so Alex, finaly you understand my argument
zero carbon policy = clutching at straws

even if we reduce co2 levels to pre industrial levels we will still be affected by dramatic and sudden climate changes

Another 1400 scientists providing propaganda for the world rulers

http://www.guardian.co.uk/environment/2007/oct/26/climatechange

Message to all incl me: Enough posturing! Let's do some justice to the original question.

Posted By: Chris WardleI agree that this "zero carbon" thing is crap. A target for energy in use (like Passive House) and also a target for embodied energy in construction of the building would be more useful. Nothing like as useful as TEQs of course

That defines the two branches of the zero-carbon aspiration nicely. Please explain why is it "crap"? Why can't TEQs be part of the strategy to achieve national zero-carbon, instead of a better alternative?

Tom, my point was that setting a zero carbon target for an individual house within a society which is very far from zero carbon is meaningless. The embodied energy in the materials will be mostly fossil energy, the workers will travel to the site in fossil fuelled vehicles, the renewable technologies installed to make the house "zero carbon" have embodied energy in them. Unless the house has battery storage, it will rely on the Grid at certain times which is mostly fossil fuelled. The water into the house is cleaned and transported using fossil fuel as is the sewage from it. The zero carbon label has no real meaning in these circumstance.

Setting a zero-carbon target for a society, as proposed in the recent CAT paper "Zero Carbon Britain" is something that could be worked towards and then all the homes in the country would be zero carbon, regardless of how energy efficient they were. That scenario used TEQs to drive the policy.

I think we should be using a low energy in use standard and also a low embodied energy standard because embodied energy becomes much more relavent in the total life cycle energy of an energy efficient building. Making indivudual building "zero-carbon" using micro-renewables is not a good allocation of resources for a society because large scale reneables are so much more cost efficient, i.e. the policy will force a misallocation of resources, unless the "green tariff" approach is used, so what is the point in having it?

no posturing here fostertom, I think it is related to the topic of the thread becaause i find the notion of zero carbon very strange, we exhale out co2!

is zero carbon a good way forward??

I am actually a believer in enviromental protection, part of my work is as a designer and builder of ecological homes, especially straw bale houses, using timber, hemp, lime and earth plasters and natural materials, aiming for high leverls of energy efficiency and autonomy.

I do not deny that there is climate change and its also possible that humans are contributing. My main concern is the best course of action going into the future and also to what extent the issue is being abused by those with alterior motives.

for me personally there are 4 prime points:

1. it is established that the earths climate changes all the time, and has always done so. throughout all of earths history the climate changes dramatically from snowball to tropical where there are no ice caps.
this is due to our orbit around the sun, called the milankovitch cycle.

2. these changes have been shown through temp records to have happened often very rapidly, within decades.

3. recent human civilisation has developed and adapted within a very short period of recent time, with what is called the halcyon age, the earth is over due to come out of this short lived warm period and back into a snowball earth. the earth spends roughly 100k years in an ice age state then comes out briefly for roughly 10k years into the warm period we are in now. we have been in this warm part of the cycle for 10k already and is due to return to a 100k year iceago. This is the Milankovitch cycle.

4. So it seems to me that it is mainly a question of adaptation!
EVEN IF WE HAD ZERO CARBON SINCE BEFORE 1700ad, we would still face at some point, with absolute certainty, possibly very soon, catastrophic (for us) natural climatic change, as it always has done and as it always has. and this change can be very very quick, as at the end of the last ice ago 11k years ago when temps rose dramaticly within decades and sea levels rose 300 feet (the origin of the flood myths around the world?)

or do we now try and keep the earths climate fixed as it is now? This would be the first time this has happened for the earths 5 billion year history.

Are we not better off spending our energy and resources on the challenge of adaptation??

Bot you said, "or do we now try and keep the earths climate fixed as it is now?"

Once king Canute sat on the beach and commanded the tide to go back. It is not even possible to change the weather never mind the climate get real!!

Posted By: Chris Wardlethe market will drive the necessary revolution

Sright - the market will choose between skyrocketing fuel costs accompanied by stagnating house value - or low-, zero- or negative fuel use accompanied by house value rising well ahead of the market. Which will they go for? How can a householder get to the second option? Only by doing- and investing - what it takes to make his/her house truly zero-energy. What does that entail? Definitely not bolt-on techie things, not cavity fill or DG-industry windows, but a wholesale reorganisation, probably extension, of the house, so the house's fabric and orientation basically does the job, techie things maybe in supporting role. The bonus - a beautiful, enlarged, functional building almost as a no-extra-cost by-product of going zero-energy, and house value rising well ahead of the general market. Cos believe me, the market will value genuinely zero-energy premises (includes shops, offices, factories - all inhabited buildings) very highly at buy/sell time, and will have great resistance to buying an un-zero'd building, including one that's been expensively uprated with useless conventional-wisdom half-measures round about now.

are we talking about zero energy or zero carbon? they are notthe same

zero energy??? thats not possible!

or do you mean self sufficient??

I think self sufficient for homes is fantastic, but for industry and buisness, is taht possible??