In Northern India, the temperatures reached 45 degrees Celsius (about 117 F). The surge in electrical usage overloaded the system, and power was not supplied to millions of people. The results were sadly predictable: people rioted.
Thousands of people stormed an electricity substation on Friday near the state capital of Lucknow, ransacking offices and taking several workers hostage. The ordeal ended after 18 hours when police intervened.This may seem like an isolated incident in a country far, far away. But it's not. Heat waves around the world have been increasing in frequency and duration. In Australia, for example ...
In Gonda, 180km to the southeast of Lucknow, an angry mob set fire to an electricity substation, which took firefighters three hours to extinguish.
A fire was also started in Gorakhpur, 320km southeast of Lucknow.
Uttar Pradesh Chief Minister Akilesh Yadav said officials were trying to purchase power from other states, though they were also facing shortages amid the extreme heat.
Residents had been particularly angry about the power cuts after receiving reliable supplies through the Indian elections, which ended May 16. Since then, only some regions have been guaranteed unbroken power supplies, while others have received little to none.
Heatwaves in Australia are becoming more frequent, hotter and are lasting longer because of climate change, a report released today by the Climate Council says. [...]
The report says heat records are now happening three times more often than cold records, and that the number of hot days across Australia has "more than doubled".
It says the duration and frequency of heatwaves increased between 1971 and 2008, and the hottest days have become hotter.
Well, that's Australia, some might say. What do you expect? Unfortunately, the increase in frequency of heat waves is not limited to our smallest continent, or to the Indian subcontinent. Heat waves have increased all around the world including in our own backyard of North America.
Since 1950 the number of heat waves worldwide has increased, and heat waves have become longer.  The hottest days and nights have become hotter and more frequent.   In the past several years, the global area hit by extremely unusual hot summertime temperatures has increased 50-fold.  Over the contiguous United States, new record high temperatures over the past decade have consistently outnumbered new record lows by a ratio of 2:1.  In 2012, the ratio for the year through June 18 stands at nearly 10:1.  ...Here's a pie chart from the report "Heat Waves and Climate Change" produced for Climate Communication by Kevin Trenberth, National Center for Atmospheric Research, Jerry Meehl, National Center for Atmospheric Research, Jeff Masters, Weather Underground and Richard Somerville, Scripps Institution of Oceanography, University of California, San Diego, showing the changes over the decades in US heat records:
In the past 3-4 decades, there has been an increasing trend in high-humidity heat waves, which are characterized by the persistence of extremely high night-time temperature.  The combination of high humidity and high night-time temperature
can make for a deadly pairing ... Extreme heat events are responsible for more deaths annually than hurricanes, lightning, tornadoes, floods, and earthquakes combined. 
Sixty years ago in the continental United States, the number of new record high temperatures recorded around the country each year was roughly equal to the number of new record lows. Over the past decade, however, the number of new record highs recorded each year has been twice the number of new record lows, a signature of a warming climate, and a clear example of its impact on extreme weather. 
limate change is set to trigger more frequent and severe heat waves in the next 30 years regardless of the amount of carbon dioxide (CO2) we emit into the atmosphere, a new study has shown.Predictions beyond 2040, however, are less predictable since they are dependent on the amount of emissions we pump into the earth's atmosphere. However, under a worst case high emission scenario, by 2100 extreme heat waves will cover 85% of the global land area, with the worst heat waves, those designated 5 sigma events, predicted to cover 60% of the earths land surface. Under such conditions, the survivability of the human race will be at risk.
Extreme heat waves such as those that hit the US in 2012 and Australia in 2009 -- dubbed three-sigma events by the researchers -- are projected to cover double the amount of global land by 2020 and quadruple by 2040.
Meanwhile, more-severe summer heat waves -- classified as five-sigma events -- will go from being essentially absent in the present day to covering around three per cent of the global land surface by 2040.
However, if we can lower emissions, there is much than can be done to mitigate the worst case outcome. To prevent that, however we need to start now. The Obama administration's recent targets to reduce emissions are a good start but that is all they are.