent by 2030 under current practices and consumption patterns."