Last year was the hottest on record without an El Nino 

Last year was the hottest on record without the influence of the El Nino weather phenomenon that helps push up global temperatures, a new study reports.

El Nino years happen when a change in prevailing winds cause huge areas of water to heat up in the Pacific, leading to elevated temperatures worldwide.

Including El Nino years, 2016 was warmer and 2017 was joint second warmest with 2015.

The main contributor to rising temperatures over the last 150 years is human activity, scientists have said.

This includes burning fossil fuels which puts heat-trapping greenhouse gases into the atmosphere. 

They say man-made climate change is has now overtaken the influence of natural trends on the climate.

Experts say the 2017 record temperature ‘should focus the minds of world leaders’ on ‘scale and urgency’ of the risks of climate change. 

Experts from the Met Office’s Hadley Centre and the University of East Anglia’s Climatic Research Unit were involved in the findings. They found that 2017 was almost 1°C (1.8°F) warmer than pre-industrial levels, measured from 1850 to 1900

Experts from the Met Office’s Hadley Centre and the University of East Anglia’s Climatic Research Unit were involved in the findings.

They produce the Hadcrut4 dataset, which is used to estimate global temperatures. 

This found that 2017 was almost 1°C (1.8°F) warmer than pre-industrial levels, measured from 1850 to 1900, and 0.38°C (0.78°F) warmer than average temperatures measured from 1981 to 2010.

That would make it the third hottest on record, including El Nino years.

Figures from a series of different international analyses, including from the NOAA and Nasa in the US, place 2017 as either second or third warmest on record.

Last year’s temperatures were outstripped only by the record heat of 2016, and in some of the analyses by 2015.

Both 2016 and 2015 saw a significant El Nino, a natural phenomenon in the Pacific Ocean that increases temperatures, on top of human-induced global warming.  

Dr Colin Morice, of the Met Office Hadley Centre, said: ‘The global temperature figures for 2017 are in agreement with other centres around the world that 2017 is one of the three warmest years and the warmest year since 1850 without the influence of El Nino.

‘2015, 2016 and 2017 were the three warmest years in the series.

Last year was 0.38°C (0.78°F) warmer than average temperatures measured from 1981 to 2010, according to the Met Office’s Hadcrut4 dataset, which is used to estimate global temperatures

The findings would make 2017 the third hottest on record, including El Nino years. This graph shows a plot of the Met Office’s global average temperature increase figures since 1850

This Met Office animation shows rising temperatures since the 1850s, with lighter colours signifying greater levels of heat globally 

‘In addition to the continuing sizeable contribution from the release of greenhouse gases, 2015 and 2016 were boosted by the effect of a strong El Nino, which straddled both years.

‘However, 2017 is notable because the high temperatures continued despite the absence of El Nino and the onset of its cool counterpart, La Nina.’

The El Nino event spanning 2015 to 2016 contributed around 0.2°C (0.36°F) to the annual average increase for 2016, which was about 1.1°C (2°F) than average temperatures measured from 1850 to 1900.

NASA AND NOAA FINDINGS ON GLOBAL TEMPERATURES IN 2017

Earth’s global surface temperatures in 2017 ranked as the second warmest since 1880, according to an analysis by NASA.

Continuing the planet’s long-term warming trend, globally averaged temperatures in 2017 were 0.90°C (1.62°F) warmer than the 1951 to 1980 average, according to scientists at NASA’s Goddard Institute for Space Studies (GISS) in New York. 

That is second only to global temperatures in 2016.

In a separate, independent analysis, scientists at the National Oceanic and Atmospheric Administration (NOAA) concluded that 2017 was the third-warmest year in their record. 

This map shows Earth’s average global temperature from 2013 to 2017, as compared to a baseline average from 1951 to 1980, according to an analysis by Nasa. Yellows, oranges, and reds show regions warmer than the baseline

The minor difference in rankings is due to the different methods used by the two agencies to analyse global temperatures, although over the long-term the agencies’ records remain in strong agreement. 

Both analyses show that the five warmest years on record all have taken place since 2010.

