Global Warming is described as the period in recent history when the earth's surface temperature warmed. Global warming is the increase of Earth's average surface temperature due to greenhouse gases that collect in the atmosphere like a thickening blanket, trapping the sun's heat and causing the planet to warm up. Through the years, Global Warming have changed the climate drastically because they have effects on the weather.In recent years, the Earth's climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era and of human civilization. Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives.