US emissions fall 2.7%

In 2017, total US emissions of greenhouse gases fell 2.7%.   Emissions for power stations fell 4.5%, but this was offset by a rise in emissions from transport.  If this had happened 15 years ago, it wouldn't have been a bad result.  That would have given us 47 years to cut emissions by 90%, and global temperatures would have been 0.3 degrees lower.   But because we have taken so long to get to this point, now we'll have to do better than this.

If emissions continue to fall by 2.7% per annum, total emissions will have fallen by 60% by 2050.  Which isn't enough.  We need a 90% decline by 2050 if we are to avoid catastrophic global warming.  That's a decline of 7% per annum.   If we could cut emissions by 5% per annum, that would mean total emissions will have fallen by 80% by 2050.  Not perfect, but hugely better than BAU (business as usual)

How will that be achieved?  For developed countries, the key from now on, will be the transition of land transport to electric power.  When EV sales reach 100% of total vehicle sales, given that light vehicles have an average life of 11.6 years, emissions from land transport would be falling by 8% per annum.   The combined decline from electricity generation and transport would then be about 7.5% per annum, even if no other sectors reduce their emissions.  So making our transport fleet electric is critical.

Fortunately, the steady decline in battery costs will make EVs cost competitive with ICEVs by the mid 2020s.  And falling battery costs will allow renewables to make up 100% of electricity generation.  That is the third tipping point for switching electricity generation to renewables.  The first was where new renewables became cheaper than new coal (5 years ago), the second was where new renewables became cheaper than existing coal (i.e., total cost of renewables was less than the operating cost of coal), which is happening now, and the third is where the cost of storage falls enough for baseload power to be replaced by renewables plus storage, which isn't here yet but will be within the next 5 years.  Cutting emissions from electricity generation is easy (when many still think it is too hard) because we can use cheap wind and solar and gas while we wait for battery prices to plunge.

After cutting emissions from electricity and transport, we would still be left with industry (iron and steel, cement, aluminium and others) as the next big sector to target. 

But there's hope.  Belatedly--and still too slowly--emissions are falling in developed countries.  And even though electricity demand is rising strongly in developing countries, this extra demand is likely to be filled by renewables, while rising transport demand in those countries (cars, 3-wheelers and 2-wheelers) will be satisfied by EVs.

US emissions from transport now exceed emissions from electricity generation

Emissions from developed countries are falling (too slowly), China's emissions have peaked
but emissions in the RotW are still rising.