Copán, Honduras (CNN) Each night after her husband left, Delmi Amparo Hernández walked to a neighbor's house to look for him on the TV news. He had fled their mountaintop community here in rural Honduras without a phone because no one in the family could afford one. Their floor was made of dirt, they grew their own food. Watching coverage of the migrant caravan heading for the United States was Hernández's only way to know if he was alive.

What she saw in the broadcasts were visions from hell. Families jumping from bridges, getting kidnapped along dusty roads, dodging tear gas cannons fired by police from richer nations. How could this be? She continued scanning, hoping to find him, hoping not to.

She had begged Germán Ramírez not to go, but her 30-year-old husband had his reasons. The town's corn and bean crops had failed during a years-long drought. There was no work aside from farming. No money for irrigation. Their four children, ages 3 to 13, had little to eat.

Ramírez told his wife that he had no choice but to leave with the "caravan" of thousands that had formed in Honduras and would make its way north. This was their chance, she recalled him saying that day. He could go with the group, find work, send back money.

It was this or risk starvation.

Delmi Amparo Hernández with her four children.

The couple's tragic story, as well as others I heard on a recent four-day trip to western Honduras, complicates two narratives being told about the migrant caravan.

To hear President Trump tell it, Central American "Gang Members and some very bad people" are attempting to storm the United States at its southern border. "This is an invasion of our Country and our Military is waiting for you," the President wrote on Twitter. American news reports, meanwhile, largely have focused on high rates of violent crime in Honduras and El Salvador that have driven families to seek asylum as refugees in the United States.

Overlooked is this factor: climate change.

The "dry corridor" of Central America, which includes parts of Honduras, Guatemala, El Salvador and Nicaragua, has been hit with an unusual drought for the last five years. Crops are failing. Starvation is lurking. More than two million people in the region are at risk for hunger, according to an August report from the UN Food and Agriculture Organization.

"Under normal circumstances, without any change in rain patterns, people are already struggling," said Edwin Castellanos, dean of research at Universidad del Valle de Guatemala and a global authority on climate change in Central America. "In some of these dry areas, we have seen events of children actually dying out of hunger. So, it is that extreme."

This drought has been longer and more intense than those seen before in the dry corridor, Castellanos said. The failure of critical springtime rains is also new, he said, and is causing such problems for farmers whose crops depend on that water.

Subsistence crops like corn and beans are all but dying. Our crew saw beans the size of Tic Tacs. And shriveled, partially blackened ears of corn could fit inside your palm.

Corn crops have been smaller than usual, leading to a hunger crisis.

Kevin McAleenan, commissioner of US Customs and Border Protection, said in a speech on Friday that drought and crop failures in Honduras and Guatemala "directly translate into who's arriving at our border."

Studies have not definitively tied this particular drought to climate change, but computer models show droughts like the one happening now are becoming more common as the world warms.

Thousands have risked their lives to flee these circumstances.

And previously unpublished data shows people started leaving certain areas of Honduras amid crop failures -- even as homicide rates were declining.

Take Copán, the region of Honduras that Germán Ramírez fled in October.

In fiscal year 2012, around the start of the drought, only about 20 family members from Copán were apprehended by the US Border Patrol while trying to cross the US-Mexico border, according to a data analysis of records shared with CNN by Stephanie Leutert, director of the Mexico Security Initiative at The University of Texas at Austin. Then drought hit, its cumulative effects growing as the years wore on. In 2017, about 1,450 family members from Copán were apprehended by US authorities at the border, the data show. In fiscal year 2018, with the data ending in September, the number of migrants picked up was more than 2,500.

Those figures are "absolutely" an underestimation, said Leutert. "You're missing people who left Copán and went to big cities, you're missing people who left Copán and went to another place in the region, you're missing people who tried to go to the United States and didn't make it -- and you're missing people who went to the United States and crossed undetected."

The figure is a "baseline" that shows something big is happening, she said.

Any person's decision to abandon their homeland is complex. For some, violence is part of it. As is extreme poverty. In Central America, it's often a combination of things.

