Global Warming Opens Up Antarctic Waterways

[Reefmagnet]

Originally Posted by Lake-Effect

Yeah. We noticed.

You guys make this too easy...

http://www.abc.net.au/science/articl...30/3080641.htm

Sent from my SGP521 using Cruisers Sailing Forum mobile app

[Lake-Effect]

Originally Posted by SV THIRD DAY

...I'm a better person than you....

I suspect that's true.

It's never been about 'us', though, it's about policy.

...politics, in other words.

But enough of that. Make my day and cite some more stuff from Alex Jones.

[SV THIRD DAY]

Originally Posted by Lake-Effect

I suspect that's true.

It's never been about 'us', though, it's about policy.

...politics, in other words.

But enough of that. Make my day and cite some more stuff from Alex Jones.

Who's Alex Jones?

[SV THIRD DAY]

Ha ha ha .....I looked the guy up on the internet and Sha-zam....I see why the MMGW Cultists would like old Alex...

» Police Raid Activist’s Home, Confiscate Son After In-school, Pro-marijuana Comments Alex Jones' Infowars: There's a war on for your mind!

[Lake-Effect]

Originally Posted by SV THIRD DAY

Who's Alex Jones?

Now, don't be coy...

[jackdale]

Originally Posted by Reefmagnet

Yep, saw that coming. Funny how nothing but the "A" in AGW applies today, ain't it?

Sent from my SGP521 using Cruisers Sailing Forum mobile app

Here's a couple of decades of GW for you.

[Reefmagnet]

Originally Posted by jackdale

Here's a couple of decades of GW for you.

...From which we can extrapolate the co2 link???

Sent from my SGP521 using Cruisers Sailing Forum mobile app

[SailOar]

How do we know more CO2 is causing warming?

Climate Myth...

Increasing CO2 has little to no effect
"While major green house gas H2O substantially warms the Earth, minor green house gases such as CO2 have little effect.... The 6-fold increase in hydrocarbon use since 1940 has had no noticeable effect on atmospheric temperature ... " (Environmental Effects of Increased Atmospheric Carbon Dioxide)


What the science says...


Humans have increased the amount of carbon dioxide (CO2) in the atmosphere by about 40% over the past 150 years.

Figure 1: Carbon dioxide concentrations in the atmosphere over both the last 1000 years and the preceding 400,000 years as measured in ice cores

As a greenhouse gas, this increase in atmospheric CO2 increases the amount of downward longwave radiation from the atmosphere, including towards the Earth's surface.

Surface measurements of downward longwave radiation
The increase in atmospheric CO2 and other greenhouse gases has increased the amount of infrared radiation absorbed and re-emitted by these molecules in the atmosphere. The Earth receives energy from the Sun in the form of visible light and ultraviolet radiation, which is then re-radiated away from the surface as thermal radiation in infrared wavelengths. Some of this thermal radiation is then absorbed by greenhouse gases in the atmosphere and re-emitted in all directions, some back downwards, increasing the amount of energy bombarding the Earth's surface. This increase in downward infrared radiation has been observed through spectroscopy, which measures changes in the electromagnetic spectrum.

Figure 2: Spectrum of the greenhouse radiation measured at the surface. Greenhouse effect from water vapor is filtered out, showing the contributions of other greenhouse gases (Evans 2006).

Satellite measurements of outgoing longwave radiation
The increased greenhouse effect is also confirmed by NASA's IRIS satellite and the Japanese Space Agency's IMG satellite observing less longwave leaving the Earth's atmosphere.

Figure 3: Change in spectrum from 1970 to 1996 due to trace gases. 'Brightness temperature' indicates equivalent blackbody temperature (Harries 2001).

The increased energy reaching the Earth's surface from the increased greenhouse effect causes it to warm. So how do we quantify the amount of warming that it causes?

Radiative Transfer Models
Radiative transfer models use fundamental physical equations and observations to translate this increased downward radiation into a radiative forcing, which effectively tells us how much increased energy is reaching the Earth's surface. Studies have shown that these radiative transfer models match up with the observed increase in energy reaching the Earth's surface with very good accuracy (Puckrin 2004). Scientists can then derive a formula for calculating the radiative forcing based on the change in the amount of each greenhouse gas in the atmosphere (Myhre 1998). Each greenhouse gas has a different radiative forcing formula, but the most important is that of CO2:
dF = 5.35 ln(C/Co)
Where 'dF' is the radiative forcing in Watts per square meter, 'C' is the concentration of atmospheric CO2, and 'Co' is the reference CO2concentration. Normally the value of Co is chosen at the pre-industrial concentration of 280 ppmv.
Now that we know how to calculate the radiative forcing associated with an increase in CO2, how do we determine the associated temperature change?

