Where Does The Carbon Go?
November 13, 2015 § 1 Comment
Signing off with your fortnightly dose of science news.
The concentration of carbon dioxide in the atmosphere recently surpassed 400 parts per million, higher than it has been anytime in the past 400,000 years. But only half of the human produced carbon stays in the atmosphere. This has scientists wondering how the other half is absorbed on land and sea, and what this will mean for climate change in the future. Because they don’t really understand the absorption process over land and oceans they don’t know whether oversaturation can occur. If oversaturation is possible, it would potentially force a higher percentage of the carbon dioxide into the atmosphere.
Turns out NASA is working on more than just sending a manned mission to Mars. In July 2014 NASA launched the Orbiting Carbon Observatory 2 (OCO-2), a satellite which measures carbon dioxide levels from the top of the Earth’s atmosphere to the surface. It is the first satellite designed to do so. This provides scientists with near global data on how CO2 behaves in the atmosphere, with 100,000 new measurements each day. While the new data is helpful in showing how carbon dioxide behaves near the surface of the planet, it does not provide concrete information about how CO2 is absorbed on land or water. In order to better understand the process, NASA will use a combination of satellite data, field experiments, and computer models.
The effect on land and water is important to determine because of concern that the ability to absorb carbon will change as temperatures rise. On land, trees and various other vegetation take in carbon dioxide through photosynthesis, some of which gets left behind in the soil once they die. But various factors such as droughts, fires, and deforestation may drastically change the amount of carbon that vegetation can store. Some forests are already releasing more carbon than they are storing.
In the ocean, some carbon dioxide is absorbed directly while some is taken in by phytoplankton. Changes in phytoplankton behavior the past few years are also cause for concern. If not eaten by zooplankton, phytoplankton normally sink to the bottom of the ocean along with all the carbon they have absorbed upon death. Scientists worry that changes in ocean chemistry might alter this process and trigger a release of carbon that has sunk to the bottom of the ocean. Last week NASA launched a ship and airborne study in the North Atlantic to study these changes.
As our world grapples with a growing climate change problem, it becomes increasingly important to understand the processes that affect how it will play out. Otherwise, we may end up facing an unstoppable algae bloom such as the one in Gregory Benford’s Timescape. Climate science fiction touches on an issue very much relevant to today’s world. Hopefully, unlike some of the technology predictions, none of the frightening climate scenarios will ever become a part of our reality.