Final answer:
In the past 50 years, there has been an increase in cropland and permanent pasturelands at the expense of forest habitats. Fragmentation of habitats has led to more edge habitat. These changes also affect Earth's climate.
Step-by-step explanation:
In the past 50 years, there have been significant changes in land cover and land use patterns. The global extent of cropland has increased from around 2.7 to 15 million km², mainly at the expense of forest habitats. Permanent pasturelands have also expanded, reaching around 34 million km² by the mid-1990s. Overall, the rate of land conversion has accelerated over time, with more land being converted to cropland from 1950 to 1980 than from 1700 to 1850.
The pattern of land cover/use change can be characterized by a decline in the total area of fragments, a decrease in the size of many fragments, increased isolation of fragments from similar habitats, and the dominance of straight edges in fragment shapes compared to natural features. Habitat fragmentation has led to an increase in the proportion of edge habitat.
The changes in land use and land cover have also impacted Earth's albedo and climate. Processes such as deforestation, reforestation, desertification, and urbanization contribute to changes in climate in the areas they occur, although the effects may be smaller when averaged over the entire globe.