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Help on getting my facts straight
Thread started on 28/2/2007 19:33

vey_straker

vey_straker

other

starting new crags

We’ve got a public meeting on Tuesday and I need to get my facts straight/up to date. Expert knowledge greatly appreciated if any of you have this stuff at your fingertips.

What is currently thought to be a sustainable level of CO2 emissions, per capita (preferably personal CO2 emissions)?
What is the UK government’s current commitment? Is it still 60% reduction by 2050? And if so – 60% reduction of what?
Whats the latest (reasonably widely accepted) required reduction for UK and by when?
What are current levels of CO2 in the atmosphere (parts per million) and what can we increase to before we are in danger of tipping?

I’ll get searching, but if anyone has instant answers that would be great,

Cheers

Vey

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382ppm now, 450ppm target

written on 28/2/2007 23:15

david

david

Given all the uncertainties involved, it’s a bit of a lottery, but I’m still going with the 450ppm target. That gives us a 90% chance of staying below 3 degrees (not pretty, is it?), and (I think) a better than odds chance of staying under 2 degrees. Read about it in our logo. On a shorter timescale, the story is that global emissions have to peak and start falling within the next ten to fifteen years (I’ll to to find the reference for that). We should probably check the recent Fourth Assessment Report (but does anyone know if it’s available for download?).

The latest Mauna Loa data on CO2 1 gives 377ppm in 2004 and climbing at 2-3ppm per year (so we’re probably at ~382ppm in 2006). There’s probably more recent data, but that source is reliable.

I’d have to do more thinking about the sustainable level (should be net carbon sink divided by the population), and I don’t know the government targets – although I don’t think anything has changed on that front. As far as I now, they’re still aiming at the more “realistic” 550ppm and 60% of 1990 levels (I presume, this is the normal baseline) by 2050.

Hope that helps.

  1. Keeling & Worph (2005) Atmospheric CO2 concentrations (ppmv) derived from in situ air samples collected at Mauna Loa Observatory, Hawaii [online]. Available from http://cdiac.esd.ornl.gov/ftp/trends/co2/maunaloa.co2

 
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IPCC Summary

written on 1/3/2007 13:56

vey_straker

vey_straker

Its here if you are interested. http://ipcc-wg1.ucar.edu/

Vey

 
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Thanks!

written on 1/3/2007 13:58

vey_straker

vey_straker

Many thanks for that David.

Vey

 
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Vey About 1.25 tonnes CO2

written on 4/3/2007 16:16

robinsmith3

Vey

About 1.25 tonnes CO2 global per capita (Cambridge Uni)
Current grandfathered emissions are about 3.8 tonnes CO2 global per capita (25Gt / 6.5Bn people)
Smart arses might ask “but what about the other GHG’s”. 2000 emissions were 42Gtonnes CO2e I believe (25 CO2)

Best
R

 
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i.e. 0.6t CO2 per person for house, car and plane

written on 4/3/2007 19:16

andy_ross

andy_ross

The 1.2t CO2 certainly squares with the figure in Colin Forrest’s Cutting Edge Climate Science paper from April 2005 on which George Monbiot based his call for a 90% cut in the UK by 2030.

Colin Forrest “Cutting Edge: Climate Science to April 2005”
http://portal.campaigncc.org/files/THE_CUTTING_EDGE_CLIMATE_SCIENCE_TO_A…

Remember this 1.2t CO2 per person is for all sources of man-made CO2. If the share of personal carbon emissions from house, car and plane is frozen at current proportions of the total, the sustainable personal carbon footprint from these sources alone is 0.6t CO2.

 
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Cool. But what am I talking

written on 6/3/2007 00:49

robinsmith3

Cool. But what am I talking about???

The only sustainable footprint must be 0 or negative (like growing lots of biomatter and sinking it in the deep ocean) Reality though makes planetary engineering some way off… and we would be meddling and stewarding again with stuff we dont understand!

But I am thinking of a zero carbon world and economy here of course (:

 
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Not necessarily ...

written on 6/3/2007 22:43

david

david

There is a natural capacity to absorb carbon dioxide emissions and this means sustainable footprints can be positive. At very low emissions levels other forcing factors for climate would come into their own anyway – for example, natural solar variability is probably responsible for ~10% of current warming.

In any case, the sustainable end-point is probably a moot point given the very enthusiastic fossil burning going on. It’s starting on the downward path that matters!

 
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Fair per capita share of CO2

written on 4/7/2008 13:33

Rachel

Hi Robin, can you give me a reference for the figure you quote from Cambridge University, please?
Thanks! And do they give an estimate for a fair shre of other GHGs?

 
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Hi Rachel Oops a

written on 8/7/2008 10:30

robinsmith3

Hi Rachel

Oops a misreference. Its was the Cambridge Zero Carbon Society. But the leader is a graduate and still works there at 4CMR a climate mitigation think tank.

“Globally, we can sustainably emit 7 billion
tonnes of CO2 per year. (Mixing of surface
layer and deep oceans is rate-limiting factor)
A world of nearly 7 billion people can
sustainably emit an average of only 1 tonne of
CO2 each per year.”

http://www.zerocarbonnow.org/?page_id=13

Brgds

 
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Fair shares for a "safe" climate

written on 9/7/2008 15:19

david

david

Hi Rachel.

A few weeks ago, I mapped out the fair shares consistent with maintaining a “safe” climate over the 21st Century, see: http://www.carbonrationing.org.uk/fora/threads/zero-carbon-what-does-it-...

This is all based on reputable literature, although these figures will always vary based on what you deem is an acceptable risk of “dangerous” climate change. The emissions pathways are also based on models with a wide range of assumptions – this analysis relies on only one (albeit reputable) atm. To be more robust it would need to review a range.

Any questions, please get back to me. Hope that helps! David.

 
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