Human migration networks and policy interventions: bringing population distributions in line with system optimization

• DOI: http://doi.org/10.1111/itor.12815
• Author: Giorgia Cappello,Patrizia Daniele,Anna Nagurney
• Published date: 01 January 2021
• Date: 01 January 2021

Intl. Trans. in Op. Res. 28 (2021) 5–26

DOI: 10.1111/itor.12815

INTERNATIONAL

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IN OPERATIONAL

RESEARCH

Human migration networks and policy interventions: bringing

population distributions in line with system optimization

Anna Nagurneya, Patrizia Danieleb,∗and Giorgia Cappellob

aDepartment of Operations and Information Management, IsenbergSchool of Management, University of Massachusetts,

Amherst, MA 01003, USA

bDepartment of Mathematics and Computer Science, University of Catania, Catania, CT 95125, Italy

E-mail: daniele@dmi.unict.it [Daniele]

Received 1 February2020; received in revised form 12 May 2020; accepted 13 May 2020

Abstract

In this paper, we demonstrate that, through policy interventions, in the form of subsidies, a system-optimum

for a multiclass human migration network can be achieved, despite the migrants, who can be refugees, be-

having in a user-optimized manner.The formulation and analysis are conducted using variational inequality

theory.The policy intervention allows governmental decision-makers to moderate the flow of migrants while

enhancing societal welfare. An algorithm is proposed and applied to compute the solutions to a series of nu-

merical examples, with changes in initial populations and utility functions, inspired by a pandemic, followed

by a natural disaster.

Keywords:human migration; networks; variational inequalities; policy interventions; system optimization;user optimiza-

tion; subsidies

1. Introduction

Massive human migrations are posing major challenges to national governments across the globe.

The reasons for recent migrations include violence, wars, and persecution, climate change, a variety

of disasters (earthquakes, hurricanes, floods, and tornadoes), and poverty and economic inequality,

with the latter driving humans to seek better lives for their families and themselves. According to

the UNHCR (2020), 70.8 million have fled their homes worldwide,the highest level of displacement

on record. The United Nations (2017) is reporting thatthe number of international migrants was an

estimated 258 million individuals in 2017, with the total number of international migrants increas-

ing by almost 50% since the new millennium. The number of refugees and asylum seekers during

this period has increased from 16 to 26 million, approximately 10% of the international migrants.

The media has been filled with news and images of migrants, including refugees, often under-

taking dangerous journeys on land and sea to flee their compromised situations. The economic

∗Corresponding author.

© 2020 The Authors.

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6A. Nagurney et al. / Intl. Trans. in Op. Res. 28 (2021) 5–26

collapse of Venezuela (Kennedy, 2019) has resulted in a surge of migrants as has the violence in

many parts of Central America (Bartenstein and McDonald, 2019). Syria continues to be in a state

of war with many seeking to escape their suffering (United Nations Refugee Agency, 2019). And

now Libya is attracting the attention of many governments, with Sakuma (2020) reporting that the

largest flow of modern African migration is through Libya, which is serving as a gateway to Europe,

via the Mediterranean Sea. Furthermore, natural disasters (cf. Nagurney and Qiang, 2009) are also

generating new migratory flows even from Puerto Rico (Cardona, 2020).

According to Jones (2018), Italy has now become the main route into Europe for economic mi-

grants and asylum seekers, with hundreds of thousands risking their lives in their journeys from

North Africa each year and thousands dying at sea. Indeed, the United Nations Refugee Agency

(2015) documented a maritime refugee crisis with 137,000 crossing the Mediterranean Sea to Eu-

rope in the first half of that year, using highly risky transportation modes. In April 2015, 800 people

perished in the largest refugee shipwreck ever recorded. Kitsantonis (2019) states that the number

of asylum seekers making the short but often treacherous journey from Turkey across the Aegean

Sea to Greece has seen a rise again, with Greek officials looking toward replacing overcrowded mi-

grant camps with centers and hoping to restrict the migrants’ movements. Recent data are showing

that Cyprus is now hosting the most refugees per capita in the European Union (Stevis-Gridneff,

2020). As emphasized in Nagurney and Daniele (2020), closer attention must be paid to human

migration problems in economic, political, sociological, and even environmental dimensions.

Indeed, how to effectively manage human migration flows has become one of the major chal-

lenges of the new millennium. The governments of many nations, hence, are now faced with identi-

fying suitable policies and regulations to address a variety of human migration flows. In managing

international migration flows, governments usually focus on distinct classes of migrants such as

highly skilled workers, dependents of migrant workers, irregular migrants, and refugees and asylum

seekers (cf. Karagiannis, 2016). The United Nations Department of Economic and Social Affairs,

Population Division (2017) has compiled a list of high-level policies of various countries regarding

international migration. For example, policies associated with “irregular migration” include fines,

detention, or deportation of migrants in an irregular situation, as well as penalizing employers of

such migrants. The International Organization of Migration (2020a) defines irregular migration as

the movement of persons that takes place outside the laws, regulations, or international agreements

governing the entry into or exit from the origin, transit or destination location; see also Kara-

giannis (2016). The United Nations (2013) emphasizes that migration policies in both origin and

destination countries play an important role in determining the migratory flows.

Furthermore, the various human migration crises have even influenced the United Nation’s 2030

Sustainable Development Goals (SDGs). In particular, the 2030 Agenda for Sustainable Develop-

ment consists of a set of 17 SDGs and 169 targets (see United Nations Foundation, 2020). Migra-

tion is specifically referenced in seven of the SDGs and is also a cross-cutting issue, relevant to all

17 goals (cf. International Organization for Migration, 2020b).

2. Literature review and our contributions

Clearly, the rigorous modeling of human migration networks with the inclusion of appropriate

policies for the evaluation of outcomes merits serious attention. Although there have been efforts

© 2020 The Authors.

International Transactionsin Operational Research © 2020 International Federation of OperationalResearch Societies