By Patti Wood
This has been a summer of unprecedented and extreme climate events around the world. Living here on Long Island, we have not suffered from devastating floods, fires or droughts, but even so, our rain events have been unusual and we’re only a few months into this year’s hurricane season.
Most people living in areas where these extreme events occurred had plans in place like moving to higher ground, evacuating to safer locations, avoiding breathing smoke by staying indoors and complying with emergency water use regulations. But what do we do when the risks are invisible and hard to accurately predict?
Some of us are very aware of the invisible threats to our health from environmental and climate-driven events. Asthmatics and people with other respiratory illnesses keep careful track of ground-level ozone readings. Ground-level ozone is created when chemicals from vehicles, power plants and factories mix with sunlight. Always worse on hot days, it can be seen from a distance as the yellow-brownish haze hanging over cities and areas with heavy industry or traffic. Asthmatics can suffer a worsening of their condition or even require hospitalization when ground-level ozone reaches dangerous levels. Climate change-driven heat and wind pattern changes will affect air-pollutant levels and ground-level ozone.
Particulate matter – microscopic particles made up of dirt, dust, smoke, soot, metals, chemicals and liquid droplets – can also cause breathing problems. The smaller they are, the deeper they can get into your lungs, affecting both the lungs and heart. These finer particles (2.5 micrometers in diameter and smaller), are emitted from forests fires and other polluting gases from the sources mentioned above.
High heat and humidity, not unusual for Long Island summers, has seemed a little more oppressive this year, and scientists around the world are raising the red flag on this combination of climate conditions called “wet-bulb temperature.” It is, literally, the reading from a thermometer when the bulb is covered in a wet cloth. By wrapping a piece of wet cloth around the end of the thermometer you can see how much evaporation can decrease the temperature.
When the wet-bulb temperature reaches 95° F, human’s survivability limit, evaporation of sweat can no longer cool our bodies down to regulate our internal temperature. According to Colin Raymond, a postdoctoral scientist at NASA’s Jet Propulsion Laboratory, “When wet-bulb temperatures are extremely high, there is so much moisture in the air that sweating becomes ineffective at removing the body’s excess heat. At some point, perhaps after six or more hours, this will lead to organ failure and death in the absence of access to artificial cooling.”
A study published in Science Advances last year found that some places on Earth are already experiencing heat and humidity conditions that humans cannot withstand, even people who are in excellent heath, despite adequate shade and water, relaxing and wearing appropriate light clothing. Those with pre-existing conditions, including heart and lung disease, the elderly and those performing strenuous exercise or engaging in physical labor outdoors would be at extremely high risk, even at lower wet-bulb temperatures in the 70s and 80s. Wet-bulb temperature was even mentioned as a possible risk factor during the Olympic marathon events. That was a first!
Today, around 30 percent of the world’s population is exposed to these serious temperature and humidity conditions for at least 20 days each year. It is predicted that will increase to nearly half by 2100, even with drastic reductions in greenhouse-gas emissions.
Air conditioning is critical when wet-bulb temperatures get high, and even energy companies are talking about the potential higher demands on their electric grids. Power outages during these crisis events could be a matter of life and death. The 2003 European heat wave caused over 50,000 deaths at wet-bulb temperatures near 79° F. In Chicago’s 1995 heat wave that reached a wet-bulb temperature of 85° F, 700 people died, even though air conditioning was more accessible.
Wet-bulb temperatures will soon be part of our weather forecasts and none too soon, according to experts. Just as temperatures around the globe are increasing, so is the amount of moisture in the air.
“I believe that humid heat is the most underestimated direct, local risk of climate change,” said Radley Horton, a Columbia University professor and team leader of NOAA’s Regional Integrated Sciences and Assessments program. “As with sea level rise and coastal flooding, we are already locked into large increases in the frequency and intensity of extreme humid heat events, and the risk is much larger than most people appreciate.”
Educating the public about these real threats of climate change will hopefully encourage more efforts to end our use of fossil fuels and engage in cooperative global efforts to restore our planet for our children.
