Yale Environment 360 claims global greening is not a positive, but rather a negative because it will harm water supplies. This claim is at best amusing, and at worst, misleading. [emphasis, links added]
While acknowledging that many scientists see the greening of the Earth due to rising carbon dioxide (CO2), especially its desert regions, to be beneficial, the writer tries to spin that as a negative.
The Yale Environment 360 article titled “With CO2 Levels Rising, World’s Drylands Are Turning Green,” is amusing because its author, Fred Pearce, couldn’t help putting a negative spin on some very positive news.
The subtitle of the article reads:
Despite warnings that climate change would create widespread desertification, many drylands are getting greener because of increased CO2 in the air — a trend that recent studies indicate will continue. But scientists warn this added vegetation may soak up scarce water supplies. [bold added]
First, we should applaud Yale Environment 360 for bringing out the good news about the effect of carbon dioxide (CO2) on greening the planet. The article adds:
What is going on? The primary reason, most recent studies conclude, is the 50-percent rise in carbon dioxide concentrations in the atmosphere since preindustrial times. This increased C02 is not just driving climate change, 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. [bold added]
This greening due to increased CO2 is something we have reported before here on Climate Realism. Data from satellite measurements indicates that the globe has increased its green area by about five percent over the first 20 years of the 21st century.
The Sahara Desert is becoming smaller as a result. A 2018 study by Venter et al found the Sahara desert had shrunk in area by eight percent over the previous three decades.
At issue is the claim made by Pearce, “But scientists warn this added vegetation may soak up scarce water supplies.”
This is simply untrue. For example, in Africa, trees make desert land fertile again:
For once there is some good news from Africa. Farmers are reclaiming the desert, turning the barren wastelands of the Sahel region on the Sahara’s southern edge into green, productive farmland.
Satellite images taken this year and 20 years ago show that the desert is in retreat thanks to a resurgence of trees. They are mainly ana trees (Faidherbia albida), a type of acacia. Wherever the trees grow, farming can resume.
Tree planting has led to the re-greening of as much as 3 million hectares of land in Niger, enabling some 250,000 hectares to be farmed again.
The key factor is evapotranspiration.
Evapotranspiration, which is the combination of evaporation and plant transpiration (water into the air from leaves) is a key factor in the formation of deserts.
Deserts form when the amount of water that evaporates from the ground is greater than the amount of rain or snow that falls. This is because deserts are arid, or dry, and receive no more than 10 inches of precipitation per year.
Evapotranspiration is an energy-driven process that increases with temperature, solar radiation, and wind. In deserts, the rapid heating and cooling of the air creates strong winds that circulate dry hot air, which further increases evaporation rates.
For example, in American deserts, evaporation can range from 70 to 160 inches per year. With that rate of water loss, deserts remain deserts – they are locked in by the evaporation process.
But with trees, the cycle is broken. Tree leaves both reflect and absorb sunlight so that solar radiation to the ground is reduced and thus ground temperatures are reduced.
With lower ground temperatures, the tree canopy sun-shield reduces evaporation and therefore helps the desert retain more groundwater.
Modest warming has already produced slightly higher rainfall totals. Also, as Agronomy and Botany explain, under higher CO2 conditions plants use water more efficiently, losing less moisture to transpiration.
So, plants use water more efficiently and the increase in plants reduces moisture loss in arid regions. How terrible!
This is basic plant science, known for decades, that [refutes] any claimed increase in water use, but Pearce missed it entirely.
Or perhaps, he knows of it and preferred to keep the narrative of “CO2-driven climate change is the cause of everything bad happening on Earth” alive and well, facts be damned.
Given the many examples we illustrate weekly here at Climate Realism of the media sticking to that narrative in the face of contrary facts, it isn’t at all surprising that Yale Environment 360 attempted to spin good news about global greening into bad.
Shameful, but not surprising. For climate alarmists, it seems that maintaining a narrative is more important than reporting the facts.
Top image by Noah Haggerty from Pixabay
Read more at Climate Realism
There was a time when the climate change movement, including one person commenting on this web site, tried to deny global greening. Now that it is very obviously happening they have done a flip flop and are claiming the greening is bad because is uses more water. The one thing that is constant is they will continue to argue in favor of draconian action to limit CO2 emissions. There are just too many agendas hitchhiking on the climate change movement.
The article has some good points on how vegetation conserves water. In addition, higher carbon dioxide levels means that plants need less water. They bring in the needed CO2 through stomata, which are pores. With higher CO2 levels, the stomata need to open for shorter periods of time which means less water loss.
What this group doesn’t understand (or are ignoring) that higher CO2 results in less water loss every time the plant takes in CO2 since it can do so more quickly than when CO2 is low.
Where is the proof more greening will be harmful? Why do green houses inject carbon dioxide up to 1500 ppm?
Don’t ever expect the truth from these Eco-Freaks and their leftists Fake News they sell us on and they all should be stranded in the Yukon for Winter