The world’s carbon dioxide levels are at highs that have never been seen in human existence. Figures from a Hawaii observatory showed that carbon dioxide levels are past 415 parts per million. Measurements of the gas have wavered between the 180 to 300 parts per million mark for hundreds of thousands of years. It’s not until the modern era that carbon dioxide levels shot to record highs. High carbon dioxide levels prevent the Earth’s natural cooling cycle from taking place, trapping heat and causing the temperatures to rise. The high levels are said to be largely due to burning fossil fuels and the large reduction of forests.