Amazon rainforest more able to withstand drought than previously thought

From the University of Exeter:

Moisture recycling is an important source of rainfall over the Amazon forest; about one-third of the annual rainfall in the southern Amazon forest can originate from moisture recycling.

New research suggests that the Amazon rainforest may be more able to cope with dry conditions than previously predicted. Researchers at the University of Exeter and Colorado State University used a computer model to demonstrate that, providing forest conservation measures are in place, the Amazon rainforest may be more able to withstand periods of drought than has been estimated by other climate models.

Many climate models over predict the water stress plants feel during the dry season because they don’t take into account the moisture that the forest itself can recycle in times of drought. In this study, published in the Journal of Climate, the researchers removed unrealistic water stress from their model and found that the moisture that is recycled by the forest is sufficient to reduce the intensity of drought conditions.

Dr Anna Harper from the University of Exeter said: “This study suggests that forests are not only more able to withstand droughts than we had previously thought, but it is the response of the forest itself that can reduce the intensity or length of the drought.

“Moisture recycling works best in large areas of undisturbed forest so it is essential that measures to protect the Amazon rain forest are in place to ensure that that this natural process can be maintained in what may be a drier climate in the future.”

IMAGE: Many climate models over predict the water stress plants feel during the dry season because they don’t take into account the moisture that the forest itself can recycle in times…Click here for more information.

Moisture recycling includes the full cycle of rain – from soil moisture to evaporated water vapour and back to rain. It depends on water both evaporating from the ground and also moving through plants from the roots to the leaves. Moisture recycling is an important source of rainfall over the Amazon forest; about one-third of the annual rainfall in the southern Amazon forest can originate from moisture recycling.

The process relies heavily upon the ability of plants to access soil moisture. During particularly severe droughts, trees reach a limit in their ability to access and use soil moisture. In many ecosystem models, plants reach this limit too soon, increasing the water stress that plants are predicted to feel during the dry season. In reality, moisture recycling can increase during the dry season resulting in increased atmospheric moisture, and even rain. This acts to reduce the water stress felt by the forest plants. The researchers took this dry season moisture recycling into account in their new model.

Climate change induced drought is likely to become a bigger problem in the coming years and forest conservation can help to mitigate the consequences. Large areas of undisturbed forest are more able to maintain moisture recycling during dry periods and are better able to recycle rainfall. Disturbed areas of forest, including those bordering pasture, are less able to maintain moisture recycling and as a result are less able to withstand drought.

Moisture recycling does not make the forest immune to drought but it can make the impacts of drought less severe. The optimum conditions for moisture recycling occur during the unstable climatic fluctuations at the end of the dry season.

IMAGE: Providing forest conservation measures are in place, the Amazon rainforest may be more able to withstand periods of drought than has been estimated by other climate models.Click here for more information.
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This research was funded by the National Science Foundation and the Natural Environment Research Council.

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20 Responses to Amazon rainforest more able to withstand drought than previously thought

  1. AnonyMoose says:

    Big old trees have deep roots and can suck up water from deeper sources. How can any computer programmer be expected to know that?

  2. H.R. says:

    If they want more forest left standing, someone better go have a chat with Drax.

  3. JimS says:

    During the last glaciation period (lasting about 100,000 years), much of the Amazon rain forest was the Amazon tropical savannah. If the warmist alarmists converted to coldist alarmism, at least they would be barking up the right tree.

  4. LeeHarvey says:

    So… It’s better than we thought?

  5. davidmhoffer says:

    So we’ve learned from this that you can prove a model is wrong by getting different results from another model.

    In the meantime nobody is checking reality…

  6. JA says:

    “……….used a computer model to demonstrate that…….”
    Oh, Oh !!!
    Computer models that affirm your belief system are no more reliable than those that do not.
    The ONLY models that are worth a damn are those that have been DEMONSTRATED to replicate the historical, real world over very long periods of time AND have been shown to accurately and reliably PREDICT the real world.

  7. David, UK says:

    Tweak the models and we can all sleep soundly.

  8. rondo smith says:

    Have you read this new lie by the WMO

    http://www.bbc.co.uk/news/science-environment-24925580

    2013 ‘one of warmest’ on record

  9. alexwade says:

    “In this study, published in the Journal of Climate, the researchers removed unrealistic water stress from their model …”

    I stopped reading right there. Since when did models become sacred pronouncements? Since when did models replace actual factual data?

  10. DesertYote says:

    davidmhoffer says:
    November 14, 2013 at 7:34 am

    So we’ve learned from this that you can prove a model is wrong by getting different results from another model.

    In the meantime nobody is checking reality…
    ###

    People are checking reality. It’s just that reality does not conform to the messaging needed to promote the agenda. When I was a kid, a lot of research was done on the Amazon Rain Forest. This was motivated by enviro-wackory, but back then, some scientists still did science (they hadn’t gotten the memo yet) and produced real science which got published (the publishers were a bit behind the times also). Most studies of the real rain forest showed that it was a very stable eco-system. So the studies were quietly ignored and then forgotten, like a lot of science that tells the “wrong” story. So the researchers have been focusing on models.

