About 800 million people worldwide do not get enough food to eat, while about 1.5 billion are overweight. As the global population expands by an additional 2 billion people by 2050 and climate change alters traditional agricultural areas, scientists and policy makers are racing to figure out how to address both problems. (Read more about how climate change might impact global food supplies in "Farmed Out.")

This uneven food landscape is not caused solely by government regulations or farming practices, but stems from many powerful forces—forces that are expected to keep increasing. "Several converging threats—from climate change, population growth and unsustainable use of resources—are steadily intensifying pressure on humanity and world governments to transform the way food is produced, distributed and consumed," wrote the authors of a new report, published online March 28, from the Commission on Sustainable Agriculture and Climate Change.

Scientists and experts from more than a dozen countries collaborated to write the report.

"Food insecurity and climate change are already inhibiting human wellbeing and economic growth throughout the world, and these problems are poised to accelerate," John Beddington, who chaired the commission, said in a prepared statement.

One of the major concerns worldwide is increasing production on ever-dwindling acres of farmable land. The world's farms continue to put out some 2.2 percent more food each year, but that is hardly on pace to keep up with growing global demand. And, many experts argue, these expansions need to be done in a sustainable way if people are to be fed without dragging down the economy—or the environment.

It's a tall order, but science can help. "If we do not advance the science and practice of sustainable intensification, our forests and our farming economies will be at risk," Carlos Nobre of the Brazilian Ministry of Science, Technology and Innovation pointed to Brazil for examples of improvement. "Brazil has made strides in reducing poverty while protecting rainforests in the last seven years," Nobre said. The country has been using satellite technology to look for illegal logging, which will also cut down on emissions.

Progress, however, will not come without compromises. "In Australia, researchers, farmers and data managers are working together to build an integrated capacity to deal with the inevitable trade-offs," Megan Clark, chief executive of the Commonwealth Scientific and Industrial Research Organization, said in a prepared statement. They are using real-time data on climate and meteorological conditions to help farmers of all kinds be better prepared for future changes.

Helping smaller farms to persist also is key to ensuring good food and local economic stability far into the future, according to the researchers. "Otherwise communities will remain vulnerable to a downward spiral of lost productivity, poverty and food insecurity," Tekalign Mamo, state minister and advisor to the Ethiopian Minister of Agriculture, said in a prepared statement.

But the changes don't just need to happen down on the farm. More sustainable eating—both environment- and health-wise—is also necessary. "If we don't start to make use of the tools at our disposal to encourage eating choices that are good for people and the planet, we must resign ourselves to a growing diet-related disease burden," Marion Guillou, president of the French National Institute for Agricultural Research, said in a prepared statement. France, for example, has been including warnings on processed foods and increased the promotion of fruit and vegetable consumption.

In order to keep the world fed through climate change and population growth, major changes will be needed, the researchers concluded. "Decisive policy action is required if we are to preserve the planet's capacity to produce adequate food in the future," Beddington said.

But in the meantime, people can help here and now by eating more healthfully and reducing waste. Some 1.3 billion tons—about a third of all food—is lost to waste each year, the authors pointed out. "The global demand for food will increase with population growth, but the amount of food per person that needs to be produced can be brought down by eliminating waste in supply chains, ensuring more equitable access to food and moving to more resource-efficient (and healthier) vegetable-rich diets," they wrote.