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Author Topic: Not twelve years left, but one  (Read 14342 times)

Tom_Mazanec

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Not twelve years left, but one
« on: May 29, 2019, 09:48:02 PM »
Greenhouse emissions must peak next year and rapidly drop thereafter to save us:
https://www.cnn.com/2019/05/23/opinions/one-year-to-tackle-climate-change-opinion-mountford/index.html

be cause

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Re: Not twelve years left, but one
« Reply #1 on: May 29, 2019, 09:55:59 PM »
Tom .. I'm sure this would have suited another thread .. rather than another thread .. b.c.

ps .. perhaps your own recently opened one on CO2 emissions .. that way one thread may continue into the future rather than being lost among the 2000+ threads that have been forgotten ..
« Last Edit: May 29, 2019, 10:01:38 PM by be cause »
We live in a Quantum universe . Do you live like you do ?

Sam

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Re: Not twelve years left, but one
« Reply #2 on: May 29, 2019, 10:39:15 PM »
Greenhouse emissions must peak next year and rapidly drop thereafter to save us:
https://www.cnn.com/2019/05/23/opinions/one-year-to-tackle-climate-change-opinion-mountford/index.html

Where ever this thread goes, the title is wrong. We do not have 1 year to peak and then decline our CO2 emissions to avoid exceeding 1.5 - 2 C rise in global temperature. The underlying article is here:
https://www.nature.com/news/three-years-to-safeguard-our-climate-1.22201

Based on a 600 GT limit, the annual rate of decline in fossil fuel use required to do that is 11.3% each and every year. Based on the 800 GT limit, the annual rate of decline required is 7.2% each and every year.

As I previously noted, country GDPs are directly correlated with fossil fuel use. There is a small leeway there for conversion to non fossil sources. There are serious and severe limits as to just how fast that conversion can happen. Over the next decade, that is likely limited to about 3% per year with great effort. That is also about the rate of growth of economies. So, that is essentially consumed in the demanded societal growth as we add population.

Anything beyond about 3% negative change in fossil fuel use in the near term requires an actual decline in the economy. That is negative growth. Economies can survive limited negative growth for a brief period without collapse. They cannot long survive with negative growth rates of 3-5% per year. They simply cannot achieve and sustain 7-11% negative growth rates without civilization and societal collapse. Clearly, no one will volunteer for that.

What this then implies is that even with broad support and agreement, and with maximum effort, we might achieve and sustain a negative 3% rate as we convert away from fossil fuels.

That implies that we might have succeeded, if we had everyone on board (which we clearly don’t) and we applied maximum effort (which we are clearly unwilling to do), if we had started no later than about 2005.

So, viewed one way we do not have 1 year to prevent exceeding 1.5-2 C rise. We passed that point 15 years ago. Viewed another way, we will not meet and cannot meet the 1.5-2 C target. Realistically, we will be very lucky not to exceed 4 C provided we all agree and get on board with maximum effort - now.  But since that clearly will not happen in the next half dozen years at least, we will inevitably blow through 6 C.

However, once we pass 3 - 4 C, it is almost certainly inevitable that we will have triggered multiple fearsome positive feedbacks that drive us all the way to hot house Earth conditions at +~10 C with the inexorable loss of both the arctic and Antarctic ice sheets and a sea level rise of ~280 feet. We should also then see a dramatic rise in atmospheric pressure. Initially we may see a fall in oxygen content to as low as 14% and the die off of virtually all large animals if the past is any indication. That happens as the oceanic flows breakdown, the atmospheric circulation reorganizes into an equable earth pattern, and the oceans go largely anoxic. We might avoid that. But if we do it won’t be because of skill. It will be pure dumb luck.

Over time, as the ecosystems stabilize in hothouse conditions, the interior of large continents may become scorching hot dead zones. Oxygen levels may once again rise to ~35% which will support massive fires during heavy rainfalls.

That is an earth quite unlike anything mankind has ever known.

Sam

Tom_Mazanec

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Re: Not twelve years left, but one
« Reply #3 on: May 29, 2019, 11:06:56 PM »
I thought such dramatic bad news deserved it’s own thread.

be cause

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Re: Not twelve years left, but one
« Reply #4 on: May 29, 2019, 11:39:47 PM »
multiple new threads are best avoided unless you are happy that the discussion is lost . Better to inform a thread that is already active and likely to still be active next year . In a few weeks or months I will not be searching for the most appropriate of your threads to comment in .. I will be commenting in a thread that is active if possible .. but .. do as you will .. b.c.
We live in a Quantum universe . Do you live like you do ?

