Ecological disasters are certainly caused by humans. A human mistake is considered to be the main cause of major environmental catastrophes of the past century. Whether the oil spill or nuclear explosion, neglect of basic safety measures is always the reason behind environmental catastrophes. People who build and operate industrial objects are responsible for the safety of their exploitation. As we can see, such objects often prove themselves very unsafe.
In some cases, the cause of environmental catastrophes is very comprehensive. It happened in London in1952 when a heavy air pollution killed thousands of citizens. The entire city burned more coal than ever before because it was a very cold winter. As the result, the pollution became disastrous.
We also cannot underestimate the power of natural forces. Tsunamis, storms, and hurricanes make feeble industrial constructions even more vulnerable. The Fukushima nuclear accident of 2011has shown how operational neglect can reveal under the influence of a tsunami. Even if climate-induced, ecological catastrophes are anyway triggered by a human mistake.