The pie chart below illustrates the causes behind land degradation, and the table gives information about how North America, Europe, and Oceania were influenced by these causes in the 1990s.
Overall, over-grazing was the primary reason for less productive agricultural lands. Besides, the proportion of land degradation in the Europe was the highest.
As shown in the pie chart, over-grazing accounted for 35% of land degradation all over the world and 30% of the degradation was caused by deforestation. On the other hand, the proportion of less productive agricultural lands due to over-cultivation was 28%, and other causes accounted for 7% of the worldwide land degradation.
To go deeper into the regional land degradation, the table shows that the land degradation in the Europe was the most severe, with 23% of their lands degraded. Deforestation, over-cultivation, and over-gazing accounted for 9.8%, 7.7%, and 5.5% of the degradation, respectively. As for Oceania, deforestation led to 1.7% of degraded land while over-gazing lead to 11.3% of degraded land, adding up to 13% total land degradation. By comparison, the North America witnessed the smallest proportion of land degradation, with only 5% of the lands become less productive.