A Planet at Risk

 Our planet is a precious resource on which we have evolved. In its orbit around the Sun, the Earth is at the right distance and has all of the necessary components to capture the Sun’s energy in the proper amount to allow life to develop and flourish for billions of years. As a relative latecomer to the planet, the genus Homo has occupied it for approximately 2.8 million years. Our species, Homo sapiens, appeared about 200 000 years ago and modern man developed only about 50 000 years ago (Stringer, 2002). While only on the planet for a relatively short time, our ability to pass on ideas and concepts from generation to generation, along with the discovery of fossil fuels as an energy source, led to the Industrial Revolution and the dramatic increase in population over the past 200 years.

In the early years of the Industrial Revolution, we were able to use dilution as a means of reducing pollution levels. Hence the slogan: “the solution to pollution is dilution.” Since the human population has now grown to the extent that it inhabits most of all of the land masses and tremendous amounts of pollutants in the form of gases, liquids, and solids are released by man’s activities into our environment on a daily basis worldwide, we can no longer rely on dilution to adequately reduce the impacts of these pollutants on the environment. Pollutant emissions impact local and regional air quality and pollute our surface and groundwater supplies, as well as our soils, vegetation, and food supplies. The emissions of pollutant species, including both gases and aerosols that affect the radiative balance of the atmosphere, are leading to impacts that can change our weather and climate. Changing climates are particularly important when one real-izes that they are linked to sea-level rise, storm frequency and severity, droughts, flooding, and the spread of tropical diseases into regions where they were not observed before. We are truly all aboard “Spaceship Earth,” where we have limited air and water resources, as well as energy options, and we can no longer ignore the effects that our activities have on the environment.

the human population growth as a function of recent time. Up until the late 1800s, the development of our society and its survival was strongly determined by environ-mental factors and the local production of the necessary food and supplies. This period can be considered to be an era of “environment vs man,” since our technology had not advanced to a point where we could control or harness our environment and we lived at the mercy of environ-mental conditions. After the Industrial Revolution, in about 1760–1840, the ability to grow and store more food, build stronger buildings capable of protecting us from the weather, and trans-port materials globally led to an incredibly rapid increase in population and the beginning of a “man vs environment” era, where we began to control the impacts of the environment on society. However, we also began to change the environment, both intentionally and unintentionally, as we focused on the growth and development of human society.

The impacts of anthropogenic pollution can now be seen on the entire planet, and they affect all of our environmental systems, including the atmosphere, hydrosphere, geosphere, and bio-sphere. The presence of H. sapiens has had such a large impact on the Earth that many geologists now consider the most recent geological period, covering about 8000 BCE to the present, to be the Anthropocene; the period during which human activity has been the dominant influence on the climate and environment. The impacts of our species on the environment are both short and long term, and we must recognize these effects and begin to minimize and, if possible, reverse these trends through a thorough understanding of the chemistry and physics of the environmental systems. We have put increasing demand on our resources, especially water, fuel, and food, and continuing our current practices and population growth rates will clearly result in worldwide shortages of these necessities and a reduction in the living standards of future generations. Other, more severe, consequences include regional-scale war, severe population decline, and a planet that is not as habitable for man, animals, and plants. Our planet is at risk, and the recognition and understanding of the chemistry of environmental systems on all scales is needed to determine the impacts of environmental pollution and how to reverse them. This will require that future chemists and environmental scientists have an understanding of how the chemistry and physics are linked to the biological systems in order to make decisions regarding possible strategies for managing our rapidly decreasing global resources.