350

[biffvernon]

a drastic reduced lifestyle,

We'll have to listen to string quartets instead of watching motor racing, sit in the local pub instead of fly to Las Vegas, eat home grown vegetables intead of stuff flown in from Kenya, go for a walk in the park instead of a drive to the shopping mall, repair old houses with pre-industrial methods and materials intead of building new with concrete and plastic. If that's a reduced lifestyle, bring it on.

 

[biffvernon]

We haven't really talked about what the effects would be if all fossil fuel burning was globally banned as of tomorrow. We speak of the future collapse of civilisation if global warning carries out the dire destruction Biff predicts. But what would happen to world economies, jobs etc if the climate campaigners got their way? Surely that would engender just as much of a collapse in civilisation. The whole foundation of our lives would just be gone. It just isn't realistic. It strikes me that only little steps towards reducing our carbon footprint are possible, and, as we keep saying, they might be woefully inadequate. You know I've said before I find it really hard to engage with the year, say, 2300.

Yes of course nobody is seriously saying ban burning all fossil fuels tomorrow. The difficulty of engaging with a 2030 target (let alone a 2300 target) is what has brought on the 10:10 campaign. Reduce you carbon emissions by 10% in 1010. It's a small but significant step, not necessarily easy but probably achievable by many of us. Weighed against the end of human civilization and perhaps the human species, the loss of 'world economies, jobs etc ' may be a small price to pay. But being realistic, I don't see us foregoing the use of any of the conventional crude oil that is available - it's just too useful. And, fingers firmly crossed, there may not be enough of it left to tip us over the edge. Coal, on the other hand, definitely needs to be left in the ground and we need to go all out for carbon sequestration. There's plenty of hope that we could keep civilization going without business as usual, business will have to be different.

I've just got back from a SPAB visit to a Grade II* 18th century building in Boston (116 High Street if you want to look it up). It's on the SAVE Buildings at Risk register and was a feature in a thread on this forum a couple of years ago. One of the factors affecting it's conservation and refurbishment is that it lies at sea level so will not get planning permission for any residential use on the ground floor, thus limiting end-user options. That's the real impact of global warming today on Period Property conservation.

 

[biffvernon]

I don't have a geology degree

Sorry, must have muddled you with someone else who used to post here, an ex-geologist turned building conservator.

why do they not do everything in their power to reduce those emissions?

It's a good question. I'm no psycholgist but there is the concept of 'denial'. Why do people smoke? Drink to excess? And those are things that affect them not just their grandchildren. Instant gratification wins over species preservation? Maybe humans are just stupid.

 

[biffvernon]

Incidentally Biff, is it the rate at which we are burning carbon-based fuels which is the issue, or the total absolute amount of carbon eventually put in the atmosphere?
In other words, are all our carbon-efficiency schemes (loft insulation, etc) simply delaying a little bit the inevtiable effect of burning all our coal/gas - or is there a sustainable rate of burn (and have I thus missed the point of a thread called 350 ?)

Complicated. A bit of both. About half of all our carbon emissions are drawn down and sequestered pretty quickly so don't contribute to global warming long term. The other half hangs about in the air for a long time (think 1000 years) and so will contribute on a cumulative basis. This means that we could burn some stuff sustainably, but nothing like as much as we do now. A secondary problem is that much of the naturally sequestered carbon is ending up in the oceans - that's fine for a while but after a bit the oceans get more acid. That could become very serious because once a certain pH is reached the previously fixed calcium carbonate that all the little creatures make their shells out of and then die and form limestone rock at the bottom of the ocean locking up the carbon forever, starts to dissolve. And when CaCO3 dissolves it releases, er, CO2. Oops a tipping point to a nasty viscous circle.

So we need to reduce our emissions, reducing the absolute amount and the rate!

 

[biffvernon]

we can't do better than a 100% reduction, i.e. cease any fossil-fuel usage,

Technically, we can. By sequestering carbon that is already in the atmosphere, whether by the much hyped 'artificial trees' or by incorporating bio-char in our soils or just by managing agricultural systems so that a net increase in soil carbon results, we could achieve a greater than 100% reduction. (I don't suppose we will.)

 

[biffvernon]

I don't necessarily agree with the detail, but the trend seems obvious, as (I'm afraid) is the root cause of the problem:
http://en.wikipedia.org/wiki/World_population

Read this week's New Scientist.

 

[biffvernon]

In terms of carbon output - how important is human exhalation (O2 in, CO2 out)? Or am I being daft?