Climate sensitivity
As the name suggests, climate sensitivity is an estimate of how sensitive the climate is to an increase in a radiative forcing. The climate sensitivity value tells us how much the planet will warm or cool in response to a given radiative forcing change. As you might guess, the temperature change is proportional to the change in the amount of energy reaching the Earth's surface (the radiative forcing), and the climate sensitivity is the coefficient of proportionality:
dT = λ*dF
Where 'dT' is the change in the Earth's average surface temperature, 'λ' is the climate sensitivity, usually with units in Kelvin or degrees Celsius per Watts per square meter (°C/[W/m2]), and 'dF' is the radiative forcing.
So now to calculate the change in temperature, we just need to know the climate sensitivity. Studies have given a possible range of values of 2-4.5°C warming for a doubling of CO2 (IPCC 2007). Using these values it's a simple task to put the climate sensitivity into the units we need, using the formulas above:
λ = dT/dF = dT/(5.35 * ln[2])= [2 to 4.5°C]/3.7 = 0.54 to 1.2°C/(W/m2)
Using this range of possible climate sensitivity values, we can plug λ into the formulas above and calculate the expected temperature change. The atmospheric CO2 concentration as of 2010 is about 390 ppmv. This gives us the value for 'C', and for 'Co' we'll use the pre-industrial value of 280 ppmv.
dT = λ*dF = λ * 5.35 * ln(390/280) = 1.8 * λ
Plugging in our possible climate sensitivity values, this gives us an expected surface temperature change of about 1–2.2°C of global warming, with a most likely value of 1.4°C. However, this tells us the equilibrium temperature. In reality it takes a long time to heat up the oceans due to their thermal inertia. For this reason there is currently a planetary energy imbalance, and the surface has only warmed about 0.8°C. In other words, even if we were to immediately stop adding CO2 to the atmosphere, the planet would warm another ~0.6°C until it reached this new equilibrium state (confirmed by Hansen 2005). This is referred to as the 'warming in the pipeline'.
Of course this is just the temperature change we expect to observe from the CO2 radiative forcing. Humans cause numerous other radiative forcings, both positive (e.g. other greenhouse gases) and negative (e.g. sulfate aerosols which block sunlight). Fortunately, the negative and positive forcings are roughly equal and cancel each other out, and the natural forcings over the past half century have also been approximately zero (Meehl 2004), so the radiative forcing from CO2 alone gives us a good estimate as to how much we expect to see the Earth's surface temperature change.

Figure 4: Global average radiative forcing in 2005 (best estimates and 5 to 95% uncertainty ranges) with respect to 1750 (IPCC AR4).

We can also calculate the most conservative possible temperature change in response to the CO2 increase. Some climate scientists who are touted as 'skeptics' have suggested the actual climate sensitivity could be closer to 1°C for a doubling of CO2, or 0.27°C/(W/m2). Although numerous studies have ruled out climate sensitivity values this low, it's worth calculating how much of a temperature change this unrealistically low value would generate. Using the same formulas as above,
dT = 1.8 * λ = 1.8 * 0.27 = 0.5°C.
Therefore, even under this ultra-conservative unrealistic low climate sensitivity scenario, the increase in atmospheric CO2 over the past 150 years would account for over half of the observed 0.8°C increase in surface temperature.

Conservation of Energy
Huber and Knutti (2011) published a paper in Nature Geoscience, Anthropogenic and natural warming inferred from changes in Earth’s energy balance. They take an approach in this study which utilizes the principle of conservation of energy for the global energy budget using the measurements discussed above, and summarize their methodology:

"We use a massive ensemble of the Bern2.5D climate model of intermediate complexity, driven by bottom-up estimates of historic radiative forcing F, and constrained by a set of observations of the surface warming T since 1850 and heat uptake Q since the 1950s....Between 1850 and 2010, the climate system accumulated a total net forcing energy of 140 x 1022 J with a 5-95% uncertainty range of 95-197 x 1022 J, corresponding to an average net radiative forcing of roughly 0.54 (0.36-0.76)Wm-2."

Essentially, Huber and Knutti take the estimated global heat content increase since 1850, calculate how much of the increase is due to various estimated radiative forcings, and partition the increase between increasing ocean heat content and outgoing longwave radiation. The authors note that more than 85% of the global heat uptake (Q) has gone into the oceans, including increasing the heat content of the deeper oceans, although their model only accounts for the upper 700 meters.
Figure 3 is a similar graphic to that presented in Meehl et al. (2004), comparing the average global surface warming simulated by the model using natural forcings only (blue), anthropogenic forcings only (red), and the combination of the two (gray).

