ROME — Pope Francis offered a preview of his hotly-anticipated eco-encyclical on Thursday, arguing that climate change is not the only threat and that the increasing use of alternative energy sources such as biofuels is also dangerous because it can cause food shortages that contribute to world hunger.

Francis called for “a reflection on the non-food use of agricultural products, which are used in large quantities to feed animals or to produce biofuels.”

The pope said that although “we must ensure increasingly healthy environmental conditions,” that can’t come at the expense of meeting people’s basic needs.

Francis’ comments came in an address to representatives of the Food and Agriculture Organization of the United Nations (FAO). The delegates are in Rome for the institution’s 39th General Conference.

Financial markets influence world hunger, Francis said, especially market speculation on the prices of wheat, rice, corn, and soybeans.

“We need to follow another path,” the Argentinian pontiff said. “We have to convince ourselves that the products of the land have a ‘sacred’ value, because they are the fruit of the daily work of individuals, families, [and] farmer communities.”

Such work is rife with uncertainty, he said, including concerns about weather and the possible destruction of crops.

Francis pointed out that natural phenomena such as drought or human action such as wasting water can force the displacement of entire populations and lead to “humanitarian tragedies.”

But it’s not enough to simply define access to water is a human right, he argued. Rather, world leaders must take action to assure a sustainable consumption of water.

Francis also called on politicians to pay more attention to hunger, even if there isn’t a consensus about how to solve the problem. He lamented that hunger is an unpopular issue because there’s a “generic resignation” that it simply can’t be ended.

He argued that there’s a lack of will to invest resources and technologies into fighting world hunger.

“We shield ourselves with the excuse of a global economic crisis,” Francis said.

It’s important to educate all countries on the type of nutritional diet that their populations need, he said, taking into consideration that it varies depending on the region.

“In the Southern part of the world, attention has to be put on the amount of food needed to ensure population growth, while in the North, the central point is the quality of nutrition,” Francis said.

Toward the end of his speech, the pontiff said the world should join forces to guarantee food for all, so that “we no longer read that food security for the North means eliminating fats and encouraging exercise, while for the South it’s obtaining at least one meal a day.”

Pope Francis’ encyclical letter on creation and the environment, called Laudato Si, will be released June 18.