According to a new study, even while greenhouse gas emissions are being reduced, individuals in the tropics, such as those in India and the Sahel region of Africa, would likely experience dangerously high temperatures practically every day by the end of the century as a result of rising global temperatures.
Risks will rise in the mid-latitudes, including the United States. It is anticipated that by the 2050s, the number of dangerously hot days—days with temperatures and humidity levels high enough to result in heat exhaustion—will have doubled.
In order to predict how heat index levels, which combine heat and humidity, will evolve over time, scientists looked at population growth, economic development patterns, energy usage, and climate models. We asked David Battisti, an atmospheric scientist at the University of Washington and a co-author of the study, to explain the results and what they signify for people all over the world.
Regarding the temperature in the future, there are two possible causes of uncertainty. One is the amount of carbon dioxide that people will emit; this is dependent on factors including population, energy usage, and economic expansion. The second is the amount of warmth those greenhouse gas emissions will bring about.
Scientists’ perceptions of the likelihood of various eventualities are very accurate in both cases. In order to determine the likelihood of harmful and life-threatening temperatures in the future for this study, we integrated those projections.
We examined the effects of these “very dangerous” and “dangerously high” heat index levels on day-to-day life in both the tropics and mid-latitudes.
In this context, “dangerous” alludes to the potential for heat exhaustion. If you can stop and slow down, heat exhaustion won’t kill you. It’s characterized by lethargy, nausea, a slowing heartbeat, and possibly fainting. But these circumstances make it impossible for you to work.
When a person is likely to cross that threshold is indicated by the heat index. 103 F (39.4 C) is the National Weather Service’s definition of “hazardous,” and 125 F is the definition of “very dangerous” (51.7 C). Heat stroke can occur if a person is exposed to “very unsafe” temperatures. You have a few hours to seek medical care to cool your body down at that point, or you will perish.
Even with low greenhouse gas emissions that would fulfill the Paris Climate Agreement objective of keeping warming under 2 C, the most likely future scenario predicts that by 2050, the number of deadly heat days in the mid-latitudes will have doubled (3.6 F).
The most likely scenario in the Southeastern United States is that people will endure one or two months of extremely severe heat per year. The same is probably true in some areas of China, where some sections have endured a heat wave in the summer of 2022 for more than two months straight.
We discovered that the majority of mid-latitude locations will experience a three- to tenfold rise in the frequency of hazardous days by the end of the century.
The heat index right now can go over the hazardous level for a few weeks each year in the tropics, including some areas of India. For the previous 20 to 30 years, things have been that way. We discovered that by 2050, those conditions are probably going to last for many months every year. And many areas will experience those circumstances for the majority of the year by the turn of the century.
In real life, this means that if you live in a wealthy nation like the U.S., most individuals can purchase or find air conditioning. However, the heat is a more significant issue for a significant portion of the year if you live in the tropics, where poverty is higher and about half of the world’s population resides. And a significant portion of the population there is employed in agriculture.
In certain locations, mostly in the tropics, we’ll start going beyond “very dangerous” conditions as the century comes to a close.
Over a month could be spent each year in severely risky conditions in northern India. There may be a few weeks every year of extremely severe weather in the Sahel region of Africa.
If you live in a wealthy nation, you can construct air-conditioning facilities and produce electricity to power them. Ideally, these facilities won’t use fossil fuels, which would further warm the world.
In developing nations, a sizable portion of the population engages in outdoor agricultural labour to generate income for food purchases. There aren’t many possibilities there, if you give it any thought.
Conditions for migrant laborers in the US are likewise more challenging. A farm might be able to offer cooling facilities, but since farmers’ margins are so slim and migrant workers are frequently paid by volume, they aren’t compensated when they aren’t picking.
Conditions will eventually deteriorate to the point that more employees start to overheat and pass away.
Crops will also experience problems from the heat. Due to heat stress, the majority of the major grains should produce less in the future. We are currently seeing temperatures that are nearly ideal for grain growth in the mid-latitudes. But crop yield decreases as temperatures rise. That might be anything from a 10% to 15% decrease per degree Celsius increase in the tropics. That was a huge hit.
Finding the likelihood that the globe will truly adhere to the Paris agreement was one of the tasks we had for this study. This was estimated to be at 0.1%. In essence, it won’t take place.
We discovered that the most probable scenario is that the globe will warm by 5.4 F (3 C) globally compared to pre-industrial times by the end of the century. This amounts to around a 7 F (3.9 C) increase for regions where we live, work, and play – and you can get a sense of the future. Land warms quicker than ocean, so that.
The greater the chances of avoiding it are, the quicker fossil fuel consumption is phased out and renewable energy is brought online.