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Thu Dec 24, 2015, 01:21 PM

How Close Are We to 'Dangerous' Planetary Warming?

by Michael Mann

In the wake of the COP 21 UN Climate Summit in Paris (see this recent Huffington Post piece for my take on the agreement), a number of important questions still remain unanswered. Take for example the commitment reached by the 197 participating nations to limit warming below the "dangerous" level of 2C relative to pre-industrial time (neglecting for the time being the aspirational goal of a substantially lower 1.5C limit acknowledged in recognition of the danger posed to low-lying island nations). The question immediately arises: How much time do we have until we reach the danger zone? How close are we to the 2C warming limit?

It has been widely reported that 2015 will be the first year where temperatures climbed to 1C above the pre-industrial. That might make it seem like we've got quite a ways to go until we breach the 2C limit. But the claim is wrong. We exceeded 1C warming more than a decade ago. The problem is that here, and elsewhere, an inappropriate baseline has been invoked for defining the "pre-industrial." The warming was measured relative to the average over the latter half of the 19th century (1850-1900). In other words, the base year implicitly used to define "pre-industrial" conditions is 1875, the mid-point of that interval. Yet the industrial revolution and the rise in atmospheric CO2 concentrations associated with it, began more than a century earlier.

Unfortunately, even the Intergovernmental Panel on Climate Change (IPCC) has fallen victim to this problematic convention in their latest (5th) assessment report. The key graphic (Fig. 1 below) in the Summary for Policy Makers ("SPM" of the report measures net anthropogenic (i.e. human-generated) carbon emissions and the resulting warming that can be expected. Both the emissions and warming and measured relative to an 1870 baseline.



The various future emissions scenarios are called "RCP"s (for "Representative Concentration Pathways" and they reflect varying assumptions regarding our future efforts to limit carbon emissions. The "RCP 2.6" scenario (dark blue), the most aggressive of the scenarios (from the standpoint of ramping down carbon emissions), corresponds to limiting net carbon emissions to about 3000 Gigatons (3 trillion tons) of CO2. We've already burned through about 2000 Gigatons, i.e. we have expended two thirds of our apparent "carbon budget".

more

http://www.huffingtonpost.com/michael-e-mann/how-close-are-we-to-dangerous-planetary-warming_b_8841534.html

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Arrow 20 replies Author Time Post
Reply How Close Are We to 'Dangerous' Planetary Warming? (Original post)
n2doc Dec 2015 OP
Rex Dec 2015 #1
Flying Squirrel Dec 2015 #18
Rex Dec 2015 #20
octoberlib Dec 2015 #2
Hayduke Bomgarte Dec 2015 #4
octoberlib Dec 2015 #12
TampaAnimusVortex Dec 2015 #19
-none Dec 2015 #3
BillZBubb Dec 2015 #5
physioex Dec 2015 #17
old guy Dec 2015 #6
Scootaloo Dec 2015 #9
-none Dec 2015 #13
Scootaloo Dec 2015 #14
GliderGuider Dec 2015 #15
-none Dec 2015 #16
tabasco Dec 2015 #7
sdfernando Dec 2015 #8
klyon Dec 2015 #10
sailfla Dec 2015 #11

Response to n2doc (Original post)

Thu Dec 24, 2015, 01:48 PM

1. Isn't it already happening?

 

I read Florida is sinking.

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Response to Rex (Reply #1)

Fri Dec 25, 2015, 02:52 AM

18. Naw

 

Florida's not sinking, the ocean is rising above it.

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Response to Flying Squirrel (Reply #18)

Fri Dec 25, 2015, 11:24 PM

20. Dam that would explain it!

 

I always knew water would rise above it.

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Response to n2doc (Original post)

Thu Dec 24, 2015, 01:53 PM

2. I just read this. It's scary and I can't see us doing enough to reverse it. We need to plant forests

but we keep on tearing them down.

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Response to octoberlib (Reply #2)

Thu Dec 24, 2015, 02:07 PM

4. I read a piece, years ago on the many advantages of

growing hemp as a cash crop, that has some relevance here, I think.

It was during the the tobacco kerfuffle and concerned tobacco growers switching to hemp. The one advantage I'm citing from that article, is that in the tobacco growing states, two crops yearly would be possible, and were comparable acreage devoted to hemp, as to tobacco, the atmosphere would be recharged at a faster rate than what the rain forests were then accomplishing.

