Our Newest Energy Consumer

We recently added a new member to our family. Since I have a tendency to look at the world through an energy lens, I’ve being wondering, what is the likely energy and climate change impact of our family expanding the global population by one? And more broadly, what is the current thinking about how global population trends will affect greenhouse gas emissions?

Within our household the impact is apparent. We’ve been running the heater more than usual to make sure the baby isn’t cold at night. We’re doing more laundry, thus using more natural gas and electricity. We’re also consuming more—diapers and baby toys. In other words, we’re directly and indirectly, through our consumption of goods and services, using more electricity, oil and gas. The little squirt is racking up a significant greenhouse gas deficit already!

Now let’s assume our child is going to be an average American. How much greenhouse gas emissions does the average American account for? Yikes! According to World Bank statistics, carbon dioxide emissions per capita in the US were 17.0 metric tons per capita in 2011. That’s over 3 times the world average!

World Bank Group. 2016. Global Monitoring Report 2015/2016: Development Goals in an Era of Demographic Change. Washington, DC: World Bank. DOI: 10.1596/978-1-4648-0669-8. License: Creative Commons Attribution CC BY 3.0 IGO

World Bank Group. 2016. Global Monitoring Report 2015/2016: Development Goals in an Era of Demographic Change. Washington, DC: World Bank. DOI: 10.1596/978-1-4648-0669-8. License: Creative Commons Attribution CC BY 3.0 IGO

Ah, but our daughter is not an average American, she’s a Californian. According to the US Energy Information Administration’s (EIA’s) latest state-level analysis California per capita greenhouse gas emissions are 45% below the national average. If she had been born in Texas, where I grew up, the statistics would suggest her contribution would have been 45% above the national average.

Is it appropriate to look to averages like these to determine the environmental impact of expanding the population?

Dr. Paul Ehrlich thought so in the late 1960s, when his book The Population Bomb popularized the idea that population growth will cause widespread environmental damage. His analysis proposed multiplying the population by the per capita environmental impact to predict the total negative environmental damages.

The Population Bomb

If you take this analysis at face value, policymakers wanting to address climate change should not only promote policies that reduce the amount of greenhouse gas generated by energy, but also push policies that reduce population and economic activity. That sort of narrow logic, however, ignores all the other ways in which growing populations and economies improve human welfare, and has, fortunately, fallen out of favor. (For an excellent history of the debate between Paul Ehrlich and his critics check out Paul Sabin’s 2014 book The Bet.)

In the early 1990’s, an update of this analysis by Dr. John P. Holdren, President Obama’s current Director of the White House Office of Science and Technology Policy, used a similar, simple model to conclude that, globally, population growth from 1850 to 1990 was responsible for 52% of energy growth, with the remainder being attributed to a growth in per capita energy use.

More recently several studies (for example, here and here) have taken a fresh look at relationships between greenhouse gas emissions and population. The papers try to model relationships between population growth, economic growth, aging, urbanization and other demographic factors.

As far as I can tell, unraveling what’s causing what among all these factors is extremely difficult. In some cases these papers imply causal relationships, but I’m skeptical that we really understand these interactions yet. I hope to see more vigorous research in this subject area because I believe that policymakers addressing climate change should try to understand demographic trends.

Two types of trends deserve special attention. First, policymakers should consider overall projections of population growth by region to help set energy priorities. Second, policymakers should look beyond the headline numbers and consider how the age profiles of populations are changing in different ways in different regions.

First, the overall projections. The United Nations Population Division develops a set of widely used population projections. A supplemental probabilistic analysis published in Science projects that global population will grow from 7.2 billion people in 2014 to between 9 billion and 13 billion in 2100, with a 95% probability.

The difference in projections between continents is especially remarkable. Asia, the most populous continent, could see a peaking population mid-century, but Africa is projected to triple or even quintuple in population. So, while today’s emissions per capita in Africa are lower than anywhere else in the world, the aggregate emissions from Africa could grow dramatically over the century, even more so if per capita emissions converge with higher income countries.

SOURCE: Gerland et al. (2014), "World population stabilization unlikely this century," Science 346(6206):234-237.

SOURCE: Gerland et al. (2014), “World population stabilization unlikely this century,” Science 346(6206):234-237.

One takeaway is that policies and technologies that are effective in Africa will have a tremendous impact over the course of the century. Catherine, for one, is exploring important issues related to energy use in Africa (here, here and here). Also, as Lucas explored last week, getting energy prices right is important, especially before countries’ get too far down the path of investing in inefficient automobiles and other capital stock.

Second, policymakers should consider how the characteristics of the global population are changing, and how these characteristics vary between countries. The World Bank tackled these trends in its latest Global Monitoring Report. The report describes how children have represented a shrinking share of the population since the late 1960s and working age adults’ share of the population peaked in 2012. Adults aged 65+, on the other hand, represent a growing share.

However, Africa diverges from the overall trend. Children and working age adults still represent a growing share of the population. Africa may eventually converge towards global aging trends, but it isn’t there yet.

In higher income countries with aging populations policymakers will need to pay more attention to 65+ energy consumers, and how they may differ from the average consumer. For example, income-tested subsidy programs that disregard overall wealth capture disproportionate numbers of older adults. Some of these programs encourage inefficient use of energy by setting lower prices for energy rather than transfers to pay for a certain basic level of energy use. Programs aimed at the poor should be better targeted to those they’re intended to help and also consider any negative impacts on the environment. Improving the energy efficiency of low-income senior housing programs could also be an important use of resources long term.

