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micromacromonkey Wrote:

-------------------------------------------------------

> In short, no, it doesn't count. There is only so

> much water on the planet, and it's been cycling

> around in and out of the atmosphere and oceans for

> hundreds of thousands of years. 'Anthropogenic'

> water vapour might have small short term effects

> (e.g. clouds near cooling towers) but they will

> dissipate. While water vapour is a greenhouse gas

> (accounts for 90% of the greenhouse effect or

> something like that) any particular effects are

> short term and relatively localised.

>

> Conversely most CO2 that we emit has been trapped

> underground for AGES, and so is effectively a new

> addition to the atmosphere, hence considered a

> pollutant. It won't disappear in a rain shower

> like water vapour will.


Most water vapour that we emit has similarly been trapped underground for ages. When we burn natural gas (methane), two molecules of water vapour are emitted for every one molecule of CO2. The ratio for refined petroleum (diesel/petrol) is closer to 1:1 but still, all that water vapour has been trapped underground as crude oil and would still be there if we hadn't dug it up and burnt it. We have added to the amount of water on this planet just as we've added to the amount of CO2.


I accept the premise that the water cycle runs on a different timescale to the carbon cycle, hence the effects of the additional water vapour may not be as long-lived as the extra CO2. But my point was that both gases, when emitted by human activities, are pollutants.

Just going back on this too - all black cabs will have to be younger than 15 years old. But all residential cars in the ULEZ will have to be less than 6 years old - feels incongruous. Haven't looked in detail but isn't clear to me what standards minicabs will have to meet? Will they be held to the same standards as residential cars? I do support initiatives to make London's air cleaner and its incumbent on all of us to act now, but these plans seem too patchy.

goldilocks Wrote:

-------------------------------------------------------

> Just going back on this too - all black cabs will

> have to be younger than 15 years old. But all

> residential cars in the ULEZ will have to be less

> than 6 years old - feels incongruous. Haven't

> looked in detail but isn't clear to me what

> standards minicabs will have to meet? Will they be

> held to the same standards as residential cars? I

> do support initiatives to make London's air

> cleaner and its incumbent on all of us to act now,

> but these plans seem too patchy.


The black cab lobby is very powerful, that's why they're still driving around in cabs that are up to 20 years old, ancient EURO2 emissions, without diesel particulate filters (DPFs) and up to half a million miles on their knackered engines.


I saw a Hackney Carriage-licensed 1997 R-reg cab in town the other day, belching out clouds of visible soot and regularly follow 02/52/03/53-reg vehicles that ought to be banned immediately.


If I recall, Uber vehicles must be less than four years old; don't know about minicabs, but plenty of them are high-milers with the DPF chopped out of the exhaust system.

But all residential cars in the ULEZ will have to be less than 6 years old - feels incongruous.


This is not so - I have checked our petrol family car(s) with the ULEZ site - they are all older than 6 years, and all 'passed'. It depends what standard they were designed and tested to. It is true that many younger (than my car) diesel cars will not pass. This has not been helped by the 'cheats' installed in diesel cars by the manufacturers (some of them).

Cardelia Wrote:

-------------------------------------------------------

> micromacromonkey Wrote:

> --------------------------------------------------

> -----

> > In short, no, it doesn't count. There is only

> so

> > much water on the planet, and it's been cycling

> > around in and out of the atmosphere and oceans

> for

> > hundreds of thousands of years. 'Anthropogenic'

> > water vapour might have small short term

> effects

> > (e.g. clouds near cooling towers) but they will

> > dissipate. While water vapour is a greenhouse

> gas

> > (accounts for 90% of the greenhouse effect or

> > something like that) any particular effects are

> > short term and relatively localised.

> >

> > Conversely most CO2 that we emit has been

> trapped

> > underground for AGES, and so is effectively a

> new

> > addition to the atmosphere, hence considered a

> > pollutant. It won't disappear in a rain shower

> > like water vapour will.

>

> Most water vapour that we emit has similarly been

> trapped underground for ages. When we burn natural

> gas (methane), two molecules of water vapour are

> emitted for every one molecule of CO2. The ratio

> for refined petroleum (diesel/petrol) is closer to

> 1:1 but still, all that water vapour has been

> trapped underground as crude oil and would still

> be there if we hadn't dug it up and burnt it. We

> have added to the amount of water on this planet

> just as we've added to the amount of CO2.