    The latest generation of scientist, well instructed in the need for their research to be socially relevant, and having a programmed in desire to save the world, are completely ignorant of what was done before and incapable of finding out. Around 2006, NASA satellites where used to conduct studies of the resilience of the Amazon to drought. Everyone eagerly awaited the results as they would provide irrefutable evidence of the evil of mankind. The researchers who knew in the depths of there greeny hearts, that the rain forest is an incredibly fragile thing, where shocked by the data they collected. They tried their hardest to massage them into a framework that supported their preconceptions. Then the press release writers, masters of propaganda, tried to spin the study. It did not work, so the study was simply ignored and forgotten.

  11. DesertYote says:

    BTW, The Amazon basin has two massive rivers.

  12. Steve C says:

    “… providing forest conservation measures are in place …”

    Sigh. How did Mother Nature manage before Hom Sap and his “conservation measures”?

  13. Louis says:

    “Climate change induced drought is likely to become a bigger problem in the coming years…”

    Last I heard, climate change was going to make wet places wetter and dry places dryer. So why would a rain forest become dryer? For a science that is “settled,” it sure changes a lot.

  14. Jimbo says:

    New research suggests that the Amazon rainforest may be more able to cope with dry conditions than previously predicted.

    It has been around for millions of years. Now, here is how some neotropical rainforests reacted to previous global warming periods. They thrived!! Good grief, how can this be?

    Check this out from 2006. The Amazon turns greener during the dry season! Oh Lordy Lord. Oh, and the Amazon turns browner during the dry season according to the second paper. Oh crap!

    Abstract – 2006
    [1] Metabolism and phenology of Amazon rainforests significantly influence global dynamics of climate, carbon and water, but remain poorly understood. We analyzed Amazon vegetation phenology at multiple scales with Moderate Resolution Imaging Spectroradiometer (MODIS) satellite measurements from 2000 to 2005. MODIS Enhanced Vegetation Index (EVI, an index of canopy photosynthetic capacity) increased by 25% with sunlight during the dry season across Amazon forests, opposite to ecosystem model predictions that water limitation should cause dry season declines in forest canopy photosynthesis. In contrast to intact forests, areas converted to pasture showed dry-season declines in EVI-derived photosynthetic capacity, presumably because removal of deep-rooted forest trees reduced access to deep soil water…..

    http://dx.doi.org/10.1029/2005GL025583

    and….

    Abstract – 2010
    …….We find no evidence of large-scale greening of intact Amazon forests during the 2005 drought – approximately 11%–12% of these drought-stricken forests display greening, while, 28%–29% show browning or no-change, and for the rest, the data are not of sufficient quality to characterize any changes. These changes are also not unique – approximately similar changes are observed in non-drought years as well. Changes in surface solar irradiance are contrary to the speculation in the previously published report of enhanced sunlight availability during the 2005 drought. There was no co-relation between drought severity and greenness changes, which is contrary to the idea of drought-induced greening. Thus, we conclude that Amazon forests did not green-up during the 2005 drought.

  15. Jimbo says:

    Louis says:
    November 14, 2013 at 9:08 am

    “Climate change induced drought is likely to become a bigger problem in the coming years…”

    Last I heard, climate change was going to make wet places wetter and dry places dryer. So why would a rain forest become dryer? For a science that is “settled,” it sure changes a lot.

    Louis my friend you don’t understand. Climate change makes the places you love drier and the water logged places wetter. By the way climate change has been making arid places greener dontcha know.

    Abstract – 31 May, 2013
    CO2 fertilisation has increased maximum foliage cover across the globe’s warm, arid environments

    [1] Satellite observations reveal a greening of the globe over recent decades. …….Using gas exchange theory, we predict that the 14% increase in atmospheric CO2 (1982–2010) led to a 5 to 10% increase in green foliage cover in warm, arid environments. Satellite observations, analysed to remove the effect of variations in rainfall, show that cover across these environments has increased by 11%.…..

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

    PS anything based on model predictions about the future should carry a warning label. Models can sometimes be useful but observations are the killer. Climate models are useful for about 6 days.

  16. Aussiebear says:

    I had to stop and gag when I read in the first paragraph;; “…used a computer model to demonstrate…”. So they got different results from the other models and therefore theirs must be right. Just one question. How did they determine that the previous water stress value used in the other models were unrealistic? Wait. Wait. I know! From running another model!

  17. BioBob says:

    DUH !!

    Tropical rain forests are some of the oldest unchanged ecosystems on earth. They would not be so life-prolific if every tom-dick-and-harry “climate change” affected them AT ALL.

    DUH !!

    Life (moderated by temp & H2O) controls the O2, CO2 & NH3 atmospheric gasses on THIS planet, not the other way around – pass that along to the AGW morons since they haven’t figured it out yet.

  18. D.J. Hawkins says:

    Steve C says:
    November 14, 2013 at 9:06 am
    “… providing forest conservation measures are in place …”

    Sigh. How did Mother Nature manage before Hom Sap and his “conservation measures”?

    I believe in this context, “conservation measures” means “Don’t level the freaking forest”.

  19. DesertYote says:

    Jimbo says:
    November 14, 2013 at 10:50 am

    Check this out from 2006. The Amazon turns greener during the dry season!
    ###

    AWESOME! That’s the very paper I was referring to earlier!

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