2021 finishes as 4th Warmest year

The Average temperature anomaly for 2021 was O.80 C above the 1961-1990 average. This is cooler than recent years probably due to La Nina. The warmest year overall was 2020 reaching 0.90 C. These calculations (spherical triangulation) are now based on the latest GHCN V4 for the station data and HadSST4 for the SST data. Upgrading  from HadSST3 to HadSST4 has also increased slightly the net warming trend (see previous post).

The final month December saw a further drop in temperature from November of 0.10 C.You can see below that a strong La Ninja redeveloped in December after nearly disappearing in October/November.  Also notice the very cold December temperatures across Western  Canada and Siberia.

Spatial temperatures for December.

The monthly and annual data can be downloaded at these links

I  suspect these results will be very similar to those of HadCRUT5

About Clive Best

PhD High Energy Physics Worked at CERN, Rutherford Lab, JET, JRC, OSVision
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8 Responses to 2021 finishes as 4th Warmest year

  1. Thanks for sharing this. What do you think about satellite data, compared to station data?

  2. I’d love to participate in a public discussion with other scientists about satellite data vs surface station data of all types, with respect to global interpretations. The earth scientists I work with seem to nominally accept satellite data. But few appear interested in a robust and public discussion of why earth temperatures that are widely reported through sources ranging from UK Met to NASA GISS and BEST, cannot be corroborated by continuous coverage by satellite.

    Temperature trends based on popular operational satellite reanalyses don’t align with a global warming narrative. But that should be a further reason to explore and discuss. Scientists are supposed to explore and discuss inconsistencies. Otherwise, objectivity degrades into partisanship and only partisans reap the benefits.

    • Clive Best says:

      I am not an expert in the satellite data. As I understand it their temperatures are based on microwave emissions from oxygen in the lower atmosphere. The advantage they have over station and buoy/ship data is that they have full spatial coverage . Station data are fixed positions and their location and accuracy varies with time.

      So the uncertainty lies in the calibration for satellite data and in the “corrections” for station data. The station corrections are for station moves and instrumentation. The base measurement is the Tmax and Tmin per day. So Tav =(Tmax+Tmin)/2

      One concern I have is the tendency to automate systematic corrections. This forces data to correlate to nearby stations in a pair wise optimization. However these can be hundreds of miles apart and at different altitudes. If you instead just use the raw measurement data you always find less warming trend.

    • Steve McGee says:

      You may be interested in the vertical profiles I have updated here:


      For the MSU era, MSU,RAOB and Reanalysis are relatively consistent.

      There are large discrepancies between models and observations ( including the somewhat prognostic “reanalysis” ).

      Temperature, clouds and humidity largely determine outgoing radiation.
      Clouds largely determine net-of-reflection incoming solar radiation.
      Winds determine motion of thermal energy within the atmosphere and of course the ‘weather’.

      There would appear to be no basis for belief that climate models can accurately predict the future state of the atmosphere.

  3. Thanks! we’ve been going at things from a geostrophic satellite reanalysis set of resources and are moving into the surfaces and profiles for explorations of interesting patterns in co2, ozone, moisture, temperature and divergence of latent heat along with winds and ocean circulations. Given interest in this intersection, I can explore datasets I’m developing with any. One example in profile is this ozone time series for the globe by latitude and altitude. The vertical scale is distorted but it seems to fit in some conventions.

    I guess it is the minor but visually interesting effect of some ozone pouring down from the stratosphere to the surface? That’s what I think. I’m also searching literature on the UV-B inflection across the stratosphere where the ozone concentrates.

  4. That’s interesting. I’d like to explore that stratospheric topic more sometime.

    Thanks for the temperature comparison link. To me, based on ERA-Interim data for the surface and for the full atmosphere, it seems that the southern third of the planet is cooling, the middle is stable and the northern third is warming. Almost as if they were three different planets.

    I know that it is important to nonetheless report and/or discuss global temperature averages so I’ll take a close look at the link soon. Maybe this is a good time to bring up a question about anomaly reports. I’ve long been curious why the anomaly convention is used for temperature records favored by many. Most of my background comes from hydrology, where we don’t typically refer to time series that way but rather to the history of the measured value of concern, such as water table, or streamflow rate, or flood height. Then one can always easily develop metrics of variability etc. To me an anomaly means something to take notice of, not a simple departure from a mean.

    I guess an exception in hydrology is drought indexes. But that’s based on numerous other measured variables, including surface temperature. Surface temperature alone is a measured variable, so a drought index makes more sense to me than a temperature anomaly. I’m also curious because the selection of a temperature baseline to produce an anomaly series seems as subjective as anything could be.

  5. Thought I might follow up after all on stratosphere touching the Earth’s surface at winter poles. I know that the tropopause between troposphere and stratosphere, is attributed as the zone where the air becomes dehydrated. So, an equivalent animation to above but for specific humidity might add interest. In this January example, the winter is in full swing in the northern hemisphere. The tropopause might be signified by the green band, which bends to the North Pole’s surface. I don’t know if that is a conventional signature or not. This example again across a profile of the full atmosphere up to 65 km altitude.

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