2020-05-01 iD

n order to answer that question,

first it’s important to understand

that most of the carbon dioxide

that’s present in the world today

existed long before the human

race appeared. About 97% of CO 2

emissions are of natural origin,

released, for example, by forest

fires, the activity of volcanoes,

and cellular respiration. However that CO 2

is part of a closed carbon cycle—dissolved

by the oceans, converted by plants to

create oxygen, and stored as carbon in

various life-forms. Before human activity

became part of the equation, the system

was in equilibrium, and atmospheric CO 2

concentrations remained almost constant

for several thousand years. But since we

began releasing gigantic quantities of CO 2

into the air by burning fossil fuels (such as

oil, gas, and coal [seen here being mined]),

much more CO 2 has been released every

year than the Earth can store. The result:

Atmospheric levels of this most prevalent

of the greenhouse gases have been rising

fast. The dimensions of this additional CO 2

release are enormous. Over the course of

human history, we had already destroyed

approximately half of the world’s forests

(an area that’s about four times the size

of Europe), before we’d started burning

large amounts of lignite and coal (close to

8 billion tons per year) as well as oil (more

than 33 billion barrels per year). The latest

figures show the CO 2 in the atmosphere

has been rising to more than 37 billion

tons each year as the result of industrial

activity and the burning of fossil fuels.

A host of other human activities, including

agriculture and land use, add even more,

for an estimated annual amount in excess

of 43 billion tons.

WHO IS RESPONSIBLE

FOR CO

2

EMISSIONS?

IN ALL, THERE

ARE TRILLIONS

OF TONS

of CO 2 on Earth, almost all of it stored

inside of rocks (such as limestone).

Only 0.05% of it is dissolved in water,

0.002% in the soil, and about 0.001%

in living creatures and in the air.

Just three countries were

responsible for half of all

the CO 2 emissions in 2015:

30%

13.7%

6.6%

4.7%

3.6%

2.15%

China

USA

India

Russia

Japan

Germany

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