Answer:
These big and hefty mountain ranges are play important role in weather and wind patterns in their related geographical region. Mountain ranges such as Himalayas, Rockies and Alps affects the weather and movement of wind on global level as well.
In absence of these mountains the global pattern of the wind can be affected and cause drastic change in global climate change as they play crucial role as barrier to wind and jet streams by diverting or dividing it.
For instance Himalayas, during the northern winters diverts the wind and acts as barrier for wind which prevents it from freezing. Rockies and Andies blocks the moisture laden winds flow from Pacific Ocean to western flanks of the american continent that leads to a dry region called rain Shadow desert zone.
Hence if these mountain ranges are gone these impacts will not be felt. Similarly Himalayas in India, cause monsoon wind to strike and cause rain in the region. So winds are greatly affected by these Mountains. If these mountain ranges were gone, winds will flow undisturbed as there would be no barrier to global wind patterns.
