Read the Beforeitsnews.com story here. Advertise at Before It's News here.

By sisterrosetta
Contributor profile | More stories

Story Views
Now:
Last hour:
Last 24 hours:
Total:

The stabilization of climate with SRM for a period of longer than two decades could lead to a scenario wherein SRM must be maintained for millennia else risking a large and uncertain level of rapid global warming

Thursday, February 20, 2014 11:20

% of readers think this story is Fact. Add your two cents.

SRM = Solar Radiation Management = Geoengineering = Chemtrails

[This is not a trusted process and must be stopped immediately. Do the authors of this paper realize they are arguing for the continuation of covert operations?]

http://web.mit.edu/karmour/www/McCusker_etal_ERL2014.pdf

Excerpt

3. Sensitivity to termination year, emissions, and

climate sensitivity

Current best estimates of climate sensitivity constrain its value

to likely be between 2 and 4.5 C and very likely exceed

1.5 C (Meehl et al 2007). We thus consider here a climate

sensitivity range of 1.5–10 C (see supplementary materials

for more details available at stacks.iop.org/ERL/9/024005/m

media), and further explore a variety of plausible background

GHG emissions scenarios and SRM termination years. We

employ a simplified, one-dimensional, climate model that has

an upwelling-diffusion ocean and energy balance atmosphere

with adjustable climate sensitivity (UD-EBM; from Baker and

Roe (2009), similar in form to that in Hoffert et al (1980)).

When tuned to capture the annual and global mean response

of CCSM4—including its equilibrium climate sensitivity of

3.2 C and transient climate response of 1.7 C (Bitz et al

2012)—the UD-EBM successfully reproduces CCSM4’s SAT

trends following SRM cessation (black symbols in figure 5).

The background radiative forcing (RF) within the UD-

EBM is prescribed to follow RCP8.5 (Riahi et al 2007)

and RCP2.6 (van Vuuren et al 2007) emissions scenarios,

representing ‘business-as-usual’ emissions and strong GHG

mitigation, respectively. SRM is simulated by maintaining RF

at year 2000 levels until the time of abrupt SRM termination,

at which point the RF is set to that of the background GHG

emissions scenario until year 2100. Each of these simulations

is performed for the range of climate sensitivities described

above and for a variety of shutoff years.

We first consider the case in which climate sensitivity

is set to that of CCSM4 and SRM is employed to mask the

business-as-usual emissions scenario (RCP8.5, as was used in

the CCSM4 experiments in figures 1 and 2). When SRM is

terminated following a 20-year implementation period (year

2020 in figure 4; blue curve), RF abruptly increases by about

1Wm2, producing a small spike in the rate of temperature

change that quickly decays to the rate of the background

RCP8.5 scenario. The 20-year temperature trends following

SRM cessation are 0.2–0.6 C/decade for the range of climate

Figure 4. (a) Evolution of the net radiative forcing (RF) due to GHGs and SRM, (b) temperature response (4T), and (c) rate of temperature

change (d4T/dt) with climate sensitivity set to 3.2 C, that of CCSM4. The business-as-usual emissions scenario (RCP8.5) and

low-emissions scenario (RCP2.6) are shown in thick, lightly shaded curves (light pink and gray, respectively). SRM termination following

20 years and 80 years of implementation are shown in thinner, dark curves (blue and green for RCP8.5 and RCP2.6 background emissions,

respectively). Figure S9 (available at stacks.iop.org/ERL/9/024005/mmedia) displays these results for the ‘very likely’ range of climate

sensitivities defined in the Intergovernmental Panel on Climate Change (IPCC) Assessment Report 4 (AR4).

sensitivities (figure 5), comparable to those trends that occur

under the RCP8.5 scenario without any SRM.

In contrast, when SRM is implemented for a period of

80 years before cessation, there is an abrupt RF increase

of over 5 W m2 (year 2080 in figure 4(a); blue curve) due

to the loss of the large SRM RF that was required to mask

the ongoing accumulation of GHGs in the atmosphere. This

spike in RF produces a rapid and substantial increase in global

averaged temperature: almost 9 C/decade in the first few

years for CCSM4’s climate sensitivity (figure 4(c)), and up to

10 C/decade for high climate sensitivities (figure S9 available

at stacks.iop.org/ERL/9/024005/mmedia). Sensitivity of ini-

tial rates of change are consistent with previous evaluations of

SRM termination with multiple climate sensitivities and/or ter-

mination year (Matthewset al2007, Ross and Matthews 2009).

Twenty-year trends over the range of climate sensitivities are

0.6–2 C/decade (figure 5). Thus, under business-as-usual

future GHG emissions, the stabilization of climate with SRM

for a period of longer than about two decades would create

the potential for sustained high rates of warming upon SRM

cessation, even if climate sensitivity were near the lower end

of its estimated range (figure 5).

We next consider the case where SRM is employed

along with concurrent aggressive GHG mitigation measures,

as represented by the low-emissions RCP2.6 scenario wherein

anthropogenic RF is about 2.6Wm2 above preindustrial in

2100 (Moss et al 2010). Due to the limited accumulation of

GHGs in the atmosphere, the SRM RF required to stabilize

climate is relatively small (compared to the RCP8.5 case),

and thus SRM termination results in an abrupt RF increase of

less than about 2 W m2 regardless of its timing (figure 4(a);

green curves). Following SRM cessation, there are high rates

of temperature change in the first few years (figure 4(c); green

curves), but 20-year temperature trends remain below about

0.4 C/decade—comparable to those trends that occur under

the RCP2.6 scenario without any SRM—over the full range of

climate sensitivity and timing of SRM termination (figure 5).

