Sentences with phrase «ar4 model projections»

Figure 5: Comparison of observed September minimum Arctic sea ice extent through 2008 (red line) with IPCC AR4 model projections.

They misplaced observations relative to AR4 model projections (presumably due to an error in transposing reference periods).

O.K. so it may be possible to misconstrue the summary for policymakers, but if you actually go back and look at the science (in this case the AR4 model projections) it is completely clear that the observations are consistent with the models.

The uncertainty envelopes from AR4 model projections really are the ones that matter for assessing model performance over the past decade, and the meaning that can be attached to IPCC claims of «certainty».

Not exact matches

It is not all that earthshaking that the numbers in Schmittner et al come in a little low: the 2.3 ºC is well within previously accepted uncertainty, and three of the IPCC AR4 models used for future projections have a climate sensitivity of 2.3 ºC or lower, so that the range of IPCC projections already encompasses this possibility.

Well, because soon (as soon as December 2005) the leading authors of the Intergovernmental Panel on Climate Change (aka IPCC) Assessment Report # 4 (AR4) will have to decide what the current knowledge in climate state, modeling and climate projection estimates is, so as to include it in the next report.

Figure 5 Comparison of the three measured data sets shown at the outset with earlier IPCC projections from the first (FAR), 2nd (SAR) 3rd (TAR) and 4th (AR4) IPCC report, as well as with the CMIP3 model ensemble.

To give people an idea of what should really be expected from looking at GCM results: the AR4 model cast exhibits a range of decadal trends for 2000 - 2010 projections between about 0.0 ºC / Decade and 0.40 ºC / Decade.

We can therefore again compare the Scenario A2 multi-model global surface warming projections to the observed warming, in this case since 2000, when the AR4 model simulations began (Figure 9).

A classic case in point was the discovery that field observations of the loss of arctic sea ice showed that by 2007 it had advanced to a level predicted by the mean of models of that loss as occurring in the 2100s, while that mean was used as the consensus projection in AR4.

Projections of sea level rise are larger than in the AR4, primarily because of improved modeling of land - ice contributions.»

I have always presumed that the elimination of the 1.5 to 2.0 interval was seen as critically necessary to avoid (further) embarrassing questions about the mismatch between the cited likely range and the range apparent in the models used to make the AR4 projections.

If we examine the climate models chosen by the IPCC to make their projections of future climate change resulting from human greenhouse gas (and particulate) emissions, we find that instead of using models with a 20 percent lower transient climate sensitivity, the transient sensitivity of the models used by the IPCC is the same in the AR5 as in the AR4.

While many more model simulations were conducted in support of the IPCC AR5 (Collins et al., 2012) under a wide range of forcing scenarios, projections of the behavior of the AMOC over the 21st century and beyond have changed little from what was reported in the IPCC AR4 (Meehl et al., 2007b).

Well, speaking only of Queensland, Chapter 11 of AR4 WG1, Regional Climate Projections, was very careful to make no specific projections for Australia and Queensland until 2080 - 2099 -LRB-(fig. 11.17), by when only those under 30 now are likely to be alive to verify whether its actual prediction of NO FLOODS in the Western Pacific proved correct: ALL 21 of the models deployed to make that prediction actually forecast precipitation at LESS than the average in 1Projections, was very careful to make no specific projections for Australia and Queensland until 2080 - 2099 -LRB-(fig. 11.17), by when only those under 30 now are likely to be alive to verify whether its actual prediction of NO FLOODS in the Western Pacific proved correct: ALL 21 of the models deployed to make that prediction actually forecast precipitation at LESS than the average in 1projections for Australia and Queensland until 2080 - 2099 -LRB-(fig. 11.17), by when only those under 30 now are likely to be alive to verify whether its actual prediction of NO FLOODS in the Western Pacific proved correct: ALL 21 of the models deployed to make that prediction actually forecast precipitation at LESS than the average in 1980 - 1999.

The «pause» and the many observation - based studies showing a much lower 2xCO2 ECS than previously predicted by the models cited by IPCC in AR4, gave IPCC the possibility for a paradigm shift to refocus away from its CAGW premise to one of reduced warming projections based on the lower observed CO2 sensitivity.

Thus changing the offset has the potential to change more than just whether they appear to agree, this change appears to invalidate a major explanation and basis for confidence in model projections of AR4.

AR4 WGI discusses extreme weather mostly in the context of model «projections» (which are often contradictory on regional scale and therefore are «more likely than not» better used as toilet paper:) Despite the title of their report, WGI says little «The Physical Science Basis» of extreme weather.

And until this basic weakness can be satisfactorily resolved, all the rest of AR4 (regarding model - derived climate sensitivity and projections of future climate trends, etc.) rests on a weak foundation and is highly questionable.

Precisely zero of the IPCC AR4 model simulations (discussed here for instance) used an interactive ozone module in doing the projections into the future.

# 8 IPCC AR4 should publish such decadal estimations from models, instead of the sole 2100 projection.

The climate projections presented in the IPCC AR4 are from the latest set of coordinated GCM simulations, archived at the Program for Climate Model Diagnosis and Intercomparison (PCMDI).