Environment

2017 ranked among warmest years on record by NASA and NOAA

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The Earth's average global temperature from 2013-2017, compared to a baseline average from 1951-1980 (yellow, orange and red indicates temperatures higher than the baseline)
NASA’s Scientific Visualization Studio
Specific events and anomalies pulled out of the NOAA's report on 2017's climate and temperature
NOAA
The Earth's average global temperature from 2013-2017, compared to a baseline average from 1951-1980 (yellow, orange and red indicates temperatures higher than the baseline)
NASA’s Scientific Visualization Studio

Parts of the Northern Hemisphere might be shivering through a bitterly cold winter right now, but global temperature averages still soared over the last year. NASA and the National Oceanic and Atmospheric Administration (NOAA) have both released reports stating that 2017 was one of the hottest years since records began in 1880. That continues a long-term trend of rapid warming that doesn't bode well for the future.

NASA's yearly analysis uses a baseline mean temperature calculated from the global average each year between 1951 and 1980, and then compares that to the global average temperature of each passing year. The agency determined that the worldwide average in 2017 was 1.62° F (0.9° C) warmer than the baseline, making it the second-hottest year on record behind only 2016.

A separate study from the NOAA determined that 2017's average was 1.51° F (0.84° C) higher than the 20th century average, ranking it the third-warmest year after 2016 and 2015, respectively. That difference is due to a range of factors: Climate science, especially on a global scale, is complex and ever-changing; weather stations move locations; the methods of measurement change over time; and different organizations use different techniques, baselines and sources for their calculations.

Generally though, findings from both NASA and the NOAA are largely in agreement on the wider warming trends. Temperatures have been higher than average for the last 41 consecutive years, and the top five warmest all fall between 2010 and now. Winter chills might lead some skeptics to trash the science, but the numbers trump those concerns – especially when several other studies from around the world all reached very similar conclusions.

Specific events and anomalies pulled out of the NOAA's report on 2017's climate and temperature
NOAA

Weather phenomena known as El Niño and La Niña can trigger short-term variations in temperature, and a strong El Niño event during 2015 and the first third of 2016 likely played a role in making 2016 the hottest on record. There was no El Niño in 2017 and conversely a La Niña pattern emerged in later months, which would have taken the edge off. In an analysis that cancelled out the effects of El Niño and La Niña, 2017 suddenly jumped to the top of the charts.

While the vast majority of the planet experienced at least some warming, the polar regions continue to be the hardest hit. The Arctic's sea ice levels were the second-smallest ever seen (again after 2016's record low). At the other end of the planet, the Antarctic sea ice extent was the smallest on record, covering an area some 154,000 sq miles (400,000 sq km) smaller than the previous record low.

NASA's full report and methods is available online at the Goddard Institute for Space Studies, while the NOAA published its report through the National Climatic Data Center. NASA outlines its results in the video below.

Sources: NASA, NOAA

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11 comments
Bob
I don't doubt some global warming but the numbers are obviously biased. The local weather reporting station in my area was several miles out in the rural country 30 years ago. It is now surrounded by subdivisions, factories, shopping centers and parking lots. It is no surprise that the average temperature is now a couple degrees higher. This is also true of every other government reporting station within a hundred miles. Private weather stations in the rural areas are still reporting slightly cooler temperatures.
MartinVoelker
@Bob -- you may be talking about a supposed 'urban heat island effect" but guess what? A possible UHI has been thoroughly investigated - and had to be dismissed. Scientists have been very careful to ensure that UHI is not influencing the temperature trends and have compared the data from remote stations to more urban sites. Result: The difference between ideal rural sites compared to urban sites in temperature trends has been very small. Plus the UHI should match where most people live. But the greatest difference in temperatures are the far northern latitudes and not where major urbanisation has occurred.
Catweazle
Yeah, right...
NOAA and NASA will still be claiming "hottest year since whenever" even as the next Ice Age commences and the glaciers roll over their offices.
piperTom
So, "2017 ranked ... warmest..."? Oh, of course it was. And here's something to bet on: 2018 will be, too. Because those doing the ranking have an agenda. And that revolves around YOU, dear reader: you are not sufficiently panicked about Global Warming. This, despite you being yelled at for a quarter century!
At least they have stopped saying the science is settled. With 20 years of data in disagreement with the climate models that made Al Gore rich, we now know "climate science... is complex and ever-changing".
Still, the global lower atmosphere temperature for December was +0.41°C warmer than the mean for 1979-2017. Yikes! Give all your money to the government now!
Catweazle
"But the greatest difference in temperatures are the far northern latitudes and not where major urbanisation has occurred."
Not only that, there aren't many weather stations either and the weather satellites generally operate between 80 deg latitude North and South, so the "climate scientists" use a technique called "Kriging"** AKA "Making Stuff Up"..
Curious thing that, the less thermometers there are, the higher the temperature is.
**Originally devised in South Africa to estimate the value of gold claims in the absence of any proper assaying surveys, and caused a lot of credulous people to lose all their money.
aki009
If you look at the map, you will notice that all the red zones are in locations where there have not been much in the way of historical measurements.
Isn't it strange that most of the "dramatic" "heating" has taken place where few historical records exist and the data is largely made up?
Douglas E Knapp
I am so sick of reading this blah blah blah global warming is made up BS. I know the person that lead the attack or perhaps I should just say she initiated it, to make people think global warming is false. It is pure propaganda. If you believe global warming is false then you have been successfully conned.
JanKowalski
I live in Poland. We used to have winters with snow etc. Now it's almost gone. Winters are so warm that none is going to prove me there is no clime warming. The best place to see it are regions with temperate climate. The strange thing is that it's enough to rise temperature by 1 C degree and make such big difference
@Bob UHI is known to scientists. They subtract certain amount from the readings
Bob
Interesting how many critics didn't seem to notice that I didn't dispute some degree of global warming and I only referred to biased data coming from my area compared to 30 years ago. I have worked with statistics for over 30 years and have never found a study that didn't include some level of data bias including errors in the choice of variables and their weighing factors. Anyone truly knowledgeable about statistics knows that they can be subtly manipulated. I am always amazed by people who think the math purifies the data and the biases don't matter.
ljaques
OHMYGODWEREALLGONNADIE! Thanks once again, NASA and NOAA, for your thoroughly biased, fully-agenda-laden reports which have been proven wrong year after year after year after year after year. But it's a religion to you Hansenites, isn't it? Put back all those weather stations he took out (cooler ones?), and de-"normalize" all that data you hacked, and move the urban-heat-island-affected stations to give us the REAL data once again. Maybe a few people might start believing your input once again. I dare not hold my breath waiting for you to do that.