When the temperatures rise, do you feel like your irritability does, too?

Well, you’re not alone. In fact, there's plenty of evidence showing that violent crime increases as the weather heats up, with the peak hitting in the summer. There are multiple explanations for this – as Whet Moser at Chicago Magazine reported, these include the fact that when it's warm, people spend more time outside and as a result, there is an increased chance of social interaction and thus, violent interactions, too.

Another explanation, however, is the strong tie between heat and anger.

Craig Anderson, a psychology professor at Iowa State University and the director of the Center for the Study of Violence, has done extensive research on the topic of heat and violence. He told ATTN: via email:

"Uncomfortably warm temperatures created negative mood states. Basically, people become more irritable when they are uncomfortably warm and cannot escape from it. This sometimes leads people to overreact to minor provocations, or to perceive an ambiguous provocation (such as being bumped in a bar) as being an intentional hostile act. In turn this can lead to anger and retaliation, which can then escalate into a violent event."

Even worse? The relationship between heat and violence has global effects.

In a 2011 study, Anderson and his colleague, Matt DeLisi, pointed out there are at least three ways that rapid global warming can increase the prevalence of violent behavior worldwide. Anderson detailed them to ATTN:

1. "One is the basic heat effect that I mentioned earlier, in which simply being uncomfortably warm tends to increase aggressive/violent behavior tendencies."
2. "A second is that rapid climate change (rapid in geologic terms) increases ecological disasters such as droughts and floods, which in turn de-stablize economic and social systems, often leading to eco-migration. For example, the current Syrian civil war was prompted in part (there are many other contributing factors) by an unprecedented drought that devastated agricultural production, which led to a large migration from agricultural regions to the cities as people searched for jobs, food, water, and housing, but the cities were unable to cope with this massive influx of eco-disaster refugees, which helped create conditions that were ripe for civil war."
3. "The third way also is related to the ecological disasters. Specifically, ecological disasters tend to increase many of the risk factors that are known to contribute to violence-prone adulthood. For example, poor pre-natal nutrition of pregnant women, poor and unstable food access during early childhood years, unstable families (e.g., fathers moving away to seek employment), all increase the likelihood that a child will grow up into a violence-prone adult. Some of these effects are because of damage to developing brain systems, others occur because of poor learning environments."

So, as the summers get longer and the days hotter, our increasingly hot planet affects more than just your mood – it can increase global violence.