The heat goes on: This past April was second warmest in records dating back to 1880 — as were February and March

By Tom Yulsman | May 17, 2017 1:41 pm

But with the monster El Niño of 2015/2016 far back in the rear-view mirror, temperatures in 2017 are running somewhat lower than last year

A map of temperature anomalies in April 2017 shows that central and northeast Asia, as well as Alaska, were much warmer than the 1951-1980 base period. (Source: NASA GISS)

A map of temperature anomalies in April 2017 shows that central and northeast Asia, as well as Alaska, were much warmer than the 1951-1980 base period. (Source: NASA GISS)

NASA has come out with its monthly analysis of global temperatures, and the results are notable, if not terribly surprising: Last month was the second warmest April in 137 years of modern record-keeping.

Last month beat out April of 2010 by just a small amount to achieve that distinction, according to the analysis by NASA’s Goddard Institute for Space Studies. It was second only to April 2016, which shattered the record for warmest year, thanks in part to a boost from El Niño.

Temperatures have moderated just a bit from the astonishing highs of 2016, as you can see in the following graph charting how the global average surface temperature has varied from that of the pre- and early-industrial time of 1880 to 1920:

This graph shows how global temperatures have changed from pre- and early-industrial times. (Source: NASA GISS)


The graph, which takes us through April, shows the 2016 peak and subsequent modest fall-off so far this year. Also noteworthy is the pattern. There are obvious short-term variations, including some periods of slower warming. But overall, since 1970 the globe has experienced an unambiguous long-term warming trend.

Although we’re clearly off last year’s peak, the globe continues to be plenty warm. January was the third-warmest such month on record. Since then, February and March, like last month, were second warmest respectively.

This graph shows how monthly global temperatures have varied from the 1980-2015 average. (Source: NASA GISS)

This graph shows how monthly global temperatures have varied from the 1980-2015 average. (Source: NASA GISS)

To see how this year has compared month by month with previous years, click on the graph at right.

The most intense warmth anomalies during April were in the high north, as well as central Asia. Alaska was particularly warm last month (following a relatively cool March), as were Russia’s Arctic reaches.

Overall, the Arctic continues to warm at twice the average rate of the rest of the globe. In fact, during 2016, land areas of the Arctic experienced the highest average temperature in the observational record, with a 6.3 degree Fahrenheit increase since 1900, according to the NOAA-sponsored Arctic Report Card.

“Rarely have we seen the Arctic show a clearer, stronger or more pronounced signal of persistent warming and its cascading effects on the environment,” said Jeremy Mathis, director of NOAA’s Arctic Research Program, quoted in a NOAA news release.

NASA’s monthly analysis “is assembled from publicly available data acquired by about 6,300 meteorological stations around the world, ship- and buoy-based instruments measuring sea surface temperature, and Antarctic research stations,” according to a summary released on May 15.

NOAA’s independent analysis of the state of the global climate during April 2017 should be released very soon.

  • Not that anyone cares but

    Did you read that folks? This past April was only the second warmest since 1880.

    BTW I believe that global warming is indeed happening. I’m with you believers. It is just that I have a quarrel with the headline writers – and – I am not sure there is anything we can do about them.

    • Tom Yulsman

      And your specific problem with the headline is… what? The news is that NASA has found that April 2017 was indeed the second warmest on record. So Mr. Brilliant Editor, given that real news, please give us your headline.

      • Not that anyone cares but

        Oh. I thought I implied that I knew of no better headline.

        • Tom Yulsman

          As I asked before: Your specific problem with the headline is… what?

          • Not that anyone cares but

            Here you have quite properly dinged me. I am peeved by the use of too many superlatives in headlines. This is just one example. I feel that overuse of superlatives dilutes their value.

  • OWilson

    At the same time, the NOAA Satellite Record is reporting that the April 2017 temperature anomaly was 0.27 degrees over its 38 year record.

    Which is basically the same as it was 30 years ago.

    Don’t be building those Arks yet! :)

    • Anton Crawford

      I’am freelancing from the internet, executing simple jobs that solely requires from you desktop computer or laptop computer and additionally internet service accessibility and so I couldn’t be happy… Six months have passed on when i initiated this and also i gained so far overall 36,000 bucks… Basically i gain almost 80 dollars/hour and work for three to four h daily.And appreciable thing regarding this job opportunity is that you are able to choose when to do the job yourself and for how long and you get paid at the end of every week.>>>> VZTURL.COM/bni15

    • Tom Yulsman

      Mr. Wilson, not that you care, but for others who may be reading:

      Satellites like those responsible for the graph above do not directly measure atmospheric temperature. As Ben Santer, a scientist at Lawrence Livermore National Laboratory, puts it: “they are not thermometers in space.” Instead, temperature estimates are derived from measurements by many satellites of microwave emissions of oxygen molecules. And these estimates are subject to large uncertainties. For the details, see:

      From Santer’s piece, published in January of 2016:

      “Satellite estimates of atmospheric temperature change are still a work in progress, and the range of estimates produced by different groups remains large. The same is true of weather balloon atmospheric temperature measurements. Surface thermometer records also have well-studied uncertainties, but the estimated surface warming of roughly 0.9°C since 1880 has been independently confirmed by multiple research groups.”