Yeah, daft.
Even all the world's volcanos only contribute about 1% of the CO2

 

[FamilyWiggs]

Mrs FW confirms I am daft. :lol:

So I guess the joke about methane-farting cows being a huge greenhouse gas contributor is daft too.

 

[biffvernon]

Not at all. Except that cows don't fart methane - they belch it. This is quite a serious one. There are an awful lot of cows and they belch an awful lot of methane, which is a much more powerful greenhouse gas than carbon dioxide. Curiously, it seems that cows belch more methane when fed grain and other concentrates in intensive cattle fattening lots rather than when grass fed. So a return to ye olde fashioned way of keeping cows - in grass fields - would help. And most of all we must stop eating so much meat.

 

[Flyfisher]

We'll have to listen to string quartets instead of watching motor racing, sit in the local pub instead of fly to Las Vegas, eat home grown vegetables intead of stuff flown in from Kenya, go for a walk in the park instead of a drive to the shopping mall, repair old houses with pre-industrial methods and materials intead of building new with concrete and plastic. If that's a reduced lifestyle, bring it on.

My spectacles don't have quite the same rose-coloured tint, I'm afraid. :wink:

 

[Flyfisher]

Yes of course nobody is seriously saying ban burning all fossil fuels tomorrow. The difficulty of engaging with a 2030 target (let alone a 2300 target) is what has brought on the 10:10 campaign. Reduce you carbon emissions by 10% in 1010. It's a small but significant step,

I disagree. If the figure of 80% reduction globally by 2030 is indeed what's required then the 10:10 campaign is a small but insignificant step. Worse than that, it may engender a false sense of security and hinder any really significant moves towards a whole solution. Environmentalists can't have it both ways; if we're really facing a major threat then surely the action has to be major?

 

[Flyfisher]

Curiously, it seems that cows belch more methane when fed grain and other concentrates in intensive cattle fattening lots rather than when grass fed. So a return to ye olde fashioned way of keeping cows - in grass fields - would help.

That may not be true according to: http://www.newscientist.com/article/mg20327261.500-better-world-eat-more-plants.html

Less methane from grain and concentrate-fed cattle makes sense because these foodstuffs must be easier to digest than grass, requiring far less of the microbial actions required to break down cellulose cell walls, which releases the methane.

Also, as the above article points out, not all meat is from methane-producing ruminants.

 

[biffvernon]

If the figure of 80% reduction globally by 2030 is indeed what's required then the 10:10 campaign is a small but insignificant step

Every journey starts with a small step. 10% in 2010, another 10% in 2011, another 10% in 2012...and before you know it...

On cattle belching, both my and the NS comments were oversimplistic. Much of the ruminant methane production is from cows, sheep and goats in the poorer parts of the world where forage quality is often poor and the addition of feed supplements, particularly to increase the protein content, would improve fermentation efficiency and reduce methane enteric production. I actually had British cows in mind, where our rich pastures provide a nutritionally balanced diet which results in less methane.

 

[Flyfisher]

I don't necessarily agree with the detail, but the trend seems obvious, as (I'm afraid) is the root cause of the problem:
http://en.wikipedia.org/wiki/World_population

Interesting special feature on "The Population Delusion" in last week's New Scientist, covering differing points of view.
http://www.newscientist.com/special/population

Edit: Oops - I've just noticed that Biff mentioned this earlier. I'll leave the link in place though.

 

[Flyfisher]

http://news.bbc.co.uk/1/hi/sci/tech/8299079.stm[/url]"]One thing is for sure. It seems the debate about what is causing global warming is far from over. Indeed some would say it is hotting up.

 

[DaveBrigg]

On the subject of insignificant carbon reductions, please excuse my ignorance, but...
If I have a room lit by four bulbs, all turned on by the same switch, can I reduce the electrity used by a quarter if I don't replace one of the bulbs when it blows? Would the same be true of low voltage halogen bulbs if there are three linked to the same transformer?
If energy saving bulbs are similar to flourescent tubes, does this mean that they also consume more electricity when first turned on? If so, what is the time span when it is more economical to leave the light on, rather than turn it off, and then back on again a few minutes later?
Do 12 volt halogen bulbs require less electricity than a 240 volt energy saving bulb?
I realise these may sound like stupid questions, but please bear in mind that I am better qualified to write a poem about a light bulb than to calculate its energy use.

 

[Lime]

On the subject of insignificant carbon reductions, please excuse my ignorance, but...
If I have a room lit by four bulbs, all turned on by the same switch, can I reduce the electrity used by a quarter if I don't replace one of the bulbs when it blows?

Yes.
Of course this assumes the four lamps are the same wattage as each other.

