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2019 Piao

crops

crops2

foliage

folig

forests

greening

more green

2019 Piao Characteristics, drivers and feedbacks of global greening Vegetation greenness has been increasing globally since at least 1981, when satellite technology enabled large-scale vegetation monitoring. The greening phenomenon, together with warming, sea-level rise and sea-ice decline, represents highly credible evidence of anthropogenic climate change. In this Review, we examine the detection of the greening signal, its causes and its consequences. Greening is pronounced over intensively farmed or afforested areas, such as in China and India, reflecting human activities. However, strong greening also occurs in biomes with low human footprint, such as the Arctic, where global change drivers play a dominant role. Vegetation models suggest that CO2 fertilization is the main driver of greening on the global scale, with other factors being notable at the regional scale. Modelling indicates that greening could mitigate global warming by increasing the carbon sink on land and altering biogeophysical processes, mainly evaporative cooling. Coupling high temporal and fine spatial resolution remote-sensing observations with ground measurements, increasing sampling in the tropics and Arctic, and modelling Earth systems in more detail will further our insights into the greening of Earth. crops We need more just to survive? The authors make the point that most plants evolved in a 7000 ppm Co2 atmosphere and atmospheric Co2 is at an all time low right now, what few plants remain are those that can cope with these low levels. But as levels go up, food production increases *without doing anything else* to the point that increased CO2 is the key do feeding the planet. Archived (local copy). crops2 Without more CO2 we can not feed everyone This paper points out that what we are doing now is insufficient to feed a soon to be global population of 10 billion. More CO2 is presently used to increase food production. foliage 2013: CO2 fertilisation has increased maximum foliage cover across the globe's warm, arid environments Satellite observations reveal a greening of the globe over recent decades. The role in this greening of the ‘CO2 fertilization’ effect – the enhancement of photosynthesis due to rising CO2 levels – is yet to be established. The direct CO2 effect on vegetation should be most clearly expressed in warm, arid environments where water is the dominant limit to vegetation growth. 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%. Our results confirm that the anticipated CO2 fertilization effect is occurring alongside ongoing anthropogenic perturbations to the carbon cycle and that the fertilisation effect is now a significant land surface process.

folig Study: Emission of smog ingredients from trees is increasing rapidly "They found that areas where farmland has been abandoned during the last century have early generations of trees that produce higher levels of VOCs than older growth forests. In the South, pine plantations used for their fast-growing supplies of timber have proven to be havens for sweetgum trees, which are major producers of VOCs. Indeed, virtually every tree that grows fast -- a desirable quality for forestry production -- is a heavy emitter of VOCs." forests Carbon dioxide emissions help tropical rainforests grow faster: Study shows trees absorb more greenhouse gas than expected Nasa study shows tropical forests absorb 1.5 billion tonnes of CO2 a year Rainforests absorb more than half of CO2 taken up by vegetation globally Scientists previously believed tropical forests emitted carbon dioxide Researchers claim their findings emphasise the need to protect rainforests from deforestation to help counteract human greenhouse gas emissions "Global air flows and data on deforestation also suggested tropical forests were releasing more carbon dioxide than they absorb. But this new study suggests the tropical forests are using far more of the carbon, and so growing far faster than previously believed" That trees use CO2 to make O2 is grade 8 biology. You can't physically have different amounts of CO2 and O2 if you think about out. greening 2013: Elevated carbon dioxide making arid regions greener WASHINGTON, DC—Scientists have long suspected that a flourishing of green foliage around the globe, observed since the early 1980s in satellite data, springs at least in part from the increasing concentration of carbon dioxide in Earth’s atmosphere. Now, a study of arid regions around the globe finds that a carbon dioxide “fertilization effect” has, indeed, caused a gradual greening from 1982 to 2010. more green NASA: Higher CO2 levels responsible for 'greening' Earth By Brooks Hays | April 26, 2016 at 5:08 PM http://www.nature.com/nclimate/journal/v6/n8/full/nclimate3004.html