As the world enters the second decade of the 21st century and beyond, conventional agriculture using tractors, pesticides, and artificial fertilisers is becoming less sustainable as prices for petroleum gasoline start to skyrocket in addition to rising electricity prices. The population of the world will reach 9.2 billion people by the year 2050; making conventional agriculture almost impossible to maintain unless massive technological advances are made. Conventional agriculture relies on butchers with a skilled level of education in addition to greengrocers and massive levels of chemicals to deliver the product from more than away so that the product is no longer considered to be local. Cattle farming (done the conventional way with bones and fat) is "responsible for 18% of greenhouse gases"; causing more damage to the environment than the combined effects of the world's transportation system. In vitro meat is speculated to replace conventional meat production by the year 2050 along with year-round vertical farming using indoor urban surroundings. The in vitro meat production method might require less of the Earth's natural resources and cause fewer greenhouse gasses than conventional agriculture can provide. Average global temperatures may also plummet to their equilibrium temperatures of . In vitro meat will also prevent the killing of animals for food; possibly leading to them becoming legally branded as persons under the laws of Western civilization. Once an animal is considered a person, it will be released from the farmer's custody and placed in a nature reserve where the animal will never be harmed or killed by human hands ever again. DNA from the animal will be allowed to be gathered (as a requirement for the production of in vitro meat) before it is sent off to freely habitate and breed at the nature reserve.