Global Warming Update


October Global Temperature Change*

October Rankings:  1880 -  2019 Temperature Reocrd
Comparisons with 20th Century Global Average Surface Temperature
(Temperatures are not compared here with a pre-industrial baseline)



Change in

Warmest October
1.04°C   1.87°F
2nd Warmest October
0.98°C   0.1.76°F
Coolist October
-0.53°C   -0.95°F
    Data retrieved:
December 3, 2019

*Surface temperature changes relative to 20th Century global average (1901 - 2000)
Source data  NOAA-NCEI State of the Climate: Global Analysis  [Web + data download]

"The combined global land and ocean surface temperature departure from average for October 2019 was the second highest for October in the 140-year record at 0.98°C (1.76°F) above the 20th century average 14.0°C (57.1°F). This value is just 0.06°C (0.11°F) shy of tying the record warm October set in 2015. The 10 warmest Octobers have occurred since 2003; however, the five warmest Octobers have all occurred since 2015. The Octobers in 2015, 2018, and 2019 were the only Octobers with a land and ocean temperature departure from average above +0.90°C (+1.62°F). This was also the 43rd consecutive October and the 418th consecutive month with temperatures, at least nominally, above the 20th century average." [NOAA/NCEI global analysis accessed December 3, 2019]


"The science is sobering—the global temperature in 2012 was among the hottest since records began in 1880. Make no mistake: without concerted action, the very future of our planet is in peril."

~ Christine Lagarde, in 2012
Managing Director, International Monetary Fund


NOAA/NCEI annual global analysis for 2018: 

The 2017 average global temperature across land and ocean surface areas was 0.84°C (1.51°F) above the 20th century average of 13.9°C (57.0°F), behind the record year 2016 (+0.94°C / +1.69°F) and 2015 (+0.90°C / +1.62°F; second warmest year on record) both influenced by a strong El Niño episode. The year 2017 is also the warmest year without an El Niño present in the tropical Pacific Ocean.

2017 also marks the 41st consecutive year (since 1977) with global land and ocean temperatures at least nominally above the 20th century average, with the six warmest years on record occurring since 2010. Since the start of the 21st century, the global temperature has been broken five times, three of those being set back to back (2014–2016). The yearly global land and ocean temperature has increased at an average rate of 0.07°C (0.13°F) per decade since 1880; however, the average rate of increase is twice as great since 1980. From 1900 to 1980 a new temperature record was set on average every 13.5 years; however, since 1981 it has increased to every 3 years.

Overall, the global annual temperature has increased at an average rate of 0.07°C (0.13°F) per decade since 1880 and at an average rate of 0.17°C (0.31°F) per decade since 1970."

[NOAA/NCEI global analysis for 2018 accessed February 18, 2019].


"Globally-averaged temperatures in 2015 shattered the previous mark set in 2014 by 0.23 degrees Fahrenheit (0.13 Celsius). Only once before, in 1998, has the new record been greater than the old record by this much."

~ NASA Goddard Institute for Space Studies [NASA post of January 20, 2016]


Before the end of 2015, scientists projected that average global temperature increase for 2015 will exceed 1°C above pre-industrial levels.  The years 1850-1990 are used as the pre-industrial baseline by the MET Office and Climate Research Unit at the University of East Anglia in the UK.  The MET Office released this statement in November 2015:


"This year marks an important first but that doesn't necessarily mean every year from now on will be a degree or more above pre-industrial levels, as natural variability will still play a role in determining the temperature in any given year.  As the world continues to warm in the coming decades, however, we will see more and more years passing the 1 degree marker - eventually it will become the norm."

~ Peter Stott
Head of Climate Monitoring and Attribution (MET Office)


>> Read More


Annual GHG Index (AGGI)

NOAA-ESRL posts an Annual Greenhouse Gas Index (AGGI) by setting a simple, understandable way to measure the warming-influence of long-lived trace gases and track changes each year.  The AGGI was designed to bridge the gap in understanding of changes in greenhouse gases (GHGs) that exists between scientists and the public.

The AGGI is directy proportional to the direct warming influence ("climate forcings") of the GHGs in the index.  The index quantifies the global climate forcings of CO2, CH4 (methane), N2O (nitrous oxide), CFC12, CFC11 and 15 minor GHGs.  In 2014, the five main GHGs accounted for about 96% of climate forcings by long-lived GHGs since 1750, the pre-industrial baseline used by the IPCC.  The remaining 15 minor halogenated gases contributed about 4%.  The index is based on measurements of long-lived greenhouse gases and, NOAA states, the index contains little uncertainty.

Changes in the AGGI are reported from 1979 (AGGI = 0.785) until present (2014: AGGI = 1.356).   The index uses 1990 as a baseline year with a value of 1.  The index increased every year since 1979.  The chart below shows the similar trajectory of CO2 and the AGGI.

NOAA Annual GHG Index

Source Graphic  NOAA Annual Greenhouse Gas Index (AGGI)



Global Average Abundances of Major, Long-Lived Greenhouse Gases

Global Average Concentrations for Major GHGs

Source Graphic  NOAA Annual Greenhouse Gas Index (AGGI) 





Butler, J.H. & Montzka, S.A. (2015) The NOAA Annual Greenhouse Gas Index (AGGI). Published online Spring 2015, retrieved October 5, 2015, from



Atmospheric Greenhouse Gas Data


GAW Programme Data Collection

For CO2, 50 WMO countries contributed CO2 data to the GAW World Data Centre for Greenhouse Gases (WDCGG).   Of these, about 50% are obtained from sites that make up the NOAA-ESRL cooperative air sampling network.  Other data contributors on the GAW network are Australia, Canada, China, Japan and many countries in Europe.  The WDCGG publishes a list of contributing sites and countries that collect CO2 and other greenhouse gas data.


GAW  World Data Centre for Greenhouse Gases (WDCGG)

GAWSIS   GAW Station Informaiton System


More GHG Data


NOAA  Global Trends in Atmospheric Methane (CH4)

WMO  Greenhouse Gas Bulletin (updated annually)

WMO  Latest Greenhouse Gas Bulletin: Nov. 2014 [.pdf]


CDIAC  Blasing | Recent GHG concentrations  [Related: tools + sites]

AGAGE (.txt)  Atmospheric concentrations for 8 GHGs (including CH4)

AGAGE  Charts | Atmospheric concentrations of 33 compounds

AGAGE  Atmospheric concentrations of 33 compounds | index of .txt files




MIT  400 ppm? Add other GHGs, and it's equivalent to 478 ppm



CO2 Past.  CO2 Present.  CO2 Future.