[SustainableTompkins] Avoiding the GHG tipping point

Tue Oct 24 02:36:43 PDT 2006

A new article on GHG tipping point from Inter Press Service appeared on 
CommonDreams yesterday.:

"Scientists estimate that to avoid dangerous climate change (generally 
viewed as a two-degree rise in global temperatures), world greenhouse 
gas emissions need to be reduced by about 60 percent from today's levels 
by 2050.

At the same time, world energy demand is projected to increase by over 
50 percent between now and 2030, and that will raise energy-related 
carbon dioxide emissions 52 percent higher than they are today, reported 
the International Energy Agency (IEA) in its 2005 World Energy Outlook, 
considered the definitive report on global energy."

Source: http://www.commondreams.org/headlines06/1023-05.htm

-- Katie Q-J

David Panofsky wrote:

>We also need to remember that if we (the human race) need to reduce GHG
>emissions by 65%, then in all fairness, we (Americans) need to reduce
>our emissions by something closer to 85% because our per capita
>emissions are so much higher than the global average.
>
>Additionally, we must be careful to not pretend we're cutting emissions
>if, through increased globalization, we're really just moving those
>emissions elsewhere.  E.g. GHG released by electricity production at a
>coal fired plant in Canada would be tallied there regardless of whether
>the electricity is consumed here.
>
>When we start to think about just how many of our consumed goods are
>manufactured elsewhere, we can see the huge risk of falsely believing
>that we are changing practices to reduce our emissions when in reality
>we may just be moving them.  We're already starting to worry about
>growing GHG emissions from China and India due to their expanding
>economies.  However, since that economic expansion is largely due to the
>growth of industries which were formerly in the West, and since the
>goods produced by those industries are still destined for America and
>Europe, we must ask ourselves who is morally responsible for those
>emissions.
>
>    dave p.
>
>Marty Hiller wrote:
>  
>
>>Hi Jon, Here's a graphic: http://www.grida.no/climate/vital/13.htm
>>
>>which shows us adding about 5.5 GT carbon from fossil fuels and the
>>oceans sequestering about 2 GT carbon each year, which implies that
>>we should reach a net zero increase if we drop our emissions from 5.5
>>to 2, which is about a 65% reduction. Obviously it's a lot more
>>complicated than that, but it'll do for a back-of-the-envelope
>>calculation.
>>
>>If you assume we have 20 years at our current usage (which is one
>>heckuva big assumption,) a 2% per year reduction would buy us an
>>extra 15 years, and a 3% per year reduction for 35 years would keep
>>us below the tipping point. Our releases are currently increasing by
>>a bit over 2% per year, if I recall correctly, so with business as
>>usual we would have about 15 years, not 20.
>>
>>If we assume it takes five years to reach global consensus, we'd have
>> to up the reduction rate to about 4% per year to back us out of
>>those five years of growth.
>>
>>- Marty
>>
>>
>>On Oct 5, 2006, at 12:33 PM, bosak at ibiblio.org wrote:
>>
>>    
>>
>>>A scientific opinion widely quoted recently is that we will reach a
>>>"tipping point" where climate change becomes irreversible when the
>>>atmospheric concentration of CO2 reaches 440 ppm.  (We're currently
>>>at about 382 ppm and at present rates of increase will hit the 440
>>>mark in about twenty years.)
>>>
>>>It should be obvious that there are a lot of problems with setting
>>>a specific figure like this, but it's useful in trying to
>>>understand the situation.
>>>
>>>What I want to know is, by what percentage would current world
>>>consumption of fossil fuels have to decrease in order to avoid
>>>hitting the tipping point?  There would appear to be a lot of
>>>hysteresis (i.e., time lag) involved, so the amount of reduction
>>>would have to be more than the amount needed to maintain a steady
>>>state once we got there, but how much is that?  Fifty percent?
>>>Sixty?  Eighty?
>>>
>>>Has anyone crunched the numbers on this?  For purposes of
>>>discussion, I need just one credible, conservative estimate of the
>>>amount we'd have to reduce global fossil fuel consumption, starting
>>>today, in order to avoid hitting 440 ppm.  (It would be best to
>>>have several estimates, since they're bound to differ depending on
>>>methodology used, but I'd be happy to have just one.)
>>>
>>>Jon
>>>
>>>
>>>_______________________________________________ SustainableTompkins
>>>mailing list SustainableTompkins at lists.mutualaid.org
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>>>
>>>
>>>      
>>>
>>------------------------- "We act as though comfort and luxury were
>>the chief requirements of life, when all that we need to make us
>>happy is something to be enthusiastic about. "  -- Albert Einstein
>>
>>_______________________________________________ SustainableTompkins
>>mailing list SustainableTompkins at lists.mutualaid.org
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>>hosting by http://www.mutualaid.org
>>    
>>
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