It’s well-known that higher CO2 concentrations encourage plant growth (up to a point). Ask a commercial grower. But in these days of climate alarmism good news isn’t welcomed by its backers. More carbon dioxide at the global scale boosts the carbon cycle, but climate obsessives want to suck some of it out of the atmosphere, using vast amounts of valuable energy.
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Southeast Australia has been getting hotter and drier, says Fred Pearce @ Yale360.
Droughts have lengthened, and temperatures regularly soar above 95 degrees F (35 degrees C). Bush fires abound. But somehow, its woodlands keep growing.
One of the more extreme and volatile ecosystems on the planet is defying meteorology and becoming greener.
And Australia is far from alone. From Africa’s Sahel to arid western India, and the deserts of northern China to southern Africa, the story is the same.
“Greening is happening in most of the drylands globally, despite increasing aridity,” says Jason Evans, a water-cycle researcher at the Climate Change Research Centre of the University of New South Wales in Sydney, Australia.
What is going on? The primary reason, most recent studies conclude, is the 50-percent rise in carbon dioxide concentrations in the atmosphere since pre-industrial times.
This increased C02 is not just driving climate change [Talkshop comment – empty assertion], but also fast-tracking photosynthesis in plants. By allowing them to use scarce water more efficiently, the CO2-rich air fertilizes vegetation growth in even some of the driest places.
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Over the past half-century, most drylands have been experiencing a decline in rainfall, along with higher temperatures and greater rates of evaporation. Many have also been degraded by poor farming practices and overgrazing of livestock.
Climate scientists and ecologists alike have until recently presumed that this combination of growing meteorological aridity and pressure from human activities would lead to less vegetation. They have routinely warned of widespread desertification, which U.N. officials have called “the greatest environmental challenge of our time.”
Yet in most drylands, this anticipated desertification has not happened. Rather than shriveling and dying, vegetation is usually growing faster and expanding its terrain, while deserts are retreating. This, researchers of the world’s carbon and water cycles say, is largely due to the extra CO2 in the atmosphere.
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Agricultural scientists have long known about the benefits of additional CO2 for plant growth. Farmers sometimes dose the enclosed atmospheres of greenhouses with the gas to boost yields. In effect, we are now doing the same thing to the entire atmosphere.
The negative impacts of hotter, drier climates have not gone away; but in most arid lands this CO2 fertilization effect is proving more powerful. This supercharging of plant growth seems unlikely to be short-lived if fossil-fuel burning causes atmospheric concentrations of CO2 to continue rising.
A new modeling study published last month found that it will, if anything, become more marked in the coming decades. “Most of the global drylands are projected to see an increase in vegetation productivity,” says Evans, a co-author of the study.
Full article here.
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Image: Photosynthesis [credit: Nefronus @ Wikipedia]
via Tallbloke’s Talkshop
July 20, 2024 at 12:39PM
Iowa Climate Science Education 