New study has revealed that nitrogen is an important element to be considered while forecasting climate change.
Humanity's carbon-belching habit is a feast for plants, which consume the greenhouse gas carbon dioxide (CO2) as they grow.
But, according to a report in Discovery News, plants also need nitrogen, and the new study says that as rising carbon levels fuel more plant growth in the coming decades, Earth's hungry greenery is going to start running low on nitrogen.
That could leave billions of tons of excess carbon in the atmosphere that would warm the climate an additional 1.19 degrees Centigrade (2.14 degrees Fahrenheit) above current estimates by the year 2100.
Nitrogen makes up over 70 percent of our atmosphere, but it's mostly locked away in a chemical bond that plants can't crack.
They depend on a few types of nitrogen-fixing plants, which employ soil-dwelling bacteria to convert the nutrient into more usable forms.
Outside of agricultural lands, where humans sew fertilizer into the soils, plant growth is mostly limited by whatever nitrogen nature provides.
Because of its complexity, this process was ignored in the computer models used to forecast future warming for the Intergovernmental Panel on Climate Change (IPCC) report in 2007.
"Of all the 11 models the IPCC will be using in its next report, not a single one has yet to consider nitrogen limitation, or limitation from any other nutrient for that matter," said Benjamin Houlton of the University of California.
This turns out to be a major oversight.
Houlton and Ying-Ping Wang of the Commonwealth Scientific and Industrial Research Organization in Australia ran the same models with added information on nitrogen fixing and the global use of artificial fertilizer.
The researcher's results indicate that global warming has been underestimated.
In the worst-case scenario, they found that nearly 300 billion tons of carbon could stay aloft in our atmosphere between 1900 and 2100 because of plants' lack of access to nitrogen - enough to warm the planet an additional 1.19 degrees centigrade (2.14 degrees Fahrenheit).
"This is the first time nitrogen has been incorporated into coupled biosphere-atmosphere models," Yiqi Luo of the University of Oklahoma in Norman said, referring to the style of model that will be used for the next IPPC report, which is due out in 2013.
"They've expanded our capability to evaluate nitrogen's impact on climate change," he added.