But there's another truth: This region is becoming less hospitable to farmers as more-industrialized countries burn loads of fossil fuels like coal, oil and gas. A December report shows the world is on track to create 37.1 billion metric tons of carbon dioxide pollution in 2018 -- yet another record. This pollution traps heat and warms the planet, making cyclical weather events like droughts, floods and certain storms worse.

The United States, which is the destination for so many migrants fleeing Honduras, bears outsize responsibility for global warming. Cumulatively, the nation has done more to cause climate change since the Industrial Revolution than any other. Today, President Trump supports increased coal production and has pledged to abandon the Paris Agreement, which aims to limit global warming to at most 2 degrees Celsius. A "rulebook" for that agreement is being debated this week at the COP24 conference in Katowice, Poland, with the United States on the sidelines.

Notably, Trump also has also made immigration his signature issues, rallying supporters around the idea of stopping people from Latin America, like Germán Ramírez, from crossing illegally into the United States. There's broad support for a crackdown on illegal immigration in the United States among Republican voters. A quarter of US midterm voters said that immigration was their No. 1 issue, and 75% of those voters were Republicans, according to a November exit poll. "Build that wall" has become a popular chant at Trump political rallies.

Federal authorities have met would-be migrants at the border near San Diego with tear gas. Officials say the tear-gassing occurred after migrants threw rocks at authorities.

Yet there's an unspoken irony here.

The nation that's become a destination for so many migrants -- a beacon of opportunity and hope --is contributing to the conditions forcing some people to abandon home.

'I was waiting for you like the rains in May'

Think of Central America like an island.

That's advice from Castellanos, the climate scientist in Guatemala.

He's not talking about just any old island. He's referencing the specks of land in the Pacific -- Kiribati, Tuvalu, the Marshall Islands -- whose very existence is threatened by rising sea levels that are linked to global warming. I visited the Marshall Islands in 2015 after readers of CNN's "Two Degrees" series voted for me to do a story on "climate refugees." Higher tides and increased flooding were already pushing people out -- and to Arkansas, of all places.

Crops have been failing in the "dry corridor" of Central America.

These little islands gained a huge voice at the United Nations climate talks in Paris in December of that year -- the predecessor to the talks happening now in Poland. Calling themselves the "High Ambition Coalition," island diplomats rallied with richer nations to make a moral case for climate action -- saying their sovereign territory would vanish if global temperatures were allowed to warm more than 1.5 degrees Celsius. That goal became embedded in the Paris Agreement. In order to achieve it, global carbon emissions would need to be cut in half in about a decade.

The climate problem in Central America isn't so much sea-level rise. But Castellanos told me an argument can be made that the region is nearly as susceptible to global warming. It is a slim stretch of land connecting North and South America -- a string of land between continents. That makes it vulnerable to storms coming from the Pacific Ocean and the Caribbean. Climate change is supercharging those. Plus, climate models show both floods and droughts getting more intense. The United Nations Development Programme considers Honduras to be "highly vulnerable" to climate change, both now and in the future as the atmosphere continues to warm.

The dry corridor gets that name because it's long been dry, situated behind a mountain range that catches weather from the Caribbean. But the recent drought there has challenged notions about how bad a drought in Central America could be, Castellanos told me. Some areas have seen 10 consecutive months without rain.

Central Americans have an expression -- "I was waiting for you like the rains in May." It references the fact that massive rains fall in May and June, like clockwork each year. Farmers plant their crops accordingly, counting on the spring rains to soak the plants and ensure a productive harvest. Many people here are subsistence farmers and can't afford irrigation systems. They're completely at the mercy of rains, and those rains aren't coming.

When they do come, they come all at once -- causing floods and damage.

"Here, unlike in the United States, we don't have a problem of convincing people" that climate change is real, Castellanos told me. "People are convinced by what they see."

Germán Ramírez, the farmer on the hilltop in Copán, lived through this. Then he heard the caravan was passing near his village. People believed that traveling together would provide safety. From Honduras to Guatemala to Mexico, the number would grow into the thousands.

