Thread by @BjornLomborg

Nobel economist Stiglitz tells us we need to suffer through hardship equal to World War III to fight climate change
His economic arguments for accepting policy costs of $100+ trillion are unfocused and wrong
Climate seems to eradicate any common sense
theguardian.com/commentisfree/…

Here is his *entire* reasoning for why we should commit trillions every year:
The high-pitched argument for a parallel to WWII rests entirely on the following arguments (which are not good)

Here is Stiglitz' *only* concrete number. There is no reference, but many other ill-informed commentators have used this $350bn estimate from GAO for the cost of extreme weather to US government over past decade, meaning 1.8% of GDP
gao.gov/assets/690/687…

This is ridiculous. Not only is $350bn a cost over ten years (so 0.18% GDP per year, and not 2%, as Stiglitz tries to claim), but it is also the costs of *all* extreme weather. Does Stiglitz believe there is no bad weather without climate change? No bad weather in past?

Even if Stiglitz had used the more appropriate measure (e.g. Aon) of $88bn/yr in weather-related damages over past decade, that is 0.48% GDP/yr, and still it is *all* weather damage, most of which obviously would remain without climate change
thoughtleadership.aonbenfield.com/Documents/2019…

Indeed, we know that most damage comes from hurricanes, and although cost have dramatically increased, this is because of more people (Florida coastal population increased 67x since 1900, US 4.3x) that are richer
When correcting for that, no increase
journals.ametsoc.org/doi/full/10.11…

Indeed, this is also true globally, where weather disaster costs are *not* increasing (seemingly slightly decreasing) in share of GDP
update of tandfonline.com/doi/full/10.10…

Stiglitz other argument is health costs, but unfortunately, he couldn't really be bothered to find any arguments. They are apparently still "being tabulated", but 'trust me, they will run into tens of billions of dollars.'

Well, if it is okay with Stiglitz, I think data is better
Here deaths from cold and heat in the US — similar to most other countries.
Heat deaths are small and declining (because richer people can afford aircon) whereas cold deaths are big and increasing
sciencedirect.com/science/articl…

Then he sums up his argument with a grandfatherly 'prevention is better than treatment', which — as he admits — is just a cliche, not an argument

So on this basis:
- climate costs of 2% GDP, exaggerated 4x and will change almost nothing even if CO₂ cut to zero
- unsubstantiated health costs, although cold is killing more and increasing
- a cliche on prevention
- metaphor on WWII
he wants us to spend $trillions

Yet, another Nobel Laureate who's actually studied climate (and got his Nobel in climate economics), Nordhaus, shows the update of the UN Climate Panel estimate of the cost of climate (these are all the major studies of costs)
2-4% of GDP by 2100
nber.org/reporter/2017n…

Stiglitz casually suggests that civilization and our lives are at risk.
He has read too much Guardian
This is simply untrue. If you read the UN Climate Panel reports, this is not what they say
Climate change costs 2-4% of GDP, not the end of the world

By the end of the century, average person in world likely 5-10x richer, with African up to 34x, UN scenarios (SSPs)
(Inconveniently, richest world is fossil-fuel world SSP5)

2-4% warming costs of incomes 500-1000% higher is NOT existential crisis

sciencedirect.com/science/articl…

Which is why the Nobel laureate in actual climate economics finds that, yes, we should do something, but not too much:
Cost of nothing: 3%
Smart policy, reduce temp a bit: 2.3%
Go towards Stiglitz, Greta Thunberg etc: 4% and upwards
aeaweb.org/articles?id=10…

How the hell can a smart guy like Stiglitz write such unfounded drivel?
Yes, climate a problem, yes, fix it smartly with moderate CO₂ tax and green innovation
But let's stop the ridiculous alarmism asking for $trillions with little or no argument but fear
project-syndicate.org/commentary/cli…