Humans have caused 1.5 °C of long-term global warming according to new estimates

The last IPCC report estimates that to limit warming to 2C, humans can only emit at most 1150 GtCO2 (at 67% likelihood) [1].

There are 8.2 billion humans, so about 140tCO2/person left on average. If we assume that we get to net zero by 2050, that means the average person can emit about 5.4tCO2/person/year from today to 2050 (hitting 0tCO2/person/year in 2050). This is what emissions look like currently [2]

    Top 5 countries > 10m population
    Saudi Arabia  22.1t 
    United Arab Emirates 21.6t  
    Australia            14.5t 
    United States  14.3t
    Canada          14.0t
    Some others
    China           8.4t
    Europe 6.7t
    World average 4.7t
    Lower-middle-income countries of 1.6t
    Low-income countries 0.3t

Guess what's going to happen and who is going to suffer, despite not doing anything.

[1] Page 82 https://www.ipcc.ch/report/ar6/syr/downloads/report/IPCC_AR6...

[2] https://ourworldindata.org/co2-emissions-metrics

> that means the average person can emit about 5.4tCO2/person/year from here on out. This is what emissions look like currently

Using a world average target number and then presenting a list that leads with world outliers is misleading. This is the kind of statistical sleight of hand that climate skeptics seize upon to dismiss arguments.

The world average is currently under the target number:

> World average 4.7t

I think you meant to imply that the CO2 emissions of poor countries were going to catch up to other countries, but I don’t think it’s that simple. The global rollout of solar power, battery storage, and cheap EVs is exceeding expectations, for example.

I don’t want to downplay the severity of the situation, but I don’t think this type of fatalistic doomerism is helping. In my experience with people from different walks of life, it’s this type of doomerism that turns them off of the topic entirely.

I believe the causation runs the other way. The IPCC was founded in 1988, when CO2 emissions were 22 gigatons per year. Nearly four decades later it's 40 gt/y, and continuing to rise.

Doomerism is the reaction to our utter failure to even pretend to try. It did not cause that failure. Nor are people looking at the data and going, "yeah, I ought to do something, but people on Hacker News were gloomy so I'm going to buy a bigger SUV instead." EVs and solar and suchlike are much, much, much too little and much, much, much too late.

Doomerism doesn't help, except in the extremely limited sense of helping someone express their frustration. But it also isn't hurting because we'd be doing exactly the same nothing if they were cheerful.

Global warming will cause suffering, but extreme poverty was worse for billions than any projections from 2.0C above baseline. The global population grow by 3 billion people since 1988 yet extreme poverty is way down.

What nobody talks about is there’s not enough oil and natural gas left to miss 2C by much. At current consumption rates we run out of both in ~50-60 years. Coal isn’t competitive with renewables and as soon as we stop pumping hydrocarbons the associated influx of Methane also stops. So we’re almost guaranteed to miss 2.5C of global warming, and stopping at 2C is likely.

So congratulations humanity, all that money spent on R&D instead of directly cutting emissions without any solid alternatives actually worked!

> At current consumption rates we run out of both in ~50-60 years

At current prices. As prices go up new sources of fuel become economical and the cycle continues. Not to mention that methane emissions from agriculture are a significant contributor as well (30% from cows) so just removing hydrocarbons doesn’t solve that problem.

It seems like an unrealistic bet that hydrocarbon-based emissions drop to 0 just because you think we’ll run out of fuel in 50 years. Does that mean airplanes stop flying in 50 years? No one is making these bets in the marketplace alongside you for good reason. And remember, consumption grows quite a bit year over year so you’re looking at a much shorter time frame if your prediction were to be true.

Isn't there a reasonable chance aircraft will be electric in 50 years?

Or running on synthetic fuel made with renewable energy

...or flying with fairy wings

We can make anything up. Why not stick to the facts, as we know them, and reasonable projections?

There is no reasonable projection for any fuel other than fossil fuel to maintain the sort of flying we do now.

This isn't a fantasy. Real airplanes have flown using synthetic kerosene manufactured using renewable energy sources. This isn't magic, it's just chemical engineering. Currently that fuel is significantly more expensive than fossil fuel but the cost differential will narrow over time.