Another important push was the onset of the Little Ice Age, a climaticphenomenon that led to cooler temperatures in the Northern Hemisphere.
另一个重要的推动因素是小冰期的开始，这一气候现象导致北半球气温下降。
2
The formation of LMLS is a specific phenomenon during the process of climatic drought, and is one of the direct causes of vegetation pattern evolution.
土壤干层的形成是气候干旱化过程中必然出现的现象，它是导致植被演替的直接原因之一。
3
The causes for the occurrence of this phenomenon are the influences of the sea-level rise and climatic change in the Mid Cretaceous.