Would the same be true of low voltage halogen bulbs if there are three linked to the same transformer?

Yes, for the most part.
A transformer (either the wound or electronic switched type) will consume a small amount of power (caused by internal losses) but it is only a small percentage of the total load connected to it.

If energy saving bulbs are similar to flourescent tubes, does this mean that they also consume more electricity when first turned on?

Old style fluorescents (the type with a choke and starter or the less common cheaper "hot wire" ) consume more power when switched on but it is usually for a few seconds only.
The extra power consumed is slight in comparison to their normal running consumption.
The modern electronic-starting fluorescents (all types including compact lamps) hardly use any extra power when starting.

If so, what is the time span when it is more economical to leave the light on, rather than turn it off, and then back on again a few minutes later?

There is no saving of power consumption by leaving fluorescents on at all.
The extra power consumed by old style fluorescents when starting amounts to a few seconds of normal consumption.
There is some extension of lamp-life with old style fluorescents by reducing the number of times a lamp is started.
That is because the switch-on wears out the filament in the ends of the tubes.
However with modern electronic fluorescents (of all types) switch on makes little difference to lamp life.

Do 12 volt halogen bulbs require less electricity than a 240 volt energy saving bulb?

No.
Do not confuse lower voltage with less power.
It is not the voltage you need to consider but the wattage (power).
A 12volt 100 watt lamp will consume the same amount of power as a 240volt 100 watt lamp.
A 12 volt 20 watt lamp will consume twice as much power as a 240 volt 10 watt lamp.

I realise these may sound like stupid questions, but please bear in mind that I am better qualified to write a poem about a light bulb than to calculate its energy use.

Not stupid at all.

 

[MdB]

Do 12 volt halogen bulbs require less electricity than a 240 volt energy saving bulb?

No.
Do not confuse lower voltage with less power.
It is not the voltage you need to consider but the wattage (power).
A 12volt 100 watt lamp will consume the same amount of power as a 240volt 100 watt lamp.
A 12 volt 20 watt lamp will consume twice as much power as a 240 volt 10 watt lamp.

A bit more info for you.

A 50W tungsten incandescent filament bulb is around 2.0% efficient at turning electricity into visible light. (240V, 0.21A)

A 50W tungsten glass halogen is around 2.4% efficient (240V, 0.21A)

A 50W tungsten quartz halogen is around 3.5% efficient (12V, 4.2A)

A 50W compact fluorescent lamp is around 10% efficient (240V, 0.21A)

All will produce exactly the same amount of heat (50W) but the CFL will produce x5 the amount of visible light.

I realise these may sound like stupid questions, but please bear in mind that I am better qualified to write a poem about a light bulb than to calculate its energy use.

Now you have the info, you can write us a poem about it ;-)

 

[Lime]

All will produce exactly the same amount of heat (50W) but the CFL will produce x5 the amount of visible light.

Yes. All consume 50 watts i.e. the same power.

If we are going to discuss light output then we are entering a complicated area.
Light output efficiency is not neccessarily an accurate means to judge a lamp as our perception may differ.
The human eye does not perceive red and blue light equally.
Different types of lamp give different light dispersion.
Filament lamps tend to give a broad spectrum of light while ionised lamps tend to give a narrow band or spike spectrum, low-pressure sodium lamps being an obvious example.
The colour of the light can affect how we feel. Tunsten lamps are said to create a contented mood because of it's yellow content.
The brightness of the light can alter how we feel too. SAD sufferers find bright lights make them feel less depressed.
There are other type of lighting that are much more efficient than fluorescent lamps (compact or otherwise), low-pressure sodium vapour lamps for example but give a "poor" light if judged by the human eye.
Then there is the effect of varying voltage on light output. A tungsten lamp is more efficient if over-run on a higher voltage.
Similarly filament lamps give less light and are far less efficient at reduced voltage.


Perhaps I misunderstood DaveBrigg when he asked

Do 12 volt halogen bulbs require less electricity than a 240 volt energy saving bulb?

because there is a common misconception that lower voltage means less electricity consumption.
It doesn't.

I think the idea of a poem rather a good idea too.

 

[Flyfisher]

The human eye does not perceive red and blue light equally.

Indeed so. In the world of television, the outputs of the red, green and blue sensors of a colour video camera are combined to create a 'luminance' signal that corresponds to a monochrome image (the reasons are somewhat involved and don't matter here). To account for the different sensitivity of the eye to different colours, they are combined in a ratio of 30% red, 59% green and 11% blue, to create a monochrome image that appears 'natural' to the human eye.

I really should get out more.