I think it may be a mistake to look at fast progress in renewables and infer that countries will be able to meet their emissions targets without significant difficulty. Ramez Naam writes:
Our hardest climate problems – the ones that are both large and lack obvious solutions – are agriculture (and deforestation – its major side effect) and industry. Together these are 45% of global carbon emissions. And solutions are scarce.
Agriculture and land use account for 24% of all human emissions. That’s nearly as much as electricity, and twice as much all the world’s passenger cars combined.
Industry – steel, cement, and manufacturing – account for 21% of human emissions – one and a half times as much as all the world’s cars, trucks, ships, trains, and planes combined.
Add industry, agriculture, and land use together and you have a very sticky, very difficult-to-improve 45% of carbon emissions.
By contrast, electricity and transportation are 39% of global emissions – nearly as big. The good news is that in electricity and transportation, we have momentum.
We do NOT have momentum in reducing the carbon emissions of industry and agriculture.
Hi, thanks for this comment. I agree with half of it. We definitely don’t have momentum in decarbonising hard to decarbonise sectors like industry and aviation. But the solution there is to make cheap hydrogen, which we can do with super cheap renewables and nuclear hydrogen gigafactories. Whether we will do this is the great unknown of climate policy. But the IEA estimates account for lack of progress in these sectors, so they don’t affect the central point of our piece. Also, some parts of industry are easier to decarbonise. Davis et al (2018) estimate that the hard to decarbonise parts of industry account for 9% of emissions.
On agriculture and land use, the first thing is that I’m not sure I agree on that IPCC assessment of their contribution to emissions. I think that estimate overweights the importance of short-lived pollutants like methane, as discussed here. When we’re thinking about tail risks the real problem is CO2 because it is so long-lived. Second, forest area is increasing in temperate regions. Depending on the source, this started in temperate regions in 1990, or perhaps decades earlier. Indeed, some sources argue that once we account for fire management, plantations and replanting, forests hold more carbon now than they did in 1900 - I’m not sure how reliable this study is though. But what all of this shows is that the solution to forest loss is development—things seem to follow a kuznets curve type relationship. As before, this is also accounted for in estimates of likely emissions pathways.
1. “But the IEA estimates account for lack of progress in these sectors, so they don’t affect the central point of our piece. “
This is important and possibly a bit confusing in the piece, the 2.5-3 degree world is now the default on fairly pessimistic assumptions about further progress.
2. Also, another thing that the estimates do not reflect are the effects of recent net-zero commitments + uptick in cleantech investment, both public and private. If the current surge in cleantech spending persists, we should expect effects in technologies beyond the usual suspects of wind/solar/electric cars/light bulbs. I think we can probably lock-in a low-carbon trajectory this decade if we are able to (a) maintain/increase momentum on clean energy innovation, (b) make sure resources for energy innovation are better spent, and (c) we manage to avoid massive emissions lock-in of new long-lived infrastructure.
3. I would also say it is not quite correct that we are not making progress on hard-to-decarbonize sectors such as industry, aviation, and agriculture. While these are the sectors to worry about most and those where a trajectory change isn’t guaranteed (unlike, say, electrification of light duty transport), Bill Gates + Breakthrough Energy + the tech community more broadly have stepped up their game significantly, also on those technologies (e.g. alternative proteins are arguably booming as a field and Gates & Breakthrough Energy have succeeded in putting those techs a lot more on the mind of the public).
(Sorry for lack of sourcing, this is quick, but I will outline all of those things more publicly and documented fairly soon)
I think it may be a mistake to look at fast progress in renewables and infer that countries will be able to meet their emissions targets without significant difficulty. Ramez Naam writes:
Hi, thanks for this comment. I agree with half of it. We definitely don’t have momentum in decarbonising hard to decarbonise sectors like industry and aviation. But the solution there is to make cheap hydrogen, which we can do with super cheap renewables and nuclear hydrogen gigafactories. Whether we will do this is the great unknown of climate policy. But the IEA estimates account for lack of progress in these sectors, so they don’t affect the central point of our piece. Also, some parts of industry are easier to decarbonise. Davis et al (2018) estimate that the hard to decarbonise parts of industry account for 9% of emissions.
On agriculture and land use, the first thing is that I’m not sure I agree on that IPCC assessment of their contribution to emissions. I think that estimate overweights the importance of short-lived pollutants like methane, as discussed here. When we’re thinking about tail risks the real problem is CO2 because it is so long-lived. Second, forest area is increasing in temperate regions. Depending on the source, this started in temperate regions in 1990, or perhaps decades earlier. Indeed, some sources argue that once we account for fire management, plantations and replanting, forests hold more carbon now than they did in 1900 - I’m not sure how reliable this study is though. But what all of this shows is that the solution to forest loss is development—things seem to follow a kuznets curve type relationship. As before, this is also accounted for in estimates of likely emissions pathways.
1. “But the IEA estimates account for lack of progress in these sectors, so they don’t affect the central point of our piece. “
This is important and possibly a bit confusing in the piece, the 2.5-3 degree world is now the default on fairly pessimistic assumptions about further progress.
2. Also, another thing that the estimates do not reflect are the effects of recent net-zero commitments + uptick in cleantech investment, both public and private. If the current surge in cleantech spending persists, we should expect effects in technologies beyond the usual suspects of wind/solar/electric cars/light bulbs. I think we can probably lock-in a low-carbon trajectory this decade if we are able to (a) maintain/increase momentum on clean energy innovation, (b) make sure resources for energy innovation are better spent, and (c) we manage to avoid massive emissions lock-in of new long-lived infrastructure.
3. I would also say it is not quite correct that we are not making progress on hard-to-decarbonize sectors such as industry, aviation, and agriculture. While these are the sectors to worry about most and those where a trajectory change isn’t guaranteed (unlike, say, electrification of light duty transport), Bill Gates + Breakthrough Energy + the tech community more broadly have stepped up their game significantly, also on those technologies (e.g. alternative proteins are arguably booming as a field and Gates & Breakthrough Energy have succeeded in putting those techs a lot more on the mind of the public).
(Sorry for lack of sourcing, this is quick, but I will outline all of those things more publicly and documented fairly soon)