From the 1980s, the population mobility has undergone important changes in the developed and developing countries.

In Brazil, new axes of migration flows involving high population figures emerged. The highlights were the diversion in the main flows in Minas Gerais and Rio de Janeiro, the reduction of the migratory attraction exerted by São Paulo, the increase of the population retention in the Northeast region, the new migratory axes in direction to the medium towns inland, the increased importance of commuting (to work and/or to study), the end of the expansion of the agricultural borders and the movement of return to Paraná. 

Those and other aspects are tackled in the publication "Population Migration Flows in Brazil", a collection of studies about population mobility. It includes the present theoretical debate about this theme and it analyzes the inter-regional and inter-state migratory movements in Brazil between 1995 and 2000 (with data from the 2000 Census) and in the 1999/2004 and 2004/2009 periods (with information from the National Household Sample Survey – PNAD).

There are six articles written by the Transversal Group of Territory and Population Spatial Mobility Studies (GEMOB), which includes researchers from the IBGE’s Directorate of Surveys, Directorate of Geosciences and Minas Gerais State Unit.

The first text presents the theoretical approaches to the theme. The second one analyzes the population migration flows in 2000, using the data from the Censuses and the PNADS. The third text brings an overview of how the internal migrations were investigated from the 1970 to the 2010 Population Censuses. The fourth article brings reflections on commuting. The last two texts are turned to the empirical treatment of the migratory phenomenon. They analyze the possible uses of the information about the international out-migration, covered by the 2010 Census, and propose a set of variables that must be investigated.

The complete publication can be accessed at

https://www.ibge.gov.br/home/estatistica/populacao/reflexoes_deslocamentos/deslocamentos.pdf

The volume of inter-region migrations has decreased in the last decade 

The PNAD 2004 and 2009 editions investigated the place where the surveyed residents lived five years before the reference date.

The data show that the inter-regional migration volume involved 2.8 million people in the 1999-2004 period and 2 million people between 2004 and 2009. That volume covered about 3.3 million people in the 1995-2000 period (data from the 2000 Population Census). The main migratory flows observed in the past are losing intensity and there is a rise in the movement of return to the origin regions.

A loss in the capacity of population attraction was observed in the Southeast region, which registered a negative net migration both in 2004 and in 2009. Northeast continues losing population, but in a smaller scale:

The Index of Migration Effectiveness (IME) measures the migratory attraction, loss or turnover and it is obtained by means of the ratio between the net migration and the total volume of migrants (immigrants + emigrants).

This indicator allows for comparability among states, independently of the absolute volume of immigration and emigration. The IME analysis of the states followed the classification below.

The IME of the Federation Units revealed that half of them have high migratory turnovers, that is, both in-flows and out-flows are similar.

Even those areas that in the past expelled or potentially attracted population had their net migration rates achieve a balance. In general, a downward trend was observed for the volume of migration flows in all Federation Units.

The states with the highest migration of return in 2009 were Rio Grande do Sul (23.98%), Paraná (23.44%), Minas Gerais (21.62%), Sergipe (21.52%), Pernambuco (23.61%), Paraíba (20.95%) and Rio Grande do Norte (21.14%).

The following table shows the net migrations, the IME and the contribution of the return immigrants to the total immigrants by Federation Unit in 2004 and 2009:

In the North region, Amazonas, Roraima and Pará had their classifications as to the capacity of migratory absorption changed.

Amazonas changed its status from high migratory turnover to low migratory absorption between 2004 and 2009, when more than 40% of its immigrants came from Pará. It no longer registered low attraction and started recording low population loss. Maranhão is the main destiny to its emigrants. The state of Roraima, which in 2000 was the only one to present a high index of migration absorption, started to register an average absorption in 2004 and a high migration turnover in 2009. That points to a downward trend in the volume of people and, maybe, in the migration flows in direction to this state.

In Northeast, the states of Piauí, Alagoas, Rio Grande do Norte and Paraíba had their capacity to absorb population decreased. Areas previously registering high migratory turnovers, such as Piauí and Alagoas, became low and average migratory loss areas, respectively; and the states of Rio Grande do Norte and Paraíba had their capacity to absorb population decreased. Bahia and Maranhão continued to be population expelling regions, despite recording a low migratory loss. Sergipe, Pernambuco and Ceará were classified as high migratory turnover areas.