Because weather station locations and measurement practices change over time, there are uncertainties in the interpretation of specific year-to-year global mean temperature differences. 

Taking this into account, Nasa estimates that 2017’s global mean change is accurate to within 0.1 degree, with a 95 per cent certainty level.

‘Despite colder than average temperatures in any one part of the world, temperatures over the planet as a whole continue the rapid warming trend we’ve seen over the last 40 years,’ said GISS director Gavin Schmidt. 

However, the main contributor to warming over the last 150 years is human influence on climate from increasing greenhouse gases in the atmosphere, experts say.

2017 remains close to 1°C (1.8°F) above pre-industrial temperatures of 1850 to 1900.

The Met Office annual average global temperature forecast for 2017 said the global mean temperature for 2017 was expected to be between 0.32°C (0.57°F) and 0.56°C (1°F) above the long-term average.

This graphic from the National Oceanic and Atmospheric Administration in the US shows significant climate anomalies and events across the globe in 2017 

The provisional figure for 2017, based on an average of three global temperature datasets, of 0.42°C (0.75°F) above the long-term average is well within the predicted range. 

The forecast, made at the end of 2016, also correctly predicted that 2017 would be one of the warmest years in the record. 

The HadCRUT4 global temperature dataset is compiled from many thousands of temperature measurements taken across the globe, from all continents and all oceans. 

Last year was the hottest on record without the influence of the El Nino weather phenomenon that helps push up global temperatures, the new study reports. El Nino years happen when a change in prevailing winds cause huge areas of water to heat up in the Pacific

The regional variations in temperature are themselves informative in understanding the mechanisms that cause warming in response to the continuing build up of greenhouse gases in the atmosphere.

Professor Tim Osborn, director of research at the University of East Anglia’s climatic research unit added: ‘It isn’t only the average global temperature that matters, we can also explain the geographical pattern of the warming.

‘Greater warming over land and in the Arctic region, and less warming in the sub-polar regions, are what we expect from our understanding of climate physics, and this is what we observe.’

The World Meteorological Organisation (WMO), which brings together five leading international datasets, said temperatures were on the rise over the long term.

WMO secretary-general Petteri Taalas said: ‘The long-term temperature trend is far more important than the ranking of individual years, and that trend is an upward one.

The Met Office annual average global temperature forecast for 2017 said the global mean temperature for 2017 was expected to be between 0.32°C (0.57°F) and 0.56°C (1°F) above the long-term average. The provisional figure for 2017 of 0.42°C (0.75°F) is well within that range

‘Seventeen of the 18 warmest years on record have all been during this century, and the degree of warming during the past three years has been exceptional.

‘Arctic warmth has been especially pronounced and this will have profound and long-lasting repercussions on sea levels, and on weather patterns in other parts of the world.’

And he said 2017’s warm temperatures were accompanied by extreme weather in many countries around the world.

The US had its most expensive year ever in terms of weather and climate disasters, while other countries saw their development slowed or reversed by tropical cyclones, floods and drought, he said.

President Donald Trump has announced his intention to pull the US out of the Paris Agreement, the world’s first comprehensive deal on cutting greenhouse emissions, which would leave the US as the only country not signed up to the treaty. 

The US had its most expensive year ever in terms of weather and climate disasters in 2017, while other countries saw their development slowed or reversed by tropical cyclones, floods and drought

Climate change expert Bob Ward from the London School of Economics and Political Science, who was not involved in the study, said: ‘This record warm year has also been accompanied by exceptional extreme weather events around the world, including devastating hurricanes in the Caribbean and United States. 

‘All countries are exposed to the growing impacts of climate change. 

‘This year governments are due to start the process of assessing the size of the gap between their collective ambitions for reducing greenhouse gas emissions and the goals of the Paris Agreement. 

‘The record temperature should focus the minds of world leaders, including President Trump, on the scale and urgency of the risks that people, rich and poor, face around the world from climate change.’

Uncertainties arising from incomplete global coverage, particularly a lack of observations from polar regions, and limitations of the measurements used to produce the data sets, have been included in the calculations.  

Differences between the various estimates arise largely from the way that the data-sparse polar regions are handled.