Approximately 160 000 - 200 000 years ago a biological change took place that would disrupt the natural equilibrium of the Earth that had existed for the previous 4.5 g a. At that time homo sapiens' with a common ancestor known as Mitochondrial Eve, evolved in east Africa and from about 70000 years ago began to spread around the earth propelled by a series of population explosions - initially in Africa. At first the hunter gatherers homo sapiens made little impact on earth systems but from about 9000 years ago settled agriculture saw the first anthropogenic changes to chemicals in the environment. Soils were depleted in essential trace elements accompanied by loss of stature and disease in human skeletal remains; many other species extinctions date from this time. Mining and mineral working initially for gold but later for copper and tin a caused local pollution especially with arsenic and mercury
Large scale disruption of the Earth system began in Europe in the 17 Century with the agricultural and industrial revolution in Britain. This was increasingly dependent on the use of fossil fuels for energy and agrichemicals and by the second part of the twentieth century the natural equilibrium of the Earth had been destroyed. There was an increasing impact from homo sapiens as a result of burgeoning populations increasingly eating energy intensive animals rather than vegetable based protein and accompanying this trend was an increasing demand for material possessions. New chemicals were developed for materials such as plastics, detergents and pharmaceuticals further damaging the biosphere. More recently, new materials such as engineered nanomaterials have begun to be released into the environment.
Politicians are battling to deal with just one of the chemical impacts of these changes- the accumulation of greenhouse gases in the environment which has the potential to cause massive global change. There are many other serious chemical threats to the Earth as a planet capable of sustaining life as a result of human activities. In this presentation we shall explore some of the most important of these and indicate some of the fundamental changes in human activity that are needed if life on Earth is to be sustained beyond the 21st century.
The onset of the Anthropocene is suggested to be 9000 years before the present by some authorities and to date from the 17 century by others. The evidence of a change in the natural equilibrium of chemicals in the environment supports the earlier date.