Global warming discussion IV

[macdoc]

The outcomes ...and when.

 

[Warmer1]

I believe we are currently not tracking RCP8.5, but are closer to RCP6.0 (up to 3C warming) and if we continue to reduce CO₂ emissions, we might just keep temperatures to around 2C to 2.5C.
Fingers crossed!

What percentage of CO2 emissions do you think need to be achieved to keep warming to 2 C without the need for significant carbon capture? I'm not sure what that number is.

( Ignoring 8 years of Donald Trump at the helm)

 

[beelzebub]

Well, I think we are still on target to achieve 2C of warming by, say, 2070, but by then CO₂ growth will have ended and possibly gone into decline.
Even if the US reverses all its alternative energy installations, the rest of the world (including China and India) will almost certainly continue reducing their reliance on fossil fuels - this will have a significant impact on CO₂ levels over the medium term and could well keep global temps from exceeding 2.5C by the end of the century.

What percentage of CO2 emissions do you think need to be achieved to keep warming to 2 C without the need for significant carbon capture? I'm not sure what that number is.

( Ignoring 8 years of Donald Trump at the helm)

 

[Warmer1]

Well, I think we are still on target to achieve 2C of warming by, say, 2070, but by then CO₂ growth will have ended and possibly gone into decline.
Even if the US reverses all its alternative energy installations, the rest of the world (including China and India) will almost certainly continue reducing their reliance on fossil fuels - this will have a significant impact on CO₂ levels over the medium term and could well keep global temps from exceeding 2.5C by the end of the century.

Does this take into account the change in albedo in the Arctic? One researcher claims the darkening land and ocean will add the equivalent energy of around 50% of the radiative forcing of CO2. (from out emissions?) There have been three winters in a row in the north with reduced snow cover and the sea ice is in decline.

It will be interesting to see if warmer ocean water pools along the west coast of California again when this El-Nino disperses. Still lots of warmer water along the coast and that heat is changing the albedo in the west. http://earth.nullschool.net/

Thanks!

 

[beelzebub]

I think the latest models do try to factor reduced ice cover in the Arctic, as well as other possible feedbacks.
However, there is always the chance of unexpected effects that could confound things.

Does this take into account the change in albedo in the Arctic? One researcher claims the darkening land and ocean will add the equivalent energy of around 50% of the radiative forcing of CO2. (from out emissions?) There have been three winters in a row in the north with reduced snow cover and the sea ice is in decline.

It will be interesting to see if warmer ocean water pools along the west coast of California again when this El-Nino disperses. Still lots of warmer water along the coast and that heat is changing the albedo in the west. http://earth.nullschool.net/

Thanks!

 

[macdoc]

That's a nasty feedback but so is the moving north of the vegetation on the taiga/tundra in a huge band. Very complex as snow cover can get heavier when it's warmer due to more moisture.

I am still leery of methane in the north...

Arctic methane emissions 'greater' than previous estimates ...
www.climatechangenews.com/2016/.../arctic-methane-emissions-greater-...
Jan 6, 2016 - NEWS: Methane, a key greenhouse gas, is released from Arctic soils not only in the short summer ... Last updated on 06/01/2016, 12:11 pm.

http://www.climatechangenews.com/20...ne-emissions-greater-than-previous-estimates/

Methane, a key greenhouse gas, is released from Arctic soils not only in the short summer period but also during the bitterly cold winters

By Alex Kirby

The quantity of methane leaking from the frozen soil during the long Arctic winters is probably much greater than climate models estimate, scientists have found.

They say at least half of annual methane emissions occur in the cold months from September to May, and that drier, upland tundra can emit more methane than wetlands.

 

[Warmer1]

That's a nasty feedback but so is the moving north of the vegetation on the taiga/tundra in a huge band. Very complex as snow cover can get heavier when it's warmer due to more moisture.

I am still leery of methane in the north...



http://www.climatechangenews.com/20...ne-emissions-greater-than-previous-estimates/

It used to be a greater concern for me until I watched this presentation by David Archer.

https://www.youtube.com/watch?v=3_me4QBImBU

Richard Alley is also not highly confident that methane is a huge issue in this brief segment.

https://www.youtube.com/watch?v=dKVSHyezW30

The concerns and reports by Natalia Shakhova and her team seem legit as well???

With conflicting reports it's difficult for me as a lay person to feel confident in any conclusion at this point. Hopefully others can provide some insight.

 

[macdoc]

My concern is that if we get repeats of the kind of insane Arctic temps we are in uncharted, not modelled AFAIK turf. The unknown unknowns.