>

> I accept the premise that the water cycle runs on

> a different timescale to the carbon cycle, hence

> the effects of the additional water vapour may not

> be as long-lived as the extra CO2. But my point

> was that both gases, when emitted by human

> activities, are pollutants.


I have broken my golden rule of not arguing on the internet about climate change. What you have written I can only assume you have read in good faith on a website somewhere, but you have probably forgotten the GCSE/O-Level science required to critique it.


The answer is: those water molecules end up in the water cycle like other water molecules. They aren't any more likely to hang around in the atmosphere because they used to be part of a hydrocarbon molecule, in some homeopathic memory-of-petrol sort of way. Sure, if the planet warms, then air can hold more water vapour, and that means more greenhouse effect, in a positive feedback loop. But there is more than enough liquid water available (hint: the sea is big) for that to happen without worrying about adding a relatively tiny amount from burning hydrocarbons.

  • 3 weeks later...
There is a massive hole in the tube network over SE London. There is a massive hole in the Boris bike network over SE London. How about fixing one, or both of these things before piling on more restrictions on private transport?

Hi rahrahrah,

You can see a heat map of Public Transport Accessibility Levels (PTAL) here - https://tfl.gov.uk/info-for/urban-planning-and-construction/planning-with-webcat/webcat

The higher the number redder the map the more pubic transport.

You are right that near the south circular PTAL is much lower - those blues in Dulwich Village are in the middle of Dulwich Park BTW.

Equally if you look to the north of London similar heat map PTAL scores before you reach the north circular.


As Londondoners do we try and fix air pollution or not. The waiting for everywhere to have high PTAL would mean not addressing air pollution. We're never going to have universal high PTAL scores.


But for clarity the ULEX means Petrol cars newer than 2006.

James Barber Wrote:

-------------------------------------------------------

> Hi rahrahrah,

> You can see a heat map of Public Transport

> Accessibility Levels (PTAL) here -

> https://tfl.gov.uk/info-for/urban-planning-and-con

> struction/planning-with-webcat/webcat

> The higher the number redder the map the more

> pubic transport.

> You are right that near the south circular PTAL is

> much lower - those blues in Dulwich Village are in

> the middle of Dulwich Park BTW.

> Equally if you look to the north of London similar

> heat map PTAL scores before you reach the north

> circular.

>

> As Londondoners do we try and fix air pollution or

> not. The waiting for everywhere to have high PTAL

> would mean not addressing air pollution. We're

> never going to have universal high PTAL scores.

>

> But for clarity the ULEX means Petrol cars newer

> than 2006.


But not all provision is equal, is it? A bus which takes an hour to get into central London, is not equal to a tube service which turns up ever few minutes and take 10 to get into the west end (for example).


Personally, I would like to see some Boris bikes at least, so that one could cycle to brixton tube - or just some secure bike parking at Brixton.

AFAIK there has never been any real incentive towards those vehicles (mostly automatic cars, but also some automatic 125 scooters) that automatically switch off the engine when stopped in traffic or at a traffic light. I am no scientist, but I would imagine that not polluting while stationary (which is a huge part of the time in a city like ours) would make quite a big difference?


I also do wonder about the generic impact of replacing an old vehicle with a less polluting one vs keeping it a bit longer. For those who live in the areas where the new vehicle will be driven, a new vehicle will be better. But for the environment overall? What's the environmental impact of scrapping an old vehicle and producing a new one? I genuinely have no idea.

PS Oh, and also the environmental efficiency of British homes is a joke by European standards. In many cases double glazing is not even allowed. The Dulwich Estate doesn't allow it, for example, because of course the "charity" must fleece homeowners by policing the beauty of the houses and overcharging them so that money can be funneled towards posh independent school attended mostly by overpriviliged kids - a most charitable endeavour.


(No, I don't live in the Dulwich Estate area - heel will freeze over before I do).

I wonder how much it would cost to provide proper, secure bike parking at Brixton tube, as opposed to all the yellow line, speed bumps etc that are scattered around our area? I suspect the former would do more to reduce local car journeys than the latter ever will.

