The pie chart shows that there are four main causes of farmland becoming degraded in the world today. Globally, 65% of degradation is caused by too much animal grazing and tree clearance, constituting 35% and 30% respectively. A further 28% of global degradation is due to over-cultivation of crops. Other causes account for only 7% collectively.

These causes affected different regions differently in the 1990s, with Europe having as much as 9.8% of degradation due to deforestation, while the impact of this on Oceania and North America was minimal, with only 1.7% and 0.2% of land affected respectively. Europe, with the highest overall percentage of land degraded (23%), also suffered from over-cultivation (7.7%) and over-grazing (5.5%).

In contrast, Oceania had 13% of degraded farmland and this was mainly due to over-grazing (11.3%). North America had a lower proportion of degraded land at only 5%, and the main causes of this were over-cultivation (3.3%) and, to a lesser extent, over-grazing (1.5%). Overall, it is clear that Europe suffered more from farmland degradation than the other regions and the main causes there were deforestation and over-cultivation.

饼图显示当今世界耕地退化的四个主要原因。在全球范围内，65％的退化是由过多的放牧和砍伐树木引起的，分别占35％和30％。全球退化的另外28％是由于农作物过度耕种造成的。其他原因总共只占7％。

这些原因在1990年代对不同地区的影响不同，欧洲因森林砍伐而导致的退化率高达9.8％，而这对大洋洲和北美的影响则微乎其微，分别受影响的土地仅为1.7％和0.2％。欧洲的土地退化总比例最高（23％），同时也遭受过度耕种（7.7％）和过度放牧（5.5％）的困扰。相反，大洋洲有13％的退化农田，这主要是由于过度放牧（11.3％）。北美的退化土地比例较低，仅为5％，其主要原因是过度耕种（3.3％），在较小程度上是过度放牧（1.5％）。

总体而言，很明显，欧洲比其他地区遭受的农田退化影响更大，主要原因是森林砍伐和过度耕种。