      Mr. Wilson: It’s obvious that you will continue to cherry pick bits of data that fit your rigid ideological perspective in order to make purely political points. You claim to be arguing on the basis of science. But any one who has bothered to follow your numerous comments on this and other blogs know that science actually has nothing to do with your perspective. And you are clearly not interested in truth.

      • OWilson

        That’s a little harsh, but I will not fall for your bait.

        Nothing I have ever said here is untrue.

        And, aside from the usual strawmen arguments and cheap ad hominem attacks like yours. nobody has ever proven that.


        Because I only post information from scientific government agencies, NASA, NOAA, NSIDC, and occasionally the two organs NYT and WP.

        You will never find me quoting “denier” sites.

        It’s not necessary! :)

        If you find anything untruthful in my post above, please share it with your readers, and we will try to rectify it :)


        • cgs

          You can calibrate satellites relatively easy

          Just a few lines above this you wrote:

          Nothing I have ever said here is untrue.

          Well that first statement quoted is. Using satellites to derive a temperature of the atmosphere is a complex process fraught with issues.

          Here is a white paper put out by RSS on the calibration of the satellite sensors.

          Just peruse the table of contents to view all the various calibrations that are required.

          Surface data sets are certainly more consistent than satellite. Just a few years ago UAH had a big adjustment downward, while last year RSS had a big adjustment upward.

          Both of the videos presented below give great information that anyone would find valuable that wants to understand the comparison between satellite and surface temperature measurements.

          You would do well to watch both! 😉

          • OWilson

            NOAA’s ground based thermometer system has less coverage (less than half the Earth’s surface, requiring proxy infilling, and subject to the constant placement and relocation of measuring devices over the years) but the record goes back to 1880, so it is considered “useful” to continue the long time record, showing long term “trends”.

            At least is was extremely necessary, before we had a satellite record.

            NOAA’s satellite data, which covers the Earth more fully and is more consistent as a benchmark (a benchmark is used to indicate and monitor changes, apples to apples) had data only going back to 1979 the beginning of the era of satellite monitoring, so until recently it was considered merely an incomplete indicator of short term “weather, not “climate”.

            But as the satellite record gets longer, (we now have some 38 years of records) and since 30 years is considered “climate”, satellite data will be relied on more and more.

            Satellite are the last word, the highest technology available for monitoring Earth processes.

            For example, we have true believers here all the time insisting that the world’s waterfront cities are being inundated by rising sea levels. They even show us how they are going to look under 30 feet of water. :)

            But satellites show us that all major waterfront cities are actually growing in area.

            Now, of course this is bound to upset true believers of catastrophic doomsday, because science is the enemy of fear and dogma.

          • cgs

            We agree on the point that satellite data will be relied upon more and more. What we disagree about is:

            1. That satellite data is more straightforward to collect than surface temperature data. If you bothered to look at the RSS link I gave, that should disabuse you of that belief. If you wish, we can both examine this subject in greater detail. Let me know.

            2. That satellite data is currently more consistent that surface temperature measurements. It’s not. That was the purpose of my pointing out that UAH and RSS have both made updates to their algorithms recently that move their data products in opposite directions. And the videos that I linked to have interviews with Carl Mears, a principle scientist at RSS, who plainly states that currently surface data sets are the more consistent data sets. This from someone who makes a living collecting and analyzing satellite temperature data!

            At some point in the future, with regards to atmospheric temperatures, the various satellite data sets will begin to give consistent results. We’re not there yet.

            And we will always want surface measures since that is the part of the Earth where we actually live. The best surface measure will, for the foreseeable future, remain ocean heat content. Most climate scientists believe this, including skeptics as confirmed in this article by Roger Pielke Sr. in 2008. See third paragraph and beyond under section “Climate system heat changes”.


          • OWilson

            I would imagine that an acceptable study of the relative accuracy of satellite vs 1880 surface records will be forthcoming before too long.

