DOI: 10.5281/zenodo.15175736
title: Population dynamics and Population Migration

description: Population dynamics, its types. Population migration (external, internal), factors determining it, main trends. Impact of migration on population health.

 

Under the guidance of Moldoev M.I. Sir By Riya Patil and Rutuja Sonar

 

Abstract

Population dynamics influence development and vice versa, at various scale levels: global, continental/world-regional, national, regional, and local. Debates on how population growth affects development and how development affects population growth have already been subject of intensive debate and controversy since the late 18th century, and this debate is still ongoing. While these two debates initially focused mainly on natural population growth, the impact of migration on both population dynamics and development is also increasingly recognized. While world population will continue growing throughout the 21st century, there are substantial and growing contrasts between and within world-regions in the pace and nature of that growth, including some countries where population is stagnating or even shrinking. Because of these growing contrasts, population dynamics and their interrelationships with development have quite different governance implications in different parts of the world.

 

1. Population Dynamics

Population dynamics refers to the changes in population size, structure, and distribution over time. These changes are influenced by four main processes:

Birth rate (natality)

Death rate (mortality)

Immigration (inflow of people)

Emigration (outflow of people)

 

Types of Population Dynamics

Natural population change: Based on birth and death rates.

Migration-based change: Caused by people moving in or out of a region.

Demographic transition: A model that explains changes in population growth as societies industrialize.

Population distribution: Changes in where people live (urban vs rural).

 

2. Population Migration

Migration refers to the movement of people from one location to another, often across political or geographical boundaries.

 

Types of Migration

External migration (international):

Movement between countries.

Examples: Refugee relocation, labor migration, education.

Internal migration:

Movement within the same country or region.

Examples: Rural-to-urban migration, inter-state migration.

 

3. Factors Determining Migration

Migration is influenced by push and pull factors:

Push factors (reasons to leave a place):

Unemployment

Conflict or war

Natural disasters

Poverty

Lack of services or opportunities

Pull factors (reasons to move to a place):

Better job prospects

Safety and security

Higher standard of living

Education and healthcare access

Family reunification

 

4. Main Trends in Migration

Urbanization: Mass movement to cities for work and better services.

Global labor migration: Movement from developing to developed countries.

Refugee and asylum seeker flows: Due to conflict or persecution.

Circular migration: Repeated movement between two or more locations.

Brain drain/gain: Movement of skilled labor away from (or toward) a country.

 

5. Impact of Migration on Population Health

Positive Impacts:

Access to better healthcare (for migrants moving to better systems).

Skills and knowledge exchange among health professionals.

Remittances improving healthcare affordability in home countries.

 

Negative Impacts:

Migrants’ health risks: Increased exposure to stress, poor living conditions, and occupational hazards.

Spread of infectious diseases: Especially when health screening is lacking.

Strain on health services: In receiving areas, especially with sudden or large influxes.

Mental health challenges: Due to cultural dislocation, discrimination, or trauma.

 

Population dynamics is one of the fundamental areas of ecology, forming both the basis for the study of more complex communities and of many applied questions. Understanding population dynamics is the key to understanding the relative importance of competition for resources and predation in structuring ecological communities, which is a central question in ecology.

 

Population dynamics plays a central role in many approaches to preserving biodiversity, which until now have been primarily focused on a single species approach. The calculation of the intrinsic growth rate of a species from a life table is often the central piece of conservation plans. Similarly, management of natural resources, such as fisheries, depends on population dynamics as a way to determine appropriate management actions.

 

Population dynamics can be characterized by a nonlinear system of difference or differential equations between the birth sizes of consecutive periods. In such a nonlinear system, when the feedback elasticity of previous events on current birth size is larger, the more likely the dynamics will be volatile. Depending on the classification criteria of the population, the revealed cyclical behavior has various interpretations. Under different contextual scenarios, Malthusian cycles, Easterlin cycles, predator–prey cycles, dynastic cycles, and capitalist–laborer cycles have been introduced and analyzed

 

Generally, population dynamics is a nonlinear stochastic process. Nonlinearities tend to be complicated to deal with, both when we want to do analytic stochastic modelling and when analysing data. The way around the problem is to approximate the nonlinear model with a linear one, for which the mathematical and statistical theories are more developed and tractable. Let us assume that the population process is described as:

