New Scientist - USA (2021-02-20)

Infrastructure

1%

Icrorrigplateandd

1 2%

Non-irrigated

cropland

1 %

2%

37 %

Ipntensivasturee

Used savannahs

and shrublands

Extensive

pasture

2%

1 9%

1 6%

22% 28%

Pforestslantation

Forests managed

for timber and

other uses

Unforested

ecosystems with

minimal human

use

Forests

(intact or primary)

with minimal

human use

Other land

(barren, rock)

7 %

9%

1 2%

2%

20%

1 0%

Proportion of Earth′s ice-free land surface under different uses

Loss of species richness

Percentage of species lost from natural state to 2005

-100% -80% -60% -40% -20% 0%

Remaining areas of wilderness in 2009

23.2%

of total ice-free

land area

LAND USE

A less granular measure of

humanity’s impact is given by

various measures of the extent to

which we control Earth’s surface.

Infrastructure and intensively

managed cropland, pasture and

forest occupies more than half of

Earth’s ice-free land surface, with

much of the remaining land also

highly modified. Human use now

directly affects more than 70 per cent

of Earth’s ice-free surface, with

wilderness largely confined to a

few areas of the Arctic, the Amazon

rainforest, the Sahara desert and

the Australian interior.

Over 25 per cent of forests have

been permanently cleared and more

than half of the original 12.6 million

square kilometres of wetlands have

been drained. Of the approximately

16 million km^2 of tropical rainforest

that originally existed, less than

9 million km^2 remain. The current

rate of deforestation is 160,000 km^2

Reduction in soil richness

Percentage change to 2010 in soil organic carbon levels from natural state

-80% -60% -40% -20% 0%

Human use of biomass

0% 20% 40% 60% 80% 100%

Percentage of maximum possible biomass production extracted for human use

per year, a loss of approximately

1 per cent of original forest a year.

In intensively farmed areas of

the world, the amount of biomass

human activities extract from the

land amounts to up to 100 per cent

of what natural conditions would

allow to grow. One result has been

a decline in soil organic carbon,

a measure of soil fertility, in many

parts of the world. The decline

in species richness is also most

marked in these regions.

None of these metrics account for

the oceans, which cover some 70 per

cent of Earth’s surface. Here our

impacts are less easily quantifiable,

but the effects of overfishing and

pollution are such that only some

3 per cent of the world’s oceans

are considered true wilderness.

LO

RR

AIN

E^ B

EN

NE

RY

/NA

TU

RE

PL

SOURCE: IPBES ASSESSMENT REPORT ON LAND DEGRADATION AND RESTORATION

SOURCE: IPCC SPECIAL REPORT ON CLIMATE CHANGE AND LAND

20 February 2021 | New Scientist | 37