global greening observed … CO2 blamed

Elevated CO2: A Key Driver of Global Greening Observations (30 June 2016)
We find yet another study indicating rising atmospheric CO2 is benefiting the biosphere, as opposed to harming it…

Obvious to most observers with a touch of common sense. Leaves out Greenie activists of course. Dr Craig Idso at co2science, reports on a new paper out at CATO, on rising atmospheric CO2 concentrations:

Elevated CO2: A Key Driver of Global Greening Observations

Despite a constant barrage of stories portraying rising atmospheric carbon dioxide (CO2) as a danger and threat to the planet, more and more scientific evidence is accruing showing that the opposite is true. The latest is in a paper recently published in the journal Scientific Reports, where Lu et al. (2016) investigated the role of atmospheric CO2 in causing the satellite-observed vegetative greening of the planet that has been observed since their launch in 1978.

It has long been known that rising CO2 boosts plant productivity and growth, and it is equally well-established that increased levels of atmospheric CO2 reduce plant water needs/requirements, thereby improving their water use efficiency. In consequence of these two benefits, Lu et al. hypothesized that rising atmospheric CO2 is playing a significant role in the observed greening, especially in moisture-limited areas where soil water content is a limiting factor in vegetative growth and function. To test their hypothesis, the three scientists conducted a meta-analysis that included 1705 field measurements from 21 distinct sites from which they evaluated the effects of atmospheric CO2 enrichment on soil water content in both dryland and non-dryland systems.

According to the authors, the meta-analysis revealed that “increasing atmospheric CO2 to between 1.2 to 2.0 times the ambient CO2 level has a positive effect on soil water content” (Panel A, figure below). What is more, the CO2-induced increase in soil water content was found to be greater in drylands (17%) than non-drylands (9%) (Panel B, figure below). Lu et al. also note their analysis showed “no evidence for any significant effects” of soil texture, vegetation type, land management practices or climate regime on soil water content under elevated CO2 conditions. Given as much, they conclude that considering the inherent water limitation in drylands, the additional soil water availability brought about by rising atmospheric CO2 concentrations over the past half-century is “a likely driver of observed increases in vegetation greenness” during this period.

Figure 1. (Panel A) Sensitivity of the soil water response ratio to CO2 enrichment for the entire data set, calculated as the soil water content under elevated CO2 divided by the soil water content under ambient CO2. The closed circles are the observations, with the solid black line providing a linear regression. The red lines represent the 95% confidence intervals of the observations and the dashed grey lines represent the 95% confidence interval of the model. (Panel B) Enhancement of soil water content under elevated CO2 for dryland versus non-dryland regimes. Adapted from Lu et al. (2016).

Figure 1. (Panel A) Sensitivity of the soil water response ratio to CO2 enrichment for the entire data set, calculated as the soil water content under elevated CO2 divided by the soil water content under ambient CO2. The closed circles are the observations, with the solid black line providing a linear regression. The red lines represent the 95% confidence intervals of the observations and the dashed grey lines represent the 95% confidence interval of the model. (Panel B) Enhancement of soil water content under elevated CO2 for dryland versus non-dryland regimes. Adapted from Lu et al. (2016).

Here is yet another study indicating rising atmospheric CO2 is benefiting the biosphere, rather than harming it.

Reference

Lu, X., Wang, L. and McCabe, M.F. 2016. Elevated CO2 as a driver of global dryland greening. Scientific Reports 6: 20716, doi:10.1038/srep20716.

About Tom Harley

Amateur ecologist and horticulturalist and CEO of Kimberley Environmental Horticulture Inc. (Tom Harley) Kimberley Environmental Horticulture Incorporated Kimberley Environmental Horticulture (KEH) is a small group of committed individuals who promote the use of indigenous plants for the landscaping of parks and gardens. Rehabilitation of Kimberley coast, bushland and pastoral regions are also high on our agenda. This includes planting seedlings, weed control, damage from erosion or any other environmental matter that comes to our attention. We come from all walks of life, from Professionals and Trades oriented occupations, Pensioners and Students, Public Servants and the Unemployed. We have a community plant nursery where we trial many old and new species, with a view to incorporating these into our landscaping trials. Our labour force are mainly volunteers, but with considerable help from the 'work for the dole' program, Indigenous Community Development Employment Program (CDEP) groups and the Ministry of Justice, with their community work orders; in this way we manage to train many people in the horticultural skills needed for indigenous plant growing. We constantly undertake field trips that cover seed and plant collection in the Kimberley. Networking around the Kimberley region and the east Pilbara is a necessary part of promoting our activities. We consult on a range of Environmental and Landscaping matters that deal with our region. Our activities involve improving Broome's residential streetscapes by including 'waterwise' priciples in planting out nature strips. Sustainable environmental horticulture is practised by members of our group. We use existing vegetation as the backbone of any plantings, using these species to advantage when planning to develop tree forms or orchards. The Broome region is sensitive to development. Subsequently many weed species have become dominant in and around developed areas. The use and movement of heavy machinery is the biggest single cause of environmental degradation. We dont live in a 'Tropical Paradise' but on the edge of the Great Sandy Desert. The plants that survive best here, grow in well-drained pindan sand, and are found from the Dampier Peninsular southward to where average rainfall is below 600mm. When we use rainforest species, detail is important when planting, water catchment, sunlight and understorey species are all considered. The use of recycled 'grey' water is an advantage here as well as treated waste-water, although many local species do not fare well with nutrients from this source. We use waterwise planting methods which include harvesting asmuch rainwater as possible, with swales designed to hold up to 200 litres, to help recharge the local groundwater aquifer. There has been a serious decline in this aquifer over the last few years. With the fast expansion of the Broome peninsular, more and more land is being covered by concrete, iron and bitumen so that much less water is available to replenish the aquifer, allowing the salt content to become significantly higher. The small Broome Peninsular is on the south-western corner of the Dampier Peninsular (bound by Broome, Derby and Cape Leveque at the northern tip). Compaction by vehicles also inhibits water retention due to the content of our local pindan sand, hard as concrete in the dry, going to soft and sloppy mud after rain. None of us are botanists, inevitably we have got some names wrong, names changed, or have not gone to sub-species level. If you note a photo or description may be wrong, please e-mail to kimenvhort@yahoo.com.au
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