Changes in the Attitudes to the Environment in the 20th Century.
Though the 20th century saw great advances and discoveries in medicine, improving the condition of human individuals, at the same time the condition of the planet itself was declining, according to many observers. From this perspective, the leading "health care" issue of the 21st century may well be the health of our environment.
The following article will briefly summarize some of the key environmental issues that scientists are currently studying. .
This is a process in which gases in the Earth's atmosphere trap infrared radiation and thus influence climate. The greenhouse effect is not in itself harmful; on the contrary, it establishes a temperature that is hospitable to life. Without this effect, heat would escape into space and the average surface temperature of the Earth would be -19°C, about 33°C colder than it is now.
The atmospheric gases that produce the greenhouse effect include the naturally occurring substances water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3), as well as artificially produced chlorofluorocarbons (CFCs). The indication is that because of human activity, such as the burning of fossil fuels, levels of greenhouse gases are now increasing, especially carbon dioxide levels. Research indicates that carbon dioxide levels in the pre-industrial era were 280 parts per million; today they are 350. One current study forecasts an eventual level of 700. It is proposed that this upward trend will lead to higher average temperatures as well as to various other significant climatic changes that cannot be predicted at this time.
The greenhouse effect is also intensified by the process of deforestation, which is the conversion by humans of forest land to other uses (such as farming). Deforestation now takes place on a large scale in tropical areas of the world.