Weather, and climate, are existential issues for those working in agriculture, so it's little wonder that the hoo-ha of the past couple of decades about climate change has been a concern, and the events of the past decade and a half are particularly interesting. Or rather, the non-events have been interesting since climate change as measured by global temperatures has been flat, or only very slightly rising, in contradiction of the alarmist community's predictions of markedly rising temperatures.

The weather is still changing as ever, and local climate changes following some mysterious pattern, or lack of pattern, it isn't clear which, within some set of historical bounds relating to geography. For example, the USA has been generally warm while Europe has been generally cold lately, for a net near zero. How can this be explained?

I. IPCC AGW hypothesis: 20th century climate variability/change is explained by external forcing, with natural internal variability providing high frequency ‘noise’. In the latter half of the 20th century, this external forcing has been dominated by anthropogenic gases and aerosols. The implications for temperature change in the 21st century is 0.2C per decade until 2050. Challenges: convincing explanations of the warming 1910-1940, explaining the flat trend between mid 1940's and mid 1970's, explaining the flat trend for the past 15 years.

II. Multi-decadal oscillations plus trend hypothesis: 20th century climate variability/change is explained by the large multidecadal oscillations (e.g NAO, PDO, AMO) with a superimposed trend of external forcing (AGW warming). The implications for temperature change in the 21st century is relatively constant temperatures for the next several decades, or possible cooling associated with solar. Challenges: separating forced from unforced changes in the observed time series, lack of predictability of the multidecadal oscillations.

III: Climate shifts hypothesis: 20th century climate variability/change is explained by synchronized chaos arising from nonlinear oscillations of the coupled ocean/atmosphere system plus external forcing (e.g. Tsonis, Douglass). The most recent shift occurred 2001/2002, characterized by flattening temperatures and more frequent LaNina’s. The implications for the next several decades are that the current trend will continue until the next climate shift, at some unknown point in the future. External forcing (AGW, solar) will have more or less impact on trends depending on the regime, but how external forcing materializes in terms of surface temperature in the context of spatiotemporal chaos is not known. Note: hypothesis III is consistent with Sneyers’ arguments re change-point analysis. Challenges: figuring out the timing (and characteristics) of the next climate shift.

I read once that when experts agree that a non-expert cannot assume the contrary, and that when experts disagree that a non-expert cannot assume either case, and that when experts are uncertain that the non-expert must stand aside and await developments.

It seems to me that we have expert disagreement with some uncertainty, and so a non-expert like me should stand down. I have no way to decide, and so should not do so. The general increase in measured global temperature, and the increase inferred from proxies (ice, trees, etc.), and the measured increase in GHG concentrations are worth attention, but it isn't clear that they matter when things like cyclical variation and climate phase change have so much larger impacts. I'm not saying that they don't, I'm saying that it isn't clear to me.

FWIW the author of the post, Judith Curry, concludes:

IMO, the standard 1D energy balance model of the Earth’s climate system will provide little in the way of further insights; rather we need to bring additional physics and theory (e.g. entropy and the 2nd law) into the simple models, and explore the complexity of coupled nonlinear climate system characterized by spatiotemporal chaos.

The 1d model is the IPCC approach:

Hypothesis I derives from the 1D energy balance, thermodynamic view of the climate system, whereas Hypothesis III derives from a nonlinear dynamical system characterized by spatiotemporal chaos. Hypothesis II derives from climate diagnostics and data analysis.

I have been most comfortable with hypothesis II, but that's just familiarity rather than reasoned judgment.