Pollution caused by land travel,
air travel and food transportation
Notes on land travel:
A substantial contribution to greenhouse gas emission comes from transport.
The sector is claimed to consume nearly 60% of the world's oil and produces a
quarter of all energy-related CO2 emissions.
1 However, the former value by Venkat Kumar appears too high.
Oil use by transportation has almost doubled since 1973, and the related
emissions are growing at about 2.5% annually.
1 According to IPCC, emissions of CO2 from all transport
sectors accounted (in 1996) for about 22% of all global emissions of carbon
dioxide from fossil fuel use. Note that the emitted CO2 and water vapor are
directly proportional to the fuel burned - according to the US Environmental
Protection Agency, every gallon of gasoline burned puts 20 pounds of CO2 into
the atmosphere. A number of additional specific details are known for the United
States, where, unfortunately, they do not seem to lead to any positive action:
Of all of the global warming pollutants that Americans release into the
atmosphere, 27% come from cars, trucks, planes, and other vehicles propelled
by fossil fuels. 2 Some
sources give 30% for cars, trucks, trains, and planes.
With 20 miles per gallon, a car produces a pound of CO2 for each mile.
With two people in the car, 0.56 pounds are released, on average, for each
passenger mile. Airlines perform about the same.
Trucks move about 70 tonnes of goods a mile for each gallon of diesel
In the US, gasoline consumption amounts to 9 million barrels of oil each
day, enough to fill more than four supertankers. 2
In the last decade, US oil use has increased by almost 2.7 million
barrels a day, which is more oil than India and Pakistan use daily
Approximately one fifteenth of all greenhouse gases (GHGs) released by
humanity worldwide, originate in the US transportation system. If current
trends persist, US transportation GHGs could be half again as much by 2020.
In the year 2000, there was in Europe enough factory capacity to make about
18 million cars a year (with only 15 million expected to be sold). The same
capacity was in the US (the market was expected to shrink to less than 17
million). In the same period, US had 770 cars per 1,000 people, versus 10 in
China, 30 in Egypt, and 552 in Japan. 4
Currently, the passenger car global production amounts to approximately 40
million cars per year. 5,6
As to consumption, American vehicles burn triple the oil they did in 1950, which
leads to the following emission rates: 7
If we assume a properly maintained average passenger with annual car mileage of
12,500 miles, and a properly maintained average annual light truck with annual
car mileage of 14,000 miles, then, with fuel consumption of 21.5 miles per
gallon (mpg) for passenger cars and 17,2 mpg for light trucks:
A passenger car consumes 581 gallons of gasoline, and emit 77.1 pounds
of hydrocarbons, 11,450 pounds of CO2, 575 pounds of CO, and 38.2 pounds of
A light truck= consumes 813 gallons of gasoline, and emit 108 pounds of
hydrocarbons, 16,035 pounds of CO2, 854 pounds of CO, and 55.8 pounds of
Even if we were to increase vehicle fuel economy by 40%, all the gains would
be wiped out within 17 years with a modest 2% annual growth in vehicle miles
It is particularly worrying that, in the US, high-horsepower automobiles and
SUVs (Sport Utility Vehicles) will continue to be manufactured, although they
have far worse economy than other vehicles. In the US, the SUVs now account for
one in four new vehicles sold, and sales continue to climb. Surprisingly, in
India sales of the fuel-guzzling SUVs account for 10% of all vehicle purchases,
and could soon overtake car sales.
Notes on air travel:
As to air travel, international travel has never been easier. In 2002, nearly
700 million trips are made abroad. 9
The demand for air travel has increased three-fold between 1980 and 2000, and is
set to double by 2020. The expansion raises growing concerns due to its impact
on the environment - air transport is one of the world's fastest growing sources
of greenhouse gases. 10 The
airlines industry consumes about 205 million tones of aviation fuel (kerosene)
each year, which, according to IPCC, represents 3.5% of man's contribution to
global warming from fossil fuel use. 11
The IPCC figure is expected to grow to between 5 and 6% in 50 year's time. In
addition, the climate impact of flying is increased by a factor of at least 2.5
(compared to the combustion of jet fuel alone) by emission of nitrous oxides and
other pollutants at high altitudes. There will be efficiency improvements, but
so far the growth in air travel has been outpacing all fuel efficiency gains. In
2000, there were around 900 airlines operating 11,600 commercial aircraft,
transporting 1.4 billion passengers and 30 million tones of freight.
