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hatrack

(59,592 posts)
Wed Oct 23, 2013, 09:45 AM Oct 2013

IPCC 5: Even With "Aggressive" Emissions Cuts, 2-Foot Sea Level Rise By 2100 Likely

What is happening to sea levels? That was perhaps the most controversial issue in the 4th IPCC report of 2007. The new report of the Intergovernmental Panel on Climate Change is out now, and here I will discuss what IPCC has to say about sea-level rise (as I did here after the 4th report).

Let us jump straight in with the following graph which nicely sums up the key findings about past and future sea-level rise: (1) global sea level is rising, (2) this rise has accelerated since pre-industrial times and (3) it will accelerate further in this century. The projections for the future are much higher and more credible than those in the 4th report but possibly still a bit conservative, as we will discuss in more detail below. For high emissions IPCC now predicts a global rise by 52-98 cm by the year 2100, which would threaten the survival of coastal cities and entire island nations. But even with aggressive emissions reductions, a rise by 28-61 cm is predicted. Even under this highly optimistic scenario we might see over half a meter of sea-level rise, with serious impacts on many coastal areas, including coastal erosion and a greatly increased risk of flooding.


Fig. 1. Past and future sea-level rise. For the past, proxy data are shown in light purple and tide gauge data in blue. For the future, the IPCC projections for very high emissions (red, RCP8.5 scenario) and very low emissions (blue, RCP2.6 scenario) are shown. Source: IPCC AR5 Fig. 13.27.

In addition to the global rise IPCC extensively discusses regional differences, as shown for one scenario below. For reasons of brevity I will not discuss these further in this post.



EDIT

http://www.realclimate.org/index.php/archives/2013/10/sea-level-in-the-5th-ipcc-report/

8 replies = new reply since forum marked as read
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IPCC 5: Even With "Aggressive" Emissions Cuts, 2-Foot Sea Level Rise By 2100 Likely (Original Post) hatrack Oct 2013 OP
We're toast. There is no political will to address this critical issue. CrispyQ Oct 2013 #1
"May you live in interesting times." Nihil Oct 2013 #2
More IPCC modeling garbage, ... CRH Oct 2013 #3
Can you direct me to some links? theHandpuppet Oct 2013 #4
Yeah sure, here are some to get your started, ... CRH Oct 2013 #6
Here are some earth system feedbacks I found in my notes, ... CRH Oct 2013 #7
the climate researchers, I guess - out of a scientist's desire to be very circumspect, are avoiding Bill USA Oct 2013 #5
It's not just the climate researchers pscot Oct 2013 #8

CrispyQ

(36,492 posts)
1. We're toast. There is no political will to address this critical issue.
Wed Oct 23, 2013, 09:59 AM
Oct 2013

There is only political will to extract every last drop of oil out of the ground. Every model shows things accelerating faster than we thought & still nothing from world leaders. Nothing.

In Thom Hartman's mini documentary, "Last Hours" he actually uses the E word, extinction.

http://lasthours.org/

"Chasing Ice" is an incredible documentary, with visual proof that the Arctic is melting. They witnessed a 75 minute calving event that was stunning. Because of the scope of the landscape, it was hard to determine just how big the glacier was, but they superimposed Manhattan over the section breaking off & it was mind boggling. Highly recommended.

It's not lookin' good for the pinnacle of creation.

CRH

(1,553 posts)
3. More IPCC modeling garbage, ...
Thu Oct 24, 2013, 08:26 AM
Oct 2013

if land based glaciers are failing at .8*c above the pre industrial benchmark, permafrost is beginning to fail, ocean clathrates are oozing methane, both the north and south poles are losing ice volume; when we reach 2*c global mean rise there will be little ice left in the Arctic regions and Antarctica will be melting quickly. It is more likely to be ten times the two foot rise in sea level predicted by these models. These models all fail to consider the feed backs already apparent today.

It is more of the same sugar coated crap meant to extend the life of hydrocarbon exploitation.

CRH

(1,553 posts)
6. Yeah sure, here are some to get your started, ...
Thu Oct 24, 2013, 08:22 PM
Oct 2013

For underestimated feedbacks - http://www.gci.org.uk/Documents/IPCC_AR5_Underestimates_Climate_Change.pdf

For complete coverage of feedbacks from one of the masters, check this site from 2007 until present - http://www.apollo-gaia.org -- don't be afraid to bang around in this site, your perceptions will be forever changed. -- don't be afraid to follow the sources listed for verification -- note the sources of studies and their participants. -- a very good primer is, "Planet Earth We Have a Problem", the Westminster Briefing.

