AGU herbevestigt klimaatkommer en -kwel

Voor de klimaatsceptici is de 'mars door de instituties' nog steeds problematisch.

De 'American Geophysical Union' (AGU) heeft haar eerdere verklaring over klimaatverandering onlangs geactualiseerd. Het is weer een en al kommer en kwel - academisch SM. De verklaring staat bol van beweringen die niet door feiten worden gestaafd en/of al overtuigend zijn weerlegd. Dat de opwarming van de aarde zo'n 16 jaar geleden is gestopt schijnt nog niet tot de auteurs te zijn doorgedrongen. Ook de recente inzichten over de lagere klimaatgevoeligheid (het temperatuureffect van een verdubbeling van de CO2–concentratie in de atmosfeer) dan eerder werd aangenomen, lijkt hen te zijn ontgaan.

De bekende Amerikaanse kritische klimatoloog, Roger Pielke Sr., die deel uitmaakte van de redactiecommissie, heeft zich van de inhoud gedistantieerd en daarop een doorwrochte kritiek geleverd.

De onvermoeibare Lord Christopher Monckton heeft zelfs een alternatieve tekst voor de AGU–verklaring geschreven. Ik pik er een aantal passages uit.

Anthropogenic climate change requires no action.

Our influence on the climate is minor but beneficial.

Human activities are changing Earth’s climate, but as the AGU must now concede not by much.

The atmospheric concentration of CO2 has increased from 0.03% before the Industrial Revolution to 0.04% today. Much of this alteration of 1 part in 10,000 of the atmospheric composition may have been caused by burning fossil fuels. The world has warmed by 0.8 C over the past 140 years, but a recent survey of the abstracts of 11,944 scientific papers on global climate change showed only 43 abstracts, or 0.3% of the sample, endorsing the notion that humans were responsible for most of that warming.

The mean residence time of a CO2 molecule in the atmosphere is 7 years, so the AGU must recognize that its earlier fears that anthropogenic emissions will influence the climate system for millennia have proven unfounded.

Observations show that recent modest increases in air and sea temperatures and in sea level have been well within natural variability. Atmospheric water vapor may or may not have increased: we lack the capacity to measure it accurately.

Some (but not all) mountain glaciers have receded, and earlier claims that all ice in the Himalayas would be gone in 25 years have been withdrawn. Most of the world’s 160,000 glaciers are in the Antarctic, nearly all of which has cooled in the past 30 years. Snow cover extent in the northern hemisphere reached a record high December value in 2012. There is no global measurement of permafrost, but its extent has probably changed little. Arctic sea ice has declined since 1979, but Antarctic sea ice has increased, and the AGU must apologize for having given only half the story before.

These changes are within natural variability and need no further explanation, though humans may have had some small influence. The changes are consistent with explanations of climate change that rely on known natural influences but allow for some human contribution.

Climate models predict that global temperatures will continue to rise, with the amount of warming primarily determined by the level of emissions; that higher emissions of greenhouse gases will lead to larger warming and greater risks to society and ecosystems; and that some additional warming is unavoidable owing to past emissions. Yet the models have consistently over-predicted global atmospheric and oceanic warming. According to satellite measurements, for 16 years 8 months, or 200 months, there has been no global warming at all. And, though some 0.2 C warming should have occurred since January 2005 according to the forthcoming Fifth Assessment Report of the Intergovernmental Panel on Climate Change, the satellite records show no global warming at all since that date. ...

Impacts harmful to society, including increased extremes of heat, precipitation, and coastal high water, are currently no more frequent or intense than usual, and are unlikely to increase for as long as global temperatures continue to fail to rise as the AGU had formerly but erroneously predicted.

Other projected outcomes, such threats to public health, water availability, agricultural productivity (particularly in low-latitude developing countries), coastal infrastructure, and biodiversity, are also unlikely in the circumstances.

The AGU must now agree that previous talk of ocean “acidification” was incorrect, since the oceans are and must remain pronouncedly alkaline for as long as they are buffered by the rocks in the basins where they lie.

Benefits of a warmer world (if and when warming resumes) will include increased availability of agricultural land formerly under permafrost in northern latitudes; reduced storminess as temperature differentials diminish; and greater crop yields thanks to a general growth in the net primary productivity of the world’s trees and plants owing to CO2 fertilization.

While important scientific uncertainties remain as to which particular impacts will be experienced where, the AGU must now accept that no uncertainties are known that could make the impacts of anthropogenic climate change significantly damaging. Furthermore, surprise outcomes, such as the unexpectedly rapid loss of Arctic summer sea ice, may entail even more dramatic advantages than anticipated. Trans-polar navigation and mineral exploration will be facilitated. However, it is known that much of the loss of Arctic sea ice is attributable to natural influences, and half of that loss since 1979 has been compensated by increases in Antarctic sea ice.

Actions that could diminish the benefits posed by climate change to society and ecosystems include the substantial emissions cuts the AGU once advocated in a futile attempt to reduce the magnitude of anthropogenic global warming, which has proven to be remarkably poorly correlated with increases in CO2 emissions.

The community of scientists must learn to recognize that it has no responsibility to promote a particular negative viewpoint on climate change and its impacts. Improvements will come from pursuing the research needed to understand why the predicted climate change is not occurring, working with stakeholders to identify relevant information, and conveying results to decision makers and to the general public clearly, accurately, honestly, and without the previous negative prejudice for which the AGU must now humbly apologize.

Aldus Christopher Monckton.

Lees verder hier.

De reactie van AGU? 'Oh Lord!'

Voor mijn eerdere DDS-bijdragen, zie hier.