Cool ideas vital to coping with heat waves


Asit K. Biswas and Cecilia Tortajada

CHINA DAILY | June 14, 2023

Historically, the majority of the people in the world have lived in places where mean annual temperatures have been between 13 and 25 degrees Celsius. Outside this range, living conditions are either too hot or too cold. Such places also have lower agricultural yield, higher energy consumption, lower economic growth rates and higher health costs and death rates. In addition, higher temperatures beyond this range contribute to impaired learning, decreased cognitive performance, increased infectious diseases, lower labor productivity, adverse pregnancy outcomes and social conflicts.

Unfortunately, in recent years, global warming caused by increasing greenhouse gas emissions has been changing the climate, and the Earth is becoming progressively hotter, as cities and regions from Shanghai to Siberia witness record maximum temperatures.

The definition of heat wave

According to World Weather Attribution, an international coalition of leading climate scientists, heat waves that raged through certain parts of Asia early this year, especially in Bangladesh, India, Laos and Thailand, were likely due to human-induced climate change. Temperatures are at least 2 C higher than what they would have been without climate change.

During the past 50 years, temperatures have been rising by 0.2 C every decade, with an accelerated rate of increase since 2010 and the warmest decade on record thus far being 2010-2019. Worryingly, the period from 2015 to 2019 has been the warmest five years on record, with 2016 being the warmest year, followed by 2019. According to the World Meteorological Organization of the United Nations, globally March 2023 was the second-hottest month on record and April 2023 the fourth hottest.

The prognosis for the future is getting worse. On May 17, the WMO said there is a 66 percent probability that the world will cross the 1.5 C threshold set by the Paris Agreement for at least one year in the next five years. Only a year ago, this probability was estimated at 48 percent.

The WMO is now virtually certain (98 percent probability) the next five years will see the hottest year in history, and there is a 93 percent chance that average the five-year temperature of 2022-26 will be higher than in 2017-21. These facts show how the situation is becoming grimmer.

Definition varies from place to place

Surprisingly, even though heat waves have become a major global concern, the definition of heat wave differs from country to country. The definition depends on what temperature a country is used to. For example, in the United Kingdom, a heat wave is defined as temperature exceeding 25-28 C for three or more days at a stretch. And while the China Meteorological Administration declares a heat wave when the temperature is equal to or above 35 C for three days, India defines a heat wave as temperatures reaching 40 C or above for two days.

China is among the countries most affected by heat waves. The average daily maximum temperature in China was relatively stable from 1961 to 1980. But it has continued to rise from 1981, with heat waves occurring with greater frequency, lasting longer and becoming more widespread. Many places have experienced up to four heat waves lasting more than 30 days.

Last summer, China had the most extensive and long-lasting heat waves since records began. In some places, it stretched to more than 70 days, affecting more than 900 million people in at least 17 provinces and regions. The problem has worsened since 2022, which incidentally was also the second-driest summer on record.

Huge impacts of heat waves

Countries all over Asia, including China, have been suffering prolonged periods of soaring temperatures during the past 10 years during which nearly 40 percent of national heat records have been set. Assuming that heat waves are likely to occur regularly in the future, how can people and the economy adapt to the expected conditions?

Even before the summer officially started this year, many Asian countries, including China, have witnessed record temperatures.

Years ago, we had a discussion with Lee Kuan Yew, former prime minister of Singapore, under whose leadership, Singapore transformed from an agglomeration of a few fishing villages to a flourishing city-state. When asked how Singapore made this economic leap forward, he said that it was primarily air conditioning which made sustainable economic development possible in a tropical country such as Singapore.

The extensive use of air conditioning and fans is an important way to keep interiors cool in a warming world. Although households need an average income of $10,000 to afford air conditioning, due to incomes rise in many Asian developing countries, more and more households can afford air conditioners.

Thanks to China’s economic miracle, average household income also increased fast, with average urban resident’s annual disposable income exceeded 21,810 yuan in 2011. Coincidentally, this was around the time heat waves started becoming more intense and serious. Not surprisingly, Chinese households began installing air conditioners extensively since then. However, in larger Chinese cities, air conditioners have reached saturation and their growth has started to stagnate. This is indicated by the share prices of the largest Chinese air conditioner manufacturers, Midea and Gree. Their prices have dropped since their 2021 peak.

The importance of air conditioning in preventing heat strokes can be seen from recent statistics from Tokyo. Nearly 90 percent of those who died last summer had not used air conditioning. That’s why the Japanese government is planning to set up cooling shelters for the elderly and vulnerable populations so they can escape the scorching heat waves in the future.

China, too, should consider the extensive use of cooling shelters for people who cannot afford air conditioning. It also needs to formulate heat action plans across the country, including extensive heat advisory alerts. In fact, heat response plans are already being piloted in major cities such as Shenzhen, Chongqing, Nanjing and Harbin. Based on the results of these pilot exercises, the heat action plan can be further refined and then rolled out all over China.

However, the responses to climate change adoption are complex. Globally, air conditioners and fans account for nearly 10 percent of all electricity consumption. Their intensive use will, by default, increase global electricity use, which in turn will require additional electricity generation. And unless electricity is generated from renewable sources and air conditioners become increasingly efficient, there will be more carbon emissions, which will further aggravate global warming.

Urgent needs require immediate solutions

However, urgent risks to people’s lives and economic productivity need immediate solutions, even though this may aggravate underlying global warming problems. Fortunately, Chinese policymakers are aware of these challenges, both in the short and long terms. For example, in 2022, China invested $546 billion in the low-carbon power sector, including solar and wind energy, electric vehicles and batteries. This is nearly four times the United States’ $141 billion.

Also, China is expected to reach its 2030 wind and solar energy generation targets by 2025. From our analysis, China has formulated a clear and implementable pathway to clean energy transition over the next four decades.

The current trends indicate heat waves will further intensify as global warming accelerates. Thus, all Asian countries should formulate urgent plans on how people and overall economies can adapt to these intensive and progressively longer heat waves.

Asit K. Biswas is a distinguished visiting professor, University of Glasgow, UK, director of the Water Management International, Singapore, and chief executive of Third World Centre for Water Management, Mexico; and Cecilia Tortajada is a professor at the School of Interdisciplinary Studies, University of Glasgow, UK.

This article was published by CHINA DAILY, June 14, 2023.