The Southeast states are characterized as high migratory turnover areas. However, Espírito Santo started to attract population, becoming an average migratory absorption area, and Rio de Janeiro, a low loss area before, became a high migratory turnover area, despite recording a negative net migration.

In the South region, Paraná had its net migration change from negative to positive, but its classification as to the migratory absorption capacity remained unchanged. It continued to be a high migratory turnover area, mainly receiving immigrants from São Paulo and Santa Catarina. Santa Catarina continued as a low absorption region, with more than 80% of the immigrants coming from São Paulo, Paraná and Rio Grande do Sul. Conversely, Rio Grande do Sul changed its status from low migratory loss to high migratory turnover, recording the most significant exchanges with Santa Catarina.

In Central-West the highlight was the Federal District’s change from low migratory loss area in 2004, when the population expanded to occupy the municipalities of Goiás in the surroundings of the capital, to high migratory turnover area in 2009, with the reduction of these movements. The state of Goiás received great amounts of immigrants from several states besides the Federal District, such as Bahia, Minas Gerais, São Paulo, Tocantins and Maranhão. It was classified as an average migratory absorption area. Mato Grosso do Sul and Mato Grosso were characterized as high migratory turnover areas. Mato Grosso in the 1999-2004 period was considered an average migratory absorption area.

2010 Census: cities with less than 500 thousand residents are those that grow the most

The 2010 Population Census results presented population volumes disaggregated by municipality. With these data, it was possible to establish population growth axes in the country and raise hypotheses about areas that gain or lose population so as to infer if there were changes in the population migration flows in the last decade. The conclusion was that cities with less than 500 thousand residents are the ones that grow the most in the country, although the great cities continue concentrating an expressive share of the population (approximately 30%). The pace of fragmentation of the territory was less intense than in the previous decades, with 58 municipalities established against 501 in the 1980s and 1,016 in the 1990s. 

By analyzing the pace of growth of the municipalities, it is possible to observe that 27%, an expressive share of the cities with up to 10 thousand residents, lose population and, considering the perspective of development, represent stagnated spaces. Among those, almost all had a very low per capita Gross Domestic Product (GDP) in 2008. In the stratum of municipalities with population decreases, four medium-sized cities can be highlighted: Foz de Iguaçu (PR), Ilhéus (BA), Lages (SC) and Uruguaiana (RS). 

About 46% of the municipalities recorded a null or low growth (up to 1.5% a year) . That performance can be attributable to the lower levels of fertility and to the low population attraction exerted by these places, including 23 big cities. In this group, the combination of low GDP and high-density areas prevails. To illustrate that, the nuclei of the nine traditional metropolitan regions registered rates below 1.5% a year in the period. Porto Alegre registered the worst performance with a rate of 0.4%. Rio de Janeiro and São Paulo recorded changes of approximately 0.8%. 

19% of the municipalities registered a growth ranging from 1.5% to 3% a year. They were medium sized and had a slightly higher GDP when compared to the previous stratum. This group also included 15 big cities, nine capitals (Brasília, Manaus, Goiânia, São Luís, Maceió, Teresina, Campo Grande, João Pessoa and Aracaju) and six cities inland (São José dos Campos, Ribeirão Preto, Uberlândia, Sorocaba, Feira de Santana, Joinville).

 Among the cities with high rates of growth (8% of the total), none has more than 500 thousand residents. The explanation for this growth does not seem to be obviously related to the per capita GDP size, although the municipalities with the best indicators are included in this group.

Population migration flows demand new approaches 

The theme, migration flows, has incorporated new criteria in each Census since 1970, when there was a more intense internationalization of the Brazilian economy and society.

In general, the last five censuses incorporated most of the criteria relevant to the study of internal migration.

One of the present challenges is to estimate the figures relative to the Brazilians that live abroad and to the international immigrants living in Brazil, considering that great part of the migration flows is generated by the so-called "illegal" immigrants.

The commuting movements also need new approaches, as economic and education accounts are not enough to explain this complex phenomenon.

 The 2010 Population Census approached for the first time the international Brazilian emigration.

The Continuous PNAD, in phase of planning, promises to treat the commuting movements in detail in the basic questionnaire. Another promise is a regular module about migration, which explores migration trajectories, social networks, motivation and labor and educational profiles.