            I have not seen one, but that is usual in the singular murky science of “global warming”, in the same way a clear daily record of the Earth’s average temperature is not published.

            What could be easier for settled science than an absolute daily global average temperature?

            What NASA and NOAA and NSIDC give us is the usual gobbledygook, second highest (lowest) anomaly based on a1980 to 2006 baseline in this particular month going back “n” number of years.

            (There’s a reason for that, which escapes the true believers, who never question the dogma!, but will eventually be revealed by curious scientists, I have no doubt)

            Keep your faith, whatever gets you through the night!

          • cgs

            You know, for someone who likes to comment on climate posts and who takes the position that the whole topic is overblown, it is apparent to me that you’ve done very little to educate yourself on the subject.

            Take for instance your first sentence above. The question of which data set is more accurate, or reliable, has been discussed a lot. The first video I linked to above tackles the subject from a consensus point of view.

            That it is a consensus argument would be your first ( and likely only) criticism of it. But a claim has to be staked first before counter arguments can be formed.

            One of the things I like is to have my position challenged with an argument I am not familiar with. One can learn by reading up on a subject, but I’ve probably learned equally as much investigating skeptic claims.

            I want to know about gaps in my knowledge. It seems pretty apparent that you don’t. This likely means that you’re afraid that you’l learn something that will make you uncomfortable.

            I don’t think Aristotle would approve of an intellectual curiosity deficient in that way.

            But, as you say, whatever gets you through the night!

          • OWilson

            I applaud your search for knowledge!


          • cgs

            Thanks for the suggestion, but I’m not ignorant of the history or philosophy of science. Is there a particular topic you have in mind to discuss?

            And while you’re at it, since you think you know them, please tell me what my assumptions are about the future of OUR planet.

            Finally, if you are indeed not afraid to challenge your beliefs, then that means you’ve perused the RSS document and watched the videos. Please tell me your thoughts.

          • OWilson

            You made the first totally wrong assumptions about me, “you’re afraid that you’l learn something that will make you uncomfortable”

            Hard to have a logical conversation about satellite data with someone at that level.

            But, once again, the subject has been dragged down to the weeds and the swamp, so I’m outta here!

            Your trolling is effective, I’ll grant you that! :)

          • cgs

            Do you know why I made such an assumption about you? It is because of responses like this. Remember back to our discussion about models and FAR? You refused to look at evidence I offered that was contrary to your belief that the models in FAR were way off.

            And here you’re doing it again with respect to satellite data.

            So if I’m wrong in my assumption about you being afraid to confront information that is contrary to your beliefs, then you only have yourself to blame for that.

            Until next time… 😉

          • OWilson

            Your assumption, that there will actually BE a next time, is false, also! :)

          • Mike Richardson

            Your compulsion to respond and have the last word, as ridiculous as it may be, makes it not an assumption, but a certainty. :)

          • OWilson

            Why, it’s “me too” Mikey! With his own contribution to the discussion of satellite data, trolling for a cheap uptick!

            You’re late! :)

            I see the topic was finally dragged down even to your level! :)

          • Mike Richardson

            LMAO! 😆 …And I rest my case! Good Ol “What me worry?” Wilson, hypocritically describing others as trolling after he’s already dragged the discussion down himself. So easily triggered, a puppet strung up by his own compulsions. ; )
            Dance puppet, dance.

          • OWilson

            So nothing at all on topic?

            OK! :)

          • Mike Richardson

            “So nothing at all on topic,” – – followed by nothing at all on topic. Like your previous 4-5 posts! LOL, yes that complete lack of self reflection will guarantee you never pass the Turing test. But you can continue to amuse whenever I pull your strings.

            No, you want satellite data that you can pick and choose, such as atmospheric temperature measurements — but not measurements of ice mass loss, such as the GRACE satellite readings. You focus on the average temperature rise globally, deliberately choosing to ignore the faster and more drastic warming at the poles. Additionally, you assume linear or even flatline progression of warming (when you aren’t jumping on some “Little Ice Age” bandwagon and rejecting facts altogether ), when it actually has been accelerating in fits and starts well beyond that as feedback mechanisms kick in. All this has been explained to you countless times, but it conflicts with your ideology so you reject it. So since you are a lost cause to logic, you can at least be appreciated as a gift to ironic humor. Let the puppet show continue. :)

          • OWilson

            We just want ALL the information to be considered, Mikey, not just some, like you true believer luddites, that hate the satellites because they are not showing the catastrophic doomsday scenarios you lefties are trying to scare folks with.

            Satellites show your lies, for all to see.

