A lack of precipitation can pose a number of issues for local populations, including agricultural loss and a lack of drinking water. These consequences can result in terrible economic and social calamities such as starvation, forced migration away from drought-affected areas, and war over remaining resources.
Lack of precipitation can also have profound effects on the environment beyond human populations. For example, extreme droughts can cause widespread vegetation change, causing environmental damage itself or serving as a precursor for more drastic actions such as desertification or forest fire.
Finally, a lack of precipitation can have significant impacts on the ability of organisms to move to new habitats. If an organism is unable to move away from an area where there is no longer sufficient moisture available, then it will likely die. This effect is called "desertion" and can be caused by factors such as urban development which prevents people from moving away when they need to, or by climate change (which we will discuss further below).
Now, what are the effects of excessive precipitation? Much like its counterpart, a lack of precipitation, excessive rainfall can have disastrous results for humans and other animals dependent on dry land for survival. For example, extensive flooding can lead to death due to drowning, while intense storms can cause considerable damage through wind and rain.
Too much precipitation, on the other hand, can have a detrimental influence on human activities, commerce and industry, agriculture, and the environment. Too much rain or snowmelt (water from melting snow) at once, for example, might cause floods. Floodwaters may kill living beings, including crops. The soil is also affected by floodwater; heavy use of pesticides in areas where there has been recent flooding is not recommended.
Climate change will likely increase both the frequency and intensity of droughts and storms. Climate-related changes have already had an impact on precipitation patterns across the world. For example, scientists attribute up to one-third of the severe drought that plagued California in 2005--the state's worst water crisis in decades--to climate change. They say this was caused by higher-than-normal temperatures in Asia that led to more humid air conditions that prevented moisture from moving into California.
Parts of Africa are experiencing longer dry seasons due to changing weather patterns related to climate change. This is bad news for people who rely on subsistence farming for their livelihood; they would need to spend more time looking for food instead of growing it.
Increasing precipitation rates could have positive effects as well. More frequent and intense hurricanes, for example, could cause extensive damage and death if we weren't prepared. Also, more water available for agriculture could end hunger in some parts of the world where it currently exists.
Precipitation is the cause Insufficient precipitation can cause dry land, shallow streams, and municipal water supply issues. Flooding, for example, can damage homes, businesses, and infrastructure. Runoff from excessive rainfall can lead to soil erosion and sedimentation problems in lakes and oceans.
Decreased precipitation can also have an impact on plant life. If there are no longer enough clouds to produce rain, then areas that were previously watered will become drought-stricken. This will typically happen where precipitation is used for farming or commercial landscaping. Without these sources of moisture, the plants will die.
Water vapor is the most common form of water vapor in the atmosphere. Clouds help to distribute water vapor around the planet through condensation into liquid form or through sublimation, the transition of gas molecules into particles and droplets that make up ice or snow. Water vapor is transported by wind patterns and comes in contact with cold surfaces such as the ground or the surface of a cloud. Here, it turns back into liquid form as rain or snow. Other forms of water vapor include fog and sprinkler spray. Fog is water vapor condensed into liquid droplets that reflect sunlight and cover Earth's surface at times of high humidity.