376Joined Apr 2015


PhD in physics (thermodynamics of ecosystems) and in moral philosophy (animal rights), master in economics, researcher in health and welfare economics at KULeuven, president of EABelgium, environmental footprint analyst at Ecolife


According to this study, the excess deaths from temperature are much larger than the deaths from climate change related famines, floods,...  I'm not sure if deaths from wars have to be included, because I would say the aggressor who starts the war is responsible for those deaths.

Just read the article by Parncutt about the 1000 tonne rule. Apparently, it is 1 death per 1000 tonnes of carbon, i.e. 1 death per 3700 tonnes of CO2, close to Bressler's estimate

Thanks for referring to that study.  That 1 death per 1000 tons is in the same order of magnitude of the 1 death per 4000 tons that I used based on Daniel Bressler's study. So I think the main takeaways are still valid.  But yes, there is a possibility that deaths from climate induced famines, wars,... are some orders of magnitude larger than deaths from temperature change

Not much is known about the impact of climate change on wild animals, so therefore I excluded it. It is very complicated. First, it could still be the case that at the expected level of warming,  the decrease in cold deaths of wild animals could be larger than the increase in heat deaths. Less freezing days, but more heat waves and forest fires... Second, it might be the case that most wild animals have a net negative welfare and that climate change decreases population sizes, which means fewer animals with net negative welfare will be born, and that is good in the long run. Third, animals have a shorter lifespan and higher reproduction levels than humans, which means  the identities of future born animals may be much more dependent on what we (CO2 emitting beings) do, compared to the influence of our actions on the identities of future born humans. Compare the world where we take climate measures with a business as usual world. Already after a few years you will see that those two worlds will contain different animals. That brings us to the difficult non-identity problem in population ethics. So... it becomes very complicated. 

Hi Neil,

my meat-to-animal conversions were not based on Saja, but simply on the weight of edible meat produced by an animal. For chickens, I used the slightly more conservative value of 1.5 kg edible meat per broiler chicken, instead of Saja's 2 kg. That means 1/1.5=0.66 animals/kg. Perhaps broiler chickens in the US grow heavier and are closer to Saja's 2 kg per chicken?

Haven't thought about using those other sources like Faunalitics. Thanks for mentioning it.

1: But how do you know when there is an acute blood shortage, when it is time for you to donate with high impact? You only know it when a blood bank actively communicates about it in order to increase donations, but then other potential donors will also be informed and become motivated to donate blood. Cfr blood shortage in New York after 9/11,  donors were recruited by mass advertisement, and quickly there was an oversupply of blood. It is like on the stock market: if you don't buy a share, someone else will, and it is difficult to know the good time when to buy or sell.

4: blood donation is not an effective means to collect blood parts such as protein that are in plasma, because the rest of the blood (e.g. the red blood cells) is waste. You can donate plasma more frequently. Plasma has a longer shelf life, can be traded internationally,... That means in general there is a chronic (global and local) undersupply of plasma (and plasma derived products), but no chronic undersupply of blood in high-income countries. 

one point of criticism if this cost-effectiveness estimate: in high-income countries there is no substantial shortage of blood. In case of acute shortage, blood banks can easily recruit donors. So if you don't donate and that results in a blood shortage of one unit, another donor is likely to step in. If you donate blood, you simply replace the donation: the other donor who would have donated in your place, will not be recruited. Your donation will not be an extra donation. Or in other words: blood donation has low additivity and blood supply is inelastic. The case for plasma might be different, as there is a global plasma undersupply. A plasma donation will not simply be a replacement of someone else's donation. But I don't know how many QALY's you save by donating plasma. 

Hi David,

sure, I've published an easier version, with more concrete examples and without jargon at my website:

I called the theory mild welfarism, hopefully that is not too much jargon? ;-)

“As you mention, increases in efficiency tend to be followed by equal increases in consumption in society absent other incentives and policies. So it's understandable that some people might think we need some limits on resource extraction.”>I think it is better to have limits on environmental impact. Price mechanisms such as a carbon tax can be used to counter rebound effects on environmental impacts.


