2015: Picture of Mass Funeral in Pakistan caused by Heat Wave last June:1200 dead then; 2500 dead from heat in May in India

Experts have been estimating for months that last year would prove to be the world's hottest in over a century. After a NASA report found that this past October was the first month to surpass the 20th century's average temperature by more than 1 degree Celsius, Gavin Schmidt, director of the agency's Goddard Institute for Space Studies, tweeted there was now a 99.9 percent chance that 2015 would be crowned the hottest year on record.

Shakil Adil/Associated Press

People attend a mass funeral in Karachi, Pakistan, for many who died during June's heat wave.

The severe heat was palpable around the planet. In May, 120-degree days in India melted New Delhi's asphalt and killed around 2,500 people, making it the fifth-deadliest heat wave on record. The next month, temperatures as high as 113 degrees killed at least 1,200 people in Pakistan and sent more than 65,000 heatstroke patients to hospitals.
The heat also broke records across Europe in June and July, when triple-digit temperatures settled on Spain, Portugal, France, the United Kingdom, Germany and Poland.