The last 10 years are the hottest ever, yet deniers are still in denial

Summary: Despite three years of La Nina, 2022 was the sixth hottest year on record. The last decade was the hottest decade on record.

As you all know by now, we're causing the world to heat up. We've not got to a stage where we've stabilised the global temperature. In fact, we seem to be nowhere near stabilisation. Yet strangely there are still a few global warming deniers floating about. These deniers are arguing once again that an ice age is coming, or it's started cooling, or global warming has stopped, or "CO2 warming is a hoax" or some such nonsense. It's prompted me to write another article about how global temperature has been changing.

According to GISS NASA, the average global surface temperature anomaly for 2022 was 0.89 °C. This is 0.13°C below the hottest year so far. The hottest was 2020 at 1.02°C above the 1951 to 1980 average.

More than 10 years on, Anthony Watts at WUWT is still befuddled by temperature anomalies

It's hard to believe but poor Anthony Watts, despite all the help offered him over the years, is still totally befuddled, perplexed and bamboozled by the notion of temperature anomalies. You know he's not the brightest spark in deniersville yet you'd have thought that by now even he might have learnt something about temperature charts. But no.

The oddest thing is that he's unashamed of being numerically illiterate. He might even regard it as a strength. It means his readers have found someone, somewhere, who's dimmer than they are, and that could be why they keep coming back for more.

Today Anthony wrote about the global average surface temperature for 2019, saying at least in the USA it wasn't another "hottest year". That's a classic conspiratorial diversion tactic, by the way: focus on a detail and try to dispute the big picture.

2019 was the second hottest year on record despite no El Nino

Summary: 2019 was the second hottest year on record. December 2019 was the second hottest December on record. The last decade was the hottest decade on record.

According to GISS NASA, the average global surface temperature anomaly for 2019 was 0.98 °C, which is just 0.04 °C cooler than the previous hottest - 2016.

Below is a chart of the average of 12 months to December each year. 2019 was 0.06 °C hotter than the 12 months to December 2017, which is the third hottest year.

Figure 1 | Annual global mean surface temperature anomaly - 12 months to December each year. The base period is 1951-1980. Data source: GISS NASA

Hottest July and hottest month on record

Summary: July 2019 was the hottest July on record and the equal hottest month on record. The 12 month period to July 2019 was the third hottest  such period on record.

According to GISS NASA, the average global surface temperature anomaly for July was 0.93 °C, which is 0.08 °C warmer than the previous hottest - July 2016.

Below is a chart of the average of 12 months to July each year. 2019 averaged 0.93 °C above the 1951-1980 mean, which was 0.12 °C cooler than the 12 months to July 2016.

This makes it the third hottest August to July 12 month period on record after 2016 and 2017.

2018 has the fourth hottest May on record

Summary: May 2018 was the fourth hottest May on record. The 12 month period to May 2018 was the third hottest June to May period on record.

According to GISS NASA, the average global surface temperature anomaly for May was 0.82 °C, which is 0.09 °C less than the hottest - May 2016.

Below is a chart of the average of 12 months to May each year. The 12 months to May 2018 averaged 0.82 °C above the 1951-1980 mean, which was 0.19 °C cooler than the 12 months to May 2016.

This makes it the third hottest June to May 12 month period on record after 2016 and 2015.

Second hottest October on record, just above October 2016

Summary: October 2017 was the second hottest October on record. The 12 month period to October 2017 was the second hottest November to October period on record.

According to GISS NASA, the average global surface temperature anomaly for October was 0.90 °C, which is 0.18 °C less than the October 2015. October 2017 was just 0.01 °C hotter than the next hottest October in 2016.

Below is a chart of the average of 12 months to October each year. The 12 months to October 2017 averaged 0.90 °C above the 1951-1980 mean, which was 0.13 °C cooler than the 12 months to October 2016.

This makes it the second hottest September to October 12 month period on record.

August 2017 is the second hottest August on record - the #climate is changing

Summary: August 2017 was the second hottest August on record. The 12 months to August 2017 was the second hottest September to August period on record.

