The proportion of greenhouse gases has increased significantly since the Industrial Revolution. Humans began burning fossil fuels, particularly , in a big way, to drive steam engines for industry, and generate electricity. In addition to escalating coal use after the Industrial Revolution, there came the use of another fossil fuel, petroleum for transport. At the beginning of the 20th century, annual global oil output was about 150 million barrels of oil; now, that amount is globally in just two days. Fossil fuels are classed as non-renewable sources of energy, formed from plants and animals over hundreds of millions of years. Burning fossil fuels billions of tons of carbon dioxide that has been locked away away in the Earth for millions of years. Humans are billions of tons of carbon dioxide to the atmosphere each year. And guess what? Carbon dioxide is a greenhouse gas. The at which the planet is warming is possibly the biggest challenge to ever face humanity. The are likely to be devastating, we need to act , and act now. A single web page cannot fully answer the question of what global warming is. Following the links on this page will allow you to see how complex and serious the of global warming is. So what is global warming? It is a disaster of our own making.