The United States helped bring the world into the Paris climate accord, the groundbreaking global agreement reached in 2015 to reduce greenhouse gas emissions in an effort to slow climate change. Under Donald Trump, the U.S. became the only country to withdraw. Now, the U.S. is coming back.

On his first day as president, Joe Biden formally started the 30-day process to rejoin the Paris Agreement, effective Feb. 19.

We asked five scholars to describe what U.S. involvement in the Paris Agreement means for the nation and the rest of the world, and for food security, safety and the future warming of the planet.

What the Paris accord means for food security

Kristie Ebi, Professor of Global Health and Environment, University of Washington

Food security will be a theme of this century, largely because of rising carbon dioxide concentrations and our changing climate.

Globally, nearly 9% of the population is food insecure, with the numbers increasing over the past few years. About 45% of childhood deaths worldwide are attributable to insufficient calories or nutrients.

As the planet continues to warm, climate change threatens to make these situations worse.

The harm to crops as global temperatures rise isn’t just about heat, floods and droughts. While carbon dioxide is necessary for plant growth, research shows that rising CO2 concentrations will reduce the nutrient density of the world’s two most important crops, wheat and rice, as well as other food sources. These nutritional losses can have serious health effects, including impaired cognitive development and metabolism, obesity and diabetes.

Further, the climatic changes resulting from rising CO2 are reducing crop yields and the stability of the food supply.

The U.S. is the second-largest CO2 emitter after China, and the largest historically. The Biden administration’s recommitment to reduce greenhouse gas emissions under the Paris climate agreement and advance research and development for solutions can help protect the health and well-being of families and future generations.

See the full story on The Conversation.