These are the most frequently used words in this book.
american
among
areas
between
billion
century
change
consumption
control
corporations
costs
countries
course
decades
developing
development
earth
economic
effects
energy
environment
environmental
especially
even
example
family
far
few
first
food
forests
fuel
future
global
good
government
great
growing
growth
high
human
humanity
important
increase
issues
land
large
less
level
life
long
market
may
might
million
must
nations
natural
need
new
now
nuclear
number
often
part
people
per
percent
policy
political
poor
population
power
problems
production
public
rate
resources
rich
scientists
seems
services
should
since
size
social
society
states
still
systems
tax
technologies
time
today
united
use
war
water
world
years