Although the large majority of climate scientists hold firmly to the belief that the climate is heating up at an unsustainable rate, an undetermined segment of the population is convinced that global warming worries are overblown\u2014a belief that runs counter to demonstrable scientific evidence, as well as everyday observation.<\/p>\n
In 1988, experts testified before Congress in the first congressional hearing about climate change<\/a>. Every year in the 21st century has been hotter than 1988, with each decade hotter than the previous. The last three years, from 2023 to 2025, were the hottest in recorded history, dating<\/a> from 1850, when sufficient direct measurements by instruments (thermometers) allowed an estimate of temperature. The last 11 years have included all of the warmest years observed using instrumental methods.<\/p>\n But one does not have to look at extreme temperature elevations to encounter convincing evidence that even less extreme examples affect the smooth operation of the human brain. If we stick to temperatures we\u2019ve already experienced, especially in 2023, 2024, and 2025, there is more than enough to worry about.<\/p>\n The Effect of Heat on the Brain<\/p>\n In general, even moderate heat elevation adversely affects the brain\u2019s reasoning power and thought patterns. As the temperature and duration of the heat wave increase, the brain\u2019s neurotransmitters suffer disruptions in their messaging of the signal from one neuron<\/a> to the next. In reaction, the receiving neurons may fire too rapidly, too slowly, slightly erratically\u2014it doesn\u2019t matter which; the results are disruptive effects on mood, memory<\/a>, thinking, and sleep. Added to that is the loss of electrolytes due to sweating\u2014leading to weakness, muscle cramps, and in some cases seizures. Additional heat exposure affects perception and behavior, especially clear thinking, sustained attention, memory, and rapid decision-making<\/a>.<\/p>\n Perhaps most striking of all are the subjective mental experiences. Think back to the last time you were ensnared in a \u201cheat wave,\u201d even one of moderate intensity by today\u2019s standards (90-100 degrees Fahrenheit). You were undoubtedly totally preoccupied with your discomfort; you could hardly think of anything else. In response to your heat-induced lethargy and restlessness, your concentration<\/a> was almost nil, and you couldn\u2019t \u201cthink straight\u2014a colloquial phrase for loss of clarity and precision.<\/p>\n Under such conditions, productivity<\/a> plummeted as you became preoccupied with thoughts of somehow shifting to an air-conditioned environment. If the humidity was also elevated (responsible for the \u201cfeels-like\u201d description on the weather reports), the effect on cognition<\/a> was even greater.<\/p>\n If the temperature reaches triple digits, a person may experience some of the early symptoms of \u201cheat stroke.\u201d But let\u2019s not go there. Let\u2019s stick to problems we can expect from temperatures that the majority of us have already encountered and will surely encounter again.<\/p>\n Heat and Frontal Lobe Changes<\/p>\n A sizable portion of heat-induced brain changes result from heat\u2019s effect on the frontal lobes, located at the farthest front of the brain. The frontal lobes are responsible for, among other things:<\/p>\n Sequencing (keeping bits of information in order). Disorders of the frontal lobes lead to planning difficulties, poor decision-making, difficulty changing one\u2019s mind, distractibility, and impulsivity.<\/p>\n Examples of the consequences of heat-induced frontal lobe failures of thought and judgment include near mishaps, such as turning one\u2019s car precipitously in front of an oncoming driver in a \u201cfailure to yield\u201d infraction that can result in an accident. Under cooler conditions, the driver would have stopped and made the turn only after the other car passed by.<\/p>\n Whatever the specific examples, the operating principle remains the same: The quality of our thinking is perpetually at the mercy of temperature. Test-taking provides a proxy for the effects of heat on cognitive function. Scores on cognitive tests plummet in tandem with temperature increases: A 4-degree increase\u2014experienced by the test-taker as only mildly uncomfortable\u2014leads to a 10% decrease in performance on tests of memory, reaction time, and judgment. Other research found a .3% drop for every 1 degree increase in temperature above 72 degrees. Overall, the hotter the average daily temperature during a typical school year, the worse students perform on standardized tests.<\/p>\n Cognition Essential Reads<\/p>\n But it\u2019s not only the quality of our thinking that is affected, but our ability to control our tempers as well. Decades of research have established that as temperatures rise, so too do riots, domestic violence<\/a>, and aggravated assaults.<\/p>\n
\nExecutive control (planning combined with anticipation of the consequences of our behavior).
\nSelf-analysis (the ability to imaginatively project ourselves into the future, dating from our current actions in the present moment).<\/p>\n