May 2015 Global Surface Temperatures Break Record

NOAA has released the data for average global surface temperature for the month of May. The number is 0.87 degrees C (1.57 degrees F) above the 20th century average for their data set. This is the highest value seen for the month of May since 1880, which is the earliest year in the database. The previous record value for may was last year. This year's May value is 0.08 degrees C (0.14 degrees F) higher than that.

According to NOAA:

  • The May globally-averaged land surface temperature was 2.30°F (1.28°C) above the 20th century average. This tied with 2012 as the highest for May in the 1880–2015 record.
  • The May globally-averaged sea surface temperature was 1.30°F (0.72°C) above the 20th century average. This was the highest for May in the 1880–2015 record, surpassing the previous record set last year in 2014 by 0.13°F (0.07°C).
  • This is the NOAA graph for May temperature anomaly values from 1880 to the present:


    Here is a graph showing the surface temperature averaged over the 12 month periods ending in May (inclusively) for the entire data set:

    Just for fun, I requested the same graph but with a trend line plotted for the time period sometimes referred to by climate science denialists as the "pause" period, which Wikipedia defines as 1998 - 2012. Notice that the trend for the "pause" (aka "FauxPause") is still rising, and that it sits among data that are rising much faster.

    Screen Shot 2015-06-18 at 10.15.08 AM

    And, for the record, the following plot shows a trend line running from the publication of the famous Hockey Stick research by Mann, Bradley & Hughes to the present. This is the amount of surface warming that has happened since, more or less, the full-on birth of the climate science denialism industry.
    Screen Shot 2015-06-18 at 10.18.20 AM

    The amount of warming in the US (where a majority of you'all live) is less than globally, because certain other regions have warmed much more (like the Arctic). But the warming still has an effect. Considering just heat, which for many is compensated for by potentially costly building cooling system, there is more heat and thus more demand for cooling. Heating and cooling engineers express this in terms of "cooling degree days." This is essentially the number of degrees you have to cool a structure accumulated over days, making certain assumptions you can read about here.

    So, how have cooling degree days changed in the US? Here's the graph.

    Screen Shot 2015-06-18 at 10.26.58 AM

    If you live in certain parts of the country, this can be more extreme. The graphic at the top of the post is the change over time in cooling degree days in the American Southwest.

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    Did they revise earlier month temps? That comment about the two largest departures doesn't match the global analysis pages for those months.

    Found the answer to my question during my minimalist-to-avoid-embarrassing-myself exertions:

    The new Sea Surface Temperature [SST] data-set used for the NOAA/NCEI "May 2015 Global Surface Temperature Data Data

    By Same Ordinry Foo (not verified) on 18 Jun 2015 #permalink

    Please delete problems.....

    By Same Ordinary Fool (not verified) on 18 Jun 2015 #permalink

    Looks like "Savetheworldfree" will close due to lack of support wow

    By Alex Reid (not verified) on 19 Jun 2015 #permalink


    If you live in certain parts of the country, this can be more extreme. The graphic at the top of the post is the change over time in cooling degree days in the American Southwest.

    As it happens, that's where I live now. I moved here five years ago, and my house keeps pretty cool without AC, so I haven't noticed the trend personally. But your bar chart is pretty compelling. How did you source it, Greg?

    By Mal Adapted (not verified) on 20 Jun 2015 #permalink