The Last 3 Months Were the Warmest on Record…

, climate scientist | April 15, 2016, 5:10 pm EST
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Looking for the three warmest months on record?  Well, the first three of 2016 have arrived…

The data for March 2016 temperatures released by NASA show that March 2016 was 1.28⁰C (2.3⁰F) above the average March temperature of the base period of 1951-1980—the third warmest month globally since record-keeping began in the late 1800s.

As a reminder, the warmest year on record, 2015, was the 39th consecutive year in which temperatures have been higher than the 20th century average. It was followed by the two warmest months on record, January and February 2016, and now by the three warmest. March 2016 was not warmer than February but it WAS warmer than January, and also set a record for the warmest March since record-keeping began.

The Japan Meteorological Agency also released its numbers for March against a 20th century baseline, and, unlike NASA, their data show a new record for warmest month since 1891, with March being 1.07⁰C warmer than the base period, warmer than any other month on record.

The consequences of global warming keep happening

The slight reduction in monthly temperature departure from average does not mean that global warming has stopped, or that the consequences of global warming will diminish any time soon. On the contrary, studies show that the CO2 already in the atmosphere has us committed to more warming and sea level rise for years to come.

As a striking example, in April 2016, the Greenland ice sheet melt season (when 10% of the sheet presents surface melting) officially started with alarming rates and at the earliest date ever recorded (the previous record was May 2010).

Sea level continues to rise at the rate of 3.42mm/year, with a total rise of 74.48mm since 1993 as of January 2016, according to NASA.

Global temperatures also drive regional shifts

Other changes are in the air. The Cherry Blossom Festival in Washington, DC is a 3-week celebration of—you guessed it—the famous cherry blossom trees given by the Mayor of Tokyo to DC back in 1912. The festival has historically been timed with the blooming. The parade in 2016 is on April 16—more than three weeks after peak bloom on March 25. It is sad to have a festival to celebrate something that is not there.

The cherry blossoms are not alone in their early arrivals: “spring creep” has been detected years ago, and many studies have since confirmed the phenomenon. Overall, spring weather is already arriving 10 days earlier than it used to.  A study published in October 2015 estimated that the median onset of plant growth in spring will happen three weeks earlier over the next century, as a result of rising global temperatures. In the Sierra Nevada, the onset of spring has already been happening three weeks earlier than historical records.

The National Phenology Network, an organization sponsored by several universities and federal agencies, has been following the phenology of plants and animals around the US for many years. Phenology refers to seasonal or cyclical phenomena such as flowering, emergence of insects and migration of birds, and their timing and relationship with weather and climate—things such as a variety of species expanding polewards or butterflies flying earlier. Their results are used to determine the start of spring, one of the national indicators of climate change used by the US Global Change and Research Program to “communicate key aspects of the changing environment, point out vulnerabilities, and inform decisions about policy, planning, and resource management.” Indicators translate data into usable information, and allow us to see the changes happening on a regular basis, and to evaluate their relevance and importance when planning adaptation to global and climate changes. And those indicators show us that, indeed, the climate IS changing.

There is consensus that global warming is happening

There have been many studies evaluating the consensus on human-caused global warming among the scientific community. One study from April 2016 actually evaluated all studies on consensus and came up with the same conclusion: the consensus on global warming hovers between 90 percent and 100 percent, well in agreement with the 97 percent so often heard. This shouldn’t come as a surprise, since that level of consensus has been found over and over again. Still, the confusion among the American public is large, and only a small percentage think that there is, in fact, a consensus—even as 70 percent believe there is solid evidence of global warming. We must strive for this misconception to end.

And, we must keep up the commitments to increase our sources of renewable energy and reduce our use of gas, coal, and oil, which release the greenhouse gases that are the main cause of global warming. A goal of net-zero emissions by mid-century is not unattainable—it can be done, if we have the right policies and commitments from all levels of government, private businesses, and communities.

