A composite image of the Western hemisphere of the Earth. Credit: NASA

A new study paints a picture of an Earth that is warmer than it has been in about 120,000 years, and is locked into eventually hitting its hottest mark in more than 2 million years.

As part of her doctoral dissertation at Stanford University, Carolyn Snyder , now a climate policy official at the U.S. Environmental Protection Agency, created a continuous 2 million year temperature record, much longer than a previous 22,000 year record. Snyder's temperature reconstruction, published Monday in the journal Nature , doesn't estimate temperature for a single year, but averages 5,000-year time periods going back a couple million years.

Snyder based her reconstruction on 61 different sea surface temperature proxies from across the globe, such as ratios between magnesium and calcium, species makeup and acidity. But the further the study goes back in time, especially after half a million years, the fewer of those proxies are available, making the estimates less certain, she said.

These are rough estimates with large margins of errors, she said. But she also found that the temperature changes correlated well to carbon dioxide levels.

Temperatures averaged out over the most recent 5,000 years—which includes the last 125 years or so of industrial emissions of heat-trapping gases—are generally warmer than they have been since about 120,000 years ago or so, Snyder found. And two interglacial time periods, the one 120,000 years ago and another just about 2 million years ago, were the warmest Snyder tracked. They were about 3.6 degrees (2 degrees Celsius) warmer than the current 5,000-year average.

With the link to carbon dioxide levels and taking into account other factors and past trends, Snyder calculated how much warming can be expected in the future.

Snyder said if climate factors are the same as in the past—and that's a big if—Earth is already committed to another 7 degrees or so (about 4 degrees Celsius) of warming over the next few thousand years.

"This is based on what happened in the past," Snyder said. "In the past it wasn't humans messing with the atmosphere."

Scientists give various reasons for past changes in carbon dioxide and heat levels, including regular slight shifts in Earth's orbital tilt.

Four outside scientists praised the study's tracking of past temperatures, with caveats about how less certain it is as it gets deeper in the past. Jeremy Shakun of Boston College said "Snyder's work is a great contribution and future work should build on it."

But many of the same scientists said Snyder's estimate of future warming seems too high. Shakun called it unrealistic and not matching historical time periods of similar carbon dioxide levels.

A fifth scientist, Michael Mann of Pennsylvania State University, called the study provocative and interesting but said he remains skeptical until more research confirms it. He found the future temperature calculations "so much higher than prevailing estimates that one has to consider it somewhat of an outlier."

Explore further Late Cretaceous Period was likely ice-free

More information: Carolyn W. Snyder. Evolution of global temperature over the past two million years, Nature (2016). Journal information: Nature Carolyn W. Snyder. Evolution of global temperature over the past two million years,(2016). DOI: 10.1038/nature19798

© 2016 The Associated Press. All rights reserved. </s> Temperatures on Earth were the warmest in 2016 since modern record-keeping began in 1880, according to independent analyses by NASA and the National Oceanic and Atmospheric Administration, boosting the argument shared by many climate scientists that our planet is changing in significant ways.

The year 2016 was the third consecutive year to set a new record for global average surface temperatures, and far exceeded the temperature mark set in 2015, scientists said today.

Gavin Schmidt, director of NASA's Goddard Institute for Space Studies (GISS), said in a statement that the consistent pattern of record-breaking temperatures is indicative of a "warming trend" taking place on Earth.

“2016 is remarkably the third record year in a row in this series,” Schmidt said. “We don't expect record years every year, but the ongoing long-term warming trend is clear.”

This is a developing story. Please check back for updates. </s> Carmen Jaspersen/picture-alliance/dpa/AP

A global temperature record published on 26 September in Nature1 extends 2 million years into the past — the longest continuous log yet published — and has sparked debate about how Earth's climate will change in the future.

The study harnesses data from dozens of ocean-sediment cores, as well as climate models, to provide estimates of global average surface temperatures. Prior reconstructions have gone back further — in some cases back to 3 million years — but were less comprehensive or focused only on particular time periods. The longest comprehensive temperature record available before this study went back 22,000 years.

“It’s a useful starting place,” says lead author Carolyn Snyder, director of the Climate Protection Partnerships Division of the US Environmental Protection Agency in Washington DC. “People can take this and improve upon it as more records become available in the future.”

Using a subset of the reconstructed temperature data, Snyder, who began the study while at Stanford University in Palo Alto, California, analysed the relationship between past temperatures and carbon dioxide (CO 2 ) levels estimated from Antarctic ice cores covering the past 800,000 years. Based on that analysis, she found that future long-term warming induced by greenhouse gases could be more severe than many previous estimates.

Even if the amount of atmospheric CO 2 were to stabilize at current levels, the study suggests that average temperatures may increase by roughly 5 °C over the next few millennia as a result of the effects of the greenhouse gas on glaciers, ecosystems and other factors. A doubling of the pre-industrial levels of atmospheric CO 2 of roughly 280 parts per million, which could occur within decades unless people curb greenhouse-gas emissions, could eventually boost global average temperatures by around 9 °C. This is on the high end of existing estimates.

Proceed with caution

And this is where the study has encountered scepticism. “The key part of this paper is the temperature reconstruction, which is really valuable,” says Eelco Rohling, a palaeoclimatologist at the Australian National University in Canberra. But he adds that the question of how the planet will respond to atmospheric CO 2 over the long term requires more detailed analysis.

In particular, the study fails to account for subtle changes in Earth’s orbit that affected global temperatures and helped to drive the expansion and retreat of glaciers throughout the time period covered by the analysis, says Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies in New York City. He says the effects of such orbital variations must be considered when comparing the glacial era to the present.

Schmidt's research into Earth's long-term sensitivity to CO 2 has focused on a warmer era before the glacial ages, about 3 million years ago. That work suggests that the millennial-scale warming that would be expected from rising greenhouse gases is around 4.5 °C for a doubling of pre-industrial atmospheric CO 2 levels2.

The new analysis has little bearing on the short-term climate sensitivity, which is what humanity might expect to see over the next century or two. The Intergovernmental Panel on Climate Change estimates that short-term climate sensitivity is around 3 °C of warming for a doubling of atmospheric CO 2 3.

Bare necessities

Snyder isn't convinced that the orbital effects are that important in this case. She says her study provides a single measure of the relationship between historic temperatures and CO 2 levels. If that relationship were to hold up, it would suggest that the Earth is in store for even more warming in the future. But she stresses that conclusions about future climate change should be viewed with caution. “This is not an exact prediction or a forecast,” she says. “The experiment we as humans are doing is very different than what we saw in the past.”

Although Snyder’s temperature record will probably be improved as new data are incorporated in the future, the study fills a crucial gap in the archives of climate science, says Jeremy Shakun, a geologist at Boston College in Chestnut Hill, Massachusetts, who developed the previous temperature record out to 22,000 years.

“This is something that just needed to be done,” Shakun says. As for the debate about long-term climate sensitivity, he says scientists can debate the details, but it’s clear that heat will continue to build up in the Earth system for a very long time. </s> Scientists say Earth is at risk of becoming 'hothouse'

A new U.S. study says Earth is approaching "hothouse" conditions if global temperatures rise more than 2 degrees Celsius. </s> GENEVA-Last year was Earth’s warmest on record, according to data compiled by the UN, confirming US findings that heat records were broken for a third year in 2016.

The study by the World Meteorological Organization found that global average temperatures were about 1.1 degree Celsius (1.98 Fahrenheit) above the pre-industrial period, and about 0.07 degrees Celsius above the record set in 2015. “2016 was an extreme year for the global climae and stands out as the hottest year on record,” said Petteri Taalas, the agency’s secretary general.

“Long-term indicators of human-caused climate change reached new heights in 2016,” he said in a statement.

“We have also broken sea ice minimum records in the Arctic and Antarctic,” he said, adding that the Arctic was warming twice as fast as the global average.

He also said the analysis found that atmospheric concentrations of both carbon dioxide and methane reached record levels.

The agency based its findings on data from the US National Oceanic and Atmospheric Administration, NASA’s Goddard Institute for Space Studies, the UK’s Met Office Hadley Centre, and the University of East Anglia’s Climatic Research Unit. According to Nasa figures, 2016 is now the warmest year in a record that dates back to 1880.

“2015 has been the warmest year on record up until now, so 2016 has just beaten that and and it’s beaten that by about 0.1- 0.12 of a degree Celsius, which doesn’t seem like a lot, but in terms of the year to year variations it’s actually huge,” Dr Gavin Schmidt from Nasa told BBC News. “And so this is a very clear record that we’re seeing, is driven mainly by changes in the tropical Pacific where we had an El Niño event that produced a lot of warmth. But we’ve also seen long term trends in warming mostly due to the increasing greenhouse gases.”

Other factors that have impacted temperatures in 2016 included unusual warmth in the Arctic. While the sea ice extent there last year didn’t break the record, the mercury stayed high and the smaller amount of ice now present in the region is at unprecedented levels for the time of year.

A number of meteorological agencies from around the world have released their figures today. They all suggest that warming in 2016 was a record that had an important contribution from El Niño.

The Met Office says it contributed about 0.2C to the annual average for 2016. However, researchers believe that while this is substantial, it is not the whole story.

“We understand the contribution El Niño makes fairly well and we’ve seen it many times,” said Prof Ellie Highwood from the University of Reading.

“But even if you take that contribution away, we would expect 2015 and 2016 to still be the warmest years we’ve seen, so a majority of it is coming from global warming and the greenhouse effect.”

The World Meteorological Organisation (WMO), which pulls together temperature data from a number of sources, agrees that 2016 broke the record by 0.07C.

Not all of the reports on temperature data in 2016 are clear that the warmest year record has been broken.

The Met Office says that 2016 was 0.77 above the long term rate, but with a plus or minus error margin of 0.1C, meaning that last year was at the very least, one of the two warmest years on record.

“The final figures confirm that 2016 was yet another extremely warm year,” said Peter Stott from the Met Office.

“The temperature for last year was very close to the year before, temperatures for 2016 exceeding those for 2015 by a small margin.”

Regardless of the small margins, when the new data on 2016 is included, 15 of the warmest 16 years on record have now occurred since 2001.

According to Noaa (the US National Oceanic and Atmospheric Administration), the only year from the 20th century to break into the top 16 is 1998, and which ranks seventh warmest.

This prolonged period of warming was having significant impacts around the world.

“We have also broken sea ice minimum records in the Arctic and Antarctic,” said Petteri Taalas from the WMO.

“The Arctic is warming twice as fast as the global average. The persistent loss of sea-ice is driving weather, climate and ocean circulation patterns in other parts of the world. We also have to pay attention to the potential release of methane from melting permafrost,” he said.

Of great concern to scientists and politicians is the fact that the newly published temperature data shows the Earth is once again more than 1 degree warmer than pre-industrial times, and edging closer to the threshold of of 1.5C set under the Paris climate pact.

With the Trump administration about to take office in the US, there are concerns that political support for climate action might fade. This would be a big mistake according to scientists.

“Climate change is one of the great challenges of the twenty first century and shows no signs of slowing down,” said Prof Mark Maslin, from University College London.

“The decarbonisation of the global economy is the ultimate goal to prevent the worst effects of climate change. The hottest year on record is such a clear warning siren that even President-elect Trump cannot ignore.”

Researchers say that 2017 is unlikely to break the warming record but will be in the top five hottest years. </s> Earth smashes yet another heat record; 16th month in a row

The National Oceanic and Atmospheric Administration on Tuesday said August's temperature of 61.74 degrees (16.52 Celsius) was .09 degrees (.05 Celsius) warmer than the old August record set last year, and was the 16th consecutive month of record-breaking heat. NOAA monitoring chief Deke Arndt said it was also the hottest summer, with 2016 on pace to smash last year's record for the hottest year.

