This topic contains 4 replies, has 2 voices, and was last updated by  Dan B. 5 years, 7 months ago.

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  • #5215

    Dan B.
    Participant

    Actually, we do produce enough food to feed the entire globe.
    http://www.worldhunger.org/articles/Learn/world%20hunger%20facts%202002.htm#Does_the_world_produce_enough_food_to_feed_everyone

    The problem is distribution, and this is where the high prices occur. Rising fuel prices are the largest component of the rising food prices. Raising taxes or substituting higher prices fuel will only exacerbate this increase. Since the increases in atmospheric CO2, temperature, and rainfall have all helped to increase agricultural yields over the past several decades (other factors have come into play also), projected increases this century will only further help crop production.

    The great Sahel drought of the 1970s and 80s occurred during a time of cooling, possibly brought about by aerosol use:
    http://www.atmos.washington.edu/~dargan/papers/hfk13.pdf

  • #5217

    Editor
    Keymaster

    [quote=5215]Since the increases in atmospheric CO2, temperature, and rainfall have all helped to increase agricultural yields over the past several decades.[/quote]

    Apparently plants do not uniformly grow better with elevated CO2 levels (-> increased rate of climate change), see for instance http://climatestate.com/2013/09/23/plant-productivity-reduction-with-climate-change/ and http://www.skepticalscience.com/co2-plant-food.htm

  • #5219

    Dan B.
    Participant

    Recent research has shown that the CO2 fertilization is significant:

    http://onlinelibrary.wiley.com/doi/10.1002/grl.50563/abstract

    Greenhouse typically operate at 1000 ppm atmospheric CO2 levels, in order to stimulate growth. This has been known for quite some time. Yes, there are a few plants that have evolved to grow in the lower atmospheric levels of today. However, most plants are CO2-deprived, and highly levels would stimulate growth.

    http://www.liebertpub.com/media/pdf/kleinman_ch19_p379-398.pdf

    I have found SKS not to be the best source of information. This may have more to do with Dana’s biases than anything else. We have disagreed on more than one occasion.

  • #5229

    Dan B.
    Participant

    Sorry, did not get any audio with the link. One of the best parameters we have to make future projections is past observations (although as they say in the investing world, “past performance does not guarantee future success”). Scientifically, unless we have a valid reason why past trends will not continue, this is the best indicator. Of course, this will only apply so long as carbon dioxide is the limiting factor to growth. This is most evident at higher elevations where CO2 levels are lowest, which Mann demonstarted in his work. Like most parameters, the increases at lower levels will have more profound effects than at higher levels. Below 200 ppm CO2, most plant growth ceases. The first increases above that level have the greatest effect. Incremental increases have progressively smaller influences (i.e. non-linear). Increases are known to occur up to at least 1000 ppm, with varying results depending on temperature, water supply, and other nutrients. Indeed, while a point will be reached whereby no more increases can be obtained, no level has been found that leads to detrimental effects.

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