Germán Ramirez left with the migrant "caravan" in October.

In mid-October, Ramírez fled Copán on foot, hoping to catch the caravan. He carried a small backpack with a few items of clothing, his wife said. In his pocket was a paper with a neighbor's telephone number on it.

That phone would ring in the village some time later.

It would not be Ramírez's voice on the phone.

And the news would not be good.

'We are losing most of the crops'

I came to meet the people left behind.

The location: several communities in the Copán Department of Honduras, near the Guatemala border. I'd chosen the place because of the data CNN analyzed with Stephanie Leutert, from the University of Texas.

The data, which tracks families apprehended at the US-Mexico border, does not prove on its own that people are fleeing Copán because of climate change. But the figures do support the idea that people newly started fleeing during that timeframe.

The first point is that the exodus from Copán has grown faster than in the rest of Honduras. In 2012, only 3.7% of Honduran migrants came from that area. By 2018, up to September, it was more than 9%.

Meanwhile, the number of murders per year in Copán has been declining.

Again, this provides only a rough sketch of what's happening, Leutert said, but it is clear that climate change is one factor driving people from the region. "Climate change is reducing (crop) yields," she said. "It's like a tax. It's making things harder for people and industries that rely on weather stability. Sometimes climate change can push people over the edge and make it impossible (to survive). We see that with the coffee industry. That last added cost is making the business model unsustainable -- and pushing people to migrate."

Copán is a mountainous place of dense forest and sweeping valleys. In the morning, mist rises from the hills like steam, making it look like molten ripples of land have just cooled. By afternoon, clouds hang on the hilltops, threatening to rain but rarely cracking. Dried-up corn stalks, which look almost unrecognizable if you're used to the engineered, Midwestern variety, dart around at odd angles between rocks and patches of dirt, clinging to steep hillsides. The more fertile land is the valleys, where most crops grow. Even during the worst of the drought, some vegetation here is green and appears almost lush. But Castellanos and others told me it's the timing and amount of rain that's critical. And many months here are now totally dry.

What was it like to live in this place?

And how and when did people feel it was impossible to stay?

The resident of this house in Copan, Honduras, emigrated. The area has seen its homicide rate go down while emigration to the US rises.

Our team drove south past a town that was abandoned by the Mayan people thousands of years ago and now is known for the remaining artifacts. Our tires kicked up dust from the path, coating every roadside fern in a film of beige.

At a construction site, Evelio Ochoa, 35, was pouring cement into the land -- helping build the foundation of a home for his niece. He's doing any odd job he can find these days. Years ago, he told me, he paid a coyote -- a smuggler -- to help him leave Honduras. His small plot of corn and bean crops had failed, he said. The coyote's price: 60,000 Lempiras, or about $2,500. He got the money from a relative, he said.

That price bought him three attempts to reach the United States.

He made the first attempt in 2014, he told me, amid record drought.

The second was earlier this year.

Both times he was deported, he said.

If he failed a third time, there would be no money to try again.

"You don't fear for yourself, you fear for your family," Ochoa said of setting out on the journey. "The moment you step out of the house and start walking it's difficult -- not because of the danger but because you miss your family" and are thinking about their safety.

In September, Ochoa said, authorities caught him a third time.

He finds himself back in Honduras, struggling to feed his family.

Evelio Ochoa said he fled to the United States three times unsuccessfully.

Ochoa's wife, Nora Vazques, said she and their five children would have starved if a relative hadn't been sending money from the United States. The 33-year-old mother, whose children are ages 1 to 12, showed me a basket of unusable black corn kernels, picked from a rotten crop.

"Before, the rain was much better," she said standing in the shadow of her doorway, the midday light half-illuminating her face. Her hand shook as she wiped away tears.

"He grew a lot of corn" back then, she said. "Now we are losing most of the crops."

'This is an injustice'

Lisandro Mauricio Arias is mayor of the town the Mayans abandoned.