August 2016 was also 1.66 degrees (0.92 Celsius) warmer than the 20th-century average. It was the fifth hottest month of any kind recorded, going back to 1880. Six of the 17 hottest months on record have been the summer months of 2015 and 2016.

FILE - In this Dec. 16, 2015 file photo, professor Stephen Hawking listens to a news conference in London. The National Oceanic and Atmospheric Administration Tuesday, Sept. 20, 2016, said that August¿s temperature of 61.74 degrees (16.52 Celsius) was the 16th month in a row that Earth set a record for the hottest month. NOAA monitoring chief Deke Arndt said it was also the hottest summer, with 2016 on pace to smash last year¿s record for the hottest year. (AP Photo/Frank Augstein, File)

The June-through-August summer was 2.18 degrees (1.21 Celsius) warmer than the 20th-century average and beat the old summer heat record, set last year, by one-fifth of a degree (0.11 Celsius), NOAA said.

"The needle has been shoved all the way over into the red by greenhouse gases," Arndt said.

NOAA's announcement came on a day when 375 members of the National Academy of Sciences, including Stephen Hawking and 30 Nobel laureates, released an open letter urging American leaders not to pull out of an international agreement to curb global warming.

Organizer and MIT climate scientist Kerry Emanuel said the scientists wrote the letter in response to the Republican party platform that rejects the Paris climate agreement reached last December. The letter said presidential nominee Donald Trump's advocacy of withdrawing from that agreement would "send a clear signal to the rest of the world: The United States does not care about the global problem of human-caused climate change."

Pulling out of the Paris accord, Emanuel said, "will accelerate our head-long plunge into a riskier and riskier climate."

"Everywhere we look we see signs that the climate really is changing," Emanuel said. "We're getting wake-up calls more frequently and we really have to do something about this." </s> WASHINGTON – Thanks to an assist from an El Nino event, Earth sizzled to a third-straight record hot year in 2016.

Two U.S. agencies and international weather groups reported Wednesday that last year was the warmest on record. They measure global temperatures in slightly different ways, and came up with a range of increases, from minuscule to what some American climate scientists described as substantial.

They’re “all singing the same song even if they are hitting different notes along the way. The pattern is very clear,” said Deke Arndt of the National Oceanic and Atmospheric Administration.

NOAA calculated that the average global temperature for 2016 was 58.69 degrees – beating the previous year by 0.07 degrees.

NASA’s figures, which include more of the Arctic, are higher at 0.22 degrees warmer than 2015. The Arctic “was enormously warm, like totally off the charts compared to everything else,” said Gavin Schmidt, director of NASA’s Goddard Institute of Space Studies in New York, where the space agency monitors global temperatures.

The British meteorological office determined that 2016 barely beat 2015 by 0.018 degrees. The World Meteorological Organization and other monitoring groups agreed that 2016 was a record, with the international weather agency chief Petteri Taalas saying “temperatures only tell part of the story” of extreme warming.

The figures are based on ground-level temperatures. Satellite calculations also showed that it was the warmest year, Schmidt said.

“This is clearly a record,” he said. “We are now no longer only looking at something that only scientists can see, but is apparent to people in our daily lives.”

Temperature records go back to 1880. This is the fifth time in a dozen years that the globe has set a new annual heat record. Records were also set 2015, 2014, 2010 and 2005.

Arndt said the 0.07 difference for 2016 is actually one of the largest NOAA has seen between record years. What’s more important than any single record is the multi-decade “clear warming trend since the late 20th Century,” said Arndt, NOAA’s climate monitoring chief.