            They show that world’s waterfront cities are actually GROWING, and the temperature is only warming slightly. 0.29 degrees of the last 38 years!

            (and that is only if you ignore any margin of error. This stuff is not “settled”, it is being “adjusted” all the time, by your government Agencies :))

            They show the world is actually GREENING!

            Go argue against satellite date all you want, but they are the most consistent monitors of changes in Global Processes.

            Hang on to those ancient tidal gauges, though, they’ll be valuable museum pieces in the future! :)

            Still have those old buggy whips? :)

          • Mike Richardson

            “Satellites show your lies, for all to see” — projecting again, Pinocchio. Satellites show more quickly eroding coastlines, particularly the coastline of my home state of Louisiana. Satellites are tracking the warming of the oceans and rising sea levels due to thermal expansion and melting ice on land. They confirm the decline of ice mass in Antarctica, continental glaciers, and sea ice coverage in the Arctic. And greening in certain areas? Not unexpected, but the thing to consider is what that actually represents. Travel throughout the American South, and you’ll see vast stretches of verdant growth– from invasive kudzu, which thrives on a warming climate, as does ragweed (which is spreading further north and blooming earlier). But that’s not good satellite data to you, because it doesn’t confirm your biases. And Wilson, I don’t have a problem with certain relics from an earlier era. Like old-fashioned puppet shows, they can be entertaining, from time to time. 😉

          • OWilson

            So now you like satellites? LOL

            Good, you are making progress!

          • Mike Richardson

            Don’t have a problem with satellite data, just folks cherry-picking only particular data sets they think confirm their contrarian views, while ignoring the mountains of data that don’t. It would be nice to see them make some progress away from that mindset. :)

          • OWilson

            I “like” all satellite data, unlike true believers, who constantly argue it is not to be trusted.

            I agree with their final findings that, “Satellite temperature measurements do not support the claim of a “leveling off of warming” over the past two decades1.”

            There has been a slight increase in temperature, as the charts I posted above clearly shows!

            Some of the other “gobbledygook” (careful now:) about their tortured examination of this 20 year period or that 20 year period is subject to other analysis, and probably will be, soon.

            They go in with the determination to “prove” no “levelling off”, which is a highly unscientific term, and which is subject to many natural variations in such small time periods, it can be dismissed as noise.


            “Trend assessments over short, 1–2 decade-long periods of time are often sensitive to small changes in the trend start date3. More reliable estimates of underlying temperature changes are obtained by averaging over all possible short-term trends or by considering longer analysis periods”

            We will have to wait until these longer term satellite records become available, in the meantime they do not argue with the fact that we have presently a 0.29 anomaly over the 38 year satellite record, but use assumptions to tell us why we should not read to much into the actual data:

            Quote: “As expected, there are multi-decadal changes in trend size12, 13. Recent 20-year trends are smaller than most of the earlier 20-year trend values. This is due to the combined effects of multiple factors: the anomalous warmth at the beginning of the last 20 years (arising from a large El Niño event in 1997/98), the shift from a warm phase to a cold phase of the Interdecadal Pacific Oscillation in the late 1990s14,15,16,17, changes in other modes of internal variability18,19,20, a succession of moderate volcanic eruptions in the early 21st century21,22,23, a long and low minimum in solar output during the last solar cycle24, and an increase in anthropogenic sulphate pollution25, 26.”

            The scattergun approach :) but they left off the increased jet travel of Global Warming Advocates (a joke for the satire challenged)!

            Can we now assume that the discussion of whether satellites are useful in determining global temperature trends is now over?

            I get tired of your arguments both ways:

          • Mike Richardson

            Except nowhere in this thread did I argue against the use of satellite data! LOL! No, you’re the one who keeps ignoring all the data that doesn’t support a minimalist or “skeptic” viewpoint, then projecting this behavior on others. You’ve gone well past straw man arguments to outright lying now, Wilson, something else you project in others. If you don’t cut that out, your nose will just keep growing and you’ll never become a real boy. Keep hanging on to your 0.29 figure like a magic talisman to protect you from acknowledging the reality documented by these researchers. You’ve proven to anyone bothering to read your posts that the actual true believer, unwilling to yield faith in ideology to scientific fact, is yourself. Just can’t cut those strings, can you? 😉

          • OWilson

            Have a nice day! :)

          • Mike Richardson

            You really do get upset when exposed as a hypocrite and a liar, don’t you? 😁

          • OWilson

            You are just too dumb to notice I am actually laughing at you! :)

            Cheers! :)

          • Mike Richardson

            So you waste your time in this thread, making arguments against made up positions and making yourself look ever more foolish, and I’m the dumb one here? 😆 Yeah, anyone reading this exchange is probably laughing — at you instead of with you! A hypocrite, a liar, and delusional to boot.