 

(1)Nt=f(Nt−1,εt)

where Nt is population density at time t and εt is a series of random variables with identical distributions (mean and variance). Function f specifies how the population density one time step back, plus the stochastic environment εt, is mapped into the current time step. Let us assume that the (deterministic) stationary (equilibrium) value of the population is N* and that ε has mean ε*. The linear approximation of Eq. (1) close to N* is then:

 

(2)xt=axt−1+bϕt

where xt=Nt−N*, a=f

f(N*,ε*)/f

N, b=ff(N*,ε*)/fε, and ϕt=εt−ε*

 

The term population refers to the members of a single species that can interact with each other. Thus, the fish in a lake, or the moose on an island, are clear examples of a population. In other cases, such as trees in a forest, it may not be nearly so clear what a population is, but the concept of population is still very useful.

 

Population dynamics is essentially the study of the changes in the numbers through time of a single species. This is clearly a case where a quantitative description is essential, since the numbers of individuals in the population will be counted. One could begin by looking at a series of measurements of the numbers of particular species through time. However, it would still be necessary to decide which changes in numbers through time are significant, and how to determine what causes the changes in numbers. Thus, it is more sensible to begin with models that relate changes in population numbers through time to underlying assumptions. The models will provide indications of what features of changes in numbers are important and what measurements are critical to make, and they will help determine what the cause of changes in population levels might be.

To understand the dynamics of biological populations, the study starts with the simplest possibility and determines what the dynamics of the population would be in that case. Then, deviations in observed populations from the predictions of that simplest case would provide information about the kinds of forces shaping the dynamics of populations. Therefore, in describing the dynamics in this simplest case it is essential to be explicit and clear about the assumptions made. It would not be argued that the idealized population described here would ever be found, but that focusing on the idealized population would provide insight into real populations, just as the study of Newtonian mechanics provides understanding of more realistic situations in physics.

 

Population migration 

 

The vast majority of people continue to live in the countries where they were born —only one in 30 are migrants.

In most discussions on migration, the starting point is usually numbers. Understanding changes in scale, emerging trends, and shifting demographics related to global social and economic transformations, such as migration, help us make sense of the changing world we live in and plan for the future. The current global estimate is that there were around 281 million international migrants in the world in 2020, which equates to 3.6 percent of the global population.

Overall, the estimated number of international migrants has increased over the past five decades. The total estimated 281 million people living in a country other than their countries of birth in 2020 was 128 million more than in 1990 and over three times the estimated number in 1970.

There is currently a larger number of male than female international migrants worldwide and the growing gender gap has increased over the past 20 years. In 2000, the male to female split was 50.6 to 49.4 per cent (or 88 million male migrants and 86 million female migrants). In 2020 the split was 51.9 to 48.1 per cent, with 146 million male migrants and 135 million female migrants. The share of female migrants has been decreasing since 2000, while the share of male migrants has increased by 1.3 percentage points.

Available data reflect an overall increase in remittances in recent decades, from $128 billion in 2000 to $831 billion in 2022.

International remittances are financial or in-kind transfers made by migrants directly to families or communities in their countries of origin.

The World Bank compiles global data on international remittances, notwithstanding the myriad data gaps, definitional differences, and methodological challenges in compiling accurate statistics. Its data, however, do not capture unrecorded flows through formal or informal channels, and the actual magnitude of global remittances is, therefore, likely to be larger than available estimates.

In 2022, India, Mexico, China, the Philippines, and Egypt were (in descending order) the top five remittance recipient countries, although India was well above the rest, with total inward remittances exceeding $111 billion, the first country to reach and even exceed $100 billion.

 

Predictive indicators

Examining the overall quality of life by country, as well as across a range of key indexes and key migration and displacement indicators, highlights the reality that some countries face far greater contextual challenges and face a higher risk of (further) migration and displacement. When combined these sets of data can act as predictive indicators, assisting decision-makers to better anticipate some of the key migration challenges and opportunities ahead.

 

Global index data and rankings often reflect systemic issues that encompass decades, if not hundreds of years, of accumulated histories. The Henley Passport Index, for example, is a global ranking of countries according to the relative entry freedom of their citizens, which reveals that an individual’s ability to enter a country is in many respects determined by nationality. Visa access also broadly reflects a country’s status and relations within the international community and indicates how stable, safe and prosperous it is in relation to other countries.

