In recent years, increasing evidence has shown that the world is warming. Scientists' research tells us that the cause of global warming in recent decades is most likely to be a large number of greenhouse gases released as a result of industrial production and everyday life habits.
Due to the huge environmental disasters it can cause on a world scale, global warming has also attracted the attention of governments, media and people in various countries. In order to avoid irreversible environmental disasters due to global warming caused by human activities, governments have convened multiple international conferences under the United Nations Framework Convention on Climate Change.
For the man in the street, global warming seems to be just an abstract concept, something far removed from him. In his view, how to deal with global warming falls within governments’ responsibility and he has nothing to do with it. Global warming, however, is something that is really happening and will affect everyone’s life on the planet.
Food, clothing, housing and transport can be affected directly or indirectly by global warming. As members of the global village, we ordinary people should also understand some basic concepts about global warming and actively respond on our own initiative.
According to the World Meteorological Organization, the global average temperature from 2016 to 2020 was the warmest one ever recorded - approximately 1.1°C higher than in the period from 1850 to 1900 (the base period for temperature changes relative to the industrial revolution), and higher than in the 2011- 2015 period. The National Aeronautics and Space Administration (NASA) predicts that by 2100 the global temperature will increase by about 1.4-5.8°C and the global climate will undergo huge changes never seen in the last 10,000 years.
Climate change is closely related to human society as the frequency, intensity and duration of extreme weather events such as floods, droughts, hurricanes and heat waves increase. The Global Risk Report 2020 issued by the World Economic Forum underlined that environmental issues such as extreme weather events, failure to respond to related problems, and natural disasters are considered high-risk events with high probability of occurrence and greater impact.
With a view to actively responding to the climate crisis and achieving sustainable development, and to helping people fully understand the socio-economic impact of future temperature increases, scientists are carrying out a great deal of research. This theoretical and empirical evidence is of great importance for the implementation of adaptive strategies to allocate resources to ensure public safety from natural disasters.
The normal metabolism of the human body requires a constant body temperature between 36~37°C. When the human body is exposed to a high temperature environment for a long time, the metabolic function of the body decreases: the blood supply to the central nervous system decreases as the blood vessels in the skin expand; the actual volume of fluid circulating in the blood vessels becomes thinner as water loss increases, and the internal body temperature gradually rises.
When the temperature of the human body exceeds 39°C, it is not only a sign of some ongoing disease, but this temperature can cause heat-related illnesses such as exhaustion, heat cramps and heatstroke. With water loss, the body's water and electrolytes can become unbalanced; blood viscosity and cholesterol levels increase; blood vessels dilate; blood circulation accelerates; the heart and lung systems overload, which in turn causes cardiovascular events (such as heart attack and stroke), thus increasing the likelihood of death.
It is worth noting that there are also significant differences in the impact of heat-related illnesses on different groups of people. The elderly, children and outdoor workers are more vulnerable to heat-related illnesses and accidental injuries than the rest of the population.
On days with high temperatures, older people with reduced physical function and poor health or chronic diseases are more likely to suffer. For the impact of heat-related illnesses such as stroke, kidney and respiratory diseases, the risk of death is 10.4% higher than on days with a temperate climate. Considering the accelerating ageing of population, the health risks caused by climate change in the future could be more severe in a geometric-sequential form.
Increased exposure to heat caused by climate change can also damage the health of unborn children. On the one hand, heat can directly lead to faster delivery, shorter pregnancies and lower birth weight.
A paper published in 2020 by Alan Barreca and Jessamyn Schaller in Nature Climate Change examined over 56 million births in various counties in the USA between 1969 and 1988. The results of the study showed that on days when the maximum temperature exceeded 32.2°C, the birth rate increased by 5%, the number of pregnancy days decreased by an average of 6.1 days and some births occurred as much as two weeks earlier.
A paper published in 2009 by Oliver Deschenes, Michael Greenstone and Jonathan Guryan in the American Economic Review found that the warm weather experienced during pregnancy (especially in the second and third quarter) had a worrying negative impact on the baby's birth weight. The authors predicted that, by the end of the 21st century, the average birth weight of white babies would decrease by 0.22% (7.5 grams) and the average birth weight of black babies would decrease by 0.36% (11.5 grams).
On the other hand, high temperatures will affect the yield potential of major crops, threaten food security and increase food prices, thus indirectly affecting health issues such as nutrition (also considering the obvious decrease in available water on the planet), immunity, and the birth of infants and the growth of young children.
Health is one of the important elements of human capital. Many research findings confirm that exposure to high temperatures during the foetal period has a significant negative impact on an individual's cognitive abilities and long-term human capital accumulation. In 2019 the Journal of Environmental Economics and Management edited a paper by Ram Fishman, Paul Carrillo and Jason Russ in 2019, based on a group of employees in an Ecuadorian education department born between 1950 and 1980. The temperature has a negative impact on the level of education and income in adulthood: for every 1°C increase in the average monthly temperature during pregnancy, the probability that a person receives secondary education will decrease by 0.2% and the level after adulthood will decrease by 0.7%, with women being the most affected (0.86% compared to 0.59% for men).
Finally, high temperature will also have a great impact on workers' productivity. When the human body is exposed to a high-temperature environment, the increase in internal body temperature will stimulate the nerve center, leading to self-protective fatigue, decreased strength and muscle endurance, thus reducing productive efficiency.
A paper published in 2018 by Peng Zhang, Olivier Deschenes, Kyle Meng, Junjie Zhang in the Journal of Environmental Economics and Management used the detailed production data of 500,000 workers from 1998 to 2007 and adopted the fixed-effect model of data to study the effect of temperature on the total factor of firm-level productivity (TFP) and the influence of input and output factor. It is demonstrated that the productive efficiency of both labor-intensive and capital-intensive firms shows sensitivity to high temperatures: compared to a standard of 10-15.6 °C, when the maximum daytime temperature exceeds 32.2°C, TFP will be reduced by 0.56%.
Professor Valori is President of the International World Group