A lot of “bother” indeed!

The ‘burn more coal’ comment was definitely tongue-in-cheek, yes. But the underlying point is that if burning coal produces CO2, and at the same time it produces enough aerosols to exactly balance out the warming effect of that CO2, why are we panicking about global warming?

Regarding natural variability, see Richard C’s answer above. Only when scientists have proven that the climate system is responding outside of the known history of natural variability, can we look at doing something about it. To date this has not been done – all the current change rates are well below historical levels, and when we start to look at geological histories, we realise just how stable we are at the moment.

Another, more subtle point about natural variation should be made here too: scientists in general are quick to point out areas of uncertainty and lack of knowledge. Among the IPCC-related scientists, however, there is an appalling degree of arrogance. They claim repeatedly that they fully understand our climate, to the degree that they can isolate one variable (CO2) and ‘prove’ that the only way they can get their models to balance is if they include the influence of CO2.
The truth is that we don’t understand our climate to this level at all. We simply don’t know what caused most of the variations in our climate history. This is true of even very recent history (MWP and LIA). So for anyone to claim that we can model the ‘normal state’ of our climate is somewhat audacious.

We’re beginning to see the early signs of panic among the climate modellers. The Kaufmann paper is an example. In essence it admits to a lack of warming, and tries to explain it away by resorting to an undemonstrated change in aerosols. The Trenberth and Fusallo paper was similar, its approach however was to claim that aerosols weren’t blocking incoming solar radiation, instead the oceans were simply absorbing it in places we can’t find it. All of these papers, however, have finally come round to admitting that they don’t, in essence, know what’s going on.

A bit more humility from these ‘scientists’ earlier on would have saved us all a lot of bother.

Plenty of reading about natural climate drivers as evidenced by the correlations (then they start on causes – nuther story) here:-

https://docs.google.com/document/d/1eNnA4UAEwc6gpqCC9_Rh4y9B4lcly5TtDMEG30-77uY/edit?hl=en_US&pli=1

http://www.nap.edu/catalog.php?record_id=5142#description

From the EXECUTIVE SUMMARY:-

Natural climate variability on decade-to-century time scales is best defined in terms of the bio-chemical-physical system that must be studied, the principal components of that system, the mechanisms active within each component, and the interactions between components. The main components of the earth system are the atmosphere, oceans, land surface, snow and ice at the surface of both oceans and land, and biota near the interfaces of atmosphere, ocean, and land. The natural mechanisms include radiative transfer, the planetary-scale circulation of the atmosphere and oceans, photochemical processes, and biogeochemical cycles of trace-gases and nutrients. The major interactions between the components of the climate system so defined are given by the exchanges of energy, momentum, water, and trace constituents, which take a large number of specific forms. For instance, ice-albedo feedback affects radiative transfer in the atmosphere and the heat exchange between it and the underlying high-latitude surfaces, and evaporation-wind stress affects the feedback between the tropical atmosphere and oceans.

From 5 PROXY INDICATORS OF CLIMATE:-

Establishing a baseline of natural climate variability over decade-to-century time scales requires a perspective that can be obtained only from a better knowledge of past variability, particularly that which precedes the pre-industrial era. Information revealing these past climate conditions is contained in historical records and “proxy” indicators. The historical records of climate (other than systematic weather observations, which began in the late 1800s), while invaluable because of their scope and often uniquely relevant perspective, are usually limited to the last several hundred years (see Chapter 2). The proxy indicators represent any piece of evidence that can be used to infer climate. Typically, proxy evidence includes the characteristics and constituent compositions of annual layers in polar ice caps, trees, and corals; material stored in ocean and lake sediments (including biological, chemical, and mineral constituents); records of lake levels; and certain historical documents. Such proxy indicators can provide a wealth of information on past atmospheric compositions, tropospheric aerosol loads, volcanic eruptions, air and sea temperatures, precipitation and drought patterns, ocean chemistry and productivity, sea-level changes, former ice-sheet extent and thickness, and variations in solar activity—among other things. These records are particularly appropriate for detecting three manifestations of climate variability: Periodic or near-periodic variations (the latter are those that become evident only after examination of considerable data through which a clear statistical signal stubbornly emerges); Large and pronounced climate signals, such as severe and sustained droughts, drastically altered precipitation patterns, anomalously warm or cold periods, or floods; and Gradual trends, infrequent shifts, or other characteristics of natural variability that are difficult to recognize without the benefit of a long, continuous (or near-continuous) record. Because the bulk of these proxy indicators are recorded naturally, their time span is potentially unlimited; their resolution and accuracy are limited only by the fidelity of the recorder itself. These “natural archives” are simply there for the taking—awaiting discovery, recovery, means of extraction, and interpretation. Consequently, proxy indicators represent a potential treasure trove of unique past climate information.

Also, how is this aerosol effect suddenly global? Would we not expect to see regional variations in this cooling effect?

In terms of the suggestion that burning coal is a “solution” to AGW, I would suggest that this comment is largely rhetorical, as I don”t think either Judith Curry or Bob think the idea is plausible in the first place.

However, given that there are some fairly crazy geo-engineering proposals knocking around, from giant mirrors in space, to cloud seeding with gigantic ships (Bill Gates) then putting more aerosols into the atmosphere should be considered a potential solution, given that the scientists are claiming that it solves the “problem” in this paper in the first place.

I’m a bit confused about the natural variability that you are talking about. You seem to use it as a catch all for any observed warming or cooling trend without any effort to quantify or measure it. I feel like you are invoking an “invisible agent” which explains everything, I sure this is not your intention so could you clarify exactly what you mean by natural variability?

Cheers