In a recent study published in the journal Environmental Research, Institute for Child, Youth and Family Policy scientist Clemens Noelke and co-authors analyzed the impact of ambient temperatures on emotional well-being. Noelke spoke with Heller Communications about the study and its implications for the impact of global climate change on happiness.
The study, titled "Increasing ambient temperature reduces emotional well-being," can be viewed and downloaded via Science Direct online.
Heller Communications: What are the key findings from your study on happiness and ambient temperature?
Clemens Noelke: Using U.S. survey data on nearly 2 million people, we found that day-to-day variation in temperature has an effect on individual emotional well-being. We observed that heat exposure reduces overall emotional well-being, increases negative emotions (such as feelings of anger and stress) and also increases fatigue. This is consistent with recent work linking heat exposure to increased interpersonal aggression, reduced labor supply, productivity and economic growth in the U.S.
HC: What groups of people may be especially vulnerable to climate-based unhappiness?
CN: Consistent with work on the health impact of heat exposure, we see stronger effects on less educated and older Americans. For example, being exposed to daily average temperatures above 90 degrees Fahrenheit reduces overall emotional well-being by around 6% of a standard deviation. This effect is about the same size as the well-being gap between college and high-school graduates.
HC: What do your findings imply, given current predictions of climate change and increasing temperatures?
CN: We used day-to-day temperature variation within respondents' zip code areas to estimate the effect of temperature on well-being. Because this variation is as good as randomly assigned, we can be reasonably sure that temperature changes cause well-being changes, and aren’t just correlated. However, we would really like to know how informative our estimates are about the long-run impact of global warming, e.g., until the end of this century.
While there are a range of scenarios predicting what future temperatures will be, we can say much less about whether and how humans will adapt to long-term changes in temperature. As temperatures slowly rise, humans may change their lifestyle or use of technology so that our negative emotional response to heat may diminish or even disappear. This has certainly happened in the course of the 20th century, for example through the widespread use of air conditioning. However, there are reasons to be skeptical about whether we can continue to adapt at a similar rate.
To get at this issue, we tested whether the effect of heat exposure differs in areas with hot summers and areas with mild summers. We made the assumption that residents in areas with hot summers should be better adapted to high temperatures, and therefore experience a smaller emotional response or none at all.
We performed a battery of statistical tests and found no consistent evidence that the temperature response differs across areas. So, our results do not support the argument that we can adapt to the effect that heat exposure has on well-being. However, these results are based on present data, and it's not clear whether these results can be projected to what will happen in the future.
Furthermore, it’s relatively easy to study the well-being effects of day-to-day variation in temperature (weather variability), but much harder to study the well-being effect of long-term shifts in temperature due to global climate change. For now, our team only had data to do the former, so we cannot say as much about the impact of global warming as we'd like to be able to. There's an interesting debate in the field about whether or not the estimates derived from weather variation can be used to say something about likely effects of climate change. We could not really agree on one view amongst ourselves, so we did not dwell on the issue too much in this study.
Still, I personally think our work provides some useful results for thinking about the consequence of increasing temperatures on individual well-being and quality of life, a topic that has barely received attention. In particular, the findings suggest that we should be skeptical about the potential for further adaptation to heat exposure and that older and less educated Americans likely face elevated risks to their happiness due to global climate change.
HC: What else should we know about this line of research? Do you have any plans to build on this study?
CN: Of course, we'd like to have a better sense of what the future will bring. An immediate goal is to link these estimates with projected temperatures from different climate predictions to get an idea of the effect of increasing ambient temperatures on population-level well-being throughout the 21st century.
Furthermore, it would be interesting to combine our estimates with population forecasts, to also factor in the impact of population aging and faster population growth in the southern U.S. These demographic trends could exacerbate the adverse effects of heat exposure on well-being. Southern states such as Texas and Florida are growing much faster than northern states; and across the U.S. the population is growing older. Taken together this implies an increase in the proportion of Americans that will be exposed to high heat and also more vulnerable to heat exposure. Even if heat exposure remained at present levels (which it will not), our results suggest that these demographic trends would imply reduced well-being in the U.S. population overall. However, these demographic trends combined with increasing temperatures could result in potentially sizeable drops in emotional well-being, which to us is an important risk that requires further study.