The Climate System Is Stable

[Chris Knight]

On this blog forecasting expert, Dr J. Scott Armstrong claims that the climate is stable (i.e. no significant change):

To assess stability, we examined the errors from naïve forecasts for up to 100 years into the future. Using the U.K. Met Office Hadley Centre’s data, we started with 1850 and used that year’s average temperature as our forecast for the next 100 years. We then calculated the errors for each forecast horizon from 1 to 100. We repeated the process using the average temperature in 1851 as our naïve forecast for the next 100 years, and so on. This “successive updating” continued until year 2006, when we forecasted a single year ahead. This provided 157 one-year-ahead forecasts, 156 two-year-ahead and so on to 58 100-year-ahead forecasts.

We then examined how many forecasts were further than 0.5°C from the observed value. Fewer than 13% of forecasts of up to 65-years-ahead had absolute errors larger than 0.5°C. For longer horizons, fewer than 33% had absolute errors larger than 0.5°C. Given the remarkable stability of global mean temperature, it is unlikely that there would be any practical benefits from a forecasting method that provided more accurate forecasts.

[Android]

That's absurd, the methodology is complete nonsense for accessing stability of the climate system.

[LadyPakal]

What was the question...?

[Chris Knight]

The full preprint of the paper, methodology and results can be found here.

[Methuselah]

Well I voted 'no'...

I do not believe that the climate is stable, ever has been stable, or ever will be stable (metastable perhaps?)...It is surely homeodynamic, in that it is constantly readjusting to both terrestrial and extraterrestrial forces...

To me, stability requires sameness over time; but I don't think that the available palaeoclimatic data demonstrate that. On this, I agree entirely with the AGW sceptics; climate change is the norm!

[Iceberg]

I agree with 99% of Climate scientists that climate isn't stable per se, but it depends on your view of stable, most people will say that climate has been pretty stable over the last 10,000 years at least compared to the previous 10K. I am not saying there is not small flucuations in rainfall and temperature but geologically wise it's been stable.

[Methuselah]

I agree with 99% of Climate scientists that climate isn't stable per se, but it depends on your view of stable, most people will say that climate has been pretty stable over the last 10,000 years at least compared to the previous 10K. I am not saying there is not small flucuations in rainfall and temperature but geologically wise it's been stable.

Agree 100% with that...