According to Drovers newsletter, Global methane emissions from agriculture and other sources have surged in recent years, threatening efforts to slow climate change, an international study has found.  According to the study, methane production surged in 2007 and grew rapidly in 2014 and 2015.  The causes of the surge are not well understood but are being attributed to cattle production and rice production.  There are other natural and human causes as well, including byproducts from oil exploration and wetlands.  You can read more about it at Drovers here.

Florida cracker cattle. Source: Dudley Farm Paint Out 29