The global temperature anomaly, as read by the UAH satellite system, dropped in January about 0.03 C to + 0.12C. This follows a drop of 0.25C to +0.15C in December of last year. Since the last El Nino, when the anomaly peaked out at +0.50C in February 2020, the anomaly has dropped by 0.38C.
. NOTE: We have changed the 30-year averaging period from which we compute anomalies to 1991-2020, from the old period 1981-2010. This change does not affect the temperature trends.
Dr Spencer’s note above, alerts the reader that the anomaly chart was change beginning in January 2021. I believe the scientific organization are all remaking their charts to comply with the new averaging period. I suspect that it is to make more room above the averaging period.
Why is the global temperature falling? Has something happened to the Green House gases? Let us take a quick tour of the natural forces and see what part they are playing.
El Nino-Southern Oscillation
Currently the La Nina is dominating the Tropical Pacific Ocean. NOAA published an advisory saying:
La Niña—the cool phase of the El Niño-Southern Oscillation climate pattern—was firmly in place across the tropical Pacific in December 2020. Forecasters estimate a 95% chance La Niña will last through Northern Hemisphere winter. La Niña can influence seasonal climate in the United States. Conditions so far have not looked especially La Niña-like, but winter is far from over.
El Nino -La Nina is a naturally occurring phenomena in that it has been observed much longer than the industrial era of fossil fuel C02 emissions.
Solar Cycle 25
Solar Cycle 25 has been underway since December 2019. The forecasts comparing SC 25 to SC24 were mostly that they would be comparable. Cycle 24 was the least active SC in 100 years.
The more active the sun is, the more solar wind and conversely a less active sun produces less solar wind. The Sun’s magnetic field carried by the solar wind regulates the number of cosmic rays that enter the atmosphere. The less active the sun, more cosmic rays enter the atmosphere. Thus, low activity should form more cloud cover, thus increasing the albedo. A briefing on how this works is briefly described by a posting on GWPF titled “Force Majeure, The Sun’s role in climate control”, written by Henrik Svensmark:
“The fundamental idea is that cosmic ray ionisation in the atmosphere is important for the formation and growth of small aerosols into CCN, which are necessary for the formation of cloud droplets and thereby clouds. Changing the number density of CCN changes the cloud microphysics, which in turn changes both the radiative properties and the lifetime of clouds.” (CNC is an acronym for Cloud Condensation Nuclei)
This would reduce the amount of solar radiation that reaches the Earth’s surface, thus reducing global temperature.
Currently, the solar activity is at a low.
So, where are we?
The El Nino is a natural phenomenon, that raises the global temperature, and it is usually followed by a La Nina that results in a lowering the global temperature. We are experiencing a La Nina now.
Solar Cycle 25 in underway and it is forecast to be of low activity. Time delays are often suggested for the impact of Solar Cycles activity. This may be the case here and that the impact of Solar Cycle 24 is just now beginning to be felt.
Part two will look briefly at two other natural phenomena that many believe are important in effecting the global temperature. They are the Atlantic Multidecadal Oscillation (AMO) and the Pacific Decadal Oscillation (PDO).