It's unlikely that governments around the world will be able to entirely reverse their trends of greenhouse gas emissions anytime soon, but experts say world leaders are working more closely together than ever before to address climate change. Coupled with more options for adaptation, they say, there's reason for hope.

People are food secure when they have consistent access to enough safe, nutritious food to maintain a healthy and active life.

That’s the World Food Programme’s definition. And based on that definition, one of every nine people in the world suffers from food insecurity. Two-thirds of Asians are hungry, as are a quarter of all Africans.

In many cases, hunger isn’t caused by a lack of food. Instead, the World Food Programme reports, a third of all food produced is never eaten.

In wartime, soldiers destroy fields and livestock herds. People who grew up hungry are less likely than those who grew up healthy to earn sufficient income to properly feed their own children, causing a cycle of poverty.

But perhaps the most worrying fact is that the people who are already the most food insecure are also the most vulnerable to climate change, an umbrella term that usually refers to the seemingly marginal temperature changes caused by the increasing greenhouse gas emissions that envelop the Earth’s atmosphere, trapping heat.

The earth’s average temperature has risen by 1.4 degrees Fahrenheit (.8 degrees Celsius) over the past century, according to the U.S. Environmental Protection Agency.

The result is irregular rainfall, droughts, floods – all problems felt most keenly by people who live nearly hand-to-mouth by growing, selling and eating their own food, often without the benefit of modern irrigation systems.

Those challenges are happening throughout the world but are perhaps most visible in regions far from the world’s biggest polluters, including China, which produces 23 percent of greenhouse gas emissions, and the United States, which produces 19 percent.

And another increase of between 2 and 11.5 degrees Fahrenheit (1.1 and 6.4 degrees Celsius) is projected over the next century.

Despite the doomsday predictions, the United Nations Climate Summit held on Sept. 23 released an action plan stating that the average global temperature must rise by no morethan 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels in order to avoid dangerous climate change levels.

The plan, which echoes previous global plans, states that this is possible if global emissions peak within the next decade and then decline.

That’s not going to happen, says Robert Stavins, director of the Harvard Project on Climate Agreements.

“It’s a political statement, not a scientific or an economic statement,” Stavins says in a phone interview. “The whole purpose was to draw attention to the problem, and that’s one of the mechanisms they used. But that doesn’t mean it’s achievable.”

Even so, Stavins says there’s room for hope.

“The prognosis is more positive than it’s been in 20 years,” he says.

Global negotiations on climate change turned a corner in 2011 at the U.N. Climate Change Conference in Durban, South Africa, when a host of countries agreed to a road map to stabilize greenhouse gas concentrations while preserving the right to sustainable development.

Most experts agree that humankind is locked in to a certain level of global warming.

Past and present industrial development – coupled with the fact that some countries are still increasing their global emissions as they attempt to improve their economies – means future warming is inevitable, says Katy Maher, a fellow at the U.S.-based Center for Climate and Energy Solutions.

She argues in a phone interview that grass-roots adaptations to a warmer globe are critical to agricultural sustainability.

“Working with farmers and communities on reducing water use and water efficiency and ensuring that food supply is there, switching crops, finding more drought-tolerant crops – that’s going to be a big focus of climate action beyond country-level agreements on reducing emissions,” Maher says.

Big strides have been made, she says.

Companies are learning to change their formulas and recipes to integrate drought-resistant ingredients, she says, adding that she can’t name those companies because of confidentiality concerns. Those changes will trickle down to the family level.

“People’s diets are probably going to change because of what is available,” she says. “That’s going to be more and more common, and people are going to have to adapt.”