Quote:
Originally Posted by awareness
That is a theory that's been considered ... and dismissed for present climate change :
Scientists have considered the sun-climate hypothesis to explain Earth’s rapid warming. The evidence collected show that the sun noticeably affects our climate over millions of years, but it is not the cause of recent warming.
https://www.ucsusa.org/global-warmin....html#bf-toc-1 |
It is a very complex picture. Yes, there is a cycle where we are closer to the sun and then further from the Sun and also a cycle where our axis of rotation wobbles a little, causing the tilt to be more extreme and less extreme. These cycles play a role.
Likewise there have been huge asteroids that have hit the earth and filled the atmosphere with dust and smoke, blocking the sun and precipitating a global drop in temperature. Likewise every time a major volcano goes off, and when the super volcanoes explode they can have an even bigger impact on global climate. At the time of the biggest extinction there was massive volcanic activity that accompanied that. In addition the movement of the continents due to plate tectonics causes ocean currents to be cut off which in turn stops warm water from going to the poles and that can precipitate an ice age. There is also a cycle where our magnetic north pole flip flops, this results in a short period of a few years without a magnetic shield to block some of the solar radiation, as a result the amount of radiation hitting the earth during those years increases. There are also sun spots which create a short cycle of increase and decrease in the radiation coming from the sun.
It is a complex interplay of factors. Anthropogenic change to the atmosphere due to the burning of fossil fuel is a brand new factor.