Klima: Hvis man har en hypotese…

Diverse, FN, Historie, IPCC, Klima, Pressen, Videnskab — Drokles on August 4, 2015 at 9:56 pm

Weekendavisens Frede Vestergaard har et glimrende interview med professor emeritus ved Fysisk Institut på Aarhus Universitet Jens Ulrik Andersen om klimaspøgelset

»I de sidste 15-16 år har der ikke været nogen signifikant global opvarmning, uanset hvilken af de forskellige temperaturserier du kigger på, og hvad enten de er jordbaserede eller satellit-baserede. De viser med lidt variation en stort set uændret global middeltemperatur, og det er i stærk modstrid med de modelbaserede forudsigelser, som IPCC er kommet med. Så meget mere som CO2-koncentrationen i atmosfæren er steget hurtigere end forventet i 1990erne.

En gang imellem gøres der forsøg på at afvise, at der er en pause. Senest for et par uger i en artikel fra folk tilknyttet NOAA (National Oceanic and Atmospheric Administration), der havde justeret på tidligere års målinger, så pausen forsvandt,« siger Jens Ulrik Andersen og påpeger, at nogle af de ældre klimaeksperter, såsom tysk klimaforsknings grand old man, professor Hans von Storch fra Hamburg, mener, at problemet med global opvarmning overdrives for at skabe opmærksomhed.

»Hans von Storch pegede for et par år siden på, at den globale middeltemperatur ifølge modellerne skulle være steget med 0,25 grader celsius i de foregående ti år, mens den kun var steget 0,06 grader over de sidste 15 år. Der er en kras modsætning mellem modeller og realiteter. Von Storch er en mainstream klimaforsker, og han mener fortsat, at global opvarmning er et problem, men også at udviklingen viser, at det ikke er i sidste øjeblik at handle, hvis ikke verden skal gå under. Vi har god tid til at vente, og derfor skal vi ikke tage alt for voldsomme skridt her og nu.«

(…)

Hvis man har en hypotese, der kan forklare alt, uanset om det går den ene eller anden vej, er den hypotese ikke meget værd. Så kan man aldrig modbevise den.

Det er kernen i videnskab. Hvad er så klimapanelets hypotese? Reasons Ronald Bailey har set på klimapanelets rapport fra 1990, der definerer hvor meget atmosfæres temperatur skal stige førend vi kan sige at menneskets påvirkning kan skelnes fra naturens støj (mine fremhævninger)

8.4 When Will The Greenhouse Effect be Detected?

The fact that we have not detected the enhanced greenhouse effect leads to the question when is this likely to occur? As noted earlier, this is not a simple yes/no issue. Rather it involves the gradual accumulation of evidence in support of model predictions, which in parallel with improvements in the models themselves, will increase our confidence in them and progressively narrow the uncertainties regarding such key parameters as the climate sensitivity. Uncertainties will always remain. Predicting when a certain confidence level might be reached is as difficult as predicting future climate change – more so, in fact, since it requires at least estimates of both future signal and future noise level.

Nevertheless, we can provide some information on the time-scale for detection by using the unprecedented change concept mentioned briefly in Section 8.14. This should provide an upper bound to the time of detection since more sophisticated methods should produce earlier results. We take a conservative view as a starting point namely that the magnitude of natural variability is such that all of the warming of the past century could be attributed to this cause. (Note that this is not the same as denying the existence of an enhanced greenhouse effect. With such a noise level the past warming could be explained as a 1°C greenhouse effect offset by 0.5°C natural variability.) We then assume, again somewhat arbitrarily that a further 0.5°C warming (i.e., a total warming of 1°C since the late nineteenth century) is required before we could say with high confidence, that the only possible explanation would be that the enhanced greenhouse effect was as strong as predicted by climate models. Given the range of uncertainty in future forcing predictions and future model-predicted warming when would this elevated temperature level be reached?

Detection WarmingIPCC

The answer is given in Figure 8.5. [Basically, the upper curve is assumes a fast warming rate and the lower one a slow warming rate. If fast, warming will be detected by 2002; if slow no detection until 2047.]

Figure 8.5 Text: If a further 0.5°C warming were chosen at the threshold for detection of the enhanced greenhouse effect then this would be reached sometime between 2002 and 2047.

On the basis of this simple analysis alone we might conclude that detection with high confidence is unlikely to occur before the year 2000. If stringent controls are introduced to reduce future greenhouse gas emissions and if the climate sensitivity is at the low end of the range of model predictions then it may be well into the twenty-first century before we can say with high confidence that we have detected the enhanced greenhouse effect.

Professor Phil Jones definerede 3 varmeperioder i moderne tid (hvor forskerne sætter lid til termometermålinger) til BBC

skc3a6rmbillede-2015-08-04-kl-214259

Jones forklarer selv på klimapanelets vegne at kun opvarmningen efter 1950′erne kan være påvirket af menneskets udledning af CO2. Det vil sige at naturlig støj, som Bailey skriver, kan sættes til 0,163 grader/årti. Inden 1990′erne var ovre stoppede temperaturen med at stige. Vi er på vej mod to årtier uden temperaturstigninger.

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