Disclaimer: I am now retired, and am therefore no longer an expert on anything. This blog post presents only my opinions, and anything in it should not be relied on.
Two new factoids:
1. The CO2 data from Mauna Loa are now showing that CO2 levels (averaged over the last ½ year plus a projection of the next six months) reached 410 ppm in Nov. This date is a little more than three years since that measure reached 400.
2. The estimate of carbon emissions – flat for years 2014-2016 – rose by 1.6% in 2017 and is projected to rise by 2.7% in 2018. Primary increases were from China and India, but the US also rose – only Europe among major contributors decreased. Although, as I have noted, this measure may well be flawed as an indicator of underlying carbon emissions rise, the very fact that it can now be monitored on a monthly basis suggests that some of the flaws have been worked out. It is, therefore, less likely to be an underestimate of carbon emissions, and hence the rate of rise is more likely to be correct or a slight overestimate.
Let me reiterate the conclusion in my Oct. addendum more forcefully: I am told that I have, on average, 8 ½ years more to live. By the time I am dead, CO2 seems all but certain to reach 430 ppm, and may well be approaching 440 ppm. By 2050, if things simply continue linearly instead of accelerating the way they have done for the past 60 years, we will be at 500 ppm, nearly doubling CO2 at the start of the Industrial Revolution. This bakes in a global temperature rise since then of 4 degrees Centigrade, or 7 degrees Fahrenheit in the long run, according to James Hansen and others, with at least 2 degrees C since the IR in the short run, or another 2 degrees F from the way things are right now.
Another point: There is a clear line between recent increases in carbon emissions and the administration of President Donald Trump. The lack of support from that administration is clearly linked not only to US increases (via a strong rise in US oil/shale/natural gas generation) but also to decreased pressure on India and China, both in unilateral relations and in the meetings regarding implementation of the Paris Agreement.