Global boiling: What is it and should we be worried?

UN sounds warning by highlighting new era of climate change

A forest fire burns near Vati village, on the island of Rhodes. AP

Firefighters watch as a forest fire reignites in Spain's Caldera de Taburiente national park. EPA

A man lifts a tile from underneath the frame of a burnt bed after a forest fire raced through the Tunisian town of Melloula. AFP

A firefighter tries to extinguish a blaze near the village of Asklipieio, on the Greek island of Rhodes. Reuters

A plane dumps water over a wildfire on Ciovo island, Croatia. AP

Residents of Gennadi village stand near a forest fire raging on the island of Rhodes. AP

People are evacuated by boat as they flee a fire burning near the Greek town of Nea Anchialos. EPA

A petrol station destroyed by a forest fire in the Italian town of Oliveri. AFP

A man watches as a house burns in the Tono district of Messina, Sicily. AFP

The fire destroyed homes and cars in Oliveri. AFP

A firefighter is overwhelmed as he looks at the trail of destruction in Messina, Sicily. AFP

A fire burns a forested area of Alto do Alvide, Portugal. EPA

A forest fire burns in Valsequillo, Spain. EPA

Calves try to escape the fire in Sesklo village, Greece. EPA

Farmers try to save their animals as the fire approaches Sesklo village. EPA

A firefighter tackles a blaze outside the village of Vati, Greece. Getty

A woman salvages produce from a building gutted by a forest fire near the town of Melloula, Tunisia. AFP

Residents block a street as they demand the restoration water supplies in Melloula, following recent heatwaves and a forest fire in the area. AFP

Algerians gather next to vehicles destroyed by wildfires in Bouira, 100km from the capital, Algiers. AP

A fire engine moves along a road as a forest fire rages near the Tunisian town of Melloula, close to the border with Algeria. AFP

A man and his children inspect the damage to their house after a fire raced through the Algerian village of De Oeud Das. EPA

Houses damaged by the forest fires in De Oeud Das village. EPA

Residents try to extinguish a fire in Tunisia's coastal town of Tabarka amid a blistering heatwave. AFP

A fireman holds a cat and two rabbits after rescuing them from a fire on the Greek island of Rhodes. AFP

German tourists and local residents try to extinguish a fire near the seaside resort of Lindos. AP

Smoke rises on Corfu following a wildfire. Reuters

Tourists wait for departing planes at the airport on the island of Rhodes, after being evacuated. Reuters

A large forest fire on the Greek island of Rhodes has forced authorities to order an evacuation of four locations. AP

A man carries a child as they leave an area where a forest fire burns. AP

A fire engine is parked in front of a blaze raging in New Peramos, near Athens. AFP

A helicopter works to extinguish a wildfire, in the area of Pico de las Nieves, on the Canary Island of Gran Canaria, Spain. Reuters

A firefighters' operations room in Marseille, France. AFP

Smoke billows from a house on fire in the Aci Catena area, 20km from Catania. Getty

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.