Also, energy use within sectors like healthcare could become more significant and is ripe for technological innovation that focuses on energy conservation. Policy and technology should turn attention to these kinds of problems and opportunities.

On the flip side, in lower income countries, especially those in Africa, policymakers should keep in mind that populations are younger and will remain that way for quite some time. Prioritizing access to the latest energy innovations for young people there will have long lasting effects. For example, energy efficiency within rapidly expanding mobile phone networks will be important.

Of course our new daughter will be hearing a lot about the importance of being a thoughtful energy user. We’ll also have to get her some carbon offsets for her first birthday to make her feel better.

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8 Responses to Our Newest Energy Consumer

  1. Pingback: Our Newest Energy Consumer - Berkeley-Haas Insights

  2. Bruce Karney says:

    If we assume that your daughter and all her descendants have children at a steady-state replacement rate of about 2.1 children per couple in perpetuity, then the birth of a child essentially locks in a new one-person-equivalent carbon footprint forever. We can only hope that her and her descendant’s carbon footprint rapidly approaches and then reaches zero, otherwise as time approaches infinity so does their combined footprint. Even if the long-term birthrate of your daughter’s descendants is below replacement level the climate impact of having a child is MUCH greater than what will occur because of just that one child.

  3. qfman says:

    Good article but you left out the effects of water. In my discussions of energy with people I find most neglect the energy requirements of water. In CA one of the first things to be turned off in an energy emergency is the several MW of pumps that other wise run 247 to move water over the foot hills and coastal range to reach the large population centers.

  4. John Seager says:

    Over the past dozen years the UN has increased its medium population projection for 2100 by 2.2 billion people. That’s equal to the entire population of the Western Hemisphere plus Europe.

    We know how to meet population challenges through positive, 100% voluntary means. But proven effective programs are starved for funding. Amidst all the buzz about electric cars and such, family planning just isn’t a sexy topic these days. Ironic, huh?

    There are 225 million women today around the world with an unmet need for contraception. A fair share of the investment needed to meet that need would cost the average American less than a penny a day. The chances of that funding being approved by the current Congress are exactly zero. The chances of climate chaos and massive suffering are considerably higher – unless we act now.

    If we are to change the outcome, we must change Congress.

    John Seager
    President
    Population Connection Action Fund

  5. mcubedecon says:

    That the projection for most of the population growth will occur in Africa offers an opportunity. That continent has relatively little infrastructure investment, which means they can avoid paying off legacy stakeholders. Instead they can leapfrog certain development steps. They are already doing this in telecommunications. But they are going to need outside assistance. We can cost-effectively reduce global emissions by allowing and encouraging those in the develop world to focus on offsetting those emissions with greater investments in low/zero emission technologies and uses. That may make some people unhappy who want all emission reductions local, but that’s failing to think globally.

  6. Joel Darmstadter says:

    The relationship between population growth and climate change allows us — at least for a moment — to resurrect that old standby, the energy/GDP ratio as the “mediator” in that relationship.. Discredited? In many ways yes, but not entirely bogus. A close friend of mine has spent most of her professional career seeking to allow women in rural and poverty-stricken Africa access to reproductive health services. Consider one arguable outcome from success in such an effort. Fewer children might allow the remaining children a better shot at an education. Similarly, it might make it possible for some mothers to enter the labor market. The combination of both factors –knowledge and income — and the associated rise in living standards, would undeniably spur the demand for modern energy carriers. I have no idea what the quantitative dimensions of that aspect of demographic trends might be. But it seems to me to be worth some reflecti

  7. Population growth without a question is a key explanatory variable of carbon intensity growth provided it is not taken in isolation. Energy studies my office conducted in Saudi Arabia over the past twenty five years illustrate that energy and carbon intensity can possibly be explained by three key factors: population growth, economic development, and energy prices, standards, and programs. For over a quarter of a century, Saudi Arabia had one of the highest population growth rates in the world resulting in significant share of the population being under 25 years of age and resulting in great demand for housing, schooling, medical services, and general support services and ultimately in significant increase in demand for energy. The same time period coincided with high economic growth marked by significant growth in GDP per capita and significant growth in personal income. The same period also saw the application of subsidized low prices for energy. For basically the same period, no energy efficiency standards and programs were available or enforced. High economic growth coupled with subsidized energy and lax efficiency standards resulted in significant allocative inefficiencies in the selection of simple technologies, the selection of energy intensive industries, and purchases of low cost and low energy efficiency durables at the consumer level. The result was growth in demand for all: automotive fuels, natural gas, and electricity in excess of 7% on average annually significantly in excess of real GDP growth. This is the primary reason for Saudi Arabia’s energy and CO2 intensities high world ranking. Based on preliminary analysis we conducted, half the long term annual energy demand growth rate can be attributed to allocative inefficiencies and to significant energy and CO2 increase in intensities that can be avoided through energy policy, pricing, standards and programs.

    Therefore, while population growth is key in determining energy demand, carbon and energy intensities are determined in turn by energy demand but to a large extent by policy actions governing economic development, policy actions governing the impact of particularly industrialization on energy demand and energy and CO2 intensities, and the implementation of sound energy policy, pricing, efficiency standards and programs.

  8. James F. Cook says:

    Thanks Andy for the blog, I learned some new things and enjoyed reading it. Here’s to hoping that the people of Africa and India and others who lack adequate or any access to electricity get more, cleaner and cheaper energy soon and their standards of living rise as a result.

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