Why Sea Ice Matters - http://www.envisionation.co.uk/index.php/arctic-methane-why-the-sea-ice-matters. -- don't hesitate to investigate the persons mentioned in this video, article, Peter Wadhams, David Wasdell, James Hansen, Dr. Natalia Skakhova

Peter Wadhams -- Head of the Polar Ocean Physics Group in the Department of Applied Mathematics and Theoretical Physics, University of Cambridge.


Peter Wadhams on arctic sea Ice collapse - here -

? -- also google Peter Wadhams for more articles -

Antarctica is a more complex situation, --

For the Antarctic sea Ice it has been thought this region has been gaining ice. This study from 1979 - 2004 covers this -- http://psc.apl.washington.edu/zhang/Pubs/Zhang_Antarctic_20-11-2515.pdf

This article, the total accumulation of sea ice in Antarctica is less important as the increased melting rate of the continental ice. It mildly counterpoints the previous opinions of the effects of increasing ice in the Antarctic polar region. -- http://www.skepticalscience.com/antarctica-gaining-ice.htm

This link indicates the land based ice of Antarctica has begun decreasing in the last few years. -- http://en.wikipedia.org/wiki/Antarctic_ice_sheet

This article also supports the recent loss of continental ice in Antarctica, and that the rate appears to be increasing. http://www.esr.org/polarscience/padman_nature.html

Also to be noted: the methane feedbacks now manifesting in the Arctic permafrost and ocean clathrates, (the beginning of Arctic frozen carbon sink failure), are in no way considered in the IPCC AR5 report, the models, or the pathway scenarios.

Hope this helps.





CRH

(1,553 posts)
7. Here are some earth system feedbacks I found in my notes, ...
Thu Oct 24, 2013, 09:05 PM
Oct 2013
http://www.meridian.org.uk/Resources/Global%20Dynamics/EEA_Presentation/frameset.htm?p=1

Feedback Dynamics Model - Meridian Programme 2006

Section 2 - Industrial Disturbance of Thermal Equilibrium

In geological history there have been several major disturbances of the basic thermal equilibrium. In each case sharp changes in atmospheric constitution have been generated by asteroidal impact or massive volcanic activity. There is typically a release of short lived aerosol particulates, sulphur gases which wash out as acid rain, and a sharp and longer lasting rise in concentration of atmospheric carbon dioxide. The resultant abnormally enhanced greenhouse effect drives radiative forcing significantly away from equilibrium. Each event precipitated un-damped positive feedback and runaway global warming. Under these conditions, previously stable bio-geo-chemical systems were disturbed and most extant life-forms became extinct. It took several millennia for the atmospheric CO2 to be sequestered, thermal equilibrium to be restored and radiative forcing to return to zero. It took several million years for the evolutionary biosphere to regenerate.


Earth System Feed Back Dynamics -

Note: below is a partial list of known systemic feedbacks, when the thermal equilibrium has been compromised, and the planet is in a heating cycle. Many of the effects listed in the categories below, become second level feedbacks unto themselves as well, resulting in yet more heat into the primary systemic feedback. Each subject in italics has been condensed by myself to give a general overview of the problems we face. Subjects are covered in more depth at the site linked.

Geo Thermal Heating feedback - driven by temperature and the effects of GHG accumulation - contribution to rise in mean global temperature is minimal as changes occur in geological time scales. After many thousands/millions of years the earth's core temperatures rises to minor significance.

Radiative Forcing Feedback - driven by temperature - as radiative forcing rises much beyond the mean of zero, global heating begins and a slow rise in global temperature is realized. Thermal equilibrium is compromised and the earth enters the heating cycle. - in positive feedback now.

CO2 Absorption Rate Feedback - driven by CO2 concentration - a non temperature related feed back of atmospheric CO2 concentration with an effect on tropical cloud albedo. Other effects derived from enhanced CO2 absorption, are ocean acidification and the destruction of plankton, reducing emissions of di-methyl-sulfide affecting tropical cloud formation, therefore albedo. The ultimate effect, increases global heating. - in positive feedback now.

** Note -- the feedback loops listed above and below seem contradictory, but are not. Above the non temperature driven feedback causes the effect derived from increased oceanic absorption; below, along with increasing global temperatures the diminished rate of absorption of the oceanic carbon sink adds to the rise in atmospheric concentrations, which in turn triggers the land based effects and eventual feedbacks.

