Martin Kolk
@martinkolk.bsky.social
Demographer at Stockholm University and the Institute for Future Studies.
https://www.su.se/profiles/mkolk
https://www.su.se/profiles/mkolk
Read the paper by Kirsti Jylhä, myself, and @mfair.bsky.social, for many more details, more models, and more thoughts on the complex relationships between peoples views on population, reproduction, and how they are related.
doi.org/10.1007/s111...
doi.org/10.1007/s111...
Attitudes towards childbearing, population, and the environment: prevalence, correlates, and connections with fertility outcomes in Sweden - Population and Environment
Environmental concerns may influence personal fertility decisions and general opinions about childbearing and population dynamics, but research on this topic remains scarce. In two analyses based on l...
doi.org
August 19, 2025 at 12:45 PM
Read the paper by Kirsti Jylhä, myself, and @mfair.bsky.social, for many more details, more models, and more thoughts on the complex relationships between peoples views on population, reproduction, and how they are related.
doi.org/10.1007/s111...
doi.org/10.1007/s111...
However, the widespread agreement to link childbearing with environmental concerns could influence societal norms, and future policy debates on reproduction and sustainability.
August 19, 2025 at 12:45 PM
However, the widespread agreement to link childbearing with environmental concerns could influence societal norms, and future policy debates on reproduction and sustainability.
We conclude that while environmental concerns are shaping how people think about population and childbearing, these attitudes haven't yet led to widespread changes in family size and fertility preferences in Sweden.
August 19, 2025 at 12:45 PM
We conclude that while environmental concerns are shaping how people think about population and childbearing, these attitudes haven't yet led to widespread changes in family size and fertility preferences in Sweden.
People with greater climate worry and propensity for climate action are more likely to be worried about the future of a child living in a deteriorating world, than that an additional child may contribute negatively towards such a future. We find weak correlations with political attitudes and trust.
August 19, 2025 at 12:45 PM
People with greater climate worry and propensity for climate action are more likely to be worried about the future of a child living in a deteriorating world, than that an additional child may contribute negatively towards such a future. We find weak correlations with political attitudes and trust.
Different eco-reproductive concerns are moderately correlated with each other, and relatively weakly correlated with whether people have children or not. We find that the same people largely support policies reducing population both in their own country, and in developing countries.
August 19, 2025 at 12:45 PM
Different eco-reproductive concerns are moderately correlated with each other, and relatively weakly correlated with whether people have children or not. We find that the same people largely support policies reducing population both in their own country, and in developing countries.
People generally agreed both factors are important.While 65-70% of respondents said in principle that environmental problems should factor into childbearing decisions, fewer went as far as saying that individuals should limit the sizes of their families for environmental reasons.
August 19, 2025 at 12:45 PM
People generally agreed both factors are important.While 65-70% of respondents said in principle that environmental problems should factor into childbearing decisions, fewer went as far as saying that individuals should limit the sizes of their families for environmental reasons.
In a second study, with over 600 participants, we asked how much environmental factors should influence childbearing decisions - both the possible impact of a worsening environment on the child, and that an additional child may contribute to an increasing population that may worsen the environment.
August 19, 2025 at 12:45 PM
In a second study, with over 600 participants, we asked how much environmental factors should influence childbearing decisions - both the possible impact of a worsening environment on the child, and that an additional child may contribute to an increasing population that may worsen the environment.
We find that younger people and women are more worried about climate change, while men are more concerned about overpopulation. Parents with more children tend to be more concerned about future generations but less worried about overpopulation.
August 19, 2025 at 12:45 PM
We find that younger people and women are more worried about climate change, while men are more concerned about overpopulation. Parents with more children tend to be more concerned about future generations but less worried about overpopulation.
Our first data set is 8,000 respondents in the Swedish Gender and Generation Survey. Respondents were asked about worries such as climate change, overpopulation, and the prospects of future generations. Worries about three things are widespread.
August 19, 2025 at 12:45 PM
Our first data set is 8,000 respondents in the Swedish Gender and Generation Survey. Respondents were asked about worries such as climate change, overpopulation, and the prospects of future generations. Worries about three things are widespread.
The study focuses on eco-reproductive concerns—the idea that environmental challenges should influence personal and societal views on childbearing.
August 19, 2025 at 12:45 PM
The study focuses on eco-reproductive concerns—the idea that environmental challenges should influence personal and societal views on childbearing.
We do not find that individual decisions about having children are clearly shaped by environmental concerns, but many people believe such concerns should play a role in reproductive choices.