 

Nationals from countries with very high levels of human development can travel visa-free to around 85 per cent of all other countries worldwide. These countries are also significant and preferred destination countries. However, the visa restrictions in place for countries with low levels of human development indicate that regular migration pathways are problematic for citizens. Irregular pathways are likely to be the most realistic (if not the only) option open to potential migrants from these countries.

When these index and migration data are visually represented in a global tile map, we can see broad regional aspects highlighted in stark terms. The more intense the green, the greater the alignment of positive index rankings and lower levels of displacement – see Europe, for example. On the other hand, the more intense pink in Africa and Asia show that lower index rankings and higher levels of displacement are strongly align. It is within these regions that we are likely to find countries that may require greater attention and focus, including operational, programmatic and policy support.

 

The 2030 Agenda for Sustainable Development recognizes the positive contribution of migrants to inclusive growth and sustainable development. The Agenda's core principle is to "leave no one behind," which includes migrants. Many of the Agenda’s Sustainable Development Goals (SDGs) contain targets and indicators which are relevant to migrants or migration. SDG target 10.7 calls on countries to “facilitate orderly, safe, regular and responsible migration and mobility of people, including through the implementation of planned and well-managed migration policies ”. Other targets directly related to migrants or migration refer to the health workforce in developing countries (3.c), mobility of international students (4.b), human trafficking (5.2, 8.7 and 16.2), labour migration (8.7 and 8.8), remittances (10.c) and legal identity (16.9). Further, SDG target 17.8 calls for disaggregating data by migratory status.

 

Factors affecting migration 

 

The total number of non-EU citizens residing within the EU as of 1 January 2021 was 23.7 million, according to Eurostat, the EU’s statistical office. This represents 5.3% of the EU population. In most EU countries, the majority of non-nationals were from outside the EU.

 

What is migration?

 

Migration is the movement of people from one place to another, to settle in a new location. Migration can be voluntary or involuntary and can occur for a variety of different reasons, including economic, environmental and social issues.

 

Reasons for migration: push and pull factors

 

Push factors are the reasons people leave a country. Pull factors are the reason they move to a particular country. There are three major push and pull factors.

 

Social and political factors

Persecution because of one's ethnicity, religion, race, politics or culture can push people to leave their country. A major factor is war, conflict, government persecution or there being a significant risk of them.

Those fleeing armed conflict, human rights violations or persecution are more likely to be humanitarian refugees. This will affect where they settle as some countries have more liberal approaches to humanitarian migrants than others. In the first instance, these people are likely to move to the nearest safe country that accepts asylum seekers.

 

The backbone of international humanitarian law is the Geneva Conventions, which regulate the conduct of armed conflict and seek to limit its effects

In recent years, people have been fleeing to Europe in large numbers from conflict, terror and persecution at home. Of the 384,245 asylum seekers granted protection status in the EU in 2022, more than a quarter came from war-torn Syria, with Afghanistan and Venezuela in second and third place respectively.

 

Demographic and economic causes

Demographic change determines how people move and migrate. A growing or shrinking, aging or youthful population has an impact on economic growth and employment opportunities in the countries of origin or migration policies in the destination countries.

Demographic and economic migration is related to poor labour standards, high unemployment and the overall health of a country’s’ economy. Pull factors include higher wages, better employment opportunities, a higher standard of living and educational opportunities. If economic conditions are not favourable and appear to be at risk of declining further, a greater number of people will probably migrate to countries with a better outlook.

 

Impact of migration on population health.

Migration and displacement have been a constant dynamic in human history. People have migrated since the beginning of human history to escape poverty, natural disasters, war and dictatorships, and to seek a better lives for themselves and their families. These flows have greatly benefited the world, leading to cultural, societal and intellectual advances. Yet the process and context of migration and displacement may have a negative impact on both migrants and communities. This can happen when their specific health needs are not met or when the circumstances of their movement act as adverse determinants for their health.

