Is attribution of recent warming 20:80 solar to GHG’s, or the other way around? This is a quantitative question, and I would like to get some discussion going on this issue of the relative proportions of factors involved in recent warming, but I realize you can’t just turn discussion on. Personally, I feel like a goose that I wasn’t converted to the CRF theory earlier, as I am blown away by the strength of the evidence. But others may feel differently, and I like to test my faith.

The delightfully modestly titled The possible connection between ionization in the atmosphere by cosmic rays and low level clouds by Pallé, E. Butler, C. J. and O’Brien, K.(2004) modeled atmospheric ionization to calculate the climatic impact of cosmic ray flux (CRF) over the last 150 years, based on the correlation with observed low cloud cover.

While the IPCC attribute most if not all warming in the last 30 years to GHG’s, until the recent IPCC report, the AR4, most warming this century was also attributed to GHG’s. Pallé shows the possible temperature contributions of solar and CRF.

Pallé finds that the sun’s combined effect from increasing radiance and decrease in low level cloud, could potentially explain over half the increase in temperature in the last 150 years: that’s at least a 50:50 ratio of CRF vs GHG at least. One of Pallé’s assumptions is climate sensitivity, the degree global temperature increases with an increase in solar radiance, of 0.5K/W/m2, less than midway in the IPCC range of 0.3 to 1 K/W/m2. A higher sensitivity would account for more centennial warming.

But wait! There is more. It’s instructive to compare the geographic distribution of correlations, and of modeled ionization with observed warming.

Using an ionization model Pallé finds a bimodal distribution of ionization correlation with latitude.

The same bimodal pattern is seen in the GISS February 2009 anomaly vs. the 1951-1980 average of global temperatures (above). The latitudinal pattern of ‘recent’ temperatures matches expectations of CRF forcing, apart for the strong warming in the North Pole seen in the GISS data.

Observed warming, by latitude and altitude as depicted in these familiar ‘fingerprint’ graphs, is also consistent with attribution of recent warming to low altitude, largely temperate origins as expected from a CRF cause.

Compare this with the predicted latitudinal and altitudinal warming from GHG’s, where warming is concentrated in the upper tropical troposphere.

Similarities can also be seen on comparing global GISS anaomoly with Pallé’s global pattern of strong correlations.

Given that only some areas of pristine ocean show correlations with CRF (above), the potential effect of CRF to affect climate is only be partially realized (as condensation nuclei are not limiting elsewhere). It also suggests the certain areas might play a larger role in initiating global weather than others.

The reduction in low cloud cover since the late 19th century, combined with the direct forcing by solar radiance explains the lion’s share of the global warming over the past century. However, it could be more if there are additional feedbacks or effects on cloud at other levels. The evidence, as they say, is incontrovertible, impossible to dispute; unquestionable.

The physical process they tend to prefer is not the direct increase in cloud nuclei, but a more complex process involving the Earth’s electric circuit, a development that would no doubt please Louis Hissink, long term advocate of the electric Earth theories.

The second process, considered by Tinsley and Yu (2003), namely electroscavenging, depends on the action of the global electrical circuit (see review by Rycroft et al. (2000)). The transport of charge by rapidly rising convective currents in the tropics and over continental land masses leads to a 200 kV positive charge of the ionosphere compared to Earth. This large voltage difference, in turn, necessitates a return current which must pass through the regions of the atmosphere where clouds are formed. As cosmic rays are the principal agent of ionization in the atmosphere above 1 km altitude, any modulation of the CRF flux due to solar activity is likely to affect the transport of charge to complete the global electrical circuit.

Tinsley and Yu (2003) discuss how the build up of electrostatic charge at the tops and bottoms of clouds could affect the scavenging of ice forming nuclei (IFN) and cloud condensation nuclei (CCN) by droplets, and how this can lead to greater rates of precipitation and a reduction in cloud cover.

They find that the electroscavenging process is likely to be more important over oceanic rather than continental regions and that it leads to a positive correlation between clouds and cosmic rays at higher latitudes and a negative correlation at low latitudes. Thus the electroscavenging process can explain several of the most striking features of Fig. 5, namely: (1) the peak in significant positive correlations at latitudes around 50 degrees North and South (Fig. 5a); (2) the tendency for a less significant but nonetheless evident trend to negative correlation coefficients at low latitudes (Fig. 5a); and (3) the location of the peak in correlation over one of the principal oceans, namely over the North and South Atlantic (Fig. 5c).