Was July 2019 the Hottest Month ever recorded?

Was July 2019 the Hottest Month ever recorded?

Hottest Month ever recorded: July 2019

June 2019 was the hottest June ever recorded. Now that July has completed and the first batch of numbers are in, the Copernicus Climate Change Service (C3S), a program of the European Union, has officially released the details for July 2019. Was July 2019 the hottest month, as is being claimed by many media outlets?

Many who promote the “Hottest Month ever recorded claim” cite C3S as their source. The problem is that C3S don’t actually confirm that it was. The best possible answer from their data is “possibly”. It is not (yet) a definitive “yes”.

Precision matters. The precise turn of phrase here is …

The global average temperature for July 2019 was on a par with, and possibly marginally higher than, that of July 2016, which followed an El Niño event

“Hottest Month” is perhaps open to challenge for a couple of reasons …

  • “Possibly Marginally Higher” is not definitively higher.
  • This is one data source – ERA5. We still need to see what the other independent datasets report as they become available.
  • They do report a record a high … but … that high is within the margin of variation that can be observed between the various independently maintained datasets.

Now that we have that wholly appropriate caveat laid down, let’s take a look at the details.

C3S Details

They have a graphic that shows you the the trend for all Julys and so you can very clearly see the ongoing warming trend over the years.

In the above the Top graph shows you the monthly global-average surface air temperatures for July. Temperatures are shown relative to the (IPCC) baseline of 1850-1900.

The Bottom graph highlights the typical difference between datasets from different institutions for July, by showing the highest, median and lowest estimate. This shows that the difference between the values for ERA5 for July 2016 and July 2019 is smaller than this typical dataset difference. 

Remember, what we have here for July 2019 is data from just one source – the ERA5 dataset from the Copernicus Climate Change Service (C3S). This is maintained by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Union.

Until we get more data from other sources we need to embrace an appropriate degree of caution.

Press Release Explanation

Their announcement with the July 2019 details explains it as follows…

July is typically the warmest month of the year in the global average. July 2016 was previously the warmest of any month on record in absolute terms. It has now been replaced by July 2019, albeit by a margin that is small compared with the typical differences between datasets for previous Julys.   

Compared to the latest standard thirty-year climatological reference period, 1981-2010, July was about 0.56 °C degrees above average. This is close to 1.2°C above the pre-industrial level as defined by the Intergovernmental Panel on Climate Change (IPCC) and about 0.04 °C warmer than July 2016, the previous warmest July in this data record.

The C3S data show that the margin between the temperatures for July 2019 and temperatures for July 2016 is very small. Typically, there is a difference between the values provided by the global temperature datasets of various institutions, and the C3S difference between July 2019 and 2016 temperatures is smaller than this margin.

C3S Summary From Around the Globe for July 2019

Beyond just July 2019, they also point out that 2019 in general has been rather warm globally.

Surface air temperature anomaly for July 2019 relative to the July average for the period 1981-2010. 

Europe

  • July temperatures were just above the 1981-2010 average, with large differences across the continent 
  • Western Europe was above average, largely due to the short, but very intense heatwave in the last week of the month 
  • The eastern parts of the continent were generally below average, particularly so in the north-east

Globe

  • Temperatures were the most above the 1981-2010 average over Alaska, Baffin Island and Greenland, parts of Siberia, the central Asian Republics and Iran, as well as large parts of Antarctica.
  • Africa and Australia were above average over almost all of each continent. 
  • Areas with temperatures below the 1981-2010 average include mid-western Canada and parts of Asia, and over the Weddell Sea and inland from there over Antarctica.

C3S have a good quote as well …

Jean-Noël Thépaut, Head of the Copernicus Climate Change Service (C3S), comments:

“While July is usually the warmest month of the year for the globe, according to our data it also was the warmest month recorded globally by a very small margin. With continued greenhouse gas emissions and the resulting impact on global temperatures, records will continue to be broken in the future.”

He is of course speaking European. Permit me to translate that for you …

“If we don’t address Climate change then we are F***ed”

Further Reading on the Hottest Month

Washington Post (Aug5th 2019): Here’s how the hottest month in recorded history unfolded around the world

Wildfires raged across millions of acres in the Arctic. A massive ice melt in Greenland sent 197 billion tons of water pouring into the Atlantic Ocean, raising sea levels. And temperature records evaporated, one after another: 101.7 degrees Fahrenheit in Cambridge, England, and 108.7 in Paris. The same in Lingen, Germany.

“We have always lived through hot summers. But this is not the summer of our youth. This is not your grandfather’s summer,” U.N. Secretary General António Guterres told reporters as July gave way to August.

“Hottest Month” Tweets

While we can’t be totally sure it truly was the hottest month ever recorded … yet, … the sentiment being articulated is wholly appropriate. Doing nothing meaningful about Global Warming is really not a viable option …

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