This interesting debate (on CDR list, cross posted) is further informed by recent work, showing that albedo has a significant additional CDR effect. Intuitively, this suggests that snow is preferable to high latitude forests. Pasted below
https://www.nature.com/articles/nclimate3376?WT.feed_name=subjects_climate-sciences Solar geoengineering reduces atmospheric carbon burden - David W. Keith <https://www.nature.com/articles/nclimate3376?WT.feed_name=subjects_climate-sciences#auth-1> - , Gernot Wagner <https://www.nature.com/articles/nclimate3376?WT.feed_name=subjects_climate-sciences#auth-2> - & Claire L. Zabel <https://www.nature.com/articles/nclimate3376?WT.feed_name=subjects_climate-sciences#auth-3> Solar geoengineering is no substitute for cutting emissions, but could nevertheless help reduce the atmospheric carbon burden. In the extreme, if solar geoengineering were used to hold radiative forcing constant under RCP8.5, the carbon burden may be reduced by ∼100 GTC, equivalent to 12–26% of twenty-first-century emissions at a cost of under US$0.5 per tCO2. On 31 Oct 2017 18:30, "David J Beerling" <[email protected]> wrote: https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html Offset of the potential carbon sink from boreal forestation by decreases in surface albedo Richard A. Betts 1. Hadley Centre for Climate Prediction and Research, The Met Office , Bracknell, Berkshire RG12 2SY, UK Correspondence to: Richard A. Betts Correspondence should be addressed to the author (e-mail: Email: [email protected] <[email protected]>). Topof page <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#top> Abstract Carbon uptake by forestation is one method proposed1 <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#B1> to reduce net carbon dioxide emissions to the atmosphere and so limit the radiative forcing of climate change2 <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#B2>. But the overall impact of forestation on climate will also depend on other effects associated with the creation of new forests. In particular, the albedo of a forested landscape is generally lower than that of cultivated land, especially when snow is lying3, <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#B3>4, <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#B4>5, <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#B5>6, <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#B6>7, <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#B7>8, <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#B8>9 <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#B9>, and decreasing albedo exerts a positive radiative forcing on climate. Here I simulate the radiative forcings associated with changes in surface albedo as a result of forestation in temperate and boreal forest areas, and translate these forcings into equivalent changes in local carbon stock for comparison with estimated carbon sequestration potentials10, <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#B10> 11, <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#B11>12 <https://www.nature.com/nature/journal/v408/n6809/full/408187a0.html#B12>. I suggest that in many boreal forest areas, the positive forcing induced by decreases in albedo can offset the negative forcing that is expected from carbon sequestration. Some high-latitude forestation activities may therefore increase climate change, rather than mitigating it as intended. On 31 Oct 2017 17:47, "Greg Rau" <[email protected]> wrote: > https://phys.org/news/2017-10-aids-absorption-carbon-dioxide.html > > "It appears that something good can come from something bad. Although > rising global temperatures are causing seasonal snow cover to melt earlier > in the spring, this allows for the snow-free boreal forests to absorb more > carbon dioxide from our atmosphere. " > > GR - On the other hand, what is the loss of snow cover (and grain in > boreal forest cover?) doing to Earth's solar reflectivity and global > warming? > > > -- > You received this message because you are subscribed to the Google Groups > "Carbon Dioxide Removal" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected] > . > Visit this group at https://groups.google.com/group/CarbonDioxideRemoval. > To view this discussion on the web visit https://groups.google.com/d/ms > gid/CarbonDioxideRemoval/1088033743.6826704.1509471929557%40mail.yahoo.com > <https://groups.google.com/d/msgid/CarbonDioxideRemoval/1088033743.6826704.1509471929557%40mail.yahoo.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Carbon Dioxide Removal" group. 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