**10.2 Global warming as cause of increased density of forests**

One reason often cited for the increased forest densities is global warming. Plants are known to thrive with a number of factors, such as increased rainfall, humidity, higher temperatures and increased carbon dioxide. Freezing temperatures are known to kill off the plants, allowing mainly coniferous plants to thrive.

Gobal warming should cause shifts of vegetation and forestation patterns away from the equator to the poles as shown below (Figure 10). This changing patterns of vegetation and forests has generally been observed.

Fig. 10. Expected migration of vegetation and marine life, if global warming were the cause. Vegetation densities have increased as expected, whereas marine life has declined dramatically.