According to GISS NASA, the average global surface temperature anomaly for August was 0.85 °C, which is 0.14 °C less than the August 2016. August 2017 was 0.05 °C hotter than the next hottest August in 2014, which had an anomaly of 0.80 °C.

Below is a chart of the average of 12 months to August each year. The 12 months to August 2017 averaged 0.91 °C above the 1951-1980 mean, which was 0.13 °C cooler than the 12 months to August 2016.

This makes it the second hottest September to August 12 month period on record.

2017 has just had the hottest July on record!

Summary: July 2017 was the hottest July on record by just a smidgen. The 12 months to July 2017 was the second hottest August to July period on record.

Because July is the hottest month, it also makes it the hottest month ever on record. Edit: it's been pointed out to me that August last year pipped July 2016 and July 2017 as the hottest month on record.

According to GISS NASA, the average global surface temperature anomaly for July was 0.83 °C, which is 0.01 °C more than the July 2016, making July 2017 the hottest July in the record.

Below is a chart of the average of 12 months to July each year. The 12 months to July 2017 averaged 0.92 °C above the 1951-1980 mean, which was 0.11 °C cooler than the 12 months to July 2016.

This makes it the second hottest August to July 12 month period on record.

June is cooler in 2017 but still the 4th hottest June on record

Summary: June 2017 was the fourth hottest June on record. The 12 months to June 2017 was the second hottest July to June period on record.

According to GISS NASA, the average global surface temperature anomaly for June was 0.69 °C, which is 0.10 °C less than the hottest June in 2016, making June 2017 the fourth hottest June in the record. It's the hottest June in any year when there was no El Nino.

Below is a chart of the average of 12 months to June each year. The 12 months to June 2017 averaged 0.91 °C above the 1951-1980 mean, which was 0.10 °C cooler than the 12 months to June 2016.

This makes it the second hottest July to June 12 month period on record.

Second hottest May on record

According to GISS NASA, the average global surface temperature anomaly for May was 0.88 °C, which is 0.05 °C less than the hottest May in 2016, making May 2017 the second hottest May in the record.

Here is a chart of the average of 12 months to May each year. The 12 months to May 2017 averaged 0.91 °C above the 1951-1980 mean, which was 0.10 °C cooler than the 12 months to May 2016. This makes it the second hottest May to May 12 month period on record.

Figure 1 | Global mean surface temperature anomaly for the 12 months to May each year. The base period is 1951-1980. Data source: GISS NASA

(Google has just made some changes to its charting program, and has yet to iron out some of the kinks. Let me know if you see any problems. I am having trouble seeing the values to the right of the charts. Hopefully it will get fixed soon.)

Second hottest April on record

According to GISS NASA, the average global surface temperature anomaly for April was 0.88 °C, which is 0.18 °C lower than the hottest April in 2016, making April 2017 the second hottest April in the record.

Here is a chart of the average of 12 months to April each year. The 12 months to April 2017 averaged 0.91 °C above the 1951-1980 mean, which was 0.07 °C cooler than the 12 months to April 2016,. This makes it the second hottest April to April 12 month period on record.

Figure 1 | Global mean surface temperature anomaly for the 12 months to April each year. The base period is 1951-1980. Data source: GISS NASA

Second hottest March on record - NASA global temperature update with year to date comparison

According to GISS NASA, the average global surface temperature anomaly for March was 1.12 °C, which is 0.16 °C lower than the hottest March in 2016, making March 2017 the second hottest March in the record.

Here is a chart of the average of 12 months to March each year. The 12 months to March 2017 averaged 0.93 °C above the 1951-1980 mean and was almost identical to the 12 months to March 2016, being just 0.02 °C cooler. This makes it the second hottest April to March 12 month period on record.

Figure 1 | Global mean surface temperature anomaly for the 12 months to March each year. The base period is 1951-1980. Data source: GISS NASA

Second hottest February on record - is another El Niño on the way already?

According to GISS NASA, the average global surface temperature anomaly for February was 1.10 °C, which is 0.22 °C lower than the hottest February in 2016 and the second hottest February in the record.

