I have been watching the progression, which is coming faster than expected for most. AT THIS TIME, the Arctic is losing 111 km3 of ice per month when it should be expanding. Reports from Alaskan fishermen of boiling seas as far as they can see, and the Siberian expedition that reported methane fountains by the hundreds in the 2011-14 expedition, to this fall up to over a km wide and by the thousands. The latest methane readings show a substantial increase from only the week before! I have read estimates of 2-5 GTs of methane self releases this year. Thousands to go.
It must be noted that the rise of each 1*C increases humidity by 7%. Thermal max is 200K thick white clouds with reflective albedo replacing their net GHG effect. along with exponential increase, eventually, of methane metabolizing bacteria. No Venus Effect is possible, IMEO. Thermal Max +13.2*C from pre-industrial, extinction rate 99%, recovery time 200K years with 5 million for surface life evolution. There is the possibility at this time of a Toba Effect large and long enough to stop the methane turnover process. Momentum must be accounted for, along with all the other environmental toxins and shut down without leaks of 400 nuclear reactors. This spring will be hot, then it will get worse. This is it, the rocket ride is at increasing G-force. We may have 4 years left in the Northern Hemisphere, another 1-3 years in the Southern. Latest calculation shows +6*C 2028.7, the point where surface life is extinct.