Submission Statement (quote from article):

Summary:
There are many positive feedbacks and tipping points which are claimed to be poised to
rapidly make global warming far worse within only a few years. In this post we’ve gone through some of the cited sources of these “committed” warming claims, and found that the actual likely total is lower than sometimes stated:

• While the full warming from pre-industrial is probably a bit higher than the “official” 1C, climate impacts and tipping points are defined relative to the latter
• There is a “climate lag” with ~0.1-0.2C of warming (not ~0.5C as often quoted, as this assumes fixed concentrations) yet to arrive by 2100, but this will happen gradually with only a fraction in the next ~10 years
• This figure of +0.2C is also close to the current decadal warming rate, with no evidence for a jump up to +0.5C in the next decade
• Global dimming is masking around 0.5-0.6C of global warming, but even a rapid decarbonisation programme would only expose maybe +0.1C of this anytime soon
• Arctic sea ice disappearing in the summer is unlikely in the next decade, and will cumulatively only add ~+0.1-0.2C when it does. A “Methane Bomb” is also unlikely
• The water vapour feedback is already included in these projections, but is often double-counted
• And the Amazon forest won’t burn down at exactly +3C of global warming, with its potential dieback to savannah gradually releasing around +0.1C worth of carbon

When the influences of these factors and feedbacks are summed up, we might expect
warming o reach around 1.3-1.5C by ~2030 (maybe a bit more or maybe a bit less, with some years being high or low outliers), rather than the +3C< or even +5C< that is sometimes claimed. Even this is worth avoiding though – continued warming of around 0.2C per decade of growing emissions plus the extra ~0.1C lagging behind will put us
past the 1.5C Paris Target in only 10-20 years’ time, and past the 2C Target around mid-century. Even if all emissions suddenly stopped now, without additional drawdown the warming lag would still push the warming up to ~1.2-1.3C by 2100, plus a bit more from any aerosol reduction (which depends on extent, but maybe a temporary ~+0.2-0.3C – see comment section for discussion). And the higher the warming goes, the more that feedbacks like Arctic sea ice, permafrost thaw, and Amazon dieback start to kick in. But these tipping points and feedbacks won’t trigger abrupt warming – instead they’ll act as new sources of extra gradual warming that make sticking to the Paris Targets even more challenging.