Here is a chart of the average of 12 months to February each year. The 12 months to February 2017 averaged 0.94 °C above the 1951-1980 mean and was almost identical to the 12 months to February 2016, being just 0.01 °C hotter. This makes it the hottest March to February 12 month period on record.

Figure 1 | Global mean surface temperature anomaly for the 12 months to February each year. The base period is 1951-1980. Data source: GISS NASA

It's still hot! Second hottest November in the NASA GISTemp record

According to GISS NASA, the average global surface temperature anomaly for November was 0.95 °C, which is the second hottest November on record, and only 0.07 °C lower than the hottest November during the El Niño in 2015.

The average for the eleven months to the end of November is 1.01 °C, which is 0.17 °C higher than the previous hottest January to November period in 2015, which with the latest data had an anomaly of 0.84 °C.

Here is a chart of the average of 12 months to November each year. The 12 months to November 2016 averaged 1.02 °C above the 1951-1980 mean and was 0.14 °C hotter than the 12 months to November 2015:

Figure 1 | Global mean surface temperature anomaly for the 12 months to November each year. The base period is 1951-1980. Data source: GISS NASA

Heat continues with a hot October - second hottest on record

According to GISS NASA, the average global surface temperature anomaly for October was 0.89 °C, which is the second hottest October on record, and 0.18 °C lower than the hottest October in 2015. This is despite the fact that NOAA has announced a La Nina advisory.

The average for the nine months to the end of October is 1.02 °C, which is 0.19 °C higher than the previous hottest January to October period in 2015, which with the latest data had an anomaly of 0.83 °C.

Here is a chart of the average of 12 months to October each year. The 12 months to October 2016 averaged 1.03 °C above the 1951-1980 mean and was 0.21 °C hotter than the 12 months to October 2015:

Figure 1 | Global mean surface temperature anomaly for the 12 months to October each year. The base period is 1951-1980. Data source: GISS NASA

Hottest September on record

According to GISS NASA, the average global surface temperature anomaly for September was 0.91 °C, which is just 0.01 °C higher than the previous hottest September in 2014.


The average for the eight months to the end of September is 1.03 °C, which is 0.23 °C higher than the previous hottest January to September period in 2015, which with the latest data had an anomaly of 0.80 °C.

There are now twelve in a row of "hottest months" from October 2015 to September 2016 (that is, hottest October, hottest November etc). If we could look back over the entire Holocene, it's probably more than 7,000 years since there was a similar run of hottest months on record, that is, not since the Holocene climatic optimum (it's probably hotter now than it was back then).

Update: It's just been pointed out to me that the latest revisions put June 16 temperature (0.75 C) below that of June 98 and June 15 (equal 0.78 C). That means that there were now eight months in a row of "hottest" - from October to May inclusive. Then another three hottest months from July to September.

Sou 10:54 am AEDT 18 October 2016

Here is a chart of the average of 12 months to September each year. The 12 months to September 2016 averaged 1.03 °C above the 1951-1980 mean and was 0.23 °C hotter than the 12 months to September 2015:

Figure 1 | Global mean surface temperature anomaly for the 12 months to September each year. The base period is 1951-1980. Data source: GISS NASA

Crikey! Hottest August on record - vies with July for hottest month ever

According to GISS NASA, the average global surface temperature anomaly for August was 0.98 °C, which is 0.16 °C higher than the previous hottest August in 2014.

Because July is the hottest month of the year, I've seen this July reported as the hottest month ever in recorded history! I asked the question whether August beat July and was told it's too close to call.

The average for the eight months to the end of August is 1.05 °C, which is 0.25 °C higher than any previous January to August period. The previous highest was last year, which with the latest data had an anomaly of 0.8 °C.

There are now eleven in a row of "hottest months" from October 2015 to August 2016 (that is, hottest October, hottest November etc). If we could look back over the entire Holocene, it's probably more than 7,000 years since there was a similar run of hottest months on record, that is, not since the Holocene climatic optimum (it's probably hotter now than it was back then).

