Does a Low Birth Rate Delay Young People's Entrance into Adulthood?

When demographers talk about low birth rates, the usual conversation is about why they are so low. And when consequences of those low rates are mentioned, it is almost always in the context of the negative effect on the age transition--with too few young people relative to the older population. Now, however, we have a new perspective from Jean Twenge, a San Diego State University psychology professor who has written famously about "Generation Me," in which her analyses suggested that younger people were growing up in an age of "entitlement" rather than "enlightenment". Her newest book is iGen: Why Today's Super-Connected Kids are Growing Up Less Rebellious, More Tolerant, Less Happy — and Completely Unprepared for Adulthood.” The San Diego Union-Tribune has a lengthy story about the substance of that book along with a paper on this topic that just came out in the journal Child Development.

Today’s 18-year-olds exhibit similar milestone behaviors as did 15-year-olds in the late 1970s, Twenge said. Moreover, they’re mostly doing this voluntarily — parents aren’t imposing this delayed independence.

But while smartphones and social media enable these trends, Twenge says it’s not the whole explanation. Advances in safety and a declining rate of childbirth drive this process. When parents have fewer children and expect them to grow up, they will expend more care on them.

Twenge said an evolutionary explanation called life history theory appears to be behind the trend. It classifies the maturation of species into “fast” and “slow” strategies.

Fast strategies involve producing prolific amounts of offspring with minimal care. Spawning fish and lobsters are examples. Very high death rates are acceptable, because only a tiny fraction need to survive to perpetuate the species.

Humans, with many years of care and training required for independence, represent the slow strategy. Modern society makes the slow strategy more feasible than before, Twenge said. 

Thus, fewer children per parent enables "helicopter parenting," but Twenge doesn't see that as necessarily bad--just different. Lower death rates with associated greater longevity (including healthy years of life expectancy) diminishes the need for children to rapidly become adults. Indeed, it may be socially useful for younger people to spend longer figuring out how the world works and where they are going to fit into it.

The Mess in Middle Africa

A few days ago I mentioned the particular concern about the world's ability to feed the still increasing global population. No where is that concern greater than in Africa. This is partly due to the fact that this is where the population is growing most quickly and where agricultural productivity may be especially vulnerable to the effects of climate change. These factors are aggravated by (and contribute to) another major problem in Africa--incessant conflict--occurring especially in middle Africa. The Humanitarian Information Unit (HIU) of the U.S. State Department recently posted a new infographic on human displacement in this region. It is startling both for its intensity and geographic complexity:

The complex part is that almost every country in the region is both a sender of refugees and a recipient of refugees. Notice that the Democratic Republic of the Congo (DRC) is in the middle of this--both politically and geographically. We don't hear about it very often, but I've mentioned before that the Democratic Republic of the Congo has recently sent more refugees to the U.S. than any other country. Indeed, the Congo, Syria, and Burma--in that order--account for half of all refugees currently arriving in the U.S. 

Meanwhile, back in middle Africa, Burundi is being wracked by violence, and you can see from the HIU infographic that Burundians are finding refugee in every direction, including in the DRC, where things have turned ugly, according to news sources:

At least 30 Burundian refugees have been killed in clashes with Congolese security forces over plans to send some of them home, a Reuters witness and local activists said on Saturday.

More than 400,000 refugees have fled Burundi - including 40,000 to neighbouring Congo - since violence erupted in April 2015 when President Pierre Nkurunziza said he would seek a third term in office, a move his opponents said was unconstitutional.

While it isn't obvious that the violence is caused by rapid population growth in an environment in which food supplies are not always secure, those factors are almost certainly contributing to the instability throughout this region of the world. 

How Many Healthy Years Will You Have in Old Age?

The population of the United States is aging, as everyone knows. In particular, we have a big bulge of baby boomers who keep pushing up the number of older people. Eventually they will all die off and the ratio of older to younger people will be a little less stressful than it currently is. In the meantime, one of the big issues is the cost of health care to the growing number of elderly. The healthier is this group of seniors, the less they will cost, and the happier will the younger taxpayers be. It is not just life expectancy, but rather it is healthy life expectancy (the number of healthy years you have left) that is important for you (because the quality is life is better if you are healthy) and for society (since healthy people cost less). 

As it turns out, researchers at the University of Washington School of Public Health have put their research results to good use by generating the Healthy Life Calculator. The underlying calculations are based on data they collected (and are still collecting) in their Cardiovascular Health Study, funded by the National Institutes of Health. The background information is available from their article published in the journal Gerontology and Geriatric Medicine. Using a relatively limited set of questions--only 11 variables, including age, sex, smoking history, activities of daily living (ADLs), and the number of medicines taken each day, they are able to compare your life expectancy (based on U.S. life tables) with your health life expectancy. The information is limited enough that you could do this not only for yourself, if you are 65 or older, but you probably can make good estimates for your parents and/or grandparents, if they are 65 or older. 

