Hi there James, glad to hear from you. My next article will deal with this, however, winter illnesses are running amok in my house, so I have been slow getting it out. Short answer: There are plenty of mechanisms that cause the climate to shift and it is clear that the Earth has undergone many, many cycles of such shifts. However, these changes in the Earth’s orbit are not enough to explain the drastic rise in temperature that we have seen since the beginning of the 2oth century. Only when we include the effects of additional GHG do our models match historical climate and current climate. We only have the one planet to observe, but we can write lots and lots of code and compare the code to each other and to the observations. It is pretty evident that we know what’s going on. Be well!