We met at the town square, which is surrounded by tile roofs and palm trees. Copán Ruinas is a tourist destination that boasts several quaint hotels, but the town has seen better times. For that reason, I figured Arias might downplay the outmigration that data shows is occurring here -- that he might have an incentive to say the drought hasn't been so bad.

He didn't do that.

The town is emptying out, he told me.

How many people have left?

His guess: 30%.

He regrets that, but says it may be the only way.

"When analyzing precipitation levels, we can see they have changed a lot -- which is really alarming," he said. "Problems associated with drought will get worse."

"We respect the decisions the United States is making," he added. "It's their country, and they have the right to defend it. However, I believe they need to take into consideration the human factor -- what is humanity? These people are not trying to meddle. [They are] looking for an opportunity to survive."

Among those people are the sons of Mariano and Gregoria Perez.

The two young men, ages 19 and 26, are stuck in Tijuana, Mexico, according to their family in Honduras. Their parents have only been able to speak with them two or three times, they said, because phone credit is so expensive. (I was unable to reach them.)

Two of Gregoria Perez's sons left Honduras in the migrant "caravan."

What the men's parents know are only the barest of details. One son was mugged and lost all of his belongings, including his passport, according to Mariano Perez, 55. Gregoria said she told the boys they could come back home. Secretly, though, the family worries. The young men have crossed international borders illegally already. Could they come back?

"I would say that this is an injustice because they did not do anything wrong," said Gregoria Perez, who, like her husband, said the boys left because farming wasn't viable amid the drought, and there were no other options. "They want to find work to sustain themselves."

I sat down outside to talk with her husband as the sun was setting. He sat on a small wooden stool and I was on the ground. The angle and time of night rendered his face in silhouette.

Mariano Perez told me his sons heard about the caravan on TV and left the same day. The father was down the hill helping a neighbor build a fence. He didn't know they'd left until he returned home that night. He doesn't fault them for it. He knew why they left, of course: drought.

What bothers him is where they are now.

He worries they're hungry in Tijuana, as they were here.

He worries they may not make it across the border.

Sometimes, in his darker moments, he wonders if this is what God predicted in the book of Revelations -- the end of the world, happening slowly and before his eyes.

The next morning, I woke up to find my news feed full of images of tent camps in Tijuana.

It had started raining on the migrants.

"I feel like a street dog," one man told the Los Angeles Times.

"Wet and cold and with no place to go."

Corn crops, shown here, and beans are among the staple foods in the area.

'Migration with dignity'

I didn't say this to the lonesome father, but it's the reality: His sons have very little chance of settling lawfully in the United States if they are able to cross the border.

That's because there's no legal status for "climate refugees."

The rules that govern the rights of refugees were developed in the aftermath of World War II and during the early Cold War, when western countries like the United States had an interest in protecting people who were persecuted in the communist Soviet Union, Alexander Betts and Paul Collier write in "Refuge: Rethinking Refugee Policy for a Changing World."

Only a few specific groups were protected -- those fleeing persecution because of their race, religion, nationality, political beliefs or social group. The 1951 UN refugee convention says people meeting those criteria should be able to seek asylum outside their home states.

Other types of migration -- including people seeking economic opportunity or those fleeing climate change -- are not protected in a similarly codified way.

Those people are typically not "refugees" in the legal sense.

They're migrants. And if they cross borders, they may break national laws.

Not everyone believes that should be so.

Anote Tong, the former president of Kiribati, one of the small island nations in the Pacific, has advocated for what he calls "migration with dignity" -- the opportunity for people from climate-affected areas to relocate if that makes their lives safer or gets them out of danger.

"There's no harm in being prepared," he told me in an interview this fall.

Coffee producers are major employers in the region, and also have struggled.

That idea runs against the current of nationalism sweeping the globe. From the United States to Hungary, Australia to Denmark, countries have been fortifying walls, filling detention centers and even detaining asylum seekers on castaway islands -- not welcoming them. The United States is accepting far fewer refugees than it has in most years in recent memory.

