Amazon Rainforest Mega Droughts Caused By CO2 Supression Of Plant Transpiration
Water from trees is what makes rainforest rain.
The most perfect explanation for the drying and dying Amazon rainforest looks to be the immediate effect of high and rising CO2 in its suppression of plant transpiration water loss. Research just published in the Journal Nature dovetails nicely with and provides clear data showing the coupling of high CO2 with plants ability to reduce their transpiration water loss.
It’s a quite simple and elegant story of plants which must obtain CO2 across wet membranes that facilitate gas exchange are reducing the time that gas exchange takes place as high and rising CO2 concentration in the air gives them an energy benefit.
It takes a lot of energy and water for plants to perform gas exchange. With the 40+% more Co2 in the air today and its rising rapidly plants are saving energy and water.
In rainforests the water, the rain and mist, that the forest thrives on doesn’t simply come from far off evaporation in a distant ocean. As the Jasechko paper in Nature shows it mostly comes from the rainforest itself. 60% of atmospheric water normally comes from the plants of the rainforest. Indeed this is the norm for atmospheric water everywhere.
In the present atmosphere where there has been a 40+% increase in CO2, the corresponding conservation of the energy and water that benefits plants by allowing them to do less transpiration is in the range of 10% – 20%.
Do the math, the present day high and rising CO2 has eliminated 6%-12% of the Amazon rainforest moisture. This is made far more potent as rain does not form in a linear relationship to atmospheric moisture, raindrops and mistdrops form only when a high threshold of moisture content in the air is reached. So a relatively small percentage loss of water results in a dramatic collapse of raindrop and mist production. That missing 6%-12% moisture due to high and rising CO2 is more than sufficient to result in the observed mega-drought.
In addition to the devastating collapse of the Amazon’s forest provided water the ravages of forest harvest are compounding the problem. Removal of more and more of the forest not only bares the thin nutrient poor soils it eliminates even more of the vital atmospheric moisture that is responsible for the “rainforest” ecosystem.
This new scientific evidence short circuits the meteorological climate models that suggest the role of CO2 is merely its physical properties as a “greenhouse gas.” The power of CO2 is in its most potent role as the primary driver of plant life and photosynthesis and now with this new evidence its incredibly potent role in controlling rainfall.