In: Biology
Air bubbles trapped in ice enable us to step back in time i.e; ancient times and see what Earth's atmosphere, and climate, were in past. They tell us that levels of carbon dioxide (CO2) in the atmosphere are becoming higher than that they have been in the past 400,000 years. During ice ages, CO2 level was around 200 parts per million (ppm), and during the warmer interglacial periods, it was 280 ppm (see fluctuations in the graph). In 2013, CO2 levels crosses 400 ppm for the first time in recorded history. This rise in CO2 shows a remarkably constant relationship with fossil-fuel burning, and can be accounted for simple premise which is about 60 percent of fossil-fuel emissions stay in the air.
Fossil-fuel burning continues at a its usual rate, such that CO2 will continue to rise to levels of order of 1500 ppm. Atmosphere would then not return to pre-industrial levels even tens of thousands of years into the future. This shows the fact that humans have a great capacity to change the climate and planet.