Insectegeddon: Monarch Butterflies

Since news outlets aren't reliable sources for detailed info on any subject (the search for scoops and sensation-seek are still the driving forces in all commercial journalism), I decided to ask here about the apparent loss of Monarch population not just in California (which is currently all over the news these days), but overall. I am aware of the problems of habitat loss here and in Mexico as well as the usage of insecticides legally or illegally. Has it been at all looked into as a consequence of climate change? I ask not to start a political flame war between believers and non-believers, but simply out of my own curiosity. I can remember growing up right into middle age the large numbers and even a few migrations by Monarchs. Nobody thought anything unusual about it then. Most people ignored it as they generally do about anything to do with insects. Over the past 30 years seeing Monarchs became rarer and rarer and the numbers seen at any site at any point in time dwindled until now I last saw Monarchs two years ago, and none since. I realize my personal observations may just be a local anomaly, but I miss 'em...