IPCC WGI: Temperature Forecasts Off

Fifteen-year-long hiatus periods are common
– IPCC AR5 “Technical Summary“, released 9/30/2013

The IPCC calls it a “hiatus”. IPCC skeptics call it “The Pause”. But everyone agrees that earth’s temperature hasn’t risen over the last 15 years.

The IPCC dismisses the importance of “hiatus” periods. They are mentioned in the IPCC’s newest AR5 report just released, but hidden in it’s deepest darkest recesses.

One of those recesses is the “Technical Summary“. In that summary there is a graph presenting the IPCC’s most fundamental data element: Temperature. The graph is called TS.3, Figure 1.

The graph proves that the latest, greatest newfangled CMIP5 modeling tools invented specifically for AR5 should be tossed out!!!

The IPCC Identifies a “Hiatus”

TS.3, Figure 1 (Source: IPCC AR5 Technical Summary)

Above is an annotated version of TS.3, Figure 1. It only includes the top half of the graph because that is the only part identifying a “hiatus” in earth’s temperature over the last 62 years.

It still looks complicated to ordinary folks.
Lets strip away the mystery and scientific mumbo jumbo:

  • The red hashed columns show earth’s actual temperature rise
  • The grey vertical bars show IPCC model temperature predictions
  • The chart furthest left shows the most recent “hiatus”
  • HadCRUT4 is a global sea/earth temperature database
  • CMIP5 is a brand new modeling tool invented specifically for AR5
  • Temperature rise is listed in degrees per decade
  • Date range is from 1951-2012 inclusive (6 decades)

The red hashed columns above show what actually happened with earth’s temperature compared to the newest CMIP5 modeling.

The graph at left shows CMIP5 didn’t come remotely close to “forecasting” the temperature rise of the last 15 years. That’s the “hiatus”.

On the other hand, the middle graph shows that CMIP5 “forecast” less temperature rise for the 15-year period prior to that than what was actually observed!!

The last graph reveals that CMIP5 “forecast”, on average, a lower temperature rise for the last 62 years than was actually measured.

As shown above, CMIP5 modeling completely missed two “hiatus” periods and folded both into the hot 15-year period sandwiched between. That’s shown in the rightmost graph.

The graphs below show that virtually all earth’s temperature rise in the last 67 years occurred in a 20-year period from 1978-1998.

Earth Temperature Profile

Earth temperature change 1850-2012 (Source: IPCC AR5)

Temperature rise since 1935 (AR5)

Earth CO2 since 1958 (Source: IPCC AR5)

These three IPCC graphs compare, by year, earth’s measured temperature rise to its atmospheric CO2 rise.

The top graph shows a two stair-step increase in Earth temperature within three “hiatus” periods since 1850.

The graph on the left just shows the top graph starting from 1935 for comparison purposes.

The graph at right shows a steady, logarithmic increase in atmospheric CO2 rise since 1958.

The CO2 graph is positioned to show CO2 rise in context with both temperature graphs above and to the left.

It is clear that the steady, logarithmic rise in CO2 is not reflected in earth’s actual temperature profile, nor in the CMIP5 model forecasts shown in TS.3, Figure 1.

In AR5, the IPCC acknowledges the existence of other temperature “hiatus” periods, but identifies none outside the most recent one. The graphs above show there have been two other rather long “hiatus” periods since 1850. CMIP5 doesn’t account for any “hiatus”.


The newest CMIP5 model predictions are totally consistent with the observed atmospheric CO2 rise. No problem there.

However, both CMIP5 modeling and observed CO2 are clearly inconsistent with earth’s actual measured temperature rise since 1850. Huge problem there!

The temperature graph since 1850 confirms that “hiatus” periods are common just like the IPCC says.

However, CMIP5-based assessments of the effects of climate change require that CMIP5 models accurately forecast temperature changes, including the stair-step “hiatus” periods. Everything else depends on it.

CMIP5 does none of that. CMIP5 fails to accurately link chunky temperature rises to steadily increasing CO2 emissions.

As strange as this sounds, nature has already invalidated the IPCC’s latest, greatest CMIP5 models in the just released AR5 report!

When CMIP5 can’t correctly “forecast” the past then it’s useless for forecasting the future.

TS.3, Figure 1 proves it’s time to discard CMIP5 for another better modeling method.


About azleader

Learning to see life more clearly... one image at a time!

Posted on Oct 7, 2013, in Climate, economics, Economy, environment, Government, IPCC, nature, news, Politics, science. Bookmark the permalink. Leave a comment.

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