Planetary bounderies

Fast facts: Human impact on earth

The earth was always under change. This will continue in the next million years.
Humans have global impact in changing biodiversity, climate, land use and water.
In the last decades humans have passed 6 of 9 global boundaries for sustainable live.
Without changes in lifestyle and habits, humans are in the risk to lose future options.
The earth will survive, with or without humans.

According to the Population Prospects by the United Nations (UN 2019), it can be predicted with 95% probability that the world population in 2100 will 10.8 billion (medium estimation). If the fertility rate will not decline as expected, the global population can even grow up to 15.6 billion. The challenges are especially great for Africa, where the population is expected to in-crease more than anywhere else (Table below).
Roughly 4.8 billion hectares (ha), or 36% of the 13 billion ha of global land surface, are used as agricultural land (2021), 3.3 billion ha of which are pastures and 1.6 billion ha of which are cropland (FAOSTAT 2024). Most of the global food and feed is produced on cropland, rather than pastures, which are mostly used for the grazing of ruminants like cows, goats, or sheep. The potential for cropland expansion is very limited (Rahmann et al. 2020). Most fertile pas-tures have already been transformed into cropland, and about 80% of the pastures that remain are of low fertility, situated in remote or mountainous terrain or unfavorably cold or arid climate. It can be calculated that the agricultural area does not change until 2100, the area of available cropland per person will decrease from current 0.22 to 0.14 ha in the world and from 0.23 to 0.05 ha in Africa, according to medium population estimations Rahmann and Grimm (2020).

Table: Global population and land availability 2015 till 2100

Source: Rahmann and Grimm (2020)

The only planet we have is exploited by humans. Rockström et al. (2008, 2015, 2023) have designed the model of Planetary Boundaries. While only 3 out of seven planetary boundaries were crossed in 2008, by 2023 this figure had risen to 6 out of 9. Agriculture plays a significant role in this, as Campbell et al. 2017 found (Figure).