Humans have invented and developed numerous advancements in technology during the past two centuries, and these innovations help cause ecosystems to change. Many machines and factories emit harmful chemicals and greenhouse gasses -- such as carbon dioxide -- into the air and water, which in turn contaminates the affected ecosystems and forces birds, land animals and fish in the areas to find other atmospheres more conducive to their health and well-being. Furthermore, technological advancements in fishing mechanisms and agricultural techniques can also alter ecosystems by changing the chemical compositions and by altering the rate of resource consumption in the affected areas.
A detrimental consequence of many technological advancements of humans is climate change. The greenhouse gasses that are released into the air by many machines and factories damage the Earth's ozone layer and obstruct heat from escaping into space. Thus, these pollutants trap heat in the Earth's atmosphere, which in turn has helped cause climate change and an increase in the average global temperature during the past century. Often referred to as global warming, the effects of the higher temperatures can have dramatic effects on ecosystems. For example, the rising water temperatures will cause population declines for salmon, trout and several other cold-water species. Also, the warmer ocean temperatures have caused massive coral bleaching, resulting in the collapse of ecosystems that sustain a large number of fish. Furthermore, climate change can change the landscape, resources and nutritional content offered by forests.
Migration entails a group of animals or humans moving away from one habitat that can no longer sustain them and migrating to another habitat that possesses the appropriate conditions. When animals or humans migrate to another area and begin consuming the resources offered by that area at rapid rates, the ecosystem changes over time as a result of the new species populating and influencing the area. Climate change can destroy the ecosystems of animals, force them to migrate to other regions and thus change the ecosystems of the new areas. For example, the melting Arctic ice caused by global warming shrinks the hunting ground of polar bears, and they in turn must take over another habitat to sustain their well-being.
The many scientific innovations and technological developments regarding medicine since the Industrial Revolution have caused a population explosion among humans. Whereas the birth and death rates prior to the revolution were relatively even due to infant deaths and diseases, advancements in medicine have decreased the infant mortality rate, have reduced the number of deaths caused by diseases and have increased the life expectancy of humans.
This population explosion has had numerous consequences on ecosystems. Resources are being consumed at very rapid rates to support the population increase, and as a result farmers are mass-producing crops to meet the increased needs in many countries. For example, between 1950 and 1984, the amount of grain harvested around the globe increased from 631 million tons to 1.65 billion tons. The increased production along with technological manipulations of the crops -- such as the use of fertilizers and pesticides -- alter the ecosystems of the affected areas.