How much environmental villain is the air traffic in relation to other emission sources?

A former colleague of mine asked me how much environmental villain air traffic is in relation to other emission sources, and added "There should be more focus on food production."

Air transport consumes annually 70 billion gallons of jet fuel and is a growing environmental hazard! The aviation industry’s contribution (carbon dioxide, water vapor, nitrogen oxides) to increased greenhouse effect is about 3.5 percent, of which carbon dioxide accounts for about 2 percent. The aviation sector is also the sector with the largest annual increase, with a doubling in fifteen years. According to the Air Transport Association, IATA, the industry's vision is zero emission from aircrafts by 2050. 

By comparison, the cement industry accounts for 6 percent of global carbon dioxide emissions (1.1 billion tonnes), which is almost twice the emissions from the aviation industry and 20 times what Sweden releases in one year!

For those who cannot afford, or rejects, to buy an electric car, do not want to change their travel patterns, there is a simple way to reduce everyone’s carbon emissions – stop wasting food! 

Using data from the U.S. – which is somewhat higher than in Scandinavia, but not that much higher – approximately 27% of the manufactured food is thrown away as waste. 

The U.S. could save the equivalent of 350 million barrels of oil each year - if you count the energy consumed in growing, packing, preservation and transportation, by not producing the huge quantities of food that is thrown in the garbage.  The savings of not producing the food that is wasted, is equivalent to the emissions from 55 million cars (= all passenger cars in Germany) - annually!