Climate change

The average global temperature is officially said to have increased by about 0.8°C over the course of the 20th century.

It rose until about 1947, cooled slightly until about 1977, peaked in 1998, and has been essentially flat since 2001, despite rapidly rising CO2 levels.

The IPCC claims that only the warming of the past 50 years is mainly attributable to man-made greenhouse gases.
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Even though nothing happening today is in any way unprecedented or outside the range of natural climate variability (wattsupwiththat.com; wattsupwiththat.com).
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The IPCC attributes all earlier warming and cooling periods to natural factors – solar, orbital, oceanic, tectonic, etc.

To support its claim that very recent warming is due to man, the IPCC cites the results of climate computer models programmed by scientists who believe that greenhouse gases are a major driver of climate change.

Other variables are adjusted until the model outputs approximately match the temperature record of the last hundred years or so.

Then the major role assigned to CO2 is removed from the models while all the other settings are left unchanged.

Not surprisingly, the models are now incapable of matching the temperature record.

To cite this as proof that CO2 drives the climate is sheer sophistry.

It goes without saying that if the role assigned to CO2 is reduced while the role of natural factors is increased, the models can still be tuned to match the past.

But the fact that models can be adjusted in different ways to reproduce past temperatures says nothing at all about whether any of the models is an accurate representation of how the climate really works.

In fact the models are well known to have serious shortcomings, particularly in their handling of the hydrological cycle (water vapour, clouds, precipitation), and they have consistently overestimated the rate of warming.

NASA’s Goddard Institute for Space Studies (GISS) admitted in 2007 that the current uncertainties in the climate impact of total solar irradiance (TSI) and aerosols (tiny solid particles or liquid droplets suspended in a gas) ‘are so large that they preclude meaningful climate model evaluation by comparison with observed global temperature change’ (indarticles.com).

This is a rare admission, but it was made when seeking funding for a new remote-sensing satellite – the Glory satellite, which was launched on 4 March 2011 but failed to reach orbit.

Using long-term projections of future climate made by flawed, unvalidated models as the justification for draconian, trillion-dollar emission-cutting measures seems rather irrational, especially when such models can’t even reliably predict the local weather more than a few days in advance.

Dry air is composed of 78% nitrogen, 21% oxygen, 0.9% argon, plus various trace gases, such as carbon dioxide.

At present, the atmospheric concentration of CO2 is just under 400 parts per million (ppm), i.e. just under four hundredths of one per cent (0.04%).

Man-made warming proponents emphasize that according to the ice-core record, this level is higher than any seen in the past 650,000 years.

Analysis of air bubbles trapped in Antarctic ice cores tends to indicate that the atmospheric CO2 concentration ranged from about 180 to 300 ppm in previous interglacials – even though many of them were several degrees warmer than today.

What receives far less emphasis are the uncertainties surrounding the ice-core record.

First, the presence in ice of liquid water alters the original composition of the air in gas inclusions; this can deplete CO2 by 30 to 50%, mostly in the upper layers of the ice sheets.

There have also been clear instances of data selection and manipulation by man-made warming proponents (Jaworowski, 2009; Schmitt, 2010).

Second, studies of leaf stomata (pores through which plants take in CO2) often show higher and more variable atmospheric CO2 levels than the ice cores.

They suggest that pre-industrial CO2 levels were commonly in the 360 to 390 ppm range.

Third, an analysis by Ernst-Georg Beck and others of about 100,000 direct measurements of CO2 in the atmosphere made from 1812 to 1961 shows that atmospheric CO2 levels have varied very widely, with peaks of around 360 ppm in the 1820s and 380 ppm in the 1940s, and are closely correlated with sea surface temperatures;

the vast majority of these measurements are rejected by mainstream climatologists (biomind.de; Climate change controversies).

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It is easy to casually read and accept what the IPCC and others say.

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Takes a little more effort to put their statements into a wider context.

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One that shows planet earth to have been much warmer than now in not to distant times.

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Yes, we should behave better.

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No, we should not be panicked or bullied into expensive new taxes, often wasted on supporting scientists doing dubiously constructive research.