Schmidt said his calculations show most of the record heat was from heat-trapping gases from the burning of oil, coal and gas. Only about 12 percent was due to El Nino, which is a periodic warming of parts of the Pacific that change weather globally, he said. Arndt put the El Nino factor closer to a quarter or a third. </s> NASA has released a report that says globally, 2016 was the hottest year on record, for the third year in a row (Credit: NASA )

Another year, another broken temperature record. As early data predicted, NASA and the National Oceanic and Atmospheric Administration (NOAA) have now reported that globally, 2016 was the warmest year since records began in 1880. That puts us on a streak of three years in a row that have surpassed previous records, painting a worrying picture of a long-term warming trend.

Taking a global average of surface temperatures, 2016 was found to be 1.78º F (0.99º C) warmer than the mean figures from the middle of the 20th century. Overall, the planet has warmed by about 2º F (1.1º C) since 1880, and the 16 years we've had of the 21st century so far are all in the top 17 hottest years on record.

Along with the dubious honor of hottest year so far, 2016 took a hammer to plenty of individual records too, with eight of its 12 months breaking the previous records for hottest average temperature for each respective month. A weak La Niña weather pattern may have slightly cooled things down later in the year, but the months of October to December were still among the warmest known.

"2016 is remarkably the third record year in a row in this series," says Gavin Schmidt, Director of NASA's Goddard Institute for Space Studies (GISS). "We don't expect record years every year, but the ongoing long-term warming trend is clear."

These records were set as a global average, which means that not every part of Earth would have experienced above-average temperatures for 2016. In the continental US, the annual mean temperature was the second warmest, while the Arctic was pummeled by a heatwave, resulting in record-low sea ice in the area. Variations like this may be responsible for skepticism of the kind that leads to Senators bringing snowballs onto the Senate floor.

This conclusion was reached by both NASA and NOAA independently, based on data gathered from 6,300 weather stations around the world, research stations in Antarctica and sea surface temperature observations from ships and buoys. From there, the two organizations use slightly different means of calculating their estimates, with NASA saying it's over 95 percent certain in claiming 2016 to be the warmest year on record. </s> The city of Ahvaz in Iran has set what could be a truly astonishing record this week by recording one of the hottest temperatures on Earth.

According to Weather Underground and French meteorologist Etienne Kapikian, the city reached a staggering 128.7 degrees making it by far the highest recorded temperature in Iran and potentially one of the highest ever recorded on Earth.

While those figures might sound almost suffocating the city’s 1.1m inhabitants would have actually felt even hotter as the heat index (which takes humidity into account) reached a whopping 142 degrees.

Iran and the middle-east weren’t the only places to experience soaring temperatures. In fact Europe, and in particular the UK suffered from a major heatwave culminating in Wednesday’s recorded spike of 94.1 degrees at London’s Heathrow Airport.

While we all love a scorching hot summer, scientists believe these record figures can only be attributed to one underlying factor, and sadly it is manmade.

Researchers from the World Weather Attribution believe that the data they’re seeing is consistent with human-caused climate change.

“We found clear and strong links between this month’s record warmth and human-caused climate change,” said Geert Jan van Oldenborgh, senior researcher at the Royal Netherlands Meteorological Institute (KNMI).

Friederike Otto, a senior researcher at Oxford University adds: “This extreme event attribution analysis makes clear that European heat waves have become more frequent, and in the South of Europe at least 10 times more frequent.”

Otto went on to say that it was ‘critical’ that scientists and public health experts should start talking to cities about how they can implement heat action plans as these spikes become more frequent.

To make matters worse, a team of eminent climate scientists recently published a report which gave national governments just three years to start tackling climate change or it will quite simply be too late.

While meeting the Paris Agreement targets are going to be incredibly difficult, experts argue that inaction will be almost immeasurably more harmful than the transitionary process to try and reach those goals.

Sharan Burrow, General Secretary of the International Trade Union Confederation and a signatory on the article, said: “2020 is a hard deadline. There’s no turning back if we don’t bend the emissions curve within three years...there are no jobs on a dead planet.”
A study published in Nature finds the Earth's surface is warmer than it has been in about 120,000 years, and is locked into eventually hitting its hottest mark in more than 2 million years.