That the two hottest Junes have been the last two is not a coincidence or a statistical fluke. It simply reflects what is happening to the planet: it is overheating because of greenhouse gases emitted by humans, primarily from the use of fossil fuels (oil, gas and coal). Climate change has ushered Earth into an era of fleeting records and a stringing together of historic highs. For example, the last 11 years have been the warmest on average for the planet as a whole.