 

[CapelDodger]

With conflicting reports it's difficult for me as a lay person to feel confident in any conclusion at this point. Hopefully others can provide some insight.

I don't think so. Nature's still doing a show-and-tell in what are very new conditions. One hopes it's getting the attention it merits, and I think it is. Quite apart from the search for knowledge there's a lot of practical interest in the Arctic these days.

 

[CapelDodger]

My concern is that if we get repeats of the kind of insane Arctic temps we are in uncharted, not modelled AFAIK turf. The unknown unknowns.

As someone put it, we are outside analogy-space here.

 

[Warmer1]

My concern is that if we get repeats of the kind of insane Arctic temps we are in uncharted, not modelled AFAIK turf. The unknown unknowns.

A number of scientists disagree with David Archer. Will a warmer Gulf Stream carry warmer water into the Arctic or will some of it get blocked by the "global warming hole"?

Seems to be lots of methane under all the small lakes as well.

https://www.google.ca/search?q=meth...r8j9PLAhVit4MKHS-oDRkQsAQIOA&biw=1093&bih=510

The two things that amaze me most are
1. The rapid increase in winter temperatures and the lack of snow in the northwest areas in North America. It rained the day after Christmas and on January 2nd three years ago which was unheard of thirty years ago.

2. How many people don't acknowledge the changes they are seeing and the high percentage of people that still believe that climate science is a hoax.

People readily admit that the winters are much warmer than they used to be and then they will claim unequivocally that it is not the same warming as climate scientists are talking about?

Very few people I know believe that climate change is happening and most of the ones that do know will not admit it publicly. I had to sit with four people the other night that were joking about climate change when there was almost no snow this winter. The disconnect is unbelievable to witness.

We've cranked up the CO2 and who knows what unknown unknowns will occur.

 

[Warmer1]

In regards to the 2 C target I would love to know how accurate Kevin Anderson's assessment of our situation is.

Kevin Anderson - Delivering on 2°C
https://www.youtube.com/watch?v=ZF1zNpzf8RM

4:36 IEA chief economist Fatih Birol "When I look at this data.. the trend is perfectly inline with a 6 C degree increase in temperature"

34:00 The review of what's left of our 1000 gigaton carbon budget after considering the impacts of cement production and deforestation. Basically there are about 20 years left. We have burned 15% of the allowable emissions since the report was concocted in 2011.

49:00 final review and summary

A lot of his presentation deals with the inaccuracies he finds in many reports and scenarios. He often claims that scientists produce reports that will please the paymasters and that many of them are understood to be unrealistic. Producing reports that indicate that there will be a lack of growth and prosperity as a result of mitigation plans is not a good idea.

He also illustrates that a very small percentage of the population is responsible for most of the emissions and these people are the ones in charge.

"Attempt to mitigate for 2 C and plan for 4 C."

Any critique is appreciated.

 

[Trakar]

In regards to the 2 C target I would love to know how accurate Kevin Anderson's assessment of our situation is.

Kevin Anderson - Delivering on 2°C
https://www.youtube.com/watch?v=ZF1zNpzf8RM

4:36 IEA chief economist Fatih Birol "When I look at this data.. the trend is perfectly inline with a 6 C degree increase in temperature"

34:00 The review of what's left of our 1000 gigaton carbon budget after considering the impacts of cement production and deforestation. Basically there are about 20 years left. We have burned 15% of the allowable emissions since the report was concocted in 2011.

49:00 final review and summary

A lot of his presentation deals with the inaccuracies he finds in many reports and scenarios. He often claims that scientists produce reports that will please the paymasters and that many of them are understood to be unrealistic. Producing reports that indicate that there will be a lack of growth and prosperity as a result of mitigation plans is not a good idea.

He also illustrates that a very small percentage of the population is responsible for most of the emissions and these people are the ones in charge.

"Attempt to mitigate for 2 C and plan for 4 C."

Any critique is appreciated.

I generally don't do youtube science, but this is a nice little video, I urge you to screen and verify on your own, via the published supporting papers and studies.

To my readings, studies, and understandings, he is much closer to the correct ballpark than most within the related climate sciences, accept. One argument predominates among those I have heard from climate researchers themselves when you show them the numbers for what has happened in previous geological eras (when we've had much lessor abrupt intrusions of previously sequestered carbon back into the active carbon cycle. The rejection argument usually runs along the lines of "...well, maybe,...hypothetically, but that assumes that even knowing what we know now, political and business leaders and even everyday people will keep doing pretty much what they've been doing up until now, and you know that is ridiculous and uncredible..."

And I've been hearing that from these people for nearly forty years now.

