Getting to zero carbon

In order to avoid a rise of more than 1.5 degrees C in global temperatures, we need to cut emissions of CO₂ to zero by 2050.   Which implies we need to cut emissions by 50% by 2035, which is halfway to 2050, and by 1/3rd by 2030.  At first sight, it seems an impossible task, but if you look closer, it's not nearly so formidable.

This is an informative chart from Climate News Network.  Note that the chart only covers CO₂ emissions, not methane, so it doesn't include agriculture (see Lab grown food will save the planet).

So, let's start with the largest emissions: base-load electricity, which is 1/3rd of CO₂ emissions.  Wind and/or solar are now the cheapest sources of bulk electricity almost everywhere in the world.  In China, the operating cost of coal is now about the same as the new-build cost of solar.  And the costs of renewables continue to fall.  My forecast is that by 2035, and prob'ly by 2030, there will be very  few coal-fired power stations left.  Not only will they cost much more than wind or solar, but there will be carbon pricing in most large  countries, and those carbon prices will be applied to imports from countries which do not themselves have carbon pricing.  The coal power stations being now planned and built in China and other east Asian countries will be stranded assets.  It's possible that their governments will subsidise coal power stations either directly or by forcing utilities to buy their output and consumers to pay the (much) higher costs of superannuated coal power stations.  However, see carbon pricing, above.   So, in the West, no coal power stations.  In China, perhaps some, heavily dependent on subsidies.  But even there, commercial reality will be compelling.  It will prob'ly be cheaper just to buy out old coal power stations and close them down than to continue subsidising them.  So, by 2030, perhaps 80% of baseload electricity replaced by renewables, by 2035, 95%?

The next biggest is "variable electricity".  What they mean by this is gas-peaking power stations, designed to run for a couple of hours each day when demand peaks.  The demand for gas peaking has increased as renewables penetration has risen.  But these too are under threat.  Battery costs are falling by 20% per annum.  Already, in much if the world, battery peaking is cheaper than gas peaking.  As battery costs fall, and as the cost of renewables falls (renewable electricity being what charges the batteries for later discharge during peak demand), the cost disadvantage of gas peaking compared to battery peaking can only worsen.   By 2035, we will only keep gas peaking plants for extremes, when it's mid-winter, the skies are grey, and there is no wind for days at a time.  And the gas we use to fuel them will be green methane, produced by surplus renewable electricity via electrolysis of water and the Sabatier process.  So, another 12% of CO₂ emissions removed by 2035.  That's a total so far of a 44% reduction.

Short-distance light road transport is the next largest sector, at 11%.  The battery cost decline is critical here too.  Already, ordinary, old-fashioned hybrids cost just a couple of thousand dollars more than their petrol equivalents, and plug-in hybrids another couple of thousand more than non plug-in hybrids.  Just switching to hybrids will cut emissions from light transport by more than half by 2035.  Yet full EVs will trump hybrids by 2030, because the cost of batteries will have fallen by 90% by then.  EVs will make up the majority, perhaps almost all of car and light-truck sales by 2030.  Since the car fleet will take time to shift, not all 11% of emissions produced by cars will be gone by 2035.  But surely, most will be. 

There's our 50%.  But wait—there's more!  Heavy road transport will also be electrified.  Iron and steel will be made with green hydrogen.  Air transport, shipping, long-distance road transport will all be using synthetic fossil fuels, or will be electrified.  Heating will be electrified, or will use synthetic natural gas (green methane).  In other words, we could cut CO₂ emissions by 75% by 2035.

That still leaves agriculture.  Methane is 100 times at effective a greenhouse gas as CO₂ and the burps and farts of ruminants (cows/sheep/goats etc) are rich in methane.  As I've said before, we won't be eating "real" meat by 2035.   And as we mine less coal and use less gas, atmospheric methane will decline rapidly.  The bad news about methane is its strong greenhouse gas effect.  The good news is that it rapidly decays into CO₂ in the atmosphere.  Agriculture is also, potentially, a key way we can remove CO₂ from the atmosphere.

It's easy to be pessimistic about global heating.  Yet, everywhere you look, there are encouraging signs that we can reduce emissions.  As global temperatures rise, and the consequences of global heating get more obvious, the political pressure to act will become irresistible.  Combined with the falling costs of renewables and batteries, that will mean that the logjam will suddenly shift, and we will move into a period where  CO₂ emissions will start to fall rapidly year by year.  It's prolly too optimistic to hope that emissions peaked in 2019, even though the covid crash has slashed emissions this year.  But as the world economy recovers, driving up emissions, so also will the world refocus on the climate catastrophe.  The shifts to renewables in electricity generation, and to electrification in transport are unstoppable, now.  And success here will encourage action everywhere. 

My confident prediction: by 2035, emissions will have fallen by way more than 50%, and we will be starting to tackle the harder sectors like cement and agriculture.