Explain this "Contaminated Water" Scenerio?

Question

I've read over the past few hours that Global Warming will make the only fresh source of water be in Canada.

First off, desalination is allways a ready process... and you don't even need fuel to do it. (Survival 101), simply get a pan, and a opaque plastic sheet (not wrap) and fold the sheet into a tent, the sun will evaporate the water and the water will dribble down as deionized H2O. (Even days of pumping means after that time, there would be a steady stream)

Even besides that, rain will always occur. Think of the atmosphere like a sponge, eventually all this heat will cause the sponge to rapidly fill with water (evaporation) and then, when full, the sponge has to release water back down again. (Don't cite deserts... there are geographic reasons for that. And it DOES rain in a desert) (And YES, Polution can cause 'acid rain' but only once)

So explain this 'theory' without saying 'It just is' or 'Wikipedia said so' or 'I heard it from a guy who knows Stephen Hawking'

The average person needs how much water to 'live'. Even then desal fails because of trying to be a 'continuous source' Lets say I have 100L of water. I can persistantly filter, clean, and use said water. Hydroponics proves to be a more effective way of growing crops... why pour water into soil when you can keep the water near the plant? In fact, placing sheet metal a few feet below the ground will prevent the water from mearly slipping down in the aquiphers.


And people keep saying sever this, sever that. I guess the Ice Age was the a perfectally stable climate, besides being cold.

Increasing in severity is just one model, saying that the model is true because current situations appear to reflect it is ignorance. Medicine doesn't take those risks, prove that the symptoms are caused by the disease before diverting your gaze.

Another note... Trevor, you predict a MINOR increase in rainfall while prediciting more sever weather?


Water Boy, the problem there is that theory requires global warming to happen very rapidly so that it overwhelms us, Floodwalls can easily be made in the years it will take for your scenario to occur (and expanded upon) and even then, the contaminates would be filtered out in at MOST a decade. (well, I predict a lower level of contamination given what you say happens).

Answer 1

On a planet that is 2/3 covered with water we don't need to worry to much about a lack of water.

It will just be a bit harder to make it fit to drink.

Answer 2

I think someone may have been exaggerating. Global warming will affect water supply in different ways but it's not going to lead to worldwide contamination bar Canada.

Global warming leads to increased temperatures which in turn leads to increased evapouration from the seas and oceans and consequently increased rainfall - not by all that much, just a few more millimetres.

GW also leads to climatic shifts which means some areas will receive more rainfall and others will receive less. As a rough rule of thumb there will be a net decrease in precipitation in tropical climates zones and a net increase in temperate zones; some areas will be more severely affected than others. There will be increased and extended periods of both flooding and drought. Both of which affect the water table and in the case of flooding often leads to contamination for several months.

GW is also causing sea levels to rise by approx 3mm a year globally. This has already led to inundation of some low lying island communities and in the years and decades to come this problem will get worse. This is leading to salination of ground water and low level fresh water sources.

A lot of people rely on meltwater runoff from glaciers as their source of drinking water, this happens in China, Tibet, Nepal, Pakistan, India, Chile, Argentina, Peru, Bolivia and the other countries that contain the world's greatest mountain ranges. Glaciers around the world are rapidly retreating and many communities have lost their water source. As glaciers retreat further, more and more people are going to lose their water source.

These changes have knock on effects. Where water supplies were once plentiful they are now diminishing which means irrigation schemes have been abandonned so as to conserve water for human consumption, the result being crop failure. Some lakes have dried up completely leaving fishing boats stranded, a food source removed and fishermen out of work.

In short, some people will be affected, some will have to move, others will have to find alternative water sources. Those hardest hit will be in the developing world where there are no reservoirs, unpredictable rains and no water supply networks.

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Quick points. Desalination is impractical due to cost, countries like the UEA have desal plants but it costs a fortune to establish and operate and the amount of fresh water produced is small.

The solar still method is very unreliable as it requires both heat and sunlight and produces very little yield. It's most practical application being in survival situations at sea, in forests, jungles and marshes.

It does reain in deserts but not much. A desert is, by definition, a place that receives substantially less than average rainfall.

Answer 3

You described a simple solar still, a design that appears in Boy's Life magazine and survival manuals. Water purification by evaporation and condensation is also the natural distillation occuring in the hydrologic cycle of earth.
Increased greenhouse gases are trapping more energy in the earth's atmosphere, and this is being absorbed and stored in the oceans. The hydrologic cycle is altered in several ways. One of them is that water stored as solid ice is being converted to liquid (by melting glaciers and the polar caps). This puts more water into the active hydrologic cycle. Because of the increase in ocean temperature, less energy has to be put into the system to evaporate water every day, meaning an acceleration of the rate of the cycle, as well as an increase in the quantity of water in the atmosphere. This means more rain more often where it does rain - an increase in the intensity and frequency of precipitation events. The land surface and vegetative covering, as modified by mankind, are matched to the previous patterns of precipitation. River channel dimensions are defined by the hydrologic cycle. With more rain, they will overflow and the banks will be cut apart. Also, city drainage systems, dams, road culverts and bridges, all have been "sized" for the previous patterns. These will all be overwhelmed by increased precipitation where it occurs. All this means more soil, debris, and waste contaminants from cities, etc. getting into surface flows, which primarily terminate in lakes, reservoirs, and the oceans. Is that what you were wondering about?