The Effects of Global Warming on Vegetation & the Land

Northward Migration

• The process of global warming is complex, with some areas increasing in temperature, others decreasing and others remaining the same. In areas where the average temperatures increases, plants fail to thrive in the more southern and hotter parts of their ranges, and extend their range northward as temperatures increase. Over time, the result of this process is for a plant's range to migrate northward. A plant may be completely extirpated in southern regions where it once thrived, and appear in areas farther north where it has never been seen before.

Drought

• Higher temperatures can lead to a decrease in rainfall and an increase in soil temperatures. These two factors can cause plants to stop growing in certain areas, leading to more exposed soil and even more soil temperature increase. Because rainfall is closely related to the types and density of plants in a certain region, drought may be made worse by the disappearance of plants. This can create a vicious circle in which drought leads to plant loss, and plant loss leads to more severe drought.

Biotic Islands

• A biotic island is an area where a particular species lives, but is cut off from the rest of its species by unsuitable climates or human development. A plant species that is bordered to its north by desert, intensive human development or water may face extinction as a result of global warming. As temperatures increase and the species' southern range is reduced, it has nowhere to extend to at its northern point because of the limitations to its range. If temperatures increase enough, an isolated species' range could be eliminated altogether, leading to its disappearance.

Desertification

• Desertification occurs when all native plants disappear from a particular area, resulting in sand, bare ground or baked clay. Most desertification occurs in conditions of heat, which become more common under the influence of global warming. Land areas are more vulnerable to desertification when global warming is combined with drought, clearcutting, crop failures or excessive urbanization. Once an area turns to desert, its rainfall patterns are altered and it is difficult to return it to a fertile condition.