By Manipadma Jena

ANKARA, Nov 12 (Thomson Reuters Foundation) - The growing flow of migrants into drought-prone Niger, whose own population often struggles with hunger, raises tough questions about why people are moving from one risky place to another and how to head off related tensions, experts say.

Intensifying conflict, political instability and militant groups like Boko Haram are driving people into Niger from surrounding Libya, Chad, Nigeria and Mali, according to Barbara Bendandi, an environment expert with the International Organization for Migration (IOM).

"It is not the usual push-pull factor of migration but a newer phenomenon where people are migrating into a country already extremely vulnerable which has nothing to offer the migrants," she told the Thomson Reuters Foundation on the sidelines of a U.N. Convention to Combat Desertification (UNCCD) conference in the Turkish capital Ankara last month.

There is a need to better understand this complex phenomenon linking climate impacts, land degradation and insecurity, she added.

Migrants from sub-Saharan African states who reach Niger enter one of Africa's poorest countries - a vast arid expanse on the edge of the desert consistently ranked at the bottom of the U.N. Human Development Index.

Its booming population depends on rain-fed agriculture, but the amount of land used for arable farming and pasture has shrunk dramatically in the past 50 years.

Meanwhile frequent droughts have impoverished many Nigeriens. In 2010, for example, a severe drought left over one-third of the West African country's 20 million people without enough food.

Climate change is expected to make the country even more prone to drought, erosion and loss of forested land, exacerbating difficult conditions, according to the UNCCD.

Historically a gateway between north and sub-Saharan Africa, Niger shares borders with seven countries.

Bendandi said it is a transit country for some people, with more than 2,000 migrants leaving Niger each week this year to travel north to Libya or further to Europe.

European Union leaders are meeting African counterparts in Malta this week, hoping aid pledges can slow the flow of migrants crossing the Mediterranean from the world's poorest continent to wealthy Europe.

Fatchima Noura, a Nigerien civil society leader working on refugees and food security, noted that some incoming migrants stay in Niger for a couple of years to work as domestic help or set up a small business to earn enough to proceed further north.

Others pay traffickers to get them across borders or become involved in contraband trade in weapons and drugs, although the numbers are unclear, she added.

In May, Niger adopted a law mandating fines and prison sentences of up to 30 years for those involved in smuggling humans without papers, in an effort to stem the flow of people northwards.

CREEPING DESERTS UPROOT MILLIONS

The IOM's Bendandi said temporary migration inside countries has long been a way of coping with seasonal shifts in the weather. But more people are now moving further and for longer periods to escape climate extremes.

According to the UNCCD, by 2020, 60 million people could leave sub-Saharan Africa's desertified areas for North Africa and Europe. And by 2050, 200 million could be permanently displaced environmental migrants, it says.

"Since we are unable to track where many of these new migrants are going, it is difficult to foresee conflict," Bendandi said, highlighting tensions that can break out with host communities.

In situations like that around Lake Chad, where 300 ethnic groups depend on waters that have shrunk 90 percent in the last half century, fierce competition for scarce natural resources is relatively easy to anticipate, she said.

"It is more difficult to predict conflict when people relocate to places like Libya where weapons are easily available, or to West Africa's coastal cities where sea levels are predicted to rise," she said.

Many migrants settle in urban sprawls where their farm skills are useless. Some resort to crime to survive, or are even tempted to join insurgent groups, she added.

The threat to these people arises not from migration itself, but the vulnerabilities it creates due to the weakness of government policies to manage their movement, she noted.

According to an Organisation for Economic Co-operation and Development (OECD) report, violent events in the "lawless" expanse of the Sahara-Sahel region topped 8,000 in 2009-2012, up from around 3,000 in 2005-2008.

"The perpetual connection to peripheral regions and the traffic that passes through the region clearly show that it can be both a connection point between hotbeds of violence and a 'sanctuary'," the OECD said in an atlas issued this year.

"There may be no food in Niger but there is safety for these people fleeing violence, house-burning, kidnapping and arson," Noura said, referring to those leaving places like Nigeria, where they are suffering at the hands of Boko Haram militants.

An alliance of civil society groups accredited to the U.N. refugee agency helped settle 20,000 Nigerians in 2014 in Niger's official refugee camps and 13,000 Malians in 2012 when civil war erupted, she added.

NO WORK, NO MONEY, NO LAND

At the same time, Niger is losing its own people, as climate stresses make it harder to earn a living from agriculture.

"The first capital our people have is land. If they have no guarantee of income from land, what are they going to do? This is the reason they migrate, hoping to find elsewhere what they lost in their homeland," Niger's environment minister Adamou Chaifou told the Thomson Reuters Foundation in Ankara.

The youngest and strongest groups in society are leaving for Ghana, Benin, Togo, Libya and Algeria, he lamented.

"Youth in Niger have no work, no money and no land rights," said civil society activist Noura. "Boko Haram gives them something to do and some money, so the youth go with these rebel groups."

Meanwhile, shifting movements among nomadic herders, who are starting out on traditional migration routes earlier in the year, have led to violent clashes, as their cattle destroy crops on their path, she added.

They are also breaking down barricades erected by companies that have leased land previously used for grazing, she said.

The IOM's Bendandi called for investment by U.N. agencies, governments and academic institutions in more research to explore the "when and where" of environmental migration flows, using land maps, satellite imagery and field surveys.

"To address (the problem) when crises blow up would be too expensive in terms of human lives and money," she said. (Reporting by Manipadma Jena; editing by Megan Rowling. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, corruption and climate change. Visit www.trust.org)