The main causes of global warming are due to the increase in greenhouse gases, carbon dioxide and methane, mainly in the upper atmosphere, caused by the use by man of fossil fuels, industrial agriculture and deforestation activities. The result is an increase in earth temperature, sea level, a reduction in ice sheets, the retreat of glaciers and so on. The evidence for the human cause is abundant and powerful, but few can make the case that global warming is a natural part of Earth's changing climate. Global warming is caused by human activities involving the burning of fossils, the use of cars, the revolution of industries which causes an increase in carbon emissions. Some people argue this issue. Like John Christy, director of the Earth Science Center at Lamia University in Huntsville. Christy states that “carbon dioxide from fossil fuels is distributed evenly around the world and is not concentrated in the Arctic, so we cannot blame greenhouse gases for the warming of the Northern Hemisphere over the past 27 years. The most likely suspect for (warming) is a natural climate change or cycle that people didn't expect or just didn't understand." This quote describes the natural causes of global warming and refrains from relating the cause to carbon dioxide emissions by humans. (IPPC, 2007) Significant increase in global average temperature over the last century. The prevailing scientific view is that the increase in temperature since the mid-20th century has been caused mainly by the increase in the concentration of greenhouse gases in the atmosphere produced by human activities. The majority of scientists believe that the planet's temperature has increased by 0.5 degrees Celsius since 1990 and will continue to increase at an increasing rate. The consequences...... half of the document......Fahrenheit science 1969. (NASA, 2011)The industrial revolution that began in 1875 changed the weather conditions. The world is warming. Industrialization and increasing population density are forcing governments to consume more fossil fuels and influencing the artificial fluctuation of greenhouse gases. Even if the use of fossil fuels were banned, the greenhouse gases produced in the atmosphere would remain for hundreds of years. The emission of greenhouse gases cannot be stopped, but people can take some precautions such as reducing carbon dioxide, enacting laws, burning fossil fuels and so on. to overcome these problems. At the national level, policymakers need to be aware that national efforts are not only possible, but also achievable at slightly higher costs than existing efforts. (Fourth edition-Edward a keller)