As an example, if you are currently a 65-year female who is in excellent health, never smoked, has no problem with ADLs, takes no medications, and gets a good amount of exercise, your can expect to live an additional 22.8 years, of which 19.3 can be expected to be healthy. That's good news for you and for society in general. Note, by the way, that the calculator also provides you with information on the chances that your healthy life expectancy will be either higher or lower. As your health indicators increase in severity, of course, your healthy life expectancy will decrease, even if your overall life expectancy does not. That's neither good for you nor society, so for everybody's sake, no matter how old you currently are, try to be healthier, OK?

Can We Keep Feeding the World?

Just ahead of the UN General Assembly meetings in New York, the UN World Food Programme has put out a report on world hunger, and it is not good news:

After steadily declining for over a decade, global hunger is on the rise again, affecting 815 million people in 2016, or 11 per cent of the global population, says a new edition of the annual United Nations report on world food security and nutrition released today. At the same time, multiple forms of malnutrition are threatening the health of millions worldwide. 

The increase – 38 million more people than the previous year – is largely due to the proliferation of violent conflicts and climate-related shocks, according to The State of Food Security and Nutrition in the World 2017.

The climate shocks are particularly noteworthy since they seem to be getting worse and, in most respects, it will be a bigger job to change human behavior regarding our polluting of the world's atmosphere than to tamp down violent conflicts. Consider a paper just published in the Proceedings of the National Academy of Science by climate researchers at UC San Diego and Texas A&M, and summarized for us non-climate scientists yesterday by the San Diego Union-Tribune:

There’s a very small but distinct possibility that rapid global warming could pose an “existential threat” to the survival of humans by 2050, UC San Diego said Thursday in one of the most dire forecasts yet about climate change. The school’s Scripps Institution of Oceanography published a paper that said there is a 5 percent chance of catastrophic change within roughly three decades, and a smaller chance that it would broadly wipe out human life. Scripps made the claim while proposing two new classifications for climate change: catastrophic and unknown, or existential. Catastrophic means that most people would have trouble adapting to such change. The latter terms means that they would not be able to.

“Other people have used the word catastrophic, but I have resisted doing so until now,” said the study’s lead author, Veerabhadran Ramanathan, a renowned climate scientist who helped influence Pope Francis to urge the world to fight global warming in 2015.
“I changed my mind because, over the past five years, I have gone back and reviewed data that we began collecting from satellites in the 1980s and data from aircraft and changes in the intensity of storms, and studies about the possible health affects of rapid global warming. “There is a low probability that the change will be catastrophic. But you would not get on an airplane if you thought there was a 5 percent chance that it was going to crash.” He noted that the probability of an existential threat is even smaller, but said, “that chance rises to 20 to 30 percent by 2070.”

These climate changes call into question our ability to continue feeding a population that is still growing and still consuming more calories per person, especially when agriculture itself contributes to climate change in a variety of ways through deforestation, methane gas production, and the increasing diversion of water for agricultural purposes. Are we already in a situation of global overshoot? 

The Gates Foundation Keeps Track of the UN Sustainable Goals for Us

This year's report from the Bill & Melinda Gates Foundation is the first in what they say will be an annual series between now and 2030, as they track world progress on the UN Sustainable Development Goals.

We are launching this report this year and will publish it every year until 2030 because we want to accelerate progress in the fight against poverty by helping to diagnose urgent problems, identify promising solutions, measure and interpret key results, and spread best practices.

As it happens, this report comes out at a time when there is more doubt than usual about the world’s commitment to development. In our own country, Congress is currently considering how to deal with the big cuts to foreign aid proposed in the president’s budget. A similar mood of retrenchment has taken hold in other donor countries. Meanwhile, most developing countries need to do more to prioritize the welfare of their poorest citizens.

This report tracks 18 data points included in the SDGs that we believe are fundamental to people’s health and well-being. To complement the data, we’re also telling the stories behind the numbers—about the leaders, innovations, and policies that have made the difference in countries where progress has been most significant.

The very first goal in the report relates to child mortality (deaths under age 5). 

As you look at the graph above, keep in mind the long-term declining trend in child mortality illustrated by Max Roser, as I noted a few days ago. This is a key to societal well-being and the drop in deaths among children represent the most potent source of population growth if not accompanied immediately by a decline in fertility. The Gates Foundation gets this connection and so third on the list of goals they are keeping track of is the rise in the use of modern contraception. Fortunately, this is going up nearly everywhere in the world with the notable exception of countries in Africa, as Michel Garenne discusses in a story posted today on the IUSSP website.