Figure 3: Time series of anthropogenic and natural forcings contributions to total simulated and observed global temperature change. The coloured shadings denote the 5-95% uncertainty range.

In Figure 4, Huber and Knutti break down the anthropogenic and natural forcings into their individual components to quantify the amount of warming caused by each since the 1850s (Figure 4b), 1950s (4c), and projected from 2000 to 2050 using the IPCC SRES A2 emissions scenario as business-as-usual (4d).

Figure 4: Contributions of individual forcing agents to the total decadal temperature change for three time periods. Error bars denote the 5–95% uncertainty range. The grey shading shows the estimated 5–95% range for internal variability based on the CMIP3 climate models. Observations are shown as dashed lines.

As expected, Huber and Knutti find that greenhouse gases contributed to substantial warming since 1850, and aerosols had a significant cooling effect:

"Greenhouse gases contributed 1.31°C (0.85-1.76°C) to the increase, that is 159% (106-212%) of the total warming. The cooling effect of the direct and indirect aerosol forcing is about -0.85°C (-1.48 to -0.30°C). The warming induced by tropospheric ozone and solar variability are of similar size (roughly 0.2°C). The contributions of stratospheric water vapour and ozone, volcanic eruptions, and organic and black carbon are small."

Since 1950, the authors find that greenhouse gases contributed 166% (120-215%) of the observed surface warming (0.85°C of 0.51°C estimated surface warming). The percentage is greater than 100% because aerosols offset approximately 44% (0.45°C) of that warming.

"It is thus extremely likely (>95% probability) that the greenhouse gas induced warming since the mid-twentieth century was larger than the observed rise in global average temperatures, and extremely likely that anthropogenic forcings were by far the dominant cause of warming. The natural forcing contribution since 1950 is near zero."

A number of studies have used a variety of statistical and physical approaches to determine the contribution of greenhouse gases and other effects to the observed global warming, like Huber and Knutti. And like Huber and Knutti, they find that greenhouse gases have caused more warming than has been observed, because other factors have had a net cooling effect over the past century (Figure 5).

Figure 5: Greenhouse gas contribution to global warming according to various peer-reviewed attribution studies

Last updated on 22 February 2015 by dana1981

[jackdale]

Originally Posted by Reefmagnet

...From which we can extrapolate the co2 link???

Sent from my SGP521 using Cruisers Sailing Forum mobile app

Fourier, Tyndall and Arrenhuis established the link in the 19th century.

Isotope analysis attributes the 405 increase in CO2 over the past 2.5 centuries to burning fossil fuels.

[Reefmagnet]

Originally Posted by SailOar

How do we know more CO2 is causing warming?

*** Golf clap *** We have a new cut and paste champion. Hail the Champ.

Sent from my SGP521 using Cruisers Sailing Forum mobile app

[Reefmagnet]

Originally Posted by jackdale

Fourier, Tyndall and Arrenhuis established the link in the 19th century.

Isotope analysis attributes the 405 increase in CO2 over the past 2.5 centuries to burning fossil fuels.

Thank you for high school science 101. Let's start again. YOUR quote about a previous 400 ppm world being X degrees hotter 4000000 years go proves that there are other significant effects. The immediate problem with your milankovitch cycles theory is that they're cycles and as such their pattern would be revealed in palaeoclimatic records. Perhaps you should have gone with something like continental drift, ocean currents etc.

Whilst on the subject of palaeoclimatic conditions, you may have noted that average global temperatures tend to "flip" between a maxima and a minima over the eons. At the present day we are in a minima range.

But anyway, I digress. The big problem with global warming being attributed entirely, or most entirely, to co2 is that the relationship of CO2 to warming is non linear. For example, the difference in average global temperature between 0 ppm and 280 ppm is around 20 degrees Celsius. Simple mathematics from this point will show this as earth's temperature, on average, hasn't risen by 10 degrees C since the 1800's. The more CO2 added to the atmosphere, the less effect it has. Perhaps that's where positive feedback climate models get it wrong?

Disclaimer: no Googling or cut and paste used in this response.

P.s. Unless current co2 ppm is 685, your statement above is wrong.

Sent from my SGP521 using Cruisers Sailing Forum mobile app

[jackdale]

Originally Posted by Reefmagnet

Thank you for high school science 101. Let's start again. YOUR quote about a previous 400 ppm world being X degrees hotter 4000000 years go proves that there are other significant effects. The immediate problem with your milankovitch cycles theory is that they're cycles and as such their pattern would be revealed in palaeoclimatic records. Perhaps you should have gone with something like continental drift, ocean currents etc.

