Researchers say that rising greenhouse gas levels could make your food less nutritious

Climate change is not only making the planet more at risk for flooding, economic collapse, record heat waves, disease, and extinction of certain animal species - it could also make some food less nutritious.

If carbon-dioxide levels continue to rise as projected, 18 countries may lose over 5% of their dietary protein from staple crops like rice and wheat by 2050, according to a new study by Harvard University.

The findings, published August 2, suggest that 150 million people could face protein deficiency due to the impact of high CO2 levels. This is the first study to quantify the risk of protein deficiency from rising CO2.

Currently, 76% of the world's population derives most of its daily protein from plants. To estimate the current and future risk of protein deficiency, the Harvard researchers analyzed experiments in which crops were exposed to high concentrations of CO2. They also looked at dietary information from the United Nations .

They found that, under elevated CO2 levels, the protein in rice, wheat, barley, and potatoes decreased by 7.6%, 7.8%, 14.1%, and 6.4%, respectively. Essentially, the crops lose some of their ability to absorb nitrate (the most common type of nitrogen in agricultural soil) and convert it into organic compounds, like protein. Those most at risk include 354 million children under 5 and 1.06 billion women -predominantly in South Asia and North Africa - who live in countries already experiencing high rates of protein deficiency.

There's an overwhelming consensus within the scientific community that human activity is contributing to increasing levels of carbon dioxide and methane in the Earth's atmosphere. Recent research also points to a strong link between rising carbon dioxide and rising global temperatures, which are already affecting agriculture in the US and abroad.

Cattle, for example, are less productive when it's warmer, causing some American farmers to install air conditioning in their barns to maintain productivity. High temperatures and CO2 have also been linked to extreme weather events, like hurricanes in Bangladesh and monsoons in Southeast Asia, which can make growing processes more unpredictable for farmers.

Research suggests that the planet will continue too get warmer if countries do not drastically reduce carbon emissions. A recent study, for example, estimates that there's only a 5% chance that the world won't warm more than 2 degrees Celsius by 2100. Most scientists consider that level to be the tipping point when the consequences of climate change become catastrophic.

"This study highlights the need for countries that are most at risk to actively monitor their populations' nutritional sufficiency, and, more fundamentally, the need for countries to curb human-caused CO2 emissions," Samuel Myers, senior research scientist in Harvard's Department of Environmental Health, said in a press release.

Meanwhile, Finnish researchers from the VTT Technical Research Centre recently figured out how to turn excess CO2 into edible protein. The process - which can run on renewable energy - requires electricity and a small amount of water and nutrients. It's one solution for curbing CO2, or at least turning it into something productive.