Windfarms may have an effect on global warming

[hawker]

So everyone agrees then? We are causing global warming?

We aren't.

I dont think localized heat like this is a major contributor to global warming. Excess CO2 is the major cause.

It isn't. CO2 lags temperature. So the increase in CO2 is as a RESULT of higher temperatures, not the other way around.

 

[w1z4rd]

We aren't.



It isn't. CO2 lags temperature. So the increase in CO2 is as a RESULT of higher temperatures, not the other way around.

You might want to read this.

CO2 didn't initiate warming from past ice ages but it did amplify the warming. In fact, about 90% of the global warming followed the CO2 increase.

Earth’s climate has varied widely over its history, from ice ages characterised by large ice sheets covering many land areas, to warm periods with no ice at the poles. Several factors have affected past climate change, including solar variability, volcanic activity and changes in the composition of the atmosphere. Data from Antarctic ice cores reveals an interesting story for the past 400,000 years. During this period, CO2 and temperatures are closely correlated, which means they rise and fall together. However, based on Antarctic ice core data, changes in CO2 follow changes in temperatures by about 600 to 1000 years, as illustrated in Figure 1 below. This has led some to conclude that CO2 simply cannot be responsible for current global warming.



Figure 1: Vostok ice core records for carbon dioxide concentration and temperature change.

This statement does not tell the whole story. The initial changes in temperature during this period are explained by changes in the Earth’s orbit around the sun, which affects the amount of seasonal sunlight reaching the Earth’s surface. In the case of warming, the lag between temperature and CO2 is explained as follows: as ocean temperatures rise, oceans release CO2 into the atmosphere. In turn, this release amplifies the warming trend, leading to yet more CO2 being released. In other words, increasing CO2 levels become both the cause and effect of further warming. This positive feedback is necessary to trigger the shifts between glacials and interglacials as the effect of orbital changes is too weak to cause such variation. Additional positive feedbacks which play an important role in this process include other greenhouse gases, and changes in ice sheet cover and vegetation patterns.

A 2012 study by Shakun et al. looked at temperature changes 20,000 years ago (the last glacial-interglacial transition) from around the world and added more detail to our understanding of the CO2-temperature change relationship. They found that:

The Earth's orbital cycles trigger the initial warming (starting approximately 19,000 years ago), which is first reflected in the the Arctic.
This Arctic warming caused large amounts of ice to melt, causing large amounts of fresh water to flood into the oceans.
This influx of fresh water then disrupted the Atlantic Ocean circulation, in turn causing a seesawing of heat between the hemispheres. The Southern Hemisphere and its oceans warmed first, starting about 18,000 years ago.
The warming Southern Ocean then released CO2 into the atmosphere starting around 17,500 years ago, which in turn caused the entire planet to warm via the increased greenhouse effect.
Overall, about 90% of the global warming occurred after the CO2 increase (Figure 2).

http://www.skepticalscience.com/co2-lags-temperature.htm
http://www.skepticalscience.com/co2-lags-temperature-intermediate.htm

 

[bekdik]

And then there's

http://www.dailytech.com/Study+Find...Hard+Data+and+Warming+Models/article22301.htm

With the following comment by the author in the articles comments:

By JasonMick (blog) on 7/29/2011 11:05:40 AM , Rating: 5
quote:
I swear I thought this was going to be a masher article when I read the title. Has your perspective changed over the years Jason?

Actually it has.

(And for the record, I'm not Mr. Asher, though I respected his opinion even in our adversarial era)

I honestly think there's some merit in climate research, still, but I also think sadly it's been corrupted by power seekers and profiteers. As I realized that my perspective greatly changed, as I learned to examine the context of certain reports.

When a matter of science becomes a matter of politics, that's a dangerous game and serious threat to the integrity of any field of research.

At this point I feel that there's no clear cut picture as to how much mankind is warming the Earth, though opportunists would tell you there is. In fact, the evidence I've covered seems to suggest that there's no pressing danger.

I'm actually still an unabashed "environmentalist", in a moderate, rational, unb@stardized sense of the term.

For example, I'd like to see reductions to emissions of sulfides and nitrides -- gases shown conclusively in peer-reviewed studies to raise respiratory disease rates and cause other issues.

I'd also love to see a return to preserving the rainforests, as the destruction of biodiversity, is most certainly real and irreversible in our lifetimes or our childrens' lifetimes.

Sadly all these legitimate issues have been lost in the corruption of the environmentalist movement by profiteers. While I believe environmentalists are generally well intentioned -- as I was when I wrote pro-warming articles -- I think they're being duped by those looking to make a cheap buck. I can only be thankful that my guiding principle of keeping an open mind helped me eventually see through the alarmism and rhetoric.

 

[w1z4rd]

snip

This makes interesting reading to understand your link in more context

While there are uncertainties with climate models, they successfully reproduce the past and have made predictions that have been subsequently confirmed by observations.