          • OWilson

            Deluding yourself that “readers” are laughing at me, and not you, is invalidated by DISQUS own approval rating system.

            (It is there as a check against lone wolf trolls and other deranged fruitcakes like you! :)

          • Mike Richardson

            So popularity means more to you than the truth? Gotcha. 😉

          • OWilson

            Means more than a lone wolf deluded fruitcake, with idiotic dreams of invincibility!

            Reality bites!

          • Mike Richardson

            “Dreams of invincibility?” Can’t recall ever stating I was invincible – – where are you getting this, the same place that you got the false narrative that I opposed satellite data? Yeah, someone here’s delusional, but you might want to look up from the screen and check a mirror to see who! 😉

          • OWilson

            You are delusional.

            My opening statement was:

            “I “like” all satellite data, unlike true believers, who constantly argue it is not to be trusted.”

            My comments are directed at “true believers”.

            But , of course, if the hat fits!

            I’m outa here now, so keep it clean! :)

        • NiCuCo

          “You can calibrate satellites relatively easy, they cover most of the earth, but it must be hard to calibrate long gone steamship intake valves, ancient tidal gauges and ice cores, from 1880 :)”

          From Dr. Spencer, how easy calibration is, in only his sixth version:

          Version 6.0 of the UAH Temperature Dataset Released: New LT Trend = +0.11 C/decade
          April 28th, 2015
          by Roy W. Spencer, John R. Christy, and William D. Braswell

          1. Introduction & Some Results

          After three years of work, we have (hopefully) finished our Version 6.0 reanalysis of the global MSU/AMSU data. Many procedures have been modified or entirely reworked, and most of the software has been rewritten from scratch. (Please, before you ask a question, read the following to see if your question has already been answered.)

          The MSU and AMSU instruments measure the thermal microwave emission from atmospheric oxygen in the 50-60 GHz oxygen absorption complex, and the resulting calibrated brightness temperatures (Tb) are nearly equivalent to thermometric temperature, specifically a vertically-weighted average of atmospheric temperature with the vertical weighting represented by “weighting functions”.

          One might ask, Why do the satellite data have to be adjusted at all? If we had satellite instruments that (1) had rock-stable calibration, (2) lasted for many decades without any channel failures, and (3) were carried on satellites whose orbits did not change over time, then the satellite data could be processed without adjustment. But none of these things are true. Since 1979 we have had 15 satellites that lasted various lengths of time, having slightly different calibration (requiring intercalibration between satellites), some of which drifted in their calibration, slightly different channel frequencies (and thus weighting functions), and generally on satellite platforms whose orbits drift and thus observe at somewhat different local times of day in different years. All data adjustments required to correct for these changes involve decisions regarding methodology, and different methodologies will lead to somewhat different results. This is the unavoidable situation when dealing with less than perfect data.

          After 25 years of producing the UAH datasets, the reasons for reprocessing are many. For example, years ago we could use certain AMSU-carrying satellites which minimized the effect of diurnal drift, which we did not explicitly correct for. That is no longer possible, and an explicit correction for diurnal drift is now necessary. The correction for diurnal drift is difficult to do well, and we have been committed to it being empirically–based, partly to provide an alternative to the RSS satellite dataset which uses a climate model for the diurnal drift adjustment.

          [lots more]

          • OWilson

            Well, that from Dr Spencer is the kind of straight talk one can understand. Thank you.

            Any link to a similar critique of the difficulties collecting and interpreting old (from 1880) steamship intake valve records, ancient tidal gauges, ice core samples, tree rings and weather balloons, and then filling in the 60% or so missing coverage data?

            One could surmise that Dr, Spencer is doing his work on a relatively small budget, compared to NOAA, and NASA’s budget to do the same for the partial terrestrial coverage of instrument data, not to mention the World’s Greatest Scientific Collaboration of all time, involving thousands of Climate Scientists from over 120 countries.the IPCC FAR 1990 Report.

            If you look carefully, the term I used was “relatively easier”.

            “Easier to calibrate” vs “more difficult to calibrate ” are relative terms, that can be, at first glance rather misleading! :)

            But I’m happy we are having this discussion, especially with not a cheap insult, or contrived strawman in sight!

            (Lots more to come!)

          • NiCuCo

            Here is some information on adjustments.

            “Understanding adjustments to temperature data”
            “Berkeley Earth: raw versus adjusted temperature data”
            “Understanding Time of Observation Bias”



ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


See More


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Collapse bottom bar