how can sudden events affect earth?

Sudden events as in disasters? Certain events, such as earthquakes, are things we cannot predict with ample time, so it can be disastrous to people in the case of landslides, buildings toppling, and tsunami waves such as those that hit japan.

Drought can result in lower water levels in reservoirs, lakes and ponds, as well as reduced streamflow in rivers. This decrease in available water can also lead to a reduction of some wetlands, groundwater depletion and even impact water quality (e.g. salt concentration can increase). Examples of drought impacts on society include anxiety or depression about economic losses, conflicts when there is not enough water, reduced incomes, fewer recreational activities, higher incidents of heat stroke, and even loss of human life. Drought conditions can also provide a substantial increase in wildfire risk.