Aprendizdetopo: marzo 2015

Oil: For and Against

Pros

Very large supply. Second largest oil field in the world.
Economically recoverable at today’s oil prices
Will help keep oil prices relatively low
Enormous growth potential. Less than 5 percent has been produced.
Big economic driver in Alberta. Jobs for Native Americans.
Stable source country (a rarity for oil)
GHG emissions could potentially be minimized through CCS

Cons

Enormous GHG emissions. Oil sands are already Canada’s largest source of CO2 emissions.
Relatively low net energy return compared to other sources
Alberta, with only 10 percent of the population, emits the most GHG emissions of any province. Provincial government has been slow to respond.
Large amounts of water required: roughly 3:1
Water pollution. Roughly 3 million gallons of toxic runoff per day. Fifty square miles now covered in toxic pools
Destructive to major boreal forest, an important carbon sink
Widespread habitat destruction, both on land and water
Destructive to ancestral lands
Requires expensive and risky pipeline to reach faraway markets

With two thirds of the earth's surface covered by water and the human body consisting of 75 percent of it, it is evidently clear that water is one of the prime elements responsible for life on earth. Water circulates through the land just as it does through the human body, transporting, dissolving, replenishing nutrients and organic matter, while carrying away waste material. Further in the body, it regulates the activities of fluids, tissues, cells, lymph, blood and glandular secretions.

An average adult body contains 42 litres of water and with just a small loss of 2.7 litres he or she can suffer from dehydration, displaying symptoms of irritability, fatigue, nervousness, dizziness, weakness, headaches and consequently reach a state of pathology. Dr F. Batmanghelidj, in his book 'your body's many cries for water', gives a wonderful essay on water and its vital role in the health of a water 'starved' society. He writes: "Since the 'water' we drink provides for cell function and its volume requirements, the decrease in our daily water intake affects the efficiency of cell activity........as a result chronic dehydration causes symptoms that equal disease..."

It is the only substance on Earth that is in liquid form at the temperatures commonly found on the Surface of our planet. It is a superb solvent, meaning that other substances regularly and easily dissolve into it. This allows water to carry nutrients to cells, and carry waste away from them.

In addition, water has the unique property of expanding as it freezes. Because water expands becoming less dense, frozen water, more commonly known as ice, floats. This is very important because it protects the water underneath, insulating it from freezing.

Agriculture as a system

Agricultural enterprises-crop or livestock-deal with such concepts as labor supply, marketing, finances, natural resources, genetic stock, nutrition, equipment, and hazards. While it is possible to effectively manipulate each mechanism of successful farming individually, better results can often be obtained by treating the farming operation as a system. Treating production operations holistically offers greater management flexibility, provides for more environmentally and economically sound practices, and creates safer and healthier conditions for workers and for farm animals.

Crop farming

Crop farming is the cultivation of plants for food, animal foodstuffs, or other commercial uses. A variety of techniques including organic production methods can be used to manage crops. People may enter this career through a family business, by training on a farm with experienced farmers, or by attending college to get a degree in agriculture or a related subject. It can involve long hours and harsh working conditions, along with unpredictable profits from year to year, which can be stressful for farmers.

http://www.wisegeek.com/what-is-crop-farming.htm