August 19, 2025 at 12:45 PM
We do not find that individual decisions about having children are clearly shaped by environmental concerns, but many people believe such concerns should play a role in reproductive choices.
Much of the increasing gender gap is compositional, with increasing shares of migrants with larger gender gaps, increasing the employment gap in the population.
Among Swedish men and women, employment has decreased, but much less.
Different time series 2005-2024 (with different age categories)
Among Swedish men and women, employment has decreased, but much less.
Different time series 2005-2024 (with different age categories)
August 11, 2025 at 4:34 PM
Much of the increasing gender gap is compositional, with increasing shares of migrants with larger gender gaps, increasing the employment gap in the population.
Among Swedish men and women, employment has decreased, but much less.
Different time series 2005-2024 (with different age categories)
Among Swedish men and women, employment has decreased, but much less.
Different time series 2005-2024 (with different age categories)
And here is the same figure for age 16-64. Essentially the same pattern, though more dramatic decline in employment (due to more enrolled students at younger ages).
August 11, 2025 at 4:17 PM
And here is the same figure for age 16-64. Essentially the same pattern, though more dramatic decline in employment (due to more enrolled students at younger ages).
Take away: Using register data to study religion allows novel research with longitudinal designs.
Register data reveal that wedding linked conversions sustain high endogamy even in secular societies.
Full open access preprint at:
doi.org/10.17045/sth...
Register data reveal that wedding linked conversions sustain high endogamy even in secular societies.
Full open access preprint at:
doi.org/10.17045/sth...
July 16, 2025 at 1:28 PM
Take away: Using register data to study religion allows novel research with longitudinal designs.
Register data reveal that wedding linked conversions sustain high endogamy even in secular societies.
Full open access preprint at:
doi.org/10.17045/sth...
Register data reveal that wedding linked conversions sustain high endogamy even in secular societies.
Full open access preprint at:
doi.org/10.17045/sth...
However, women are not consistently more endogamous, nor are they always less likely to switch. Patterns depend on the strictness and size of the denomination.
July 16, 2025 at 1:28 PM
However, women are not consistently more endogamous, nor are they always less likely to switch. Patterns depend on the strictness and size of the denomination.
Gender matters, but not uniformly. In endogamous unions created by conversion, wives more often adopt the husband’s faith — especially in Islam and Judaism. For Lutherans, it is husbands who usually join the wife’s religion.
July 16, 2025 at 1:28 PM
Gender matters, but not uniformly. In endogamous unions created by conversion, wives more often adopt the husband’s faith — especially in Islam and Judaism. For Lutherans, it is husbands who usually join the wife’s religion.
Total effect: by age 45, conversions add ≥ 20 percentage points to endogamy for most minorities, but subtract ~8 points for Lutherans. Marriage is a powerful catalyst for religious mobility.
July 16, 2025 at 1:28 PM
Total effect: by age 45, conversions add ≥ 20 percentage points to endogamy for most minorities, but subtract ~8 points for Lutherans. Marriage is a powerful catalyst for religious mobility.
When do switches happen? For every group except Lutherans, conversions spike in the two year band around the wedding, driving sharp jumps in homogamy. Among Lutherans, secularisation means conversions reduce endogamy over the life course.
July 16, 2025 at 1:28 PM
When do switches happen? For every group except Lutherans, conversions spike in the two year band around the wedding, driving sharp jumps in homogamy. Among Lutherans, secularisation means conversions reduce endogamy over the life course.
Once we control for group size, odds of marrying inside one’s faith explode for stricter or migrant dense groups: 50 to 1 000 fold higher than random matching for Other Protestants, Other Christians, Islam and Judaism, reflecting strong endogamy.
July 16, 2025 at 1:28 PM
Once we control for group size, odds of marrying inside one’s faith explode for stricter or migrant dense groups: 50 to 1 000 fold higher than random matching for Other Protestants, Other Christians, Islam and Judaism, reflecting strong endogamy.
Endogamy at the wedding is high in the majority church (≈ 81 % of Lutherans marry another Lutheran) but far lower for minority groups (≈ 40 % among the unaffiliated, ≈ 15 % among Orthodox).
However, this is largely due to the relative size of the different groups.
However, this is largely due to the relative size of the different groups.
July 16, 2025 at 1:28 PM
Endogamy at the wedding is high in the majority church (≈ 81 % of Lutherans marry another Lutheran) but far lower for minority groups (≈ 40 % among the unaffiliated, ≈ 15 % among Orthodox).
However, this is largely due to the relative size of the different groups.
However, this is largely due to the relative size of the different groups.