Scientists have found that limiting global warming to the targets proposed in the Paris Agreement will keep tropical regions from rising temperatures beyond human limits. This is reported by the Healthday Reporter, citing a new study in the journal Nature Geoscience.
The researchers estimate that if countries limit warming to 1.5 ° C above pre-industrial levels, the tropics will not have temperatures above the “survival limit.” But life in the hottest latitudes of the world can become unbearable if these controls are not followed.
The study, published in Nature Geoscience, took into account the warmth and humidity of the tropics. The point is that the body not only reacts to temperature, it reacts to moisture. It cools the body mainly due to perspiration and evaporation of sweat from the skin. At a certain temperature and humidity, it becomes “thermodynamically difficult,” the scientists explain.
They believe that a wet bulb temperature (WBT) of 35 ° C is the upper limit for humans.
Wet bulb thermometer concept
Wet bulb temperature is the temperature read by a thermometer covered with a cloth soaked in water through which air passes. At 100% relative humidity, the wet bulb temperature is equal to the air temperature (dry bulb temperature); at a lower one, it is lower due to evaporative cooling.
Even those who are accustomed to heat cannot engage in normal outdoor activities below 32 ° C wet bulb. This is equivalent to a thermal index of 55 ° C. The theoretical limit for human survival for more than a few hours in the shade, even with unlimited water, is 35 ° C, which is theoretically equivalent to a thermal index of 70 ° C.
The body usually maintains a fairly stable internal temperature of 37 ° C. A person’s skin needs to be colder, otherwise the person’s internal temperature can rise rapidly. High temperatures are dangerous or even fatal.
Implications for the tropics
In a new study, scientists predicted how global warming will affect wet bulb temperatures in the tropics. This region includes the Amazon rainforest, much of Africa, the Indian subcontinent and parts of Southeast Asia. They found that limiting global warming to 1.5 ° C would prevent temperatures in the tropics from rising to unbearable levels.
Under the Paris Agreement, the international agreement on climate change, countries need to limit global warming to “well below” 2 ° C, or better 1.5 ° C, compared to pre-industrial levels.