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As it looks increasingly unlikely we’re going to meet our climate mitigation targets, scientists have been investigating more and more extreme solutions, such as geoengineering.
Examples include spraying huge amounts of sunlight-reflecting particles into the atmosphere, or dumping trillions of tons of fake snow onto glaciers to stabilise them. These ideas are untested, incredibly risky, and could end up causing more damage in unexpected ways.
But what if there’s a way we can alter our current environment to mitigate climate change that is already safe and proven? Well… there is.
Restoring forests, marshes, peatlands, seaweed and other ecosystems has a massive potential to take back some of that carbon dioxide we’ve spewed into our precious atmosphere.
In 2017, a PNAS study estimated that natural carbon solutions (essentially ecosystem regeneration) have the potential to provide up to 37 percent of the CO2 mitigation that we’d need through 2030, for a 66 percent chance of holding warming to below 2°C.
“Much of Earth’s ecosystems are now substantially modified or degraded, but with care and increased investment there is huge potential to reap benefits for humans and other species,” ecologist Euan Ritchie from Deakin University told ScienceAlert.
Of course, how we do this matters as well. Merely plonking trees down, plantation style, is not going to cut it if the goal is to permanently improve our situation.
“Ecosystems are a bit like engines, all the various components relate to each other in some way. Take one part out and things can go awry,” explained Ritchie. “Conserving a diversity of species (parts) leads to healthier and better functioning ecosystems.”
For example, Utah State University ecologist Trisha Atwood and colleagues have found evidence that maintaining predator populations in a marine ecosystem is critical to maintaining or growing these ecosystems’ ability to store carbon.
“Predators protect organic carbon stocks in Heron lagoon by creating high-risk predation zones that offer a refuge for algal growth and organic carbon accumulation and retention in sediments,” the researchers concluded.
A 2012 study calculated that by eating sea urchins, otters allow carbon-sequestering kelp forests to grow, potentially helping to trap the equivalent amount of carbon as taking up to 5 million cars off the road per year.
This strategy only removes CO2 while ecosystems are expanding; once they’re established they settle into a neutral equilibrium, whereby they produce and consume the same amount of greenhouse gases.
It’s also a race against time – these restorations would need to happen before climate change gets so bad that they can’t grow. But if these ecosystems are allowed to flourish, they will continue acting as storage for the CO2 they took in as they grew.
As Ritchie points out, healthy ecosystems also offer a lot of other value to us and the incredible array of species we share our planet with. These include water filtration, flood buffering, healthy soils, and enhanced resilience to climate change, among other things.
Their ability to store so much CO2 is only one of many reasons it’s vital to preserve all our remaining functioning ecosystems. Yet even wealthy countries like Australia are failing dismally at doing this.
And ecosystem regeneration would only have any chance of helping draw down carbon if we also stop our rampant consumption of fossil fuels – there’s a limit to how much trees and other parts of our ecosystems can take in!
“We have so much still to learn, including the true extent of the effects individual species may have within ecosystems, how adaptable certain species are to change and how other limiting factors are going to help/hinder recovery efforts in the face of a warming climate,” said Ritchie.
Considering the potential here, you would think ecosystem regeneration would be high on our to do list. Yet, only a small amount of the money directed towards climate mitigation has gone into this area.
“In general we invest a pathetic amount in environmental conservation, protection and regeneration, despite biodiversity being unquestionably our most valuable asset now and in the future,” said Ritchie.
As lack of consideration for our ecosystems is one of the main reasons for this giant mess we’ve created for ourselves, it’s far beyond time we start taking them into account.
“Ecosystems have developed over millions of years, and to think we humans can replace their vital functions with technofixes etc. is arrogant, foolish, and dangerous,” he added.
Even with all the unknowns, we can sure as heck bet the ‘geoengineering’ of ecosystem regeneration would be far safer than pumping another unknown into Earth’s atmosphere.
This article is part of ScienceAlert’s special climate edition, published in support of the global #ClimateStrike on 20 September 2019.