12 Dominant were large passenger and freight carriers; the
total economic impact was estimated to be in the range of $1,300 billion (3.5%
of the world's GDP!). 12
Expected is an average annual traffic growth of 5% with freight traffic being
one of the main growth factors. Overweight Americans contribute to the problem.
They cause airlines to burn more fuel and raise air ticket prices. Extra weight
adds up to $275 million each year in extra fuel cost! 13
Air transport is essential for world business and tourism. Over the last 25
years, the number of international tourists has more then doubled. In 2002, 715
million international tourist receipts were accounted for. 14 Even more important is trade.
Unfortunately, it is to be regretted that in many instances both in tourism and
trade the policy is dictated not by the common good but by excessive demands on
profit and on satisfaction of narrow personal preferences. Typically, both the
World Trade Organization and the World Bank - the two premier institutions that
promote global trade - have been silent about the links between trade,
transportation, and climate. This applies particularly to trade which appears to
be contributing to the carbon dioxide emissions for purely financial gains.
Notes on food transport:
The price of food is disguising externalized cost - damage to the
environment, damage to climate, damage to infrastructure, and the cost of
transport. The environmental cost of food transport is given as US 3.8 billion
dollars a year 15, and it is
claimed that it in-creased by 12% in the period between 1992 and 2002. Among the
factors that drove the increase was the rise in global trade, concentration of
power in the hands of the supermarkets with centralized systems of distribution,
greater car use for shopping, and a rise in packaging and processing.
The trend toward eating food from farther and farther away is becoming
wide-spread. While much of food goes by sea, air-freighted food - such as
chickens from Brazil and Thailand, mainly for use in processed food - makes a
major contribution to global warming. It has an extremely high carbon dioxide
emission per tonne, and is the fastest growing mode of transport. On top of it,
some of the food transport by air simply makes no sense: Why should spring
onions from Mexico be sold in an Irish supermarket, or why should iceberg
lettuce from Los Angeles be flown to London? In the latter case, Sustain,
a U.K. based food and farming alliance, has shown that the lettuce requires 127
calories of fuel for every food calorie. 16
Quantitative data on food transport are known in detail for Britain. 28% of
all freight on the roads of Britain is food or agricultural produce: 1.6 billion
tones are carried 148 tonne-kilometres. 23% more food than 20 years ago is on
the road, and due to centralized storage it is traveling 65% further. Carbon
dioxide emitted by food transport in 2002 amounted to 19 million tones.
17 The average distance we now
drive to shop for food each year is 898 miles, compared with 747 miles a decade
ago. 17 If all of the U.K.
food came from within 20 km of where we live, we could save £2.1 billion a year
in environmental and congestion costs. 15
According to Brian Halweil from the World Watch Institute, a meal of
meat, grain, fruit, and vegetables accounts for 4 to 17 times as much petroleum
if it comes from afar than if a consumer buys the ingredients locally. The fuel
burned to transport and refrigerate the food contributes to global warming. As
to food coming from abroad, about 12.2 millions tones are imported into Britain,
and 7.4 million tonnes are exported. 15 Countries often swap food instead of
importing critical items that cannot be produced locally. In this, U.K. is no
exception: In 1998 Britain imported 61,000 tonnes of poultry meat from the
Netherlands, and also exported 33.100 tonnes of poultry meat to the
Netherlands.18 Also, Britain exports approximately 400,000 tonnes of milk each
year, but imports a similar amount from abroad.
There are surprisingly few data on food transport in the US on the Internet.
What is available mostly concerns earth-bound transport.
The following information sources were used to prepare and update the above
essay. The hyperlinks are not necessarily still active today.