New Scientist jumps the climate gun

Is the Pacific Jet Stream drifting poleward?

This week’s prize for jumping the climate gun goes to New Scientist, twice.

Firstly, it tells us that low sea ice levels in Antarctica signal a permanent shift. This, they say, because for the second year in a row Antarctic sea ice has reached near-record low levels, “initiating concern that climate change has initiated a ‘regime shift’ in the amount of ice that forms in the Southern Ocean each year.”

Sorry New Scientist, but two years does not a trend make. Looking at the data, 2023 was indeed a record low and 2024 slightly above that, but if you look at previous years, especially the 2011–2020 average, you will see no trend, just confirmation that 2023 and 2024 are outliers. Much more data than the past two years will be required to signal a permanent regime change.

Their second example of spurious trend-setting concerns the questions of if there is a long-term poleward shift in the jet stream, and if it might be the result of global warming.  The jet stream is powered by the Earth’s rotation and by temperature differences between the tropics and higher latitudes. Its poleward drift is a prediction of some climate models.

According to New Scientist, a new analysis indicates that the Pacific Jet Stream has started its poleward drift, moving at 30–80 km a decade. The problem with this research, which is clearly stated in the paper, is that the Jet Stream’s natural bounds of variability are not known, and despite the data going back several decades, if the past ten years are excluded from the analysis then no poleward trend is seen. The researchers say it’s going to take to the end of this century to be sure of any systematic Pacific Jet Stream drift.

Over the past few months, something very unusual has been happening in the equatorial Atlantic Ocean. Temperatures have declined at their fastest for over 40 years. Climate scientists are at loss to explain it, as the usual culprit – trade winds – haven’t developed as expected.

It has been called an “Atlantic Niña.” Along with the developing La Niña in the Pacific, it is expected to reduce global temperatures. It’s a puzzle, as the equatorial Atlantic was hot throughout 2023 – in fact the warmest for decades. Again the reaction by some has been alarmist, fearing that the climate system has gone off the rails, but my initial response is to wait and see, as it is probably an example of misunderstanding of natural variability.