Increased carbon dioxide emissions since industrialization have accelerated climate change, and its widespread negative impacts have been reported worldwide. But the rising concentrations of CO2 in the atmosphere are also making some parts of our planet greener in what’s called the CO2 fertilization effect. Some politicians claim this effect means more atmospheric CO2 is doing more good than harm.
In an October episode of Mongabay’s weekly podcast Newscast, co-host Rachel Donald spoke with remote-sensing scientist Arden Burrell, who explained what the CO2 fertilization effect really means for the world, especially for drylands like deserts, savannas and dry subtropical forests that account for 40% of the world’s land surface.
Despite being water-limited landscapes, drylands play an important role in human society because they contribute to more than half of global food production, Burrell said.
Burrell, who co-authored the first-ever observation-based study on dryland desertification, told Donald in the podcast that photosynthesis, the process key to plants’ growth, works by taking in CO2 and water. “If there’s more CO2 in the air, the plants can use less water for the same amount of growth,” he said. “And so, drylands have been experiencing this really kind of interesting phenomenon where over the last 30 years, they have been getting hotter, but they’ve also been getting greener,” he added.
But while it’s considered a “positive effect,” there are places facing desertification where “the temperature and rainfall trends are so severe that even the increased CO2 fertilization effect is not offsetting the decrease in rainfall,” Burrell said.
Burrell’s study found that drylands could become greener by 10-15% by 2050. But it “doesn’t necessarily translate to 10-20% growth in plants,” he said.
Neither does it mean that we’ll start seeing forests springing up on drylands, Donald added.
“What we’re really likely to see and what we’re likely to have been seeing is in some places the plants will just be a bit more productive, they’ll just grow a bit more,” Burrell said.
Moreover, the study only looked at projections of up to 2050. “It’s just after 2050, where things start to diverge drastically, and you start to see the truly horrific differences of not managing CO2,” he said. “That’s why it’s so important to act now, to be … reducing emissions now, because we’ve already locked ourselves in for at least another decade of warming if we stop right now.”
Burrell said in the long run, the CO2 fertilization effect only “buys us a little bit more time” as the plants grow and sequester a small amount of carbon. “It is a net benefit for the planet, but not enough to offset the actual damage we’re doing to the planet by increasing, by releasing large amounts of CO2 continuously.”
Listen to the full episode here.
Banner image of a dryland forest at the southern tip of Madagascar by Rod Waddington via Wikimedia Commons (CC BY-SA 2.0).
This story first appeared on Mongabay
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