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. 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 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. One current study forecasts an eventual level of 700.
Deforestation now takes place on a large scale in tropical areas of the world.
When tropical forest is cleared for pasture land, there is an immediate loss of carbon to the atmosphere as carbon dioxide. Global Warming Probably no single environmental issue generates more debate than global warming, the premise that the surface temperature of the Earth is gradually rising due to human effects. An upward trend in global surface temperatures began in about 1920, and temperatures are reported to have been especially high since 1980. Ocean temperatures are now reported to be rising as well, based on a study just released covering the past 40 years. One current report states that the last three winters represent the warmest trend ever in North America.