Another major hurdle to ending hunger is a changing climate. In wealthy countries we turn up the air-con — generating more CO2 — and debate the existence of climate change. But climate change is here, and it's hitting the poorest people in the poorest countries hardest.

In the last few years, the impact of climate change has dealt a major setback to the fight against extreme poverty. Weather is more severe and less predictable. While arid regions may get the same amount of rain, it now comes in torrents, washing away the topsoil. And as struggling people cut down trees for fuel, land becomes even more vulnerable to erosion.

In Africa, with each decade, more arable land becomes desert. The result: more hunger, more conflict, more refugees. When climate change destabilizes the poor world, it drives migration. That threatens the security of the wealthy countries. And what we're seeing today could be just the beginning.

Poverty has long been widespread in the highlands of Guatemala. And when listening to a farmer, whose family has worked the land here for generations, it's clear that climate change is making the fight against poverty even harder

Rick: Is there any question that climate change is real for the farmer?
Pascale: Don Simeon was telling us that there's always been a hunger season. What is happening now, with climate change, is that it's longer, and the harvest starts later, so, meaning that they have a longer season during the year when they don't have enough food to feed their family. For an example, before, the hunger season could start in April; now it's in February.

In Ethiopia — so notorious for droughts — the government has organized local communities to reforest and terrace eroded hillsides. People here understand that planting trees increases rainfall. And terracing allows rainwater to soak into the earth. Abadi is able to irrigate his crops thanks to a replenished water table.

And water-management infrastructure is also critical in dealing with the impact of climate change. Reservoirs enable farmers to dole out their precious water as needed, and more efficiently.

Thanks to this, reforestation projects, and improvements in agriculture — a new approach called "climate-smart agriculture" — Ethiopian farmers are becoming more resilient. For instance, they believe that while there will always be droughts, famines are now preventable. In fact, in recent years, Ethiopia has had several serious droughts — but no famines.