evidence: - Carbon moves from fossil fuels to the atmosphere when fuels are burned. When humans burn fossil fuels to power factories, power plants, cars and trucks, most of the carbon quickly enters the atmosphere as carbon dioxide gas. Each year, five and a half billion tons of carbon is released by burning fossil fuels. Of this massive amount, 3.3 billion tons stays in the atmosphere. Most of the remainder becomes dissolved in seawater. [...] Carbon dioxide is a greenhouse gas and traps heat in the atmosphere. Without it and other greenhouse gases, Earth would be a frozen world. But since the start of the Industrial Revolution about 150 years ago humans have burned so much fuel and released so much carbon dioxide into the air that global climate has risen over one degree Fahrenheit. The atmosphere has not held this much carbon for at least 420,000 years according to data from ice cores. The recent increase in amounts of greenhouse gases such as carbon dioxide is having a significant impact on the warming of our planet.