As the UN tells the world the planet has entered a new era of "global boiling", what does the term mean and how will it affect life in the near future?
July 6 is reported to have been the hottest day on Earth since mean global temperatures were first calculated in 1979, reaching an average temperature of 17.18ºC, data from the US Centres for Environmental Prediction indicates.
While that number is well below the scientific boiling point of 100ºC that turns water from liquid into gas, "global boiling" is a term recently used to underline the severity of climate change.
Record-breaking temperature
According to the Climate Change Institute, the average global air temperature has risen from 16.25ºC on July 25 from 1979 to 2000, to 17.14ºC on July 25 this year.
July is on course to become the hottest month since records began.
The global average has been calculated using data gleaned from about 20,000 weather stations, ocean vessels, buoys and satellites for the past 44 years.
Records of the planet’s surface temperature date back to the mid-ninth century, when measurements of near-surface air temperatures from weather stations were combined with data recorded from the ocean surface by ships and buoys.
To evaluate temperatures before then, scientists relied on proxy data recorded through evidence left behind in ice cores and tree rings of ancient forests.
Global temperatures are evaluated each year by scientists who examine data sets from four main outlets.
They are the UK Met Office Hadley Centre and the University of East Anglia’s Climatic Research Unit, the Nasa Goddard Institute for Space Sciences and the National Oceanic and Atmospheric Administration, as well as the Japan Meteorological Agency.
Dangerous combination
This current era of global boiling, which the UN now says is upon us, is largely a result of a dangerous combination of climate change, the return of the El Nino weather pattern and the onset of summer in the Northern Hemisphere.
El Nino is associated with above average temperatures and is half of a weather cycle that alternates every three to seven years called La Nina.
Pacific trade winds fluctuate, changing the course of warm water from the ocean, bringing more extreme weather in winter and summer.
Extreme weather
This year it has led to record air temperatures across Southern Europe and wildfires in tinder-dry woodlands in Greece, Spain, Portugal and Croatia – as well as parts of North Africa – although some fires are suspected to have been arson-related.
Millions of people have been also affected across Asia, the US and Canada by above average temperatures.
The concept of global boiling reflects a transition from global warming, towards a more intense period of heatwaves, climate-related disasters and extreme weather patterns.
Wildfires cause chaos in Greece