There are two major questions in climate modeling - can they accurately reproduce the past (hindcasting) and can they successfully predict the future? To answer the first question, here is a summary of the IPCC model results of surface temperature from the 1800's - both with and without man-made forcings. All the models are unable to predict recent warming without taking rising CO2 levels into account. Noone has created a general circulation model that can explain climate's behaviour over the past century without CO2 warming.


Figure 1: Comparison of climate results with observations. (a) represents simulations done with only natural forcings: solar variation and volcanic activity. (b) represents simulations done with anthropogenic forcings: greenhouse gases and sulphate aerosols. (c) was done with both natural and anthropogenic forcings (IPCC).

Predicting/projecting the future
A common argument heard is "scientists can't even predict the weather next week - how can they predict the climate years from now". This betrays a misunderstanding of the difference between weather, which is chaotic and unpredictable, and climate which is weather averaged out over time. While you can't predict with certainty whether a coin will land heads or tails, you can predict the statistical results of a large number of coin tosses. In weather terms, you can't predict the exact route a storm will take but the average temperature and precipitation over the whole region is the same regardless of the route.

There are various difficulties in predicting future climate. The behaviour of the sun is difficult to predict. Short-term disturbances like El Nino or volcanic eruptions are difficult to model. Nevertheless, the major forcings that drive climate are well understood. In 1988, James Hansen projected future temperature trends (Hansen 1988). Those initial projections show good agreement with subsequent observations (Hansen 2006).


Figure 2: Global surface temperature computed for scenarios A, B, and C, compared with two analyses of observational data (Hansen 2006).

Hansen's Scenario B (described as the most likely option and most closely matched the level of CO2 emissions) shows close correlation with observed temperatures. Hansen overestimated future CO2 levels by 5 to 10% so if his model were given the correct forcing levels, the match would be even closer. There are deviations from year to year but this is to be expected. The chaotic nature of weather will add noise to the signal but the overall trend is predictable.

When Mount Pinatubo erupted in 1991, it provided an opportunity to test how successfully models could predict the climate response to the sulfate aerosols injected into the atmosphere. The models accurately forecasted the subsequent global cooling of about 0.5 °C soon after the eruption. Furthermore, the radiative, water vapor and dynamical feedbacks included in the models were also quantitatively verified (Hansen 2007). More on predicting the future...


Figure 3: Observed and simulated global temperature change during Pinatubo eruption. Green is observed temperature by weather stations. Blue is land and ocean temperature. Red is mean model output (Hansen 2007).

Uncertainties in future projections
A common misconception is that climate models are biased towards exaggerating the effects from CO2. It bears mentioning that uncertainty can go either way. In fact, in a climate system with net positive feedback, uncertainty is skewed more towards a stronger climate response (Roe 2007). For this reason, many of the IPCC predictions have subsequently been shown to underestimate the climate response. Satellite and tide-gauge measurements show that sea level rise is accelerating faster than IPCC predictions. The average rate of rise for 1993-2008 as measured from satellite is 3.4 millimetres per year while the IPCC Third Assessment Report (TAR) projected a best estimate of 1.9 millimetres per year for the same period. Observations are tracking along the upper range of IPCC sea level projections (Copenhagen Diagnosis 2009).


Figure 4: Sea level change. Tide gauge data are indicated in red and satellite data in blue. The grey band shows the projections of the IPCC Third Assessment report (Copenhagen Diagnosis 2009).

Similarly, summertime melting of Arctic sea-ice has accelerated far beyond the expectations of climate models. The area of sea-ice melt during 2007-2009 was about 40% greater than the average prediction from IPCC AR4 climate models. The thickness of Arctic sea ice has also been on a steady decline over the last several decades.



Figure 5: Observed (red line) and modeled September Arctic sea ice extent in millions of square kilometres. Solid black line gives the average of 13 IPCC AR4 models while dashed black lines represent their range. The 2009 minimum has recently been calculated at 5.10 million km2, the third lowest year on record and still well below the IPCC worst case scenario (Copenhagen Diagnosis 2009).

Do we know enough to act?
Skeptics argue that we should wait till climate models are completely certain before we act on reducing CO2 emissions. If we waited for 100% certainty, we would never act. Models are in a constant state of development to include more processes, rely on fewer approximations and increase their resolution as computer power develops. The complex and non-linear nature of climate means there will always be a process of refinement and improvement. The main point is we now know enough to act. Models have evolved to the point where they successfully predict long-term trends and are now developing the ability to predict more chaotic, short-term changes. Multiple lines of evidence, both modeled and empirical, tell us global temperatures will change 3°C with a doubling of CO2 (Knutti & Hegerl 2008).