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Response to Hayduke Bomgarte (Reply #4)

Thu Dec 24, 2015, 05:10 PM

12. Interesting!

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Response to octoberlib (Reply #2)

Fri Dec 25, 2015, 12:40 PM

19. I wouldn't worry too much..

With exponentially accelerating technology, solar will become cheaper than fossil fuels very shortly, and mature nanotechnology capable of cleaning the atmosphere for practically no cost should be here within 2-4 decades.

Granted, nanotech will bring new challenges, but at least solving global warming will get wrapped up pretty nicely.

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Response to n2doc (Original post)

Thu Dec 24, 2015, 02:05 PM

3. The "Planetary Warming" we are experiencing is the result of

too many people for this planet to support.
The warming is a symptom. And as usual we try to treat the symptoms , while ignoring the root cause/s.
We need to get our numbers down to something reasonable as part of fighting Global Warming/Climate Change.

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Response to -none (Reply #3)

Thu Dec 24, 2015, 02:23 PM

5. Well, you can always volunteer to take the lead in decreasing the surplus population.

As for your premise, it is baloney. The US doesn't have an unusually high population, but it produces the most waste by far.

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Response to BillZBubb (Reply #5)

Thu Dec 24, 2015, 10:43 PM

17. Horrendous....

Taking an opinion and turning it into a personal attack.

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Response to -none (Reply #3)

Thu Dec 24, 2015, 02:23 PM

6. Definitely part of the equation.

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Response to -none (Reply #3)

Thu Dec 24, 2015, 03:08 PM

9. Actually consumption is the issue there

 

The planet isn't warming because there are lots of mouthbreathers, you know? The planet is warming because of consumption of fossil fuels, themselves used to provide ease for a consumptive lifestyle that is fast becoming all the rage the world over.

Most of the people in "overpopulated" areas of the world actually contribute relatively little to the problem - Bangladesh, for example. Which has a sad irony since they will be the ones to suffer the hardest down the road.

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Response to Scootaloo (Reply #9)

Thu Dec 24, 2015, 05:16 PM

13. And it is people doing the consumption.

Whether it is burning wood, dung or coal. Everyone is contributing. That cell phone the 3rd and 4th world are using? That is not helping either.

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Response to -none (Reply #13)

Thu Dec 24, 2015, 05:42 PM

14. But we can't pretend it's all on the same level

 

Burning cow pats is dozens of orders of magnitude less impactful than industrial coal use.

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Response to -none (Reply #3)

Thu Dec 24, 2015, 06:11 PM

15. Since 1960 the world's population has gone up 240%

 

In the same time CO2 emissions have risen 380%

Both increases are utterly unsustainable.

To get the world's CO2 emissions back to where they were in 1960 we would need to cut average per-capita emissions by 90%. Which means that the world's industrialized nations would need to cut their per-capita emissions by about 98% to leave any room at all for the developing nations. And the rate of CO2 emissions in 1960 were already damaging the biosphere.

We are so fucked it's neither arguable nor funny any more.

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Response to GliderGuider (Reply #15)

Thu Dec 24, 2015, 07:05 PM

16. We are an arrogant species and believe we are somehow above it all.

The reality is, we ain't. We are just another species trying to survive, but we are killing off the rest of the life forms. Live forms we need to survive ourselves. Our specie's "ME FIRST" mentality is inhabitable the only home we will ever know.

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Response to n2doc (Original post)

Thu Dec 24, 2015, 02:43 PM

7. Jeepers! A senator had a snowball in Congress.

 

You must be some kind of kook to believe in that stuff after a senator had a snowball in Congress.

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Response to n2doc (Original post)

Thu Dec 24, 2015, 02:50 PM

8. I mostly like to be the optimist but...

In my opinion that time has past and it is too late already.

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Response to n2doc (Original post)

Thu Dec 24, 2015, 03:35 PM

10. We are already there

if we stop burning fossil fuel today, we will still reach 2 degrees. Greenhouse gases stay for a long time. At least that is my understanding. The targets are nice but totally not possible. If B. Clinton had stopped us we might have made it. I am not hopeful.

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Response to n2doc (Original post)

Thu Dec 24, 2015, 04:18 PM

11. Something drastic has to happen unfortunatly

Inhofe will build a fucking arc and advise everyone else to do so...no problem

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