I keep up with the news about the urgent need to tackle climate change. As a mathematician focused on this issue, I wasn’t surprised by what I read, though I am very concerned. Last Christmas, I photographed a cherry tree blossoming by the Charles River in Boston. As a scientist from Tufts University who examines seasonal trends, I saw this early blooming as yet another sign of rising temperatures linked to climate change. Personally, I found the sight’s colors amusing before moving on.The unusually warm summer in Boston set several records. I was fortunate enough to afford more air conditioning, spend time in Maine, and reschedule a work trip to South India from August to January, where I could operate at my best.
But what about those who lack these privileges? Last summer, I edited a paper discussing heat’s impact on health. Securing funding, finding students, collecting data, building, and testing the model took 15 years, all to defend that hypothesis “beyond reasonable doubt” before publishing. Our findings showed that during about 10 days of summer in Boston, when nighttime temperatures exceed 65.5 degrees Fahrenheit for three nights in a row, around 14 older adults were admitted to hospital due to heatstroke – an entirely preventable situation. Is this excessive or should it be anticipated? Over 15 years, these avoidable hospital visits cost over $5 million in medical bills in the Boston area, almost matching the state’s annual budget of $5.5 million for senior housing in 2015. However, the elderly are not the only ones at risk. So are you. A healthy adult can remarkably regulate their core temperature within a narrow range of 36.6 to 37.7 degrees Celsius (98°F to 100°F) despite significant temperature variations outside.
Core temperature is managed through intricate physiological feedback mechanisms and a precise balance between heat production, conservation, and dissipation depending on the environment. When the body fails to release sufficient heat, heatstroke or a rise in core temperature beyond healthy levels occurs. If core temperature hits 40.5°C (105°F) because the body’s temperature control system fails, it can cause serious health issues, like central nervous system problems and cardiovascular and respiratory system failures, leading to serious health outcomes and even death. During heatwaves, older adults suffer more due to weakening physiological mechanisms to regulate temperature, medication side effects, and limited mobility. Moreover, a high sweating threshold combined with thicker blood, higher cholesterol, and a reduced ability to sense body temperature changes may worsen severe heat-related health issues. Heatwaves endanger vulnerable groups, especially those less adept at coping with extreme temperatures, such as people with conditions like asthma, diabetes, or those needing ongoing support like dialysis or oxygen. Heatstroke rates are 12 to 23 times higher for those aged 65 and above than other age groups, reflecting their greater vulnerability to climate challenges.
The problem with extremely hot days is that a temperature rise from 100°F to 101°F has a more severe impact than a 90°F to 91°F rise. While people in hotter southern areas are more acclimated to high temperatures, poverty, inadequate infrastructure, and limited healthcare access can negate these regional adaptations. Short heatwaves end with cooling nights, bringing needed relief. However, long heatwaves build up their effects and begin to impact even healthy individuals who can usually endure brief heat spells. Long heatwaves particularly jeopardize those most exposed to the elements, such as construction workers or farmers. About 600 annual deaths are officially linked to extreme heat, but this number might not account for all heat-related deaths. For instance, the hundreds of deaths during Chicago’s 1995 heat wave may not be listed as such on death certificates. Other causes, like heart failure, may be recorded, even if heat contributed to them. A study in Europe proposed that dry soil leading to high surface temperatures might result in unusually high night temperatures, a hallmark of extreme heatwaves. Average temperatures have already increased by nearly 1°C above pre-industrial levels, and the latest IPCC report suggests limiting temperature rise to 1.5°C is unlikely. How does a 1.5°C global temperature increase affect me personally? It’s not like baking a cake at 350°F, then at 351.5°F, and wondering about the outcome.
Nor is it like a child’s fever rising from 102°F to 103.5°F, prompting immediate action. It’s understanding that in our interconnected world, seemingly “small” changes have significant impacts, even if they’re not immediately visible. Seasonal patterns are shifting, and a heatwave arriving too early or late can catch us off guard, leaving us scrambling for responses. These global challenges require us to have a broader perspective. I wonder how Galileo and Copernicus would react if asked how it feels to consider the sun, rather than Earth, as the universe’s center. Perhaps they would trust scientists, recognizing that regardless of perception, Earth orbits the sun. As an educator, I question what our education missed that created a risky mix of ignorance and hubris, endangering a future we daily influence. To assess a heatwave’s impact accurately and on time, I think we need a national monitoring system. This system should integrate existing features from national and global surveillance for the flu or other reportable diseases, including standardized reporting, a network of trustworthy regional units, and routine reporting and analysis.