The Galactic Cosmic Rays (GCR) hypothesis is not a "new paradigm", it's a failed old hypothesis with no real evidence to support it and plenty of evidence to refute it. A couple of fringe dwellers like Svensmark and Shaviv keep struggling to keep it alive for ideological reasons, not science.
The IPCC reports are an assessment of all the latest published research at the time of the report. See what was said about the GCR hypothesis:
From the IPCC 5th Assessment report. WGI – The Physical Science Basis. Chapter 7 pg 573
https://archive.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter07_FINAL.pdf
“the effect on the concentration of cloud condensation nuclei is too weak to have any detectable climatic influence during a solar cycle or over the last century (medium evidence, high agreement). No robust association between changes in cosmic rays and cloudiness has been identified. In the event that such an association existed, a mechanism other than cosmic ray-induced nucleation of new aerosol particles would be needed to explain it. {7.4.6}”
Since that report in 2013 there have been more research papers putting the nail in the coffin for the failed GCR hypothesis:
Note the one from the CERN CLOUD team because it also pre-addresses the issues with Svensmark's latest paper which is based on CERN CLOUD data.
Dunne, E. M., Gordon, H., Kürten, A., Almeida, J., Duplissy, J., Williamson, C., ... & Barmet, P. (2016).
Global atmospheric particle formation from CERN CLOUD measurements. Science, 354(6316), 1119-1124.
"New particle formation in the atmosphere produces around half of the cloud condensation nuclei that seed cloud droplets. Such particles have a pivotal role in determining the properties of clouds and the global radiation balance. Dunne et al. used the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN to construct a model of aerosol formation based on laboratory-measured nucleation rates. They found that nearly all nucleation involves either ammonia or biogenic organic compounds. Furthermore, in the present-day atmosphere, cosmic ray intensity cannot meaningfully affect climate via nucleation."
Erlykin, A. D., Sloan, T., & Wolfendale, A. W. (2013).
A review of the relevance of the ‘CLOUD’ results and other recent observations to the possible effect of cosmic rays on the terrestrial climate. Meteorology and Atmospheric Physics, 121(3-4), 137-142.
The problem of the contribution of cosmic rays to climate change is a continuing one and one of importance. In principle, at least, the recent results from the CLOUD project at CERN provide information about the role of ionizing particles in ’sensitizing’ atmospheric aerosols which might, later, give rise to cloud droplets. Our analysis shows that, although important in cloud physics the results do not lead to the conclusion that cosmic rays affect atmospheric clouds significantly, at least if H2SO4 is the dominant source of aerosols in the atmosphere. An analysis of the very recent studies of stratospheric aerosol changes following a giant solar energetic particles event shows a similar negligible effect. Recent measurements of the cosmic ray intensity show that a former decrease with time has been reversed. Thus, even if cosmic rays enhanced cloud production, there would be a small global cooling, not warming
