According to an article on Reuters, future farmers will have to raise livestock and plants that put out less methane and nitrous oxide, respectively, and send in greenhouse gas emission reports to the government (http://www.alertnet.org/thenews/newsdesk/SP410451.htmFarmers face growing climate change dilemma-scientist 26 Mar 2009 10:54:46 GMT By David Fogarty, Climate Change Correspondent, Asia; Editing by Valerie Lee).
Efforts are being made in Australia to breed livestock that produce less methane and plants that produce less nitrous oxide, because methane "is about 20 times more powerful at warming the atmosphere than carbon dioxide" and nitrous oxide is "about 310 times more powerful than CO2" (ibid).
But what if the only emissions anyone had to contend with were those from agriculture because there were no emissions from vehicles, factories, or power plants? It's possible. Cf. www.campaignforgreen.com.