An apparent downward trend from a "Medieval Warm Period," roughly as warm as the s, into the cooler "Little Ice Age" gave way to a steep rise in the 20th century.
Visit Website Today, the leading cause of air pollution in the U. Auto emissions also increase the amount of greenhouse gases in the atmosphere, which in turn contribute to global warming. Inin an effort to reduce air pollution, the U.
Congress passed the Clean Air Act, legislation which has been amended and strengthened in the ensuing decades. However, inalmost half 46 percent of all Americans resided in counties with unhealthy levels of either ozone or particle pollution, according to the American Lung Association ALA.
In the eastern U. In the western U. It causes many other health effects, premature births to serious respiratory disorders, even when the particle levels are very low. It makes asthma worse and causes wheezing, coughing and respiratory irritation in anyone with sensitive airways.
It also triggers heart attacks, strokes, irregular heartbeat, and premature death. For centuries, humans unknowingly contaminated sources of drinking water with raw sewage, which led to diseases such as cholera and typhoid. Water pollution intensified with the advent of the Industrial Revolution, when factories began releasing pollutants directly into rivers and streams.
In the developing world [according to UNESCO] as much as 70 percent of industrial waste is just dumped untreated into the rivers and lakes. China is a perfect case in point. Leaky septic tanks, pesticides and fertilizers are among the other sources that can contaminate groundwater.
Over half the American population including the majority of those living in rural areas relies on groundwater for drinking water, according to The Groundwater Foundation www. InCongress passed the Clean Water Act to reduce water pollution.
Various pieces of anti-pollution legislation have followed since that time and today the U. However, water pollution is still a problem. The disaster, which created a 3,square-mile oil slick, instantly killed hundreds of thousands of birds, fish and other wildlife and devastated the area for years afterward.Nine of the 10 warmest Julys on record have occurred during the 21st century (since ), with only one year from the 20th century () among the top 10 warmest Julys on record.
July also marks the 41st consecutive July and the st consecutive month with a global temperature at least nominally above the 20th century average. Learn topic earth science changing environment with free interactive flashcards. Choose from different sets of topic earth science changing environment flashcards on Quizlet.
Geology Chapter Global Climate Change. STUDY. PLAY. 2 million years ago, peaked at 18, years ago with numerous changes in Earth's temperature since then. With a warming trend over the last years, what time had the warmest temperatures?
natural variability failing to explain the warming at the end of the 20th century. There is clear evidence of changes in the composition of the greenhouse gases in the and the UN Environment Program (UNEP) and countries are members.
It does not conduct any research nor does it monitor climate-related data or parameters. More than half of the observed increase in globally averaged temperatures since the midth. Nov 07, · The January–July global land surface temperature was °C (°F) above the 20th century average of °C (°F) and the second highest temperature for January–July period in the year record, behind the record year by °C (°F).
Since , the global average temperature has risen about °F, with the most substantial increases occurring since The U.S.
average temperature has risen by a comparable amount and is very likely to rise more than the global average over this century, with some variation from place to place.