Question

Earth presently has 1.4 billion hectares of arable land, and each hectare produces between 1 and 2 tons of grain annually. What is the amount of grain (in tons/yr) produced annually? tons/yr If every human being became vegetarian (as feeding livestock and consuming the products of livestock is far less efficient), then 200 kg of grain would be sufficient to feed each human being on the planet. Based on this data, what is the number of people Earth can support? (Use your value for the amount of grain produced annually.)

Answer 1

Answer:

a) 2.1 billion tons/yr

b) 10.5 billion people

Explanation:

Given:

Total arable land = 1.4 billion

Grain produced by each hectare of land = 1 and 2 tons annually

therefore,

The average Grain produced by each hectare of land = $\frac{\textup{1+2}}{\textup{2}}$ = 1.5 tons/yr

Therefore,

The total grain produced annually

= average Grain produced × Total arable land

= 1.5 × 1.4 billion

= 2.1 billion tons/yr

b) Sufficient grain for each people = 200 kg

Now,

1 ton = 1000 kg

thus,

2.1 billion tons = 2.1 × 10⁹ × 1000 kg = 2.1 × 10¹² kg

The number of people Earth can support = $\frac{\textup{ total grain produced annually }}{\textup{Sufficient grain for each people}}$

or

The number of people Earth can support = $\frac{\textup{ 2.1}\times10^{12}}{\textup{200}}$

or

The number of people Earth can support = 10.5 × 10⁹ people

= 10.5 billion people