However, humans are adding greenhouse gases to the atmosphere. This is making the planet's average temperature rise by increasing the greenhouse effect. The most important greenhouse gas that humans add to the atmosphere is carbon dioxide, which is now about 0.04% of the atmosphere. Carbon dioxide is released when people burn fossil fuels, like oil, coal, and natural gas. Carbon dioxide emissions come mostly from transportation, energy and industries. The biggest is burning fossil fuels to make heat and electricity: but if we look at where the electricity is used the biggest is industry. The Food and Agriculture Organization said emissions associated with livestock added up to 7.1 gigatonnes (GT) of carbon dioxide equivalent (CO-eq) per year – or 14.5% of all human-caused greenhouse releases. This is more than the 13% that comes from global transport (including all cars and planes) each year.