The health of refugees and migrants bridges the spheres of human rights, public health, humanitarian assistance and development:

migrants are human-beings and have a right to health;

migrant-inclusive health systems improve public and global health outcomes for all;

saving lives, reducing mortality and morbidity and creating better health systems for both the migrants and the hosting communities are key tenets in the context of displacement and humanitarian crises; and

healthy migrants are better able to contribute to positive and sustainable development outcomes.

The adoption of inclusive health policies in relations to refugees and migrants has not been universal; in most countries, the level of access to health care for refugees and migrants is determined by factors such as their status; national migration policies; societal values; and their capability in overcoming linguistic, cultural, economic and social barriers. A further determinant is the capacity of the health sector to produce evidence for and advocate for the adoption of adequate public health responses to the growing and changing reality of modern migration, which is a global megatrend. Additionally, migration places individuals in situations that may impact their physical and mental well-being; this is particularly true for those who are forced to flee natural or man-made disasters (whether across borders or within their own country), those in an irregular situation and those with particular vulnerabilities and health and protection needs.

 

Although comprehensive data sources on refugee and migrant health are scant, and often systematic disaggregation of health data as a function of migratory status is lacking, there are converging views in the available literature. These views identify recurring areas of concern in relation to migration and health outcomes, particularly infectious diseases, noncommunicable diseases, trauma and mental health; gender- and age-specific factors of vulnerability are also identified. Some studies have shown that migrants frequently experience poorer health and a lower average life expectancy than that of the general population and have increased infant/child mortality and lower reproductive health, ineffective access to health services (over- or underuse, or both) and a higher risk of being insufficiently treated by health services.

 

There is no universally accepted definition of the term migrant. Migrants may be granted different legal status depending on their country of stay because national legislations may have different interpretations regarding entitlement and access to essential health-care services. However, such access is a universal right for all under international law, in line with the 2030 Agenda for Sustainable Development (2030 Agenda) and its Sustainable Development Goals (SDGs), in particular SDG 3 (ensure healthy lives and promote well-being for all at all ages

 

Current migration and displacement situation and trends

It is estimated that there were 1 billion migrants worldwide in 2020, of whom 281 million were international migrants (i.e. 3.6% of the world population), and approximately 763 million were internal migrants, with a tendency for a marked increase in this last group (UNHCR, 2020). The International Organization for Migration estimates that 

There is no universally accepted definition of the term migrant. Migrants may be granted different legal status depending on their country of stay because national legislations may have different interpretations regarding entitlement and access to essential health-care services. However, such access is a universal right for all under international law, in line with the 2030 Agenda for Sustainable Development (2030 Agenda) and its Sustainable Development Goals (SDGs), in particular SDG 3 (ensure healthy lives and promote well-being for all at all ages

 

Current migration and displacement situation and trends

It is estimated that there were 1 billion migrants worldwide in 2020, of whom 281 million were international migrants (i.e. 3.6% of the world population), and approximately 763 million were internal migrants, with a tendency for a marked increase in this last group (UNHCR, 2020). The International Organization for Migration estimates that the vast majority (65%), of international migrants, both displaced people and economic migrants, are workers or people seeking employment. Those seeking employment tend to be a young and productive population, with an estimated average age of 39 years and 15% (37 million) under 20 years of age. There is a marked female preponderance within migration, with women making up 48% of global migrants. The vast majority of these women are economically active

 

Reference 

 

https://www.sciencedirect.com/topics/social-sciences/population-dynamics

 

https://www.europarl.europa.eu/topics/en/article/20200624STO81906/exploring-migration-causes-why-people-migrate

 

https://www.pewresearch.org/short-reads/2022/12/16/key-facts-about-recent-trends-in-global-migration/

 

https://worldmigrationreport.iom.int/msite/wmr-2024-interactive/

 

https://www.who.int/tools/refugee-and-migrant-health-toolkit/essential-knowledge-health-and-migration#:~:text=Some%20studies%20have%20shown%20that,a%20higher%20risk%20of%20being

 

https://ourworldindata.org/migration

 

https://www.un.org/en/global-issues/migration

 

https://www.oecd.org/en/topics/sub-issues/international-migration-trends.html

 

https://www.un.org/en/desa/latest-migration-trends-revealed

 

https://www.iom.int/fundamentals-migration

 

https://www.researchgate.net/publication/330496325_Factors_Influencing_Migration