Thursday, February 16, 2023

GISS January global temperature up by 0.06°C from December.

The GISS V4 land/ocean temperature anomaly was 0.87°C in January 2023, up from 0.81°C in December. This rise is rather more than the 0.014°C rise reported for TempLS. GISS seems to have more warmth in N America and Europe than TempLS.

As usual here, I will compare the GISS and earlier TempLS plots below the jump.

Here is GISS V4

And here is the TempLS V4 FEM-based plot

This post is part of a series that has now run for seven years. The GISS data completes the month cycle, and is compared with the TempLS result and map. GISS lists its reports here, and I post the monthly averages here.
The TempLS mesh data is reported here, and the recent history of monthly readings is here. Unadjusted GHCN is normally used, but if you click the TempLS button there, it will show data with adjusted, and also with different integration methods. There is an interactive graph using 1981-2010 base period here which you can use to show different periods, or compare with other indices. There is a general guide to TempLS here.

The reporting cycle starts with a report of the daily reanalysis index on about the 4th of the month. The next post is this, the TempLS report, usually about the 8th. Then when the GISS result comes out, usually about the 15th, I discuss it and compare with TempLS. The TempLS graph uses a spherical harmonics to the TempLS mesh residuals; the residuals are displayed more directly using a triangular grid in a better resolved WebGL plot here.

A list of earlier monthly reports of each series in date order is here:

  1. NCEP/NCAR Reanalysis report
  2. TempLS report
  3. GISS report and comparison with TempLS


  1. Nick, I suppose you have noticed that in WUWT clicking on a + after one of your comments usually results in 2 minuses. This seems juvenile as well as dishonest.

    1. Hi Ken,
      No, I haven't noticed. I'm not allowed to click on them, which is maybe just as well.

      Actually I do occasionally get positive scores, usually late in the day.

      I've never been worried about downvotes - it's just a useful guide to what is being read. Although with your information, maybe not so useful.

  2. Speaking of your comments on WUWT: I noticed you engaged in the methane discussion. One part that annoys me is the complete misunderstanding of how to apply the GWP. Clyde says, "Assuming that the equivalent long-term global warming potential of CH4 is about 32X that of CO2, the reduction goal would be equivalent to 0.044 ppmv of CO2 (32 x 0.0014)." But the GWP is NOT meant to be applied to concentrations - it is meant to be applied to mass emissions. For concentrations, there are radiative forcing equations - 5.35*LN(C/C0) for CO2, and approximately 0.03*(sqrt(M)-sqrt(M0)) for methane (ignoring interaction terms with N2O, and in both cases using the simpler IPCC TAR equations rather than the AR6 equations). Sigh.