The 2030 Emissions gap

To prevent global temperatures rising by more than 1.5 degrees C  above pre-industrial levels, the world needs to cut emissions by 50% by 2030.  This is because global temperatures are rising by 0.2 degrees C  every decade.  The transient (decade by decade, as opposed to the century-by-century) rise is roughly proportional to the level of emissions.  In other words, if we halve emissions, we will also halve the decadal temperature increase to 0.1 degrees.  And the sooner we do this, the sooner global temperatures will stop rising.  

Emissions may have peaked (I'm cautious because I thought they had 5 years ago, and they still rose from then, though the increase was small), but without moving away from coal and petrol-/diesel-powered cars, they're not going to fall rapidly.  Indeed, as poorer countries industrialise, global emissions will go up.  If emissions remain around current levels, then temperatures will continue to rise by 0.2 degrees C per decade, taking global temperatures to 3 degrees above pre-industrial levels by 2100.  If on the other hand, we cut emissions by half by 2030, the decadal rise will slip to 0.1 degrees.  That means that temperatures will be just 2 degrees C higher in 2100 than they were before industrialisation.  Still bad, but much less bad than 3 degrees.  If we halve emissions again by 2040, the global decadal rise in temperatures will fall to 0.05 degrees, meaning that temperatures in 2100 will be ~1.7 degrees above pre-industrial levels.  And that is in the middle of the 1.5 to 2 degrees target.

So we need to halve global emissions by 2030 and halve them again by 2040.  Climate Action tracker (see chart below) has calculated how much emissions will fall as a result of commitments made at the recent Leaders Climate Summit convened by President Biden.  As you can see, it's still not enough.  But I suspect emissions may fall much faster. First, because renewables continue to get cheaper than fossil fuels; second, because battery pack prices are plumetting; third, because EVs will soon have the same 'sticker price' as ICEVs; fourth, because the EU carbon price is rising fast, and the EU will soon start applying it to imports from countries which don't have a carbon price.  At current levels (EU48/tonne), coal-powered generation becomes extremely uneconomic.

From Climate Action Tracker