No confidence in uncertain predictions
Hurricane Milton. October 2024.
Some climate campaigners, and not a few scientists, forget that in a changing system, like the warming of the climate, not all the climate change parameters will be moving in the same direction, especially given that natural variability can be larger than human-made effects.
This leads to the question of where you place the point at which such changes cast doubt on the prevailing narrative of a climate crisis? You don’t have to look hard to see these changes in contemporary climate research.
Not everywhere is warming; far from it. According to scientists from three Chinese research institutions, including the Academy of Meteorological Science, writing in Environmental Research Letters, Autumn air temperatures in Eurasia have been declining for the past 20 years, at a rate of 5.38% per decade, a non-trivial amount.
Not all ice is decreasing. Antarctic ice is increasing after at least 20 years of decline. Chinese researchers, using NASA’s GRACE satellites that determine the glacier mass by its gravitational effects, found that between 2002 and 2010 the polar cap lost 74 bn tonnes a year, a figure that almost doubled between 2011 and 2020. However, more recent data have shown an increase of 108 bn tonnes. It will be interesting to see if this trend continues. Coupled with the so-called ‘ice-pause’ observed in the Arctic since 2012, the possibly similar behaviour is noteworthy.
The clouds are changing as well. James Hansen, who started the recent political concern in global warming in the 1980s, has jointly published a paper that details the well know global reduction in cloud cover over the past 25 years. Clouds, as is known, are a great uncertainty in climate models and Hansen’s paper is contradictory, avoiding the pertinent question as to why there is more sunlight than 25 years ago!
You might be aware that hurricane season has begun, along with the now customary predictions that we are due for an intense season. NOAA has excelled itself with its forecast, which gives a 60% chance of an above-normal season, a 30% chance of a near-normal season and a 10% chance of a below-normal season. NOAA says it has a 70% confidence in these figures. This is meaningless! I note that there has been no statistical change in hurricane statistics for at least 54 years!
A similar approach is used in forecasting the global temperature for the next few years. The World Meteorological Organisation says there is a 70% chance that the 2025–2029 period will be more than 1.5°C hotter than the pre-industrial period. They say there is an 80% chance of a record warm year in this period. They are probably 80% confident in their prediction, but I wonder how confident they are in their estimation of the confidence in their prediction?