Models don't need to be exact in every respect to give us an accurate overall trend and its major effects - and we have that now. If you knew there were a 90% chance you'd be in a car crash, you wouldn't get in the car (or at the very least, you'd wear a seatbelt). The IPCC concludes, with a greater than 90% probability, that humans are causing global warming. To wait for 100% certainty before acting is recklessly irresponsible.

http://www.skepticalscience.com/climate-models-intermediate.htm

 

[hawker]

You might want to read this.


http://www.skepticalscience.com/co2-lags-temperature.htm
http://www.skepticalscience.com/co2-lags-temperature-intermediate.htm

That is saying exactly what I just told you.

However, based on Antarctic ice core data, changes in CO2 follow changes in temperatures by about 600 to 1000 years, as illustrated in Figure 1 below. This has led some to conclude that CO2 simply cannot be responsible for current global warming.

 

[w1z4rd]

We aren't.

The natural cycle adds and removes CO2 to keep a balance; humans add extra CO2 without removing any.
Before the industrial revolution, the CO2 content in the air remained quite steady for thousands of years. Natural CO2 is not static, however. It is generated by natural processes, and absorbed by others.

As you can see in Figure 1, natural land and ocean carbon remains roughly in balance and have done so for a long time – and we know this because we can measure historic levels of CO2 in the atmosphere both directly (in ice cores) and indirectly (through proxies).



Figure 1: Global carbon cycle. Numbers represent flux of carbon dioxide in gigatons (Source: Figure 7.3, IPCC AR4).

But consider what happens when more CO2 is released from outside of the natural carbon cycle – by burning fossil fuels. Although our output of 29 gigatons of CO2 is tiny compared to the 750 gigatons moving through the carbon cycle each year, it adds up because the land and ocean cannot absorb all of the extra CO2. About 40% of this additional CO2 is absorbed. The rest remains in the atmosphere, and as a consequence, atmospheric CO2 is at its highest level in 15 to 20 million years (Tripati 2009). (A natural change of 100ppm normally takes 5,000 to 20,000 years. The recent increase of 100ppm has taken just 120 years).

Human CO2 emissions upset the natural balance of the carbon cycle. Man-made CO2 in the atmosphere has increased by a third since the pre-industrial era, creating an artificial forcing of global temperatures which is warming the planet. While fossil-fuel derived CO2 is a very small component of the global carbon cycle, the extra CO2 is cumulative because the natural carbon exchange cannot absorb all the additional CO2.

The level of atmospheric CO2 is building up, the additional CO2 is being produced by burning fossil fuels, and that build up is accelerating.

http://www.skepticalscience.com/human-co2-smaller-than-natural-emissions-basic.htm

That is saying exactly what I just told you.

Just giving people more context

 

[hawker]

http://www.skepticalscience.com/human-co2-smaller-than-natural-emissions-basic.htm


Just giving people more context

I thought you were arguing with me

Fair enough!

 

[Nanfeishen]

Anyone know the price of a 5/10kw wind turbine in SA? 6M pole preferred...

Pretty much the same as the solar market in S.A. very limited selection of over-priced products.

One is left with the impression that disuasion is the aim of the game rather than persuasion.

Some local prices:
http://www.sustainable.co.za/wind-power/wind-turbines.html?order=price&dir=asc

Check out this listing of small wind turbines, almost everyone available, you can get a 1-kW for as little as about R5000.
All small wind turbines; all the world's small wind turbines in one overview
http://www.allsmallwindturbines.com/

Here we have an amazing domestic rooftop system 4.2kW (High Output) 3 Rooftop Turbine Wind/Solar
http://windenergy7.com/

A very nice chinese design Turbine/Solar Combo
Wind Electric System with 3.47kWh Output Power
http://proanwindturbine.manufacture...-electric/1051470429/Wind-Electric-System.htm

As you can see there are some amazing products available in the real world , that we will probabily never have direct affordable access to in the the third world.

Such a pity

 

[JerryMungo]

Pretty much the same as the solar market in S.A. very limited selection of over-priced products.

One is left with the impression that disuasion is the aim of the game rather than persuasion.

Some local prices:
http://www.sustainable.co.za/wind-power/wind-turbines.html?order=price&dir=asc

Check out this listing of small wind turbines, almost everyone available, you can get a 1-kW for as little as about R5000.
All small wind turbines; all the world's small wind turbines in one overview
http://www.allsmallwindturbines.com/

Here we have an amazing domestic rooftop system 4.2kW (High Output) 3 Rooftop Turbine Wind/Solar
http://windenergy7.com/

A very nice chinese design Turbine/Solar Combo
Wind Electric System with 3.47kWh Output Power
http://proanwindturbine.manufacture...-electric/1051470429/Wind-Electric-System.htm

As you can see there are some amazing products available in the real world , that we will probabily never have direct affordable access to in the the third world.

Such a pity

Crikey! Someone's having a laugh with those prices. Ridiculous. 1Kw for R40k!

 

[JerryMungo]

These guys are a bit cheaper, but still expensive
http://dl.dropbox.com/u/12043489/CLC PRICE LIST FROM 17-04-2012.pdf