Tom_Mazanec

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Re: Not twelve years left, but one
« Reply #5 on: May 30, 2019, 12:58:05 AM »
thanks for the tip, bc. I'll keep it in mind.

Tom_Mazanec

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Re: Not twelve years left, but one
« Reply #6 on: July 24, 2019, 06:00:45 PM »

Bugalugs

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Re: Not twelve years left, but one
« Reply #7 on: July 24, 2019, 11:53:58 PM »
Even if everyone disappeared off the planet tomorrow, is the world not in for continued heating from the existing aggregate of GHGs?

At least we aren't living with black plague, fatal dental abscesses, and fighting with shield and mace. 

oren

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Re: Not twelve years left, but one
« Reply #8 on: July 25, 2019, 12:13:42 PM »
At least we aren't living with black plague, fatal dental abscesses, and fighting with shield and mace.
I get the feeling our descendants may have to, though.

Rich

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Re: Not twelve years left, but one
« Reply #9 on: July 25, 2019, 01:12:04 PM »
I'm glad you started a separate thread for this Tom. Otherwise, I might have missed it

Thanks.

jai mitchell

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Re: Not twelve years left, but one
« Reply #10 on: July 26, 2019, 11:22:44 PM »

So, viewed one way we do not have 1 year to prevent exceeding 1.5-2 C rise. We passed that point 15 years ago. Viewed another way, we will not meet and cannot meet the 1.5-2 C target. Realistically, we will be very lucky not to exceed 4 C provided we all agree and get on board with maximum effort - now.

. . .

That is an earth quite unlike anything mankind has ever known.

Sam

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+3C today

Tom_Mazanec

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Re: Not twelve years left, but one
« Reply #11 on: August 03, 2019, 09:37:37 PM »
Here is another 18 month deadline article:
https://www.forbes.com/sites/mikehughes1/2019/08/02/climate-change-18-months-to-save-the-world/#15a3fac49bd4
(luv the UK temperature graph).

Tom_Mazanec

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Re: Not twelve years left, but one
« Reply #12 on: August 27, 2019, 09:18:08 PM »
Even if we have twelve (now eleven) years left, we can't wait till then to act (nor will we drop dead on January 1 if we don't)
What Does '12 Years to Act on Climate Change' (Now 11 Years) Really Mean?
https://insideclimatenews.org/news/27082019/12-years-climate-change-explained-ipcc-science-solutions
Quote
The number began drawing attention in 2018, when the United Nations' Intergovernmental Panel on Climate Change released a report describing what it would take to keep global temperatures from rising more than 1.5 degrees Celsius, a goal of the Paris climate agreement. The report explained that countries would have to cut their anthropogenic carbon dioxide emissions, such as from power plants and vehicles, to net zero by around 2050. To reach that goal, it said, CO2 emissions would have to start dropping "well before 2030" and be on a path to fall by about 45 percent by around 2030 (12 years away at that time).

Mid-century is actually the more significant target date in the report, but acting now is crucial to being able to meet that goal, said Duke University climate researcher Drew Shindell, a lead author on the mitigation chapter of the IPCC report.

"We need to get the world on a path to net zero CO2 emissions by mid-century," Shindell said. "That's a huge transformation, so that if we don't make a good start on it during the 2020s, we won't be able to get there at a reasonable cost."

rboyd

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Re: Not twelve years left, but one
« Reply #13 on: August 28, 2019, 05:39:04 PM »
The truth is that if we use some reasonable assumptions we passed the "2 degrees" level quite a few years ago:

- Use a normal risk management confidence interval of 95% (as is used in financial risk management, so one would assume it would be correct for the threat of societal collapse. The UN IPCC uses 66% normally, and even went down to 50% for their 1.5 degrees report)

- Assume that we will not be able to suck phenomenal amounts of carbon out of the atmosphere using unproven / speculative technologies

- Use the 20-year CO2 equivalent for methane, much more reasonable than 100 years given how close we are to 2 degrees and to positive feedbacks (forest die offs, sea ice, permafrost etc.). That provides an all GHG CO2 equivalent of significantly north of 600ppm. This number is increasing at 5ppm+ per year, as atmospheric methane levels keep increasing.

These are only three of the many underestimations used by "official" reporting such as the UN IPCC. Only massive reductions in emissions AND protecting carbon sinks such as the Amazon AND geo-engineering will have a chance of holding global average temperatures below a 2 degree rise and more.

I will not hold my breath, especially with the escalating conflict between the USA and China which will push each to emphasize continued economic growth (relative economic size is highly correlated to relative geopolitical power).