The Union Carbide Bhopal disaster at Bophal, Madaya Pradesh, India, ranks as one of the biggest man made disasters. Since the disaster occurred on December 3, 1984, over 25,000 eventually died from direct effects of the release of a combination of methyl isocyanate and other toxins. But the ongoing nature of this disaster keeps it in the list of most profound man made disasters. The continued leaching of the toxic chemicals into the water that supports a dense population. The man made decision factors that went into the disaster included management faults that contributed to corroded and poorly maintained equipment, failure to use a less toxic and available chemical, failure to implement basic safety measures, and placing the system in a densely populated area.
The Chernobyl Nuclear Accident of April 26, 1986, is recorded as one of the most destructive breakdowns of a process designed to use nuclear power for peaceful means. Some reports state the total death toll at around 200,000, with an estimated 5 million suffering from the psychological aspects of the disaster. Like the Bhopal disaster, the environmental impact of the release of radioactive gas, plus sealing the horrifically contaminated plant is expected to take tens of thousands of years before the area is safe again.
The Salton Sea is an example of mankind's foolishness in trying to tame nature. In this case, water from the Colorado river was diverted by canals with the goal of providing fresh water to California's fertile Imperial Valley by The California Development Company. After floods raised the water level, causing catastrophic damage to the controlling equipment, it took over two years to stop the water and to seal the sea. At the end, 350,000 acres were flooded with water that was impregnated from salt that was believed to come in through underground aquifers from the Gulf Of Mexico, creating a dead, salty, brackish sea.
China is undergoing desertification that qualifies as one of the most impressive man made disasters in recent times. The bad farming practices that came from overgrazing of grasslands that bordered the Gobi desert has triggered a massive removal of fertile topsoil, leaving sand that threatens the valleys of China, and the capital, Beijing. Warnings came about overgrazing when the American Dust Bowl crisis was caused by poor farming controls. Over 2,500 square miles was the total in the 1990's. There is no current information about the total, but planting of 3,000 linear miles of billions of trees gives an idea of the magnitude of the problem. The sand from the Gobi desertification actually crosses the Pacific Ocean and reaches the United States. Desertification from bad farming is also occurring on the Latin American and African continents.
These four disasters were chosen because of their long term ecological effects, their massive examples of bad engineering and management decisions, or the devastation that can be caused by over farming to feed growing populations.