grundar t1_j1a380i wrote on December 22, 2022 at 7:54 PM

Reply to comment by giuliomagnifico in Changes in Earth’s orbit that favored hotter conditions may have helped trigger a rapid global warming event 56 million years ago that is considered an analogue for modern climate change by giuliomagnifico

> Guys we are fucked :)

That's not a very scientific analysis. Let's look at what the scientists said:
> "The findings also indicated the onset of the PETM lasted about 6,000 years....“We are now emitting carbon at a rate that’s five to 10 times higher than our estimates of emissions during this geological event”"

Let's parse that numerically:

This event occurred over 6,000 years.
We are currently emitting at 5-10x the rate of this event.
Thus, at current rates we will match this event's emissions in 600-1,200 years.

So, yes, it would be very bad news if we continued current emissions rates for another 5-10 centuries. Is that a realistic assumption, though?

Almost certainly not, for several reasons:

First and most obvious, there probably aren't enough accessible fossil fuels to emit at the current rate for that long even if we tried.
Second, emissions growth rates have declined 80% in the last 15 years, yearly emissions are expected to peak within 3 years, and emissions are expected to fall 10-20% by 2030.

Climate change is a hard enough problem without demoralizing people with doomist hyperbole.

nordiques77 t1_j1a3znv wrote on December 22, 2022 at 7:59 PM

Good analysis. It’s bad, but it’s important to have a “cosmic perspective” as Neil DeGrasse Tyson often says. We will reach energy independence and sustainability sooner than people realize. The growth curve of new energy sources suggests it will happen.

Arborensis t1_j1b3enp wrote on December 23, 2022 at 12:05 AM

Critically though, your argument does also make the assumption that we can lower/stop emissions gradually and halt effects. There are some tipping points present which may be irreversible.

grundar t1_j1bbj41 wrote on December 23, 2022 at 1:07 AM

> > emissions growth rates have declined 80% in the last 15 years, yearly emissions are expected to peak within 3 years, and emissions are expected to fall 10-20% by 2030.
>
> Critically though, your argument does also make the assumption that we can lower/stop emissions gradually and halt effects.

That's not an assumption, that's an observation of recent data.

> There are some tipping points present which may be irreversible.

Important tipping points have their effects over centuries of highly elevated temperatures.

This paper examined known tipping points; I extracted a list of them with the paper's values for:

Threshold temperature
Effect
Timescale
If you look at those values, it turns out that there are no nearer-warming (<4C), near-term (<200 year timescale) tipping points with large global impact.