In the first case, renowned geochemistry professor Jan Veizer of the university of Ottawa overcame years of reluctance (out of fear of reprisals) to report his theory in Geoscience Canada. An excerpt:
The standard explanation for vagaries of our climate, championed by the IPCC (Intergovernmental Panel on Climate Change), is that greenhouse gases, particularly carbon dioxide, are its principal driver. Recently, an alternative model that the sun is the principal driver was revived by a host of empirical observations. Neither atmospheric carbon dioxide nor solar variability can alone explain the magnitude of the observed temperature increase over the last century of about 0.6[degrees]C. Therefore, an amplifier is required. In the general climate models (GCM), the bulk of the calculated temperature increase is attributed to "positive water vapour feedback". In the sun-driven alternative, it may be the cosmic ray flux (CRF), energetic particles that hit the atmosphere, potentially generating cloud condensation nuclei (CCN). Clouds then cool, act as a mirror and reflect the solar energy back into space. The intensity of CRF reaching the earth depends on the intensity of the solar (and terrestrial) magnetic field that acts as a shield against cosmic rays, and it is this shield that is, in mm, modulated by solar activity.The second example came out just recently by Vladimir Shaidurov of the Russian Academy of Sciences. He says that instead of human activity, the likely source of global warming is the result of something called the Tunguska Meteorite Event, which occured in 1908 in remote Russia.
Quoted from Mosnews.com:
The Tunguska Event, sometimes known as the Tungus Meteorite is thought to have resulted from an asteroid or comet entering the earth’s atmosphere and exploding. The event released as much energy as fifteen one-megaton atomic bombs. As well as blasting an enormous amount of dust into the atmosphere, felling 60 million trees over an area of more than 2000 square kilometres. Shaidurov suggests that this explosion would have caused “considerable stirring of the high layers of atmosphere and change its structure.” Such meteoric disruption was the trigger for the subsequent rise in global temperatures.
Anthropogenic Global Warming