Zero Carbon Britain

[Billhook]

Woodburner -

I too can't see how we could restore pre-industrial CO2 level in a short time.
Given recognition of its importance both for the oceans and for limiting warming and for removing the 'historic emissions' obstacle from the climate negotiations,
then with present technologies and a strong global effort the best schedule I can model achieves the goal about 100 years after the start date. I.e. 2115 at the earliest.

Re technologies, the 'artificial trees' that Prof Lackner has promoted for fossil companies to recover their CO2 outputs fail to scale up viably. To recover 1.0ppmv of CO2 (out of at least 160ppmv airborne, plus oceanic outputs) means collecting 2.1Gts carbon, which means extracting, transporting and spreading along the trees' shelves at least 1.8Gts of the compound that naturally reacts with CO2 and seizes its carbon. After that around 3.9Gts of the product compound must be got down from the trees' shelves, loaded to trucks and hauled to a really large disposal site. All with no income stream apart from the carbon credit value.

Re the need of an endothermic reaction to recover carbon from CO2, you are in a sense spot on. Currently the planets's biosphere has an energy capture rate of about 130 terrawatts via photosynthesis (about six times anthro power usage) which drives the collection of ~110GTs of carbon for use in growing biomass.

The proposed native afforestation for biochar & coproduct methanol would extend coppice forestry over at least 1.6GHa.s of non-farmland (going some way to restoring the natural total area of tree cover) and would raise the capture of carbon by around 10Gts. Only about 70% of that is converted to charcoal in a good retort (which process is highly exothermic of course) so even with urban and agricultural biomass wastes we'll be doing well to recover much over 4.0ppmv CO2 /yr once a 25 year lead-time for total planting and growing is completed.

To be successful, it looks as if it has to be seen as a new sustainable global industry, with triple income streams and a whole raft of secondary benefits. But it still takes 100 years.

Regards,

Lewis

[JavaScriptDonkey]

Woodburner -
The proposed native afforestation for biochar & coproduct methanol would extend coppice forestry over at least 1.6GHa.s of non-farmland (going some way to restoring the natural total area of tree cover) and would raise the capture of carbon by around 10Gts.

I had to read that twice to be sure I caught it....1.6GHa is around 6 million square miles.

That'll be the entire surface area including all current forest, arable, retail, residential and industrial land of all of the USA and Europe.

I suspect that may also have a massive effect on the climate.

[RenewableCandy]

There seem to have been two incidents in recorded history when 100 million people have been unlucky enough to lose their lives within a few years: the Mongol conquests and the arrival of Europeans in the western hemisphere. Both, it has now been suggested, were followed by a noticeable dip in global average temperature.

100 million is only a small fraction of today's population.

[woodburner]

I suppose we could stop burning carbon and use solar power to drive a carbon sequestration strategy. We don't have to actually reduce the CO2 - it could just be stuffed down holes in the ground (aka CCS).

Pigs might fly and we may not be doomed.

Just as well you added the last sentence, otherwise it looked like a couple of ill thought through suggestions.

[clv101]

There seem to have been two incidents in recorded history when 100 million people have been unlucky enough to lose their lives within a few years: the Mongol conquests and the arrival of Europeans in the western hemisphere. Both, it has now been suggested, were followed by a noticeable dip in global average temperature.

100 million is only a small fraction of today's population.

Indeed, the down-tick in CO2 concentrations following historic die-offs as woodland regrows are a key bit piece of evidence for the early anthropocene.

[emordnilap]

Great. When I'm planting trees I can tell my neighbours I'm heavily involved in geo-engineering.

[RenewableCandy]

I have geoengineered nearly 2 1/2 kg of beans from the Plot...

It depresses me that the increased variability in the weather, which we now seem to be stuck with, doesn't make this process any easier. Well, it doesn't just depress me. On a good day it presents itself as a Possibility For Achievement

[emordnilap]

Friend of mine said, "Any day I can get up and dress myself is going to be a good day!"