Dr Satyawan Saurabh
In India, nine of the 10 warmest years have been recorded in the last 10 years, and all since 2005. Last year was the fifth warmest year on record. Induced stress due to heat waves increases respiratory and mortality rates, reduces fertility, modifies animal behavior, and suppresses the immune and endocrine systems, increasing susceptibility to certain diseases. Since 1992, there have been over 34,000 heatwave-related deaths in India. Heat waves also increase the likelihood of animals experiencing heat stress, especially when temperatures are high at night and animals are unable to cool down. Heat-stressed cattle may experience a decline in milk production, slower growth, and lower conception rates. Heat waves can exacerbate droughts and wildfires, which can hurt the agricultural sector. For example, in past years cattle herders had to sell their stock due to a shortage of fodder. This special report points to some startling facts revealed in some recent reports. It also talks about the steps taken by the government to reduce the ground suffering arising out of the stress of climate change/heat waves in India. Around the world, hot days are getting hotter and more frequent. Over the past decade, daily record high temperatures have been twice as high as record lows across the continental United States, up from a ratio of about 1:1 in the 1950s. Heat waves are becoming more common, and intense heat waves are more frequent in the US West, although some parts of the country still hold records for the number of heat waves dating back to the 1930s. In India, nine of the 10 warmest years have been recorded in the last 10 years, and all since 2005. Last year was the fifth warmest year on record. Induced stress due to heat waves increases respiratory and mortality rates, reduces fertility, modifies animal behavior, and suppresses the immune and endocrine systems, increasing susceptibility to certain diseases. Since 1992, there have been over 34,000 heatwave-related deaths in India. This special report points to some startling facts revealed in some recent reports. It also talks about the steps taken by the government to reduce the ground suffering arising out of the stress of climate change/heat waves in India.
If greenhouse gas emissions are not cut significantly, daily high and low temperatures will increase by at least 5°F in most regions by the middle of the century, rising to as much as 10°F by the end of the century. The National Climate Assessment predicts more than 90 degrees Fahrenheit in most areas by mid-century. Heat waves are more dangerous when combined with high humidity. The combination of temperature and humidity is measured by the heat index. A recent study projected that the annual number of days with a heat index above 100 °F will double, and days with a heat index above 105 °F will triple nationwide, compared to the end of the 20th century. Extreme heat is one of the leading causes of weather-related deaths, killing an average of more people per year in past decades than all other effects (except hurricanes) combined. It also lists heat waves as six of the top 10 deadliest US disasters since 1980. Extreme heat can increase the risk of other types of disasters. Heat can exacerbate drought, and hot, dry conditions can in turn create conditions for wildfires. Buildings, roads, and infrastructure absorb heat, which can cause temperatures to be 1 to 7 degrees F warmer in urban areas than outside-a phenomenon known as the urban heat island effect. This effect is most intense during the day, but at night the slow loss of heat from infrastructure (or an atmospheric heat island) can keep cities warmer than surrounding areas. Rising temperatures across the country pose a threat to people, ecosystems, and the economy. Heat stress occurs in humans when the body is unable to cool itself effectively. Normally, the body can cool itself through sweating, but when the humidity is high, the sweat will not evaporate quickly enough, potentially leading to heat stroke. High humidity and elevated nighttime temperatures are major factors in heat-related illness and mortality. When there is no break from the heat at night, it can cause discomfort and lead to health problems, especially for people who do not have access to cooling, which are often low-income people. Other groups that are particularly vulnerable to heat stress include older adults, infants and children, people with chronic health conditions, and outdoor workers.
Hotter days are also associated with an increase in heat-related illnesses, including cardiovascular and respiratory complications and kidney disease. Air quality is also affected by extreme temperatures. Hot and sunny days can increase the production of ground-level ozone, a harmful pollutant that is a main component of smog, which can damage the respiratory system and is particularly harmful to people with asthma. In addition, increased use of air conditioning requires more electricity, which, depending on the source of electricity, emits other types of pollution, including particulates that also affect air quality.
These increases in ozone and particulate matter can pose serious risks to people, especially the same vulnerable groups directly affected by the heat mentioned above. Higher temperatures can be harmful to agriculture. Plant growth is negatively affected by high daytime temperatures and some crops require cool nighttime temperatures. Heat waves also increase the likelihood of animals experiencing heat stress, especially when temperatures are high at night and animals are unable to cool down. Heat-stressed cattle may experience a decline in milk production, slower growth, and lower conception rates. Heat waves can exacerbate droughts and wildfires, which can harm the agricultural sector. For example, in past years cattle herders had to sell their stock due to a shortage of fodder. Warmer temperatures affect many aspects of the US energy system, including generation, transmission, and demand. While higher summer temperatures increase electricity demand for cooling, at the same time, they can reduce the capacity of transmission lines to carry electricity, potentially leading to power reliability issues such as rolling blackouts during heat waves may cause. Although warmer winters will reduce the need for heating, modeling shows that overall energy use will increase in a warmer future. In addition, as rivers and lakes warm, their ability to absorb waste heat from power plants decreases. This can reduce the thermal efficiency of power generation, making it difficult for power plants to comply with environmental regulations regarding the temperature of their cooling water, and may lead to plant shutdowns. Identifying vulnerable populations to build resilience to extreme heat and creating a heat preparedness plan for all residents, including opening cooling centers during periods of extreme heat and adopting workplace heat stress standards can installing cool and green roofs and cool pavements to reduce the urban heat island effect, planting trees to provide shade and cooling the air through transpiration, pursuing energy efficiency to reduce demand on the electricity grid, can be especially effective during heat waves.
(The author is a Poet,
freelance journalist and columnist).
