Thursday, January 24, 2008
The Earth's Hydrologic (Water) Cycle
There is much talk and "reporting" going on about the melting of Antarctica, the Arctic and the ice caps of Greenland. Of course directly stated, or implied, this melting is invariably attributed to man-caused global warming. The big scare that follows (of course) is this melting will cause sea level to rise, flooding all of the world's low-lying coastal areas.
Of course this is nonsense at best, at a worst a concerted effort to lie and deceive. It seems a refresher course in the basics of the Earth's hydrologic cycle is in order. First of all, it needs to be understood that there is a finite, or relatively fixed amount of water on or in the Earth. This does not, has not, and can not change much. It can not escape the Earth's atmosphere because of the force of gravity. Essentially all of the water on the Earth now has been here for millions, if not hundreds of millions of years.
This water is continually being recycled. It is evaporated from the oceans, moved by clouds over land masses (and oceans) where it falls as rain and snow. This water can be stored temporarily in the form of snow, ice and in underground reservoirs. However, eventually and inevitably all of this water is recycled.
The main point here is that as glaciers and ice caps melt in the summers, they are added to with snow in the colder times, thus maintaining an approximate balance. There have been numerous ice ages, where the amount of ice increases and sea level drops. Conversely, during the shorter inter-glacial warm periods, such as the Earth is experiencing now, the amount of ice decreases and sea levels rise. These are all very natural processes than have gone on for millions of years before man even appeared.
Once the basic hydrologic or water cycle is understood, here is a look at how that water is distributed:
Volume of water stored inthe water cycle's reservoirs (source: )
Reservoir Volume of water (10 to 6th km3) Percent of Total
Oceans 1370 97.25 %
Ice caps & glaciers 29 2.o5%
Groundwater 9.5 .068%
Lakes 0.125 0.01%
Atmosphere 0.013 0.001%
Ok, lets' do some simple math. Note that 97.25% of all the Earth's water is stored in the oceans, while just 2.05 % is locked up in ice caps and glaciers. Now if 10% of this snow and ice were to melt, that would equal (.10 X 2.05) just .205 % of all the water on Earth. In terms of volume, (2.9/1370) this would be just .00211 % of the water in the oceans. Does this equate to a catastrophic rise in sea level? No, that is not possible.
In fact, if all of the snow and ice on Earth were to melt, it would still add only approximately 2.1% of the ocean's volume. So even if all the ice were to melt, sea level would barely rise. Al Gore and the IPCC are using inaccurate scare tactics to influence people's thinking about global warming. The sad, or evil fact is that they know better.