Attempting to add a "climate refugee" category in international law could pose problems of its own. Among them: How do you define who is and is not a climate refugee? Scientists are getting better at finding human fingerprints on heatwaves, droughts and storms that are being supercharged by global warming. But this is a realm of probabilities and complexities. It's difficult to say, with certainty, "climate change made me move." Then there are political concerns, as well. Some scholars argue it's politically dangerous to try to amend international refugee conventions because this is such an anti-refugee moment in history. The process could lead to refugee rights being stripped instead of added. Others contend that the UN refugee convention is so rarely followed that it's almost irrelevant anyway, especially after the 2015 migrant crisis in Europe.

"If you were to create this whole new category and give people grounds to apply for asylum based on climate, you're likely to get an enormous number of people applying because it's so ill-defined," said Steven Camarota, director of research at the conservative Center for Immigration Studies. "How much below-average rainfall does the rainfall have to be in your region before you're a climate refugee? At present, the primary receiving countries already are experiencing tremendous resistance to the current level of asylees and refugees. It doesn't seem like resettling people in developed counties is going to be much of an answer to this problem. ... A much more effective use of resources is always to help people in place."

It's also unclear that climate change is the main reason people are fleeing Central America, he said; the "pull factors" of wealth and opportunity in the United States may be more important.

"You can think of climate change as one of the push factors," he said, "but it isn't the reason we get the caravan, per se. And it's also important to understand if people were just starving, and they were desperately fleeing the total breakdown of the food chain, why travel 1,500 miles across Mexico to the US border? Mexico has lots of places you could stop to get basic sustenance."

A 2018 report from the World Bank proposes two additional solutions.

First, cut carbon emissions, which is the aim of the Paris Agreement.

Second, help would-be migrants adapt to the warmer world. The international Green Climate Fund, which President Trump promised to walk away from, too, has approved projects to help farmers in Central America to become more productive, blunting the force of drought. USAID also has supported irrigation and farming projects in the region, according to a federal official.

Don't let the greenery fool you, scientists say. Western Honduras has been hit with a crop-damaging drought in recent years.

Combined, those two tools could reduce forced, internal displacement from climate change by about 80%, according to the World Bank's "Groundswell" report on climate migration.

Barring substantial changes, however, the scope of the migration crisis could be enormous.

An estimated 17 million people in Latin America could be forced to relocate within their countries because of climate change by 2050 under the worst-case scenario, according to the World Bank report. Across three regions that the World Bank examined -- which also included sub-Saharan Africa and South Asia -- more than 143 million people could be forced to relocate because of global warming.

That figure doesn't include extreme weather, such as hurricanes, which also are getting worse and tend to get more attention from the news media. The report only looks at slow onset climate disasters, from sea level rise to crop failures and water stress.

In other words -- events like the drought in Central America.

Germán Ramírez

The phone rang in the hilltop community.

Delmi Amparo Hernández's husband, Germán Ramírez, had left several days before, looking for the caravan, carrying with him a phone number in his pocket in case he could find a way to call the village.

She'd been worried sick the entire time, scanning for his face on TV.

The voice did not bring relief.

Her husband was missing, the person said.

Later, she would learn the worst had happened.

Ramírez died on the road in Guatemala.

Delmi Amparo Hernández buried her husband in the earth he used to till.

The precise circumstances are unclear to her. Perhaps he was hit by a car while walking along the highway. Perhaps he was hitching a ride in a car that crashed. These are the stories people have relayed. What she knows for sure is that he died October 20 near Guatemala City.

Cause of death: severe trauma.

Authorities were able to bring his body back to the village; she is thankful for that. She buried him on the slope of a mountain above the town, in the same earth he used to till.

She doesn't know what exactly will become of her family now.

She hasn't been farming, hasn't been able to.

The nonprofit World Vision has had to help with food.

But when she looks at her youngest child, she finds hope.

He is 3 years old -- and named Germán, like his father, and grandfather, too.

Will he farm this same land? I asked her.

Yes, she told me.

"I imagine he will be just like his dad."