2015 was the hottest year ever recorded, beating 2014 – the previous hottest year – by a wider margin than ever before.

Fifteen of the last 16 hottest years have occurred this century. This animation, created using data from the National Oceanic and Atmospheric Administration (NOAA), shows the long-term warming trend of the planet.

Over 136 years, scientists have been measuring the Earth’s temperature every month, both on land and at sea.

Records began in 1880 and several agencies keep track of the global temperature, including the UK Met Office, NASA and NOAA.

Every year since 1977 has recorded an annual temperature above the 20th Century average. And in increasingly large increments. 2015 outdid the previous year by 0.90, the largest rise ever recorded.

 2015: The Hottest Year
Image: Bloomberg

If the trend for 2016 continues, this will become the latest hottest year on record.

Global warming

Global warming is producing record-breaking temperatures. Globally, 90% of the excess heat caused by the rise in greenhouse gas emissions is absorbed by the oceans. The warming of the oceans creates weather patterns that can cause havoc on land.

Some parts of the world experience heatwaves and droughts, others suffer record rainfall leading to floods. Meanwhile, the Earth’s coldest regions are warming up even faster.

A NOAA report on the state of the Arctic showed the region experienced record air temperatures, and its peak ice cover reached new lows in 2015.

Air temperatures in all seasons between October 2014 and September 2015 exceeded 3°C above average over broad areas of the Arctic, while the annual average air temperature (+1.3°) over land was the highest since 1900. The melting of Arctic ice contributes to rising sea levels which swallow up land.

Although world governments came together in Paris in 2015 to agree carbon-cutting pledges in an attempt to keep global warming at 2°C or below, we are already at 1°C.

 Land & Ocean Temperature Percentiles Jan-Jun 2016
Image: NOAA

The role of El Niño

El Niño, the warming of tropical Pacific waters that affects global weather patterns, is partly responsible for 2015’s record year. Last year had an exceptionally strong El Niño event.

However, experts believe that 2015 would have broken records regardless, due to human actions.

The amount of greenhouse gases in the atmosphere reached yet another record in 2014, according to the World Meteorological Organization (WMO) Greenhouse Gas Bulletin. “Every year we report a new record in greenhouse gas concentrations,” said WMO Secretary-General Michel Jarraud. “Every year we say that time is running out. We have to act now to slash greenhouse gas emissions if we are to have a chance to keep the increase in temperatures to manageable levels.”