Bicentennial Decrease of the Total Solar Irradiance Leads to
Unbalanced Thermal Budget of the Earth and the Little Ice Age.
http://icecap.us/images/uploads/abduss_APR.pdf
(amusingly, found via Bing, not by Google)
I've read that the TSI number is very close to the trigger point, and dropping.
SuspiciousObservers.org has covered this extensively. They've gained a well earned reputation as the leading solar observation group in the country, in recent years.
In the paper linked via Bing: written in 2011 predicted irradiation at 1363 now, we are actually getting 1360.5 a big difference. We are declining faster than predicted, we werent supposed to be this low until 2030. Look out below.