Here is a chart of the average of 12 months to August each year. The 12 months to August 2016 averaged 1.03 °C above the 1951-1980 mean and was 0.23 °C hotter than the 12 months to August 2015:

Figure 1 | Global mean surface temperature anomaly for the 12 months to August each year. The base period is 1951-1980. Data source: GISS NASA

Hottest July on record - global surface temperature with year to date

According to GISS NASA, the average global surface temperature anomaly for July was 0.84 °C, which is 0.1 °C higher than the previous hottest July in 2011.

Because July is the hottest month of the year, I've seen it reported as the hottest month ever in recorded history!

The average for the seven months to the end of July is 1.06 °C, which is 0.25 °C higher than any previous January to July period. The previous highest was last year, which with the latest data had an anomaly of 0.81 °C.

There are now ten in a row of "hottest months" from October 2015 to July 2016 (that is, hottest October, hottest November etc). If we could look back over the entire Holocene, it's probably more than 7,000 years since there was a similar run of hottest months on record, that is, not since the Holocene climatic optimum (it's probably hotter now than it was back then).

Here is a chart of the average of 12 months to July each year. The 12 months to July 2016 averaged 1.02 °C above the 1951-1980 mean and was 0.21 °C hotter than the 12 months to July 2015:

Figure 1 | Global mean surface temperature anomaly for the 12 months to July each year. The base period is 1951-1980. Data source: GISS NASA

Hottest June on record - global surface temperature with year to date

According to GISS NASA, the average global surface temperature anomaly for June was 0.79 °C, which just pipped June 2015 (0.78 C) and June 1998 (0.77 °C). Last month is only the second time in nine months that the GISTemp monthly anomaly is less than one degree Celsius above the average from 1951-1980. It probably won't be the last, now that El Nino is over.

The average for the six months to the end of June is 1.09 °C, which is 0.28 °C higher than any previous January to June period. The previous highest was last year, which with the latest data had an anomaly of 0.81 °C.

There are now nine in a row of "hottest months" from October 2015 to June 2016 (that is, hottest October, hottest November etc). If we could look back over the entire Holocene, it's probably more than 7,000 years since there was a similar run of hottest months on record, that is, not since the Holocene climatic optimum (it's probably hotter now than it was back then).

Each of the previous months except May and June this year (that is, from October to April inclusive) had an anomaly more than one degree Celsius above the 1951-1980 mean. All of the previous months had an anomaly higher than any month outside of that October to April period.

Below is a chart of the month of June only. Hover over the chart to see the anomaly in any June:

Figure 1 | Global mean surface temperature anomaly for the month of June only. The base period is 1951-1980. Data source: GISS NASA

Hottest May on record with year to date temperature

Yes, another "hottest" on record - this time for May 2016. According to GISS NASA, the average for May was 0.93 °C, which is 0.07 °C above the previous hottest May, in 2014. Last month is the first time in seven months that the GISTemp monthly anomaly is less than one degree Celsius above the average from 1951-1980.  This month the anomaly is the ninth highest for any month, lower than all anomalies from October last year, and lower than that for January 2007.

The average for the five months to the end of May is 1.15 °C, which is 0.29 °C higher than any previous January to May period. The previous highest was last year, which with the latest data had an anomaly of 0.86 °C.

There are now eight in a row of "hottest months" from October 2015 to May 2016 (that is, hottest October, hottest November etc). If we could look back over the entire Holocene, it's probably more than 7,000 years since there was a similar run of hottest months on record, that is, not since the Holocene climatic optimum (it's probably hotter now than it was back then).

All of the previous months (October to April inclusive) had an anomaly more than one degree Celsius above the 1951-1980 mean. All of the previous months had an anomaly higher than any month outside of that October to April period. May this year had an anomaly of 0.93 °C, which is lower than the anomaly in January 2007 (0.96 °C.)

Below is a chart of the month of May only. Hover over the chart to see the anomaly in any May:

Figure 1 | Global mean surface temperature anomaly for the month of May only. The base period is 1951-1980. Data source: GISS NASA