The United Nations expects the Earth's population will grow substantially over the next century, potentially as much as 130%. Past 2100, the UN expects the global population to remain relatively constant, though increased longevity and potentially higher fertility rates in the developing world could see the population rise as high as 36.4 billion by 2300.

Source: UN Expert Meeting on World Population in 2300

A major concern in the coming decades and centuries is providing enough food for this growing multitude, and many environmentalists are concerned not just about quantities of food but what kinds of food people will want to eat. For example, as developing nations such as China grow richer, consumption of meat and milk increases. In fact, meat consumption in China quadrupled from 1985 through 2005, according to the UN Food and Agricultural Organization (FAO). Not only is this trend expected to continue but Chinese appetites are shifting toward beef and away from traditional meat choices such as pork. 

This is potentially a large concern for two main reasons. First, the average cow produces between 250 and 500 liters of methane per day.

Methane is thought to be 34 times more potent of a greenhouse gas (GHG) than CO2 over a 100-year period; however, a greater concern is that cattle flatulence also contains nitrous oxide -- which is 300 times as potent a GHG. Therefore cow farts pose a potential risk to global climate and humanity at large.

The second cause of concern is because beef represents a monstrously inefficient use of grain and energy. For example, according to David Pimentel, professor of ecology in Cornell University's College of Agriculture and Life Sciences, 50% of US and 40% of global grain production is consumed by livestock. The amount of grain used to feed US livestock could feed 800 million people.

In addition, the amount of energy it takes to produce 1 gram of beef protein is 54 times greater than for 1 gram of plant protein, a ratio that falls to 13:1 for turkey and 4:1 for chicken. 

Give me steak or give me death
Now I'm not advocating we all become vegetarians to save the planet. Let me be perfectly clear -- I love my steak, and the only way you'll take it from me is by prying it from my cold, dead hands. However, the reason I pointed out the inefficiencies and environmental costs of meat production is so you could have a better understanding of challenges that might face us in the future as billions more people wish to partake in the joys of meat. Luckily, around the globe scientists, engineers, and business people are working for a solution that could allow us to have our sirloin and eat it too. 

Factory-grown meat: just $335,000/lb
Back in 2012 Dr. Mark Post, of Eindhoven University in the Netherlands, successfully created the first artificial hamburger patty grown from cow stem cells in a petri dish. Whereas just 15% of calories fed to livestock turns into meat, Dr. Post was able to achieve a 50% efficiency with his factory-grown beef. The biggest downside is that the experimental beef cost $335,000/lb, though this is a number that will decrease as the process is scaled up for mass production.    

That process would include replacing petri dishes with biodegradable tube scaffolding. Nutrients and oxygen would we piped into the beef to help it grow, while algae would be used to provide certain amino acids and fats.  

Not only could factory-grown meat solve many environmental and economic concerns, but it could also alleviate the ethical qualms of vegetarians and enrich their lives by allowing them the guiltless pleasure of a good rib-eye.  

Supply side solutions
The key to feeding tens of billions of people will require several innovative ideas to increase the supply of crops. Another step toward achieving the 70% increased food production the UN estimates we'll need by 2050 is through vertical farming, which utilizes hydroponics and aquaculture. 

This system brings food production to where the customers are, urban areas. According to Dickson Despommier, a professor of public and environmental health at Columbia University, considered by many to be the father of vertical farming, this method of food production is ideal for generating large amounts of crops efficiently. Because crops are grown in controlled conditions with nutrients piped to their roots, soil erosion and pesticide use is eliminated or greatly reduced. 

Aquaculture of fish, on separate floors, would provide both high-quality protein and fertilizer. Dr. Despommier estimates that 150 30-story towers could provide sufficient produce to feed all of New York City. 

Foolish takeaway
As the earth's population grows larger and richer, its desire for meat is likely to grow as well. Thankfully, brilliant innovators around the globe are hard at work finding ways to supply future generations with the joys of both a bountiful harvest and a full plate of succulent meat -- all while preserving the environment and benefiting the global economy in the process.