CO2 Concentration/Absorption Feedback - driven by temperature and CO2 concentration - as CO2 sinks, (oceans, forests, soils, etc.) become more saturated with CO2, absorption rate diminishes allowing more CO2 to rise and increase concentration in the atmosphere. Also temperature driven, is increased evaporation, fire, and expansion of tetonic plates and volcanic activity - in positive feed back now.

Albedo Effect Feedback -- driven by temperature - the effect changes the reflection of solar energy back out into space. With less albedo effect, more heat is retained at the earth surface realizing higher temperature. Affecting albedo are contrails, aerosols industrial and natural, reflection from land and sea, reflection from vegetation, ice, snow and clouds. As temperature rises the effect of albedo is lessened, leading to more heating, then temperature. - in positive feedback now.

Cloud Formation Feedback - driven by temperature - Water Vapor, without it we would not live, with too much of it, we will not live. Water vapor is the 'most dominant greenhouse gas'. It results from the cycle, of cloud formation and precipitation, evaporation from land, plant and water surfaces, then returning to water vapor. With higher temperature, more evaporation forms more atmospheric water vapor, then releases heat into the atmosphere during cloud formation, as well as increasing the greenhouse effect; leading to global heating and higher temperature. Basically, higher temperature, changes the 'balance' between surface water and atmospheric water. - in positive feedback now.

** Within both cloud formation and density, and evaporation feedbacks, is the 'potential' to find negative feedback or damping mechanisms through increased albedo, however this has not been demonstrated in studies to date.

Evaporation Feedback - driven by temperature - higher temperatures increase evaporation, leading to higher density water vapor, increasing the greenhouse effect and global heating. Again it is noted, increases in albedo resulting from increased water vapor density, have not been shown in studies to dampen the heating effect enough to result in negative feedback, or cooling. -- Awaiting further studies in this area, increased evaporation from higher temperatures 'appear' to be acting in positive feedback.

Methane Emission Feedback - driven by temperature - methane emissions result from human activity, plant and animal sources, bacterial activity, and are released from sinks in the thawing parts of the ocean, permafrost, etc. The emissions rising into the atmosphere increase the existing concentrations. Methane potency as a greenhouse gas is thought to be about 24 times that of CO2. It is transformed through molecular breakdown by average between eight and twelve years, depending on altitude and latitude. For the most part, it becomes water vapor and CO2, so once transformed the effect of methane lingers beyond its early potency, for many centuries. Methane has a delayed effect in that it later increases the CO2 concentrations, causing global heating, then rising temperatures that liberate more methane from various sinks. The quantity of sink stored methane is staggering, compared to present anthropogenic CO2 emissions. Only a fraction of stored methane would tip the climate into heating most species would not survive. -- in positive feedback now.

The melting of ocean hydrates and permafrost are irreversible in human time frames.

~~ end of Meridian Programme 2006, sourcing ~~

** Again it should be noted -- all the above feedbacks have been paraphrased by myself, for a more thorough coverage see the link to the Meridian Programme at the top of this post.

Hope this helps.

Bill USA

(6,436 posts)
5. the climate researchers, I guess - out of a scientist's desire to be very circumspect, are avoiding
Thu Oct 24, 2013, 06:36 PM
Oct 2013

pointing out to the rest of the population something the scientists know.

It has been stated that the Greenland ice-sheets' movement off the Greenland land mass is accelerating but what I have not seen mentioned is that this acceleration is very likely NOT going to remain stable. The ice sheets will at some point will reach a boundary, as the amount of melt water flowing down to the ground underneath them increases and reaches a certain point where the ice sheets movement will suddenly start to increase. They will probably reach another rate of movement that will remain accelerating in a more modest linear way - until the next boundary is reached.

The scientists all know this is not going to continue in a linear fashion, but as of right now, I guess nobody has enough data to make even a guess as to when that point of inflection will be. That's probably why nobody in the scientific community is bringing this up.

pscot

(21,024 posts)
8. It's not just the climate researchers
Thu Oct 24, 2013, 10:22 PM
Oct 2013

There are a lot of very smart people who don't seem to see the implications of 2 degrees centigrade increase, let alone the 4 to 6 degrees we're more likely to get because we can't be bothered to do jack shit by way of mitigation. It's a real failure of imagination on the part of our "leaders".

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