The International Organization for Migration said it was seeking a total of $7.9 billion in 2024 to "save lives and protect people on the move, drive solutions to displacement, and facilitate safe pathways for regular migration."
"Irregular and forced migration have reached unprecedented levels and the challenges we face are increasingly complex," IOM chief Amy Pope said in a statement.
"The evidence is overwhelming that migration, when well-managed, is a major contributor to global prosperity and progress," said Pope, who last October became the first woman to lead the organisation.
"We are at a critical moment in time, and we have designed this appeal to help deliver on that promise," she said.
"We can and must do better."
60,000 dead or disappeared
IOM was founded more than 70 years ago, but only became a UN agency in 2016 as a smaller, parallel operation to the UNHCR, which focuses on refugees.
It works in emergency situations, advocates for migrants' rights, and sees humane and orderly migration as a benefit to people on the move and the societies they settle in.
The agency said Monday that full funding of its appeal would allow it to serve almost 140 million people, including internally displaced people and the local communities that host them.
It would also help IOM to expand its development work, aimed at helping prevent further displacement, it said.
Breaking down the appeal, it said a full $3.4 billion of the requested funds would go towards saving lives and protecting those on the move.
Another $2.7 would be used to work on solutions to displacement, including reducing the risks and impacts of climate change.
The remainder would help facilitate regular pathways to migration and to help make IOM's service delivery more effective.
"This funding will address the large and widening gap between what we have, and what we need in order to do the job right," Pope said.
IOM said that its Missing Migrants Project showed that more than 60,000 people had died or disappeared during perilous migration journeys over the past nine years.
Migration brings prosperity
"The consequences of underfunded, piecemeal assistance come at a greater cost, not just in terms of money but in greater danger to migrants through irregular migration, trafficking and smuggling," it warned.
Like a number of other UN agencies, IOM is calling for funds to be able to take a more longterm, preventative approach, instead of being forced to always respond in crisis mode.
The agency said that properly funding its operations would help it streamline and optimise its response, and would effectively reduce the cost of crisis management.
It also urged countries to recognise the benefits of migration.
"Migration is a cornerstone of global development and prosperity," it said, adding that "the 281 million international migrants generate 9.4 percent of global GDP."
"Well-managed migration has the potential to advance development outcomes, contribute to climate change adaptation, and promote a safer and more peaceful, sustainable, prosperous and equitable future."
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