evidence: Human activities since the beginning of the Industrial Revolution (around 1750) have increased carbon dioxide by over 50%,[8] and methane levels by 150%.[9] Carbon dioxide emissions are causing about three-quarters of global warming, while methane emissions cause most of the rest.[10] The vast majority of carbon dioxide emissions by humans come from the burning of fossil fuels,[11] with remaining contributions from agriculture and industry.[12]: 687 Methane emissions originate from agriculture, fossil fuel production, waste, and other sources.[13] The carbon cycle takes thousands of years to fully absorb CO2 from the atmosphere,[14] while methane lasts in the atmosphere for an average of only 12 years.[15]