DulwichLondoner Wrote:

-------------------------------------------------------


> I also do wonder about the generic impact of

> replacing an old vehicle with a less polluting one

> vs keeping it a bit longer. For those who live in

> the areas where the new vehicle will be driven, a

> new vehicle will be better. But for the

> environment overall? What's the environmental

> impact of scrapping an old vehicle and producing a

> new one? I genuinely have no idea.


Very, very roughly, a car produces around three tonnes of CO2 during its production and scrappage phases. If you had a car producing 150g/km of CO2 and swapped it for a new one producing 100g/km, over five years of average (8,000 miles p.a.) use you'd save about five tonnes of CO2, so in general the new car would be the greener option, but of course there are lots of variables - if you only ever use your car for a trip to Brighton once a fortnight keeping the old one would be the better bet.


I wonder how much it would cost to provide proper, secure bike parking at Brixton tube, as opposed to all the yellow line, speed bumps etc that are scattered around our area? I suspect the former would do more to reduce local car journeys than the latter ever will.



Different boroughs, different budgets.


Very much agree though.. while personally, by the time I've ridden to Brixton or Kennington, I might as well bike the rest of the way, I can understand others not wanting to. And especially once you start talking e-bikes - there's no way I'd leave a ?1000+ bike locked outside either of those tube stations.


I reckon dockless hire bikes like OFO would do a roaring trade along the EDG - Herne Hill - Brixton corridor (a bit heavy & poor gearing for going over Dog Kennel Hill, but fine on the flat). Anyone know if Southwark will be adopting them? Seems the phone app and no-strings T&Cs appeal to youngsters in particular.

I was wondering about how valid the comparison is between the emissions of a new car that you would buy, and the emissions of your old one. If you are the sort of person who buys a new car, you're probably NOT the sort of person who has run the old one into the ground. So you sell your old one to someone who has an older (== more polluting) car, and that may happen a few times. At the end of the chain a real old banger is getting scrapped somewhere, so you might reasonably claim that you saved a lot more. (Clearly this also assumes that we have reached saturation point for our roads, and are operating a one-out, one-in policy, which isn't yet true. Car numbers are still increasing.)


The above takes into account only CO2, which is very much a non-localised concept. It's great for global warming, and the notion that possibly our great-grandkids might have less chance of dying in climate related manners in 80 years time. But kids are dying right now because of localised NOx and particulate emissions, both of which will be more immediately and locally impacted by the choice of buying a new vehicle.


TL;DR: buying a new car is probably more of a good idea than you think.

5 cycle superhighways - none in SE London

hundreds of bike docking stations - none in SE London

A couple of hundred tube stations and only 4 in SE London (outside of Zone 1)


How can we get people out of their cars? I know, making driving a little more difficult will do it.

Oh, please, how much more difficult do you want driving to become, and what do you think it will achieve?

And I say this as someone who does not even own a car.


If you go from zone 2 to zone 3 or 4, driving might be feasible, but if you're going to a more central area, whether for work or else, driving is already so expensive (and rightly so) and infuriating that I do wonder how many people do it. Do you know anyone who goes to central London, for shopping or for work, by car?


Maybe regulating minicabs (we might have too many...) and trying to make sure that delivery vans and construction trucks do not congest the roads at rush hour might help somewhat.

DulwichLondoner Wrote:

-------------------------------------------------------

> PS Oh, and also the environmental efficiency of

> British homes is a joke by European standards. In

> many cases double glazing is not even allowed. The

> Dulwich Estate doesn't allow it, for example,

> because of course the "charity" must fleece

> homeowners by policing the beauty of the houses

> and overcharging them so that money can be

> funneled towards posh independent school attended

> mostly by overpriviliged kids - a most charitable

> endeavour.

>

> (No, I don't live in the Dulwich Estate area -

> heel will freeze over before I do).


Err, in most cases Dulwich Estate do allow it:


http://www.dulwichestate.co.uk/som/policy-guidelines/8-replacement-doors-and-windows

Lowlander Wrote:


> Err, in most cases Dulwich Estate do allow it:

>

> http://www.dulwichestate.co.uk/som/policy-guidelin

> es/8-replacement-doors-and-windows


Most or some? There have been discussions here about people being refused double glazing, e.g. http://www.eastdulwichforum.co.uk/forum/read.php?5,1403483,page=3 and I know a few such cases, too

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