“The 40 hour work week was once unthinkable. So were child labor laws. So was a ban on CFCs.”> Economic growth made these policies much more politically feasible.


“What if people had just given up?”>Anti-degrowth environmentalists are not saying we should give up. They say we should invest more in technological innovation.


“Technology does not develop in a political vacuum, and we would not have seen over 90% cost reductions in technologies like solar during the past 10 years without major investments and support from the Obama administration.”>These are points primarily used by anti-degrowth environmentalists to argue for the importance (effectiveness) of more government funding of clean tech innovation. Degrowth environmentalists, on the other hand, are more skeptical about the importance of such clean tech innovations: they prefer a shrinking economy, where we have less money available for technological research. Looking at degrowth thinkers, organizations, panels and declarations, you don’t see a promotion of increased clean tech innovation funding. It is definitely not a top policy proposal. What you do see, is an explicit rejection (proposal to ban) of some technologies such as genetic modification, nuclear power and nanotechnology, a moratorium on techno-scientific research, an orientation research toward low-tech research and convivial tools, raising awareness about “technological addiction”, opposing digital technologies in education. These are not really helping the acceleration of clean tech innovation. 


“Reducing carbon emissions is an example of "degrowth" in one sector of the economy.”> The energy sector can still grow, even when decarbonizing.


“The wealthiest 10% of the world are responsible for over half of emissions in 2015.”> But they own 85% of the wealth. Hence, per unit of wealth, they emit less. Suppose you had a policy that annihilates 85% of global wealth, namely all the wealth owned by the richest 10%. The richest 10% can no longer consume anything. That would only reduce emissions with 50%. With clean tech innovation, we can reduce more than 50% of emissions, without such politically unfeasible policies as 85% wealth reduction. 


“And we know that happiness barely increases above $75,000 a year,”>Environmental impact also shows such a diminishing marginal effect. Above a certain income, someone’s environmental footprint barely increases when income increases. Richer people have a higher propensity to save than to consume. In high income countries, we see that an increasing income over time even correlates with reduced CO2 emissions (absolute decoupling). Cfr environmental Kuznets curve.


“so is rising GDP really benefiting most people when it mainly goes to the top 10%?”> The rising CO2 emissions mainly go to the bottom 90%...


“For example, banning all new fossil fuel extraction and creating a carbon tax that is used to fund clean energy jobs”>This is not specifically a degrowth policy proposal. Anti-degrowth environmentalists also favor such proposals. Such proposals are compatible with economic growth.

“Most people would prefer to work less so that they can spend more time with friends, family, and passion projects.”>They can choose to do so, in a free market. At least when the labor market is competitive and flexible enough, such that it is easier to chose a job that has less working hours. Instead of degrowth regulations (e.g. maximum work hours per week), it is more effective to increase job flexibility. 


 “and hoping for the best with technology investments.”>You can also say that degrowth environmentalists hope for the best with degrowth campaigns, with income and working hour regulations,…

“1. Why shouldn't we set sustainable limits on resource extraction and continue to invest in technology?”> Sure, let’s do that. But only set limits on resource extraction when that resource extraction really correspond with environmental impact. What would be the sustainable limit for energy use? Suppose you set a limit on energy use per capita. e.g. 50 kWh per day per person. Now I invent a clean technology, namely feasible nuclear fusion, that can generate trillions of kWh per day. Is my invention not allowed, merely because you chose a limit of 50 kWh/day/person? 


“Why is ignoring the possibility of running out of resources and betting everything on innovating our way out of all of those limits within a few decades better than a more careful approach?”>If you prefer degrowth, then why do we not have a degrowth world? Why don’t you just make the global economy degrow? Perhaps it is difficult, but then you are betting on feasibility of changing the global economy. In the end, we are interested in cost-effectiveness. Which policy campaigns are most cost-effective: a campaign for degrowth with e.g. income and working hour regulations, or a campaign for increased government funding for clean tech R&D (funded by a carbon tax or an income tax)? Suppose the economy (GDP) grows, and only 1% of the extra income is taxed. This should be extremely feasible. If these tax revenues go to clean tech R&D, we double funding for R&D, which could almost double tech innovation, which could almost double the speed to implement these technologies. We saw a 25% reduction in consumption-based per capita CO2 emissions in dozens of high-income countries in 15 years. Imagine we have in 15 years a 50% reduction…


“There are plenty of people who chop down an entire forest today for a quick buck rather than harvest sustainably in perpetuity, even if the latter would generate more wealth in the long run.”>Why would they chop down the forest so quickly? Because the interest rate is high. But that basically means the marginal productivity of capital is high. Selling the wood and investing in capital, might be the most efficient (productive). Once marginal productivity of capital declines, a lower harvest rate would become optimal. In other words: there is not necessarily a market failure when chopping down a forest. But you may refer to the real underlying market failure: the decrease in a public good such as biodiversity. The most effective policy interventions to solve that problem of biodiversity loss due to clearcutting too much forests, is a taxation, and funding tech innovation to have better alternatives than wood (substitutes for wood).


“2. A lot of people would rather have more time and meaningful work than money. Why should we ignore their preferences”> Why would they not simply choose to work less, if that is what they prefer? Whatever the reason you come up with, I honestly don’t think that economic growth is the main obstacle or reason why they are not so able to choose fewer working hours and more leisure time. In contrast: we do see a negative correlation between economic growth and working hours: a higher GDP correlates with fewer working hours.


“3. It's not clear to me that all increases in growth and consumption necessarily mean greater happiness, creativity, and innovation forever.”> And it is not clear to me that all decreases in growth and consumption necessarily mean lower CO2 emissions and environmental impacts.


“Why not reduce certain kinds of consumption and use those resources to increase investments in innovation?”> Sure, but that is not incompatible with economic growth.

I didn't particularkly steelman degrowth, because I thought the arguments in favor of degrowth are pretty obvious: you can decrease environmental impact by reducing economic activity and resource throughput. I tried to find reasons why such reductions would be most feasible and most effective, but couldn't find them.

"I don't think reducing population is a universal, or even dominant, objective amongst people who support degrowth."> That's why I called it the population degrowth approach, to be distinguished from the resource degrowth aproach. The common usage of degrowth refers to resource degrowth. but population degrowthers are arguing in just the same way as resource degrowthers, that reducing X (be it economic activity, consumption or usage of dirty technologies) is not enough, just like resource degrowthers are arguing that reducing Y (e.g. usage of dirty technologies) is not enough. Population degrowthers are skeptical about the potential of consumption reductions (econo-fix), just as resource degrowthers are skeptical about the potential of technology innovations (techno-fix).


"2) It seems pretty clear that rich people produce a lot more emissions - e.g. reports like this or this highlighting huge disparity in emissions between the richest 1% and the poorest 50% globally."> True, but those richest 1% created 82% of the economic wealth (also from the same Oxfam source: According to your Oxfam reference,  the richest 1% cause 15% of  carbon emissions. Hence, 82% of created economic wealth corresponds with only 15% of emissions. If you would reduce all economic wealth creation by the richest people, which means reducing it with 82%, you only reduce carbon emissions with 15%.  This proves again my point about the non-linear relationship between GDP (created wealth, income) and carbon emissions. Income growth shows a decreasing marginal environmental impact. That makes degrowth measures like income ceilings less effective. 


"3) It's quite possible capitalism has led to people working more, not less. While a chart like this shows a decline in working hours since the end of the Industrial Revolution, it's quite plausible people worked far less before the Industrial Revolution"> That could be true, but as long as degrowthers are not arguing to move back to preindustrial societies, I don't think this point is relevant. Plus, importantly: humans have longer lifespans now compared to preindustrial times. That means it could be the case that I still have more leisure time over my whole life, than someone in the 16th century over her whole life.  And what about our pensions? They didn't have that in the 16th century. 

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