Basic Science of Climate Change
Question: What’s the actual science behind global warming?
Answer: The earth gets heat from the sun and normally sends an equal amount back into space as infrared radiation. Certain gases – ‘greenhouse gases’ – intercept part of this outgoing heat radiation, keeping the temperature higher than it would be without them. Carbon dioxide, CO2, is this most important of these gases. If there was no CO2 in the atmosphere, we would all freeze, but just a tiny amount keeps the earth warm enough to sustain life.
For about 10,000 years, that CO2 level was quite steady, giving us a stable climate in which to live and grow. But when we discovered coal, oil, and gas and all the energy we could harvest from them, we started burning them faster and faster. Burning those fuels converts ‘fossil’ carbon that’s been buried underground for millions of years into CO2, exceeding the natural level we had for millennia.
Scientists discovered the greenhouse effect in the 1850’s, [1,2] but it wasn’t until 1958 that we were able to precisely measure the amount of CO2 in the air and track how fast it’s increasing.  Just since that time, it’s climbed by more than 30 percent,  about 100 times faster than any natural cycle can explain. 
Not only is this raising the global temperature, but almost half of the CO2 we produce is going into the oceans, causing the water to become more acidic. That’s detrimental to important marine life. 
Human activity, mostly fossil fuel burning, currently adds over 1,000 tons of CO2 per second to the atmosphere and the oceans.  Natural cycles, volcanoes, and the sun have all been ruled out as the cause of the current heat buildup.  They are either too small, too slow, or going in the opposite direction.
Related: Where Scientists Stand on Climate.
- “The Discovery of Global Warming.” American Institute of Physics (Feb 2018).
- “Meet the woman who first identified the greenhouse effect.” Climate Home News (9 Feb 2016).
- “Charles David Keeling.” Wikipedia (1 Apr 2018).
- Specifically, from 315 to 413 parts per million (ppm). “Global CO2 Levels.” 2° Institute (accessed 29 Dec 2019).
- Lindsey, R. “Climate Change: Atmospheric Carbon Dioxide.” NOAA Climate.Gov (19 Sep 2019).
- “Ocean Acidification.” NOAA Fisheries (28 Jun 2017).
- Ritchie, H. and M. Roser. “CO2 and Other Greenhouse Gas Emissions.” Our World in Data online (2018).
- Roston, E. and B. Migliozzi. “What’s Really Warming the World?” Bloomberg Business Week (24 Jun 2015).
This page was last updated on 12/30/19 at 14:09 CST.