Climate Denial Crock of the Week

Above, an interview with Kevin Trenberth, I think from the Fall AGU meeting in 2015, in which he discusses how global temperature tends to proceed in stair step fashion, with jumps that take place during El Nino events.

EuanMearns:

The basic point at issue can be summarized very simply. Using the “raw” International Comprehensive Ocean-Atmosphere Data Set (ICOADS) SST series as an example, is the post-1976 warming defined by the linear trend shown in Figure 1(a) or by the stair-step jumps shown in Figure 1(b)? (All the temperature data used in this post are from KNMI Climate Explorer unless otherwise specified.)

Figure 1(a) defines “mainstream” AGW thinking and requires no further discussion. The key questions relative to Figure 1(b), however, are whether the stair-step jumps are real and if so what caused them? I claimed in the introductory paragraph that they are a) real and b) caused by Niño/Niña events,..

New Scientist:

A global shift to an El Niño climate pattern later this year could pave the way for the world to breach 1.5°C of warming for the first time in 2024, according to the UK Met Office.

New modelling from the agency suggests the current three-year La Niña phase will end in March and this looks likely to be followed by an El Niño pattern later this year.

“At the moment, the vast majority of forecasts are going into El Niño in the latter half of 2023,” says Adam Scaife at the Met Office.

UPDATE: Mike Mann posted this today

Re-upping this w.r.t. when human-caused warming crosses the 1.5C threshold [spoiler: It's NOT when an El Nino event temporarily breaches that threshold, despite what some headlines today might imply] https://t.co/KRCTHumBTb

— Prof Michael E. Mann (@MichaelEMann) January 17, 2023

New Scientist again:

El Niño and La Niña are terms used to describe fluctuations in Earth’s climate system, driven by changing sea surface temperatures in the equatorial Pacific.

El Niño is declared when sea temperatures in the tropical eastern Pacific rise 0.5°C above the long-term average. La Niña describes the opposite side of the fluctuation, when eastern Pacific temperatures drop below average.

Both phenomena trigger shifts in weather patterns around the world, affecting everything from heatwave risks in Australia to rainfall patterns in Chile. Because El Niño events bring higher than average temperatures, they can also temporarily drive up the global average temperature.

A shift later this year to a strong El Niño that pushes Pacific sea surface temperatures to 3°C above average could temporarily raise the global average temperature by 0.3°C, says Scaife.  This would come on top of the existing 1.2°C increase in global temperatures since pre-industrial times, caused by rising greenhouse gas emissions.

Taken together, it could mean average temperatures in 2024 could reach 1.5°C above pre-industrial levels, he says. “If you add on a big El Niño… then we’re going to get close, potentially, to the first year of 1.5 degrees,” he says.

Countries set a goal to limit global warming to 1.5°C in the 2015 Paris Agreement, but that aim would only be missed if such a temperature rise is sustained over a couple of decades.

Below, most recent Global Surface Temperature graph from NASA Goddard Institute for Space Studies shows a definite bump upward about the time that Kevin and I spoke in 2015, with a flattening in recent years concurrent with the triple La Nina.