I just read an article in the Seattle Times (reprinted from the NYT) about how climate change is already causing serious (as in life threatening) health issues in cities across India. Key quote:
An analysis of South Asia’s biggest cities found that if current warming trends continued, wet bulb temperatures — a measure of heat and humidity indicating when the body can no longer cool itself — will become so high people directly exposed for six hours or more would die.
The title (taken from the article) is a bit of an understatement — sounds like the heat is already health and life threatening to anyone who has to work outside of air conditioned buildings during the hot season. Worldwide, close to 100 of the most populous cities are expected to reach temperatures of at least 95 degrees (F) by 2050. Twenty-four of those cities are in India (and many of them are already way over that (Ahmedabad in western India hit 118 degrees (F) in May 2010 and has since gotten hotter, Delhi was at 111 degrees heat index recently). The heat index has been rising steadily since 1951. Differing rates and some timing differences in different cities in India — but steadily up.
Note — “wet bulb temperature” is a measurement taken with a thermometer whose bulb has been wrapped in a wet cloth. From an earlier NYT article:
A person who is physically active at a wet-bulb temperature of 80 degrees will have trouble maintaining a constant core temperature and risks overheating. A sedentary person who is naked and in the shade will run into the same problem at a wet-bulb temperature of 92 degrees. A wet-bulb temperature of 95 degrees is lethal after about six hours.