Yes, according to a latest study:
Global warming doesn’t just hurt the planet’s health — it harms people’s too. An alarming new study from Stanford University brings one major human-afflicting consequence of climate change into focus by exploring the link between rising temperatures and suicide rates.
Researchers discovered a positive association between the two, and a shocking one at that. They predict something to the tune of 21,000 suicides in just the U.S. and Mexico by 2050.
The study, led by Stanford economist Marshall Burke, gathered a broad set of data, including historical temperature and suicide rate data across thousands of regions, along with half a billion tweets and Twitter updates, to help establish the correlation between hot weather and suicide rates. Suicide is now one of the world’s leading causes of death, making this research more timely than ever.
While previous research had established that warm weather was linked to a higher incidence of suicide, there was no consensus on whether balmy temperatures were the cause of the epidemic or merely correlated. Extra daylight hours or high unemployment rates, for example, could be the true culprit.
Hot weather, on its own, the researchers found, does increase both suicide rates and the use of depressive language on social media, which confirmed their hypothesis.
“Surprisingly, these effects differ very little based on how rich populations are or if they are used to warm weather,” says Burke, an assistant professor of Earth system science at the university.
This study might benefit from some unpacking by experts, of which I don’t claim to be one, but there are a number of questions and issues that spring to mind in relation to this apparent “positive association”:
1. Why exactly would increased temperatures lead to increased suicides? Says the study’s co-author Solomon Hsiang: “We’ve been studying the effects of warming on conflict and violence for years, finding that people fight more when it’s hot. Now we see that in addition to hurting others, some individuals hurt themselves. It appears that heat profoundly affects the human mind and how we decide to inflict harm.” Does heat make us more irritable and impulsive, and therefore prone to violence? If that’s the case, God help us about science resurrecting some old stereotypes about the cool head northerners and the hot head southerners.
2. Considering that accurate temperature records and suicide statistics are relatively recent historically speaking, can any reliable conclusions be drawn about any relationships between them? For example, the recorded suicide rates in the past are likely undercounts, considering the stigma that was attached to self-harm.
3. “The researchers came to their headline figure of 21,000 added suicides by combining their data with established climate model projections.” Considering that “established climate model projections” do not accord with the observed past temperature data and considering that none of the models have accurately predicted temperature over the past two decades, maybe Burke et al can’t really predict very much with any degree (no pun intended) of reliability?
4. If as Hsiang says, “heat profoundly affects the human mind and how we decide to inflict harm”, shouldn’t there be more consistency between suicide rates and average temperatures? The number one country for suicides at the moment is Sri Lanka at 34.3 suicides per 100,000 of population. Other countries in the top ten are Lithuania, Guyana, South Korea, Mongolia, Kazakhstan, Suriname, Belarus, Equatorial Guinea and Poland at 22.3 per 100K), representing just about every climatic zone. Furthermore, the temperature seems to affect neighbours quite differently – India’s rate, for example, is less then half that of Sri Lanka’s; Germany’s rate is almost 10 fewer per 100K than Poland’s. Six of the ten countries with the lowest suicide rates in the world are in the tropical Caribbean.
5. OK, you say, it’s not the heat itself (and besides, there are many other factors) but the change in the level of heat (i.e. changes in average temperature). The authors of the study, I assume and hope, have worked with much larger, global data sets, so any examples I might quote would appear quite anecdotal. Nevertheless. Take a look at our unfortunate number one, Sri Lanka, during the time frame when the temperature was increasing:
Or take this selection of developed countries, again in a similar time frame:
See any correlations with increasing temperature? Lastly, the United States itself: