Apr 1, 2023·edited Apr 1, 2023Liked by Hannah Ritchie

Hannah, this is a great example of how while we might not always agree, we greatly admire your work. We find your intellectual honesty and avoidance of fear mongering so refreshing.

We like per capita comparisons for use in some situations but not in others.

And, the world should be infinitely grateful for your outstanding work. OWID is of enormous value. We wish more people would be more curious and use it more frequently.

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Great post as always Hannah. I'd be really interested if you could do a post focused on the sulphur dioxide cooling effects and how much of an issue that is likely to be. E.g. how rapid would the warming impact be if this cooling effect was limited via policy changes?

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Very good presentation of basic numbers BUT there's a huge problem. You walk up to it when you state.

"You might notice that this adds up to 1.6°C. That’s already past the 1.5°C global target! The reason is that this data does not include the cooling effects of sulphur dioxide and aerosols. When we include them, the net change in global mean surface temperature is around 1.1°C. That’s the number we’re used to hearing."

Huzzah, you are the first "Climate Optimist" I have seen acknowledge this fact. A fact that was clearly shown in the graph of the IPCC, Climate Change 2021 Summary for Policymakers, page 7.

Real Warming is already at 1.6C-2.0C per the IPCC estimate in 2021. We are OBSERVING 1.2C of Warming and there is an ESTIMATED 0.3C-0.8C of MASKED Warming in the Climate System.

You say it yourself, there are cooling effects of Sulfur Dioxides (SOx) that we know are in place, yet we only have a rough estimate for.

In this paper “Climate effects of aerosols reduce economic inequality” published in 2020, the lead author states: https://www.nature.com/articles/s41558-020-0699-y

“Estimates indicate that aerosol pollution emitted by humans is offsetting about 0.7 degrees Celsius, or about 1.3 degrees Fahrenheit, of the warming due to greenhouse gas emissions. This translates to a 40-year delay in the effects of climate change. Without cooling caused by aerosol emissions, we would have achieved 2010-level global mean temperatures in 1970.”

How are we doing this?

Mostly by injecting massive amounts of sulfur dioxide into the atmosphere all around the planet via the diesel fuel used in the world’s shipping and military fleets. This cools the planet by making it more reflective to the sun’s energy. It increases the Earth’s albedo.

The shipping industry is among the world’s largest emitters of sulfur behind the energy industry, with the sulfur dioxide (SOx) content in heavy fuel oil up to 3,500 times higher than the latest European diesel standards for vehicles.

“One large vessel in one day can emit more sulfur dioxide than all the new cars that come onto the world’s roads in a year.”

The important thing to remember is.

If we stop putting sulfur dioxide into the atmosphere, ALL the cooling effect goes away in 3–5 years.

Now, what happened in 2020 that is related to this and has a HUGE effect on what's about to happen to our weather over the next 3-5 years?


The International Maritime Organization’s (IMO) Marine Environment Protection Committee met in London on Oct. 24–28 (2016) and decided to impose a global cap on SOx emissions starting from 2020, which would see sulfur emissions fall from the current maximum of 3.5 percent of fuel content to 0.5 percent.

In January 2020 the European Commission followed through on that ruling.

Cleaner Air in 2020: 0.5% sulfur cap for ships enters into force worldwide


From January 2020, the maximum sulphur content of marine fuels is reduced to 0.5% (down from 3.5%) globally — reducing air pollution and protecting health and the environment. Sulphur Oxide (SOx) emissions from ships’ combustion engines cause acid rain and generate fine dust that can lead to respiratory and cardiovascular diseases, as well as reduced life expectancy.

Now it's three years later and SOx concentrations in the atmosphere are crashing.

How much MASKED HEAT are we about to get?

Because, we know from previous "volcanic winter" episodes like Pinatubo in the 90's, that ALL of that MASKED HEAT will happen in the next 2-3 years. It's about to get HOT.

We are about to have a MASSIVE CLIMATE SHOCK.

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This was such a clean well summarized easy to read article. 👏👏👏👏

I'm not interested in the blame game per se as nations are in different stages of their own evolutions but would also like to see this applied to say plastic pollution, hazardous waste, water pollution etc.......

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Fine work that is very informative. A query on the per capita emissions problem. Granted it is problematic when considering CUMULATIVE emissions but is it not valid to at least do so when looking at the ANNUAL emissions data for a country when you know the population for that year.


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Another fantastic post!

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This is really interesting. Often we hear estimates of warming by 2100 or 2050; I wonder how the data would change if instead we calculated the net effect by 2100 of emissions up to today

If I'm reading correctly, all of this is calculating the warming contribution by country rather than the net warming contribution. Do you know why the authors chose to do that?

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A relevant per capita metric would be cumulative adjusted GHGs divided by cumulative person-years since 1851. If we take the concept of carbon budget seriously, we can certainly imagine that each individual is born with a carbon budget per year per person, say 2 tons of CO2 eq per year per person. We can then figure out which country has exceeded its country carbon budget by the largest amount on per capita and aggregate terms.

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Do the per country emissions include emissions generated offshore because corporates have shifted manufacture to low wage economies?

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That there is no good way to geographically standardize this measurement should be cause for a serious pause in thought: what is the value in mapping cumulative contributions toward climate change? Presumably, such a project is rooted in a crude notion of "environmental justice," suggesting that the burden of addressing climate change today (and into the future) should be disproportionately assigned to members of global society based on the historical track record of where they find themselves living. But is this really justice? The vast majority of humanity (~98%) lives in the country in which they were born, so our national residence is not much of a choice. And for those two percent who have moved across borders, does their responsibility suddenly go up or down by migrating internationally? Can someone from China be absolved of their presumed climate guilt by moving to New Zealand? Does someone from El Salvador inherit historical climate guilt by moving to the United States?

We need measures that help us create actions now that can effectively move us toward a better and more sustainable future. Looking backwards like this harms that cause, rather than helps. There is a very good and basic rule in cartography and spatial analysis: if you cannot standardize the data across your geographical units of analysis, then you need new data or new geographical units. And it does not help much, either, that the geographic units used here have changed quite a bit during the nearly two centuries being analyzed.

Despite the thoughtful presentation, this is an example of "How to Lie with Maps" (hat tip to Mark Monmonier), and I will be using it as an example of how *not* to do Geography with my undergrads. Thank you, I guess, for the classroom-discussion fodder. But also thank you, sincerely, for the excellent work you and the Our World in Data team generally do. Your resources are invaluable, almost always as good examples that further our understanding of world geography, not bad examples to critique.

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How is contribution, eg. for Slovenia calculated, since we had been part of Yugoslavia before we became independent?

Also, would it be possible to calculte contribution per country area? Slovenia contributed only 0.0007 °C to total global warming, but how much is it only for our area, wich is 20271 sq km?

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Look, if you want to see the IPCC charts on this, here is the start of my analysis.

Heat doesn't "just happen". --Where it’s coming from, and why that matters to all of us.


The BIG STORY you are all missing is that the RATE of WARMING has changed dramatically upwards. The observable warming is only half the problem, the SPEED of the warming is what will crash all of our efforts for a sustainable future.

Do you know the current rate of Warming?

From 1975-2015 it was about 0.18C per decade. Do you know what is now?

GISS is saying 0.225C per decade. Hansen is saying 0.36C per decade.

From the amount of energy flow into the oceans since 2015, I would say Hansen is probably right.

We are out of time. We have to do a "crash translation" of the global energy system "right now".

That's what the Climate Scientists mean when they say it's "Now or Never".

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