Within each of the above scenarios, the initial rate of

temperature change following SRM cessation depends on

climate sensitivity only nominally (see supplementary note

and figure S10 available at stacks.iop.org/ERL/9/024005/mm

edia). Climate sensitivity does become an important factor in

setting longer-term temperature trends, particularly under a

large RF increase (compare 20-year trends in figure 5 with 5-

year trends in figure S10 available at stacks.iop.org/ERL/9/024

005/mmedia). However, figure 5 (and figure S10 available at st

acks.iop.org/ERL/9/024005/mmedia) shows that the principal

control on the rate of temperature change following SRM

cessation is the size of the abrupt RF increase, which, in turn, is

determined jointly by the background GHG emissions scenario

and the duration of time that SRM has been deployed.

Critically then, even for the lowest plausible values

of climate sensitivity, decadal temperature trends would be

extremely large (double that of the largest 20-year historical

trend in CCSM4; horizontal black line in figure 5) in the event

of a late 21st century SRM termination under high (RCP8.5)

future emissions (figure 5; blue asterisks); conversely, even

for the highest plausible values of climate sensitivity, decadal

temperature trends would remain relatively small in the event

of SRM cessation at any point in the 21st century, under low

(RCP2.6) future emissions (figure 5; green asterisks). Thus, the

only way to avoid creating the risk of substantial temperature

Figure 5. Twenty-year temperature trend following SRM

termination — after 20, 50, and 80 years (boxed numbers) of

implementation — as a function of climate sensitivity for the

RCP8.5 (blue asterisks) and RCP2.6 (green asterisks) background

emissions scenarios and the maximum RCP8.5 (blue squares) and

RCP2.6 (green squares) 20-year trends. Background shading

indicates the Intergovernmental Panel on Climate Change (IPCC)

Assessment Report 4 (AR4) likelihood ranges for climate sensitivity

(‘likely’ has a >66% probability, and ‘very likely’ has a >90%

probability; Hegerl et al 2007). The vertical black line is CCSM4’s

climate sensitivity (3.2 C), the horizontal black line is the

maximum global mean, annual mean 20-year trend sampled from

the CCSM4 Historical simulations, the black triangle shows the

CCSM4 20-year global mean, annual mean trend following SRM

cessation (1.16 C/decade), and the black circle shows the 20-year

UD-EBM trend for SRM termination after 65 years of balanced RF

(1.0 C/decade), when the RF jump is roughly equivalent to that

estimated in CCSM4 (about 4–5W m 2).

trends through SRM is concurrent strong reductions of GHG

emissions.

While we have considered here only SRM cessation

scenarios within the 21st century, these findings have long-

term implications as well. If SRM was used to stabilize global

climate under high future GHG emissions, it would need to be

maintained on timescales determined by the turnover time of

GHGs in the atmosphere, which in the case of carbon dioxide

is multiple millennia (Archer 2005). Indeed, the stabilization

of global temperature with SRM would also preclude further

observations of the climate response to the ongoing GHG

emissions (Matthews et al 2007), on which many estimates of

global climate sensitivity are based. Thus, the large-scale use

of SRM to mask business-as-usual GHG emissions could lead

to a scenario wherein SRM must be maintained for millennia,

else risking a large and uncertain level of rapid global warming

upon any unanticipated cessation.

http://www.reportingclimatescience.com/news-stories/article/warning-that-planet-may-get-hooked-on-geoengineering.html

http://www.atmos.washington.edu/~david/McCusker_etal_revised_w_supp.pdf

http://iopscience.iop.org/1748-9326/9/2/024005/article

Source:

#SRM #SolarRadiationManagement #Geoengineering #Chemtrails

http://rosettasister.wordpress.com/2014/02/19/the-stabilization-of-climate-with-srm-for-a-period-of-longer-than-two-decades-could-lead-to-a-scenario-wherein-srm-must-be-maintained-for-millennia-else-risking-a-large-and-uncertain-level-of-rapid-gl/

About ”rosettasister”

Image Credit: Niles Heckman

+++

Before It’s News® is a community of individuals who report on what’s going on around them, from all around the world.

Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.

"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.

Please Help Support BeforeitsNews by trying our Natural Health Products below!

Order by Phone at 888-809-8385 or online at https://mitocopper.com M - F 9am to 5pm EST

Order by Phone at 866-388-7003 or online at https://www.herbanomic.com M - F 9am to 5pm EST

Order by Phone at 866-388-7003 or online at https://www.herbanomics.com M - F 9am to 5pm EST

Humic & Fulvic Trace Minerals Complex - Nature's most important supplement! Vivid Dreams again!

HNEX HydroNano EXtracellular Water - Improve immune system health and reduce inflammation.

Ultimate Clinical Potency Curcumin - Natural pain relief, reduce inflammation and so much more.

MitoCopper - Bioavailable Copper destroys pathogens and gives you more energy. (See Blood Video)

Oxy Powder - Natural Colon Cleanser! Cleans out toxic buildup with oxygen!

Nascent Iodine - Promotes detoxification, mental focus and thyroid health.

Smart Meter Cover - Reduces Smart Meter radiation by 96%! (See Video).

Comments

Online:
Visits:	1,606,020,733
Stories:	8,157,817