UPDATE: NOAA released their data for March 2016, stating: “The March average temperature across global land and ocean surfaces was 2.20°F above the 20th century average of 54.9°F. This was the highest for March in the 1880–2016 record, surpassing the previous record set in 2015 by 0.54°F. March 2016 was also the highest monthly temperature departure among all months on record, at 0.02°F higher than the previous record set just last month. This also marks the 11th consecutive month a monthly global temperature record has been broken, the longest such streak in the 137-year record.”

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  • StevenLJones

    Can anybody explain why there is such a huge difference between what Japan’s monitoring system reports and Nasa? It’s confusing. Is it only 1.07 reported by Japan or 1.22 reported by Nasa? The difference is significant.

    • Astrid Caldas

      Hi Steven, it is due to different methods for processing temperature data. Yes the difference is significant, but within each method the trends are similar in that the recent months have been the warmest since last century.

      • StevenLJones

        Thanks. The UK Guardian media and others have chosen to quote the JMA. Either NASA or JMA must be wrong. I’m sure the deniers will have a field day on how scientist don’t know the correct value. If NASA is correct then we are 0.3 degrees from the 1.5 danger zone. If JMA is correct we still have some time.

      • Astrid Caldas

        Thanks for your comments. It is important to remember that these are monthly data. The 1.5C goal is for annual global average. One hot month contributes, but does not set where we are in the global quest. As for a correct value, neither agency is wrong – as mentioned, it is just different methods, which are explained by each agency and are both valid. More important, both make the point that we need to adopt mitigation measures sooner than later, because the more emissions we release, the more warming we lock in for future years.

      • StevenLJones

        In my understanding of science, 2+2=4 not maybe 4 or 6 or 8. Deniers are going to use it to make NASA look stupid. They will say that scientists can’t agree on anything. For me if we are only 1.07 above the average it allows me to relax a little and not pressure big oil to stop while 1.23 or 1.35 concerns me. What do we do split the difference? Deniers can now cook up their own methodology.

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  • Lyle Crump

    In the Arctic the temperature has been even greater, in some areas 3 C above the averages in the same time period. The Arctic is seen the greatest impact of global warming. http://www.arctic.noaa.gov/reportcard/air_temperature.html
    and here http://climate.nasa.gov/climate_resources/139/ or how most of the far artic was over 5C warmer in Feb. http://earthobservatory.nasa.gov/IOTD/view.php?id=87691

    • Astrid Caldas

      Yes, and that is one of the reasons the ice sheet in Greenland was off to the earliest melt start ever this month. The contribution of arctic ice melt can be a significant factor in the rate of sea level rise, so we got to keep an eye on this one!

  • John

    I have one question that hasn’t been answered yet. You make
    wild claims and show temperature charts with tenths or hundredths of a degree
    on your charts. You show a temperature rise of around 0.8 degrees. Yet your
    weather station and thermometers used to gather this data can only measure to a
    few degrees accurately. How do you ignore the errors in you data? Isn’t it
    impossible to get that kind of resolution? The fact is the measurements you
    make are in the noise of you measurements and are meaningless for all practical
    purposes.

    • Leslie Graham

      Just in case you are actually serious the figures are derived from taking multiple readings and then dividing the total temperature by the number of readings. You know – the way you were taught to do find an average figure in maths class at school when you were about 12 years old.
      Maybe you skipped school that day?
      But in any case the thermometers are accurate to a tenth of a degree anyway so your question is doubly moronic.

      • John

        Well obviously you are like the rest
        of the climatologist. You have errors in your measurements greater than you
        results. Averaging the errors doesn’t make them go away. Try re-reading the
        question and give an intelligent answer. Plus or minus 1 or 2 degrees means your
        results can’t be less that that error and have any meaning. This is a simple
        fact. The errors I am talking about are in your thermometers or temperature sensing
        devices. The numbers you get are not absolute like you obviously assume.