 

[Warmer1]

Thanks Trakar!

Kevin Anderson said that he didn't check the IPCC data and I agree with Alec and Beezelbub about the trajectory being to high but other than that it was very interesting.

 

[Warmer1]

Here is another timely presentation by Dr James Hansen, just posted yesterday, supporting his most recent and controversial co-authored paper on rapid sea level rise.

https://www.youtube.com/watch?v=JP-cRqCQRc8

A 15 minute presentation which covers

The paleoclimate record indicates that ice melt is non-linear and much more rapid than predicted by current models due to feed back mechanisms not included in the models.

Fresh water melt in Antarctica is sinking and circulating back up to melt the base of the ice shelves.

Melting Greenland and Antarctic fresh water are likely starting to slow down the Atlantic overturning circulation (AMOC) and Southern overturning circulation (SMOC).

Skepticism regarding the paper is part of the scientific process and is the life blood of science.

One of the most important questions people seeking information can scientists is " do you think we are approaching a point of no return..?"

 

[Warmer1]

Dr Hansen's paper http://www.columbia.edu/~jeh1/mailings/2016/20160322_IrreparableHarm.pdf

 

[Trakar]

Thanks Trakar!

Kevin Anderson said that he didn't check the IPCC data and I agree with Alec and Beezelbub about the trajectory being to high but other than that it was very interesting.

I see nothing indicating that his projections are too high, from several studies I am aware of there are compelling indications that he may still be on the conservative side of interpretation. If I were a betting man, I'd say 6^o C +/- 1.5^o C within the next 100years. I think we'll top 3^oC within the next 40 years give or take half a decade. The only thing that would dramatically lower such estimates would be action unlike anything we have seen, or are likely to see anytime in the next couple of decades.

 

[macdoc]

One of the most important questions people seeking information can scientists is " do you think we are approaching a point of no return..?"

yes - we have altered the climate out at least 3k years ...so we are not heading back to sub 300 ppm barring some crazy sequestration technology.
No "next ice age" for a good long while.

 

[OCaptain]

Thanks

Have to remember where I am.

Logger,

I wonder if it's possible t begin to build some bridges here, to try to establish some basic points on which we all here agree?

With that said, I would suggest starting with the Greenhouse Effect.

Do you understand that the Greenhouse Effect (outside of greenhouses) exists and is a real phenomenon?

 

[Trakar]

Ice Melt, Sea Level Rise and Superstorms Video Abstract

Ice Melt, Sea Level Rise and Superstorms Video Abstract



(for the YoyTube Science aficionados)

For those who prefer actual published science:
http://www.atmos-chem-phys-discuss.net/15/20059/2015/acpd-15-20059-2015.pdf

...Our analysis paints a dierent picture than IPCC (2013) for how this Hyper-
Anthropocene phase is likely to proceed if GHG emissions grow at a rate that continues
to pump energy at a high rate into the ocean. We conclude that multi-meter sea
level rise would become practically unavoidable. Social disruption and economic consequences
of such 5 large sea level rise could be devastating. It is not dicult to imagine
that conflicts arising from forced migrations and economic collapse might make the
planet ungovernable, threatening the fabric of civilization.
This image of our planet with accelerating meltwater includes growing climate chaos
and storminess, as meltwater causes cooling around Antarctica and in the North At10
lantic while the tropics and subtropics continue to warm. Rising seas and more powerful
storms together are especially threatening, providing strong incentive to phase down
CO2 emissions rapidly.
8 Summary implications
Humanity faces near certainty of eventual sea level rise of at least Eemian proportions,
15 5–9m, if fossil fuel emissions continue on a business-as-usual course, e.g., IPCC scenario
A1B that has CO2 700 ppm in 2100 (Fig. S21). It is unlikely that coastal cities
or low-lying areas such as Bangladesh, European lowlands, and large portions of the
United States eastern coast and northeast China plains (Fig. S22) could be protected
against such large sea level rise.
20 Rapid large sea level rise may begin sooner than generally assumed. Amplifying
feedbacks, including slowdown of SMOC and cooling of the near-Antarctic ocean surface
with increasing sea ice, may spur nonlinear growth of Antarctic ice sheet mass
loss. Deep submarine valleys in West Antarctica and the Wilkes Basin of East Antarctica,
each with access to ice amounting to several meters of sea level, provide gateways
25 to the ocean. If the Southern Ocean forcing (subsurface warming) of the Antarctic ice
sheets continues to grow, it likely will become impossible to avoid sea level rise of
several meters, with the largest uncertainty being how rapidly it will occur....