Whilst on the subject of palaeoclimatic conditions, you may have noted that average global temperatures tend to "flip" between a maxima and a minima over the eons. At the present day we are in a minima range.

But anyway, I digress. The big problem with global warming being attributed entirely, or most entirely, to co2 is that the relationship of CO2 to warming is non linear. For example, the difference in average global temperature between 0 ppm and 280 ppm is around 20 degrees Celsius. Simple mathematics from this point will show this as earth's temperature, on average, hasn't risen by 10 degrees C since the 1800's. The more CO2 added to the atmosphere, the less effect it has. Perhaps that's where positive feedback climate models get it wrong?

Disclaimer: no Googling or cut and paste used in this response.

P.s. Unless current co2 ppm is 685, your statement above is wrong.

Sent from my SGP521 using Cruisers Sailing Forum mobile app

No climate scientist says that CO2 is the only factor.

The IPCC says that H2O has a stronger forcing. H2O is an amplifier that has to have something that triggers more heat so that the atmosphere can hold more more H2O. In geological history that trigger was Milankovitch cycles (an external forcing) which increased temperatures increasing H2O and warming the oceans which released more CO2 causing more warming resulting in warmer oceans increasing more CO2 - a vicious cycle.

Ocean currents are also cycles that also considered in climate science.

[sailorchic34]

Ah, water vapor, Love water vapor. Yes its by far a strongest greenhouse gas, far more then CO2. It's not mentioned much as it's 99.999 natural caused and is not a AGW greenhouse gas. So most warmists just ignore water vapor. But it's the lions share of greenhouse gases. CO2 is #2 at about 3.6% of which about 3.5% of that CO2 is Anthropomorphic or man made.

So taking the total green house gases and reducing 100% of man made greenhouse gases, that is complete reduction to zero, would reduce the total greenhouse gas by 0.27%. So a real world reduction of say 20% of co2 would reduce total greanhouse gas by 0.05%.

From Global Warming: A closer look at the numbersthe Greenhouse System


Just how much of the "Greenhouse Effect" is caused by human activity?
It is about 0.28%, if water vapor is taken into account-- about 5.53%, if not.
This point is so crucial to the debate over global warming that how water vapor is orisn't factored into an analysis of Earth's greenhouse gases makes the difference between describing a significant human contribution to the greenhouse effect, or a negligible one.
Water vapor constitutes Earth's most significant greenhouse gas, accounting for about 95% of Earth's greenhouse effect (5). Interestingly, many "facts and figures' regarding global warming completely ignore the powerful effects of water vapor in the greenhouse system, carelessly (perhaps, deliberately) overstating human impacts as much as 20-fold.
Water vapor is 99.999% of natural origin. Other atmospheric greenhouse gases, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and miscellaneous other gases (CFC's, etc.), are also mostly of natural origin (except for the latter, which is mostly anthropogenic).
Human activites contribute slightly to greenhouse gas concentrations through farming, manufacturing, power generation, and transportation. However, these emissions are so dwarfed in comparison to emissions from natural sources we can do nothing about, that even the most costly efforts to limit human emissions would have a very small-- perhaps undetectable-- effect on global climate.

[sailorchic34]

Originally Posted by jackdale

In geological history that trigger was Milankovitch cycles (an external forcing) which increased temperatures increasing H2O and warming the oceans which released more CO2 causing more warming resulting in warmer oceans increasing more CO2 - a vicious cycle.

AH, Milankovitch cycles; Deals with orbital dynamics and Axial progression. That external forcing that we normally call the sun. So as the earth rotates and wobbles about on a 21,000 year cycle, the amount of energy hitting a portion of the earth increases and decreases. That heat does cause more co2 and water vapor to be released from the oceans. The oceans being a natural carbon sink. Has nothing at all to do with AGW though.

Sunlight hitting the earth in in one hour exceeds total anthropomorphic/ man made energy production in one year. And it does it 24 hours a day/ 7 days a week.

[jackdale]

Originally Posted by sailorchic34

Sunlight hitting the earth in in one hour exceeds total anthropomorphic/ man made energy production in one year. And it does it 24 hours a day/ 7 days a week.

You need to tell the solar scientists that; they seem to be unaware.

During the initial discovery period of global climate change, the magnitude of the influence of the Sun on Earth's climate was not well understood. Since the early 1990s, however, extensive research was put into determining what role, if any, the Sun has in global warming or climate change.

A recent review paper, put together by both solar and climate scientists, details these studies: Solar Influences on Climate. Their bottom line: though the Sun may play some small role, "it is nevertheless much smaller than the estimated radiative forcing due to anthropogenic changes." That is, human activities are the primary factor in global climate change.

http://solar-center.stanford.edu/sun...09RG000282.pdf