Saturday, August 27, 2011

Who Owns the Water in the Atmosphere?


I would have guessed that we all "own" the water in the air, just like we "own" the air we breathe. Closer scrutiny of this ownership, however, reveals that we are in, pardon the pun, uncharted waters.


Water Rights
Owning a cloud
Source-nicholsoncartoons.com.au
Water laws enable individuals and companies and others to buy water from a particular source like, a stream or river, a well or a pond or groundwater below a certain location.
Under these laws any activity that tampers and reduces water amounts or flows is tantamount to having violated some one's water rights.
As human populations and the land for agriculture have grown over time, so have the cost of water rights. 
Source - seekingalpha.com
Today, much of the water on land is spoken for. 


















Rain Water Harvesting
Catching rainwater and storing it for later use, can be interpreted as not allowing the rainwater to enter into the ground or a nearby stream and, thus, interfering with someone downstream who owns the flow from that stream.
Diverting rainwater into a barrel was illegal in Colorado till mid-2009, when the State Legislature approved the capture of rainwater by individuals whose homes are in rural areas not supplied through a water municipality.
Other states are also currently looking into ways to support water rights in an era of water supply shortages. US states in the arid southwest have already loosened up laws to allow rainwater collection and reuse.

Saturday, August 20, 2011

Water Demand in 2025

Demand for water is growing most everywhere on Earth. But demand growth is largest in the developing world.


Population Growth
Source-Sustainablescale.org
The population of the developed world is projected to grow at a fraction of the growth in population in the developing world.
Of the 10 billion people projected to reside on Earth by 2050, only about 15% are seen to reside in the developed world.
Both the high growth in developing countries' population and the fact that water consumption increases as living standard increase, fuel growth in water demand in the developing world.

As a percentage, developing country water demand is expected to grow approximately 300% over the growth of demand in the industrialized countries.

Saturday, August 13, 2011

Body Water Cycle Linked to Global Water Cycle?

How come the residence time that nature has established for water molecules on Earth and through the human body are so close and supportive of life? Are they interdependent in ways that we do not understand?


Water Residence Time in Human Body
Source - archive.stsci.edu.
Soon after the discovery of deuterium in 1931 , a Hungarian scientist, Gyorgy Hevesy and his colleagues used dilute volumes of heavy water to study the uptake of water by fish, other animals and humans.  
Gyorgy Hevesy
Source - nndb.com
Employing non-radioactive isotopes, like deuterium, Hevesy determined that "heavy" water, taken through the mouth, appeared in human urine (his own) after about 26 minutes. Also by monitoring urine levels, they were able to ascertain the average lifetime of a water molecule in the human body as 11-13 days.
Hevesy and his colleagues also used the same process to estimate the total water content of the average human body as 10 to the power of 27 molecules or 1,000,000,000,000,000,000,000,000,000 molecules. I have found no description of what an "average human" was commonly meant in Hevesy's time.
Water Residence Time in the Atmosphere
As described in the post dated June 25, 2011, water residence time is the lowest for water vapor in the atmosphere and equal to 9 days, as reported in Wikipedia. Other sources put this residence time at 11 days.
The residence time of water molecules is larger in all other stages of the global water cycle by orders of magnitude.


It is interesting to note that the residence times of a water molecule (on average) in the human body of 11-13 days, is just slightly larger than the residence time in the atmosphere of 9-11 days. Is nature taking care of living beings' water replacement need by making sure that rain and other forms of precipitation continuously provide new water in time to nourish life on Earth?

Saturday, August 6, 2011

Faster & Slower Water Cycles on Earth

The fastest water cycle exists at the Equator. As we move to higher latitudes, the water cycle is slower, in comparison to that at the Equator.


Water Cycle Speed
Source - cotf.edu
The speed of nature's water cycle is defined by the rates of precipitation and evaporation everywhere on Earth.
Source - kentsimmons.uwinnipeg.ca
At the equator, the energy of falling sunlight heats water and increases evaporation. As sunlight is strongest at the equator, water bodies located here experience the highest rate of evaporation.
This water vapor moves to higher latitude (in both the upper and the lower hemispheres) and precipitates back to Earth till there is very very little moisture left to precipitate at 30 degrees of latitude (in both the upper and lower hemispheres).
Deserts in white
Source - desertmuseum.org
The precipitation amount and rate is lowest at the 30 degree latitudes. Most of Earth's desert areas lie at the 30 degree latitude mark.
Not all the deserts lie within the 30 degree latitudes as local weather and climatic conditions influence water vapor concentrations in the atmosphere, proximity